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Question 1
Correct
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You have recently conducted rapid sequence induction utilizing ketamine and rocuronium and successfully inserted an endotracheal tube under the guidance of a consultant. What should have been the available reversal agent to counteract the effects of Rocuronium if necessary?
Your Answer: Sugammadex
Explanation:Sugammadex is a medication used to quickly reverse the effects of muscle relaxation caused by drugs like rocuronium bromide or vecuronium bromide. The 2020 guidelines for sedation and anesthesia outside of the operating room recommend having a complete set of emergency drugs, including specific reversal agents like naloxone, sugammadex, and flumazenil, readily accessible. Sugammadex is a modified form of gamma cyclodextrin that is effective in rapidly reversing the neuromuscular blockade caused by these specific drugs.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 2
Incorrect
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You are caring for a pediatric patient in the resuscitation bay. Your attending physician notices you selecting an oropharyngeal airway adjunct (OPA) and recommends using a laryngeal mask airway (LMA) instead. Which of the following statements about the advantages and disadvantages of using a laryngeal mask airway (LMA) is correct?
Your Answer: There is a high risk of aspiration when using an LMA
Correct Answer: Greater risk of inducing laryngospasm using LMA compared to endotracheal intubation
Explanation:The use of a laryngeal mask airway (LMA) carries a higher risk of inducing laryngospasm compared to endotracheal intubation. However, LMAs are still considered excellent alternatives to bag masks as they reduce the risk of gastric inflation and aspiration. While they do decrease the risk of aspiration, they are not as protective as endotracheal tubes. Complications associated with LMA use include laryngospasm, nausea and vomiting, and a low risk of aspiration. LMAs have advantages over bag-mask ventilation, such as more effective ventilation, less gastric inflation, and a lower risk of aspiration. However, they also have disadvantages, including the risk of hypoventilation due to air leak around the cuff, greater gastric inflation compared to endotracheal intubation, and a very low risk of aspiration.
Further Reading:
Techniques to keep the airway open:
1. Suction: Used to remove obstructing material such as blood, vomit, secretions, and food debris from the oral cavity.
2. Chin lift manoeuvres: Involves lifting the head off the floor and lifting the chin to extend the head in relation to the neck. Improves alignment of the pharyngeal, laryngeal, and oral axes.
3. Jaw thrust: Used in trauma patients with cervical spine injury concerns. Fingers are placed under the mandible and gently pushed upward.
Airway adjuncts:
1. Oropharyngeal airway (OPA): Prevents the tongue from occluding the airway. Sized according to the patient by measuring from the incisor teeth to the angle of the mandible. Inserted with the tip facing backwards and rotated 180 degrees once it touches the back of the palate or oropharynx.
2. Nasopharyngeal airway (NPA): Useful when it is difficult to open the mouth or in semi-conscious patients. Sized by length (distance between nostril and tragus of the ear) and diameter (roughly that of the patient’s little finger). Contraindicated in basal skull and midface fractures.
Laryngeal mask airway (LMA):
– Supraglottic airway device used as a first line or rescue airway.
– Easy to insert, sized according to patient’s bodyweight.
– Advantages: Easy insertion, effective ventilation, some protection from aspiration.
– Disadvantages: Risk of hypoventilation, greater gastric inflation than endotracheal tube (ETT), risk of aspiration and laryngospasm.Note: Proper training and assessment of the patient’s condition are essential for airway management.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 3
Incorrect
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You are summoned to the resuscitation bay to provide assistance with a patient who has experienced cardiac arrest. The team is getting ready to administer amiodarone. What is the mechanism of action of amiodarone in the context of cardiac arrest?
Your Answer: Blockade of sodium channels
Correct Answer: Blockade of potassium channels
Explanation:Amiodarone functions by inhibiting voltage-gated potassium channels, leading to an extended repolarization period and decreased excitability of the heart muscle.
Further Reading:
In the management of respiratory and cardiac arrest, several drugs are commonly used to help restore normal function and improve outcomes. Adrenaline is a non-selective agonist of adrenergic receptors and is administered intravenously at a dose of 1 mg every 3-5 minutes. It works by causing vasoconstriction, increasing systemic vascular resistance (SVR), and improving cardiac output by increasing the force of heart contraction. Adrenaline also has bronchodilatory effects.
Amiodarone is another drug used in cardiac arrest situations. It blocks voltage-gated potassium channels, which prolongs repolarization and reduces myocardial excitability. The initial dose of amiodarone is 300 mg intravenously after 3 shocks, followed by a dose of 150 mg after 5 shocks.
Lidocaine is an alternative to amiodarone in cardiac arrest situations. It works by blocking sodium channels and decreasing heart rate. The recommended dose is 1 mg/kg by slow intravenous injection, with a repeat half of the initial dose after 5 minutes. The maximum total dose of lidocaine is 3 mg/kg.
Magnesium sulfate is used to reverse myocardial hyperexcitability associated with hypomagnesemia. It is administered intravenously at a dose of 2 g over 10-15 minutes. An additional dose may be given if necessary, but the maximum total dose should not exceed 3 g.
Atropine is an antagonist of muscarinic acetylcholine receptors and is used to counteract the slowing of heart rate caused by the parasympathetic nervous system. It is administered intravenously at a dose of 500 mcg every 3-5 minutes, with a maximum dose of 3 mg.
Naloxone is a competitive antagonist for opioid receptors and is used in cases of respiratory arrest caused by opioid overdose. It has a short duration of action, so careful monitoring is necessary. The initial dose of naloxone is 400 micrograms, followed by 800 mcg after 1 minute. The dose can be gradually escalated up to 2 mg per dose if there is no response to the preceding dose.
It is important for healthcare professionals to have knowledge of the pharmacology and dosing schedules of these drugs in order to effectively manage respiratory and cardiac arrest situations.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 4
Correct
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You are asked to help with a 68-year-old patient who initially arrived at the emergency department complaining of chest discomfort and was found to have a slow heart rate before experiencing a cardiac arrest. Which of the following statements about medications used during cardiac arrest and peri-arrest is accurate?
Your Answer: Atropine is an antagonist of muscarinic acetylcholine receptors
Explanation:Atropine acts as a blocker for muscarinic acetylcholine receptors, making it an antagonist. It is commonly administered during peri-arrest bradycardia. In adults, a dose of 500 mcg is given every 3-5 minutes, with a maximum total dose of 3mg. On the other hand, the initial intravenous dose of amiodarone is 300 mg. Amiodarone works by prolonging repolarization and decreasing myocardial excitability. Additionally, lidocaine functions by blocking sodium channels.
Further Reading:
In the management of respiratory and cardiac arrest, several drugs are commonly used to help restore normal function and improve outcomes. Adrenaline is a non-selective agonist of adrenergic receptors and is administered intravenously at a dose of 1 mg every 3-5 minutes. It works by causing vasoconstriction, increasing systemic vascular resistance (SVR), and improving cardiac output by increasing the force of heart contraction. Adrenaline also has bronchodilatory effects.
Amiodarone is another drug used in cardiac arrest situations. It blocks voltage-gated potassium channels, which prolongs repolarization and reduces myocardial excitability. The initial dose of amiodarone is 300 mg intravenously after 3 shocks, followed by a dose of 150 mg after 5 shocks.
Lidocaine is an alternative to amiodarone in cardiac arrest situations. It works by blocking sodium channels and decreasing heart rate. The recommended dose is 1 mg/kg by slow intravenous injection, with a repeat half of the initial dose after 5 minutes. The maximum total dose of lidocaine is 3 mg/kg.
Magnesium sulfate is used to reverse myocardial hyperexcitability associated with hypomagnesemia. It is administered intravenously at a dose of 2 g over 10-15 minutes. An additional dose may be given if necessary, but the maximum total dose should not exceed 3 g.
Atropine is an antagonist of muscarinic acetylcholine receptors and is used to counteract the slowing of heart rate caused by the parasympathetic nervous system. It is administered intravenously at a dose of 500 mcg every 3-5 minutes, with a maximum dose of 3 mg.
Naloxone is a competitive antagonist for opioid receptors and is used in cases of respiratory arrest caused by opioid overdose. It has a short duration of action, so careful monitoring is necessary. The initial dose of naloxone is 400 micrograms, followed by 800 mcg after 1 minute. The dose can be gradually escalated up to 2 mg per dose if there is no response to the preceding dose.
It is important for healthcare professionals to have knowledge of the pharmacology and dosing schedules of these drugs in order to effectively manage respiratory and cardiac arrest situations.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 5
Incorrect
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You examine the X-ray of a 70 year old male who has fallen onto his outstretched right hand. The X-ray confirms a fracture of the distal radius with dorsal displacement. Your plan is to perform a reduction of the fracture using intravenous regional anesthesia (Bier's block). The patient's blood pressure is 145/90 mmHg and his pulse rate is 75 bpm. What inflation pressure would you use when inflating the cuff?
Your Answer: 170 mmHg
Correct Answer: 250 mmHg
Explanation:During Bier’s block, the cuff is inflated to a pressure that is 100 mmHg higher than the patient’s systolic blood pressure. For example, if the systolic blood pressure is 150 mmHg, the cuff would be inflated to 250 mmHg. It is important to note that Bier’s block should not be performed if the systolic blood pressure is greater than 200 mmHg, as this is considered a contraindication. Therefore, the maximum pressure ever used during Bier’s block is 300mmHg.
Further Reading:
Bier’s block is a regional intravenous anesthesia technique commonly used for minor surgical procedures of the forearm or for reducing distal radius fractures in the emergency department (ED). It is recommended by NICE as the preferred anesthesia block for adults requiring manipulation of distal forearm fractures in the ED.
Before performing the procedure, a pre-procedure checklist should be completed, including obtaining consent, recording the patient’s weight, ensuring the resuscitative equipment is available, and monitoring the patient’s vital signs throughout the procedure. The air cylinder should be checked if not using an electronic machine, and the cuff should be checked for leaks.
During the procedure, a double cuff tourniquet is placed on the upper arm, and the arm is elevated to exsanguinate the limb. The proximal cuff is inflated to a pressure 100 mmHg above the systolic blood pressure, up to a maximum of 300 mmHg. The time of inflation and pressure should be recorded, and the absence of the radial pulse should be confirmed. 0.5% plain prilocaine is then injected slowly, and the time of injection is recorded. The patient should be warned about the potential cold/hot sensation and mottled appearance of the arm. After injection, the cannula is removed and pressure is applied to the venipuncture site to prevent bleeding. After approximately 10 minutes, the patient should have anesthesia and should not feel pain during manipulation. If anesthesia is successful, the manipulation can be performed, and a plaster can be applied by a second staff member. A check x-ray should be obtained with the arm lowered onto a pillow. The tourniquet should be monitored at all times, and the cuff should be inflated for a minimum of 20 minutes and a maximum of 45 minutes. If rotation of the cuff is required, it should be done after the manipulation and plaster application. After the post-reduction x-ray is satisfactory, the cuff can be deflated while observing the patient and monitors. Limb circulation should be checked prior to discharge, and appropriate follow-up and analgesia should be arranged.
There are several contraindications to performing Bier’s block, including allergy to local anesthetic, hypertension over 200 mm Hg, infection in the limb, lymphedema, methemoglobinemia, morbid obesity, peripheral vascular disease, procedures needed in both arms, Raynaud’s phenomenon, scleroderma, severe hypertension and sickle cell disease.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 6
Correct
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A 32-year-old man with a history of severe asthma is brought to the Emergency Department by his girlfriend. He is experiencing extreme shortness of breath and wheezing, and his condition worsens rapidly. After receiving back-to-back nebulizer treatments, hydrocortisone, and IV magnesium sulfate, he is taken to resus, and the intensive care team is called for consultation. He is now severely hypoxic and has developed confusion. It is decided that the patient needs to be intubated.
Which of the following medications would be the most appropriate choice for inducing anesthesia in this patient?Your Answer: Ketamine
Explanation:Intubation is rarely necessary for asthmatic patients, with only about 2% of asthma attacks requiring it. Most severe cases can be managed using non-invasive ventilation techniques. However, intubation can be a life-saving measure for asthmatic patients in critical condition. The indications for intubation include severe hypoxia, altered mental state, failure to respond to medications or non-invasive ventilation, and respiratory or cardiac arrest.
Before intubation, it is important to preoxygenate the patient and administer intravenous fluids. Nasal oxygen during intubation can provide additional time. Intravenous fluids are crucial because patients with acute asthma exacerbations can experience significant fluid loss, which can lead to severe hypotension during intubation and positive pressure ventilation.
There is no perfect combination of drugs for rapid sequence induction (RSI), but ketamine is often the preferred choice. Ketamine has bronchodilatory properties and does not cause hypotension as a side effect. Propofol can also be used, but it carries a risk of hypotension. In some cases, a subdissociative dose of ketamine can be helpful to facilitate the use of non-invasive ventilation in a hypoxic or combative patient.
Rocuronium and suxamethonium are commonly used as paralytic agents. Rocuronium has the advantage of providing a longer period of paralysis, which helps avoid ventilator asynchrony in the early stages of management.
Proper mechanical ventilation is essential, and it involves allowing the patient enough time to fully exhale the delivered breath and prevent hyperinflation. Therefore, permissive hypercapnia is typically used, and the ventilator settings should be adjusted accordingly. The recommended settings are a respiratory rate of 6-8 breaths per minute and a tidal volume of 6 ml per kilogram of body weight.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 7
Incorrect
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A 32 year old has undergone reduction of fracture-dislocation to the right shoulder under procedural sedation. Following the reduction, the patient reports feeling nauseated and subsequently vomits. What is the most significant risk factor for postoperative nausea and vomiting?
Your Answer: Smoker
Correct Answer: Female gender
Explanation:The most significant factor in predicting postoperative nausea and vomiting (PONV) is being female. Females are three times more likely than males to experience PONV. Additionally, not smoking increases the risk of PONV by about two times. Having a history of motion sickness, PONV, or both also approximately doubles the risk of PONV. Age is another factor, with older adults being less likely to suffer from PONV. In children, those below 3 years of age have a lower risk of PONV compared to those older than 3.
Further Reading:
postoperative nausea and vomiting (PONV) is a common occurrence following procedures performed under sedation or anesthesia. It can be highly distressing for patients. Several risk factors have been identified for PONV, including female gender, a history of PONV or motion sickness, non-smoking status, patient age, use of volatile anesthetics, longer duration of anesthesia, perioperative opioid use, use of nitrous oxide, and certain types of surgery such as abdominal and gynecological procedures.
To manage PONV, antiemetics are commonly used. These medications work by targeting different receptors in the body. Cyclizine and promethazine are histamine H1-receptor antagonists, which block the action of histamine and help reduce nausea and vomiting. Ondansetron is a serotonin 5-HT3 receptor antagonist, which blocks the action of serotonin and is effective in preventing and treating PONV. Prochlorperazine is a dopamine D2 receptor antagonist, which blocks the action of dopamine and helps alleviate symptoms of nausea and vomiting. Metoclopramide is also a dopamine D2 receptor antagonist and a 5-HT3 receptor antagonist, providing dual action against PONV. It is also a 5-HT4 receptor agonist, which helps improve gastric emptying and reduces the risk of PONV.
Assessment and management of PONV involves a comprehensive approach. Healthcare professionals need to assess the patient’s risk factors for PONV and take appropriate measures to prevent its occurrence. This may include selecting the appropriate anesthesia technique, using antiemetics prophylactically, and providing adequate pain control. In cases where PONV does occur, prompt treatment with antiemetics should be initiated to alleviate symptoms and provide relief to the patient. Close monitoring of the patient’s condition and response to treatment is essential to ensure effective management of PONV.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 8
Incorrect
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A 35-year-old woman is brought in by ambulance following a car accident where her car was hit by a truck. She has sustained severe facial injuries and shows signs of airway obstruction. Her cervical spine is immobilized. She has suffered significant midface trauma, and the anesthesiologist decides to secure a definitive airway by intubating the patient.
Which of the following does NOT indicate proper placement of the endotracheal tube?Your Answer:
Correct Answer: Presence of borborygmi in the epigastrium
Explanation:The presence of borborygmi in the epigastrium can indicate that the endotracheal tube (ETT) is incorrectly placed in the esophagus. There are several ways to verify the correct placement of the endotracheal tube (ETT).
One method is through direct visualization, where the ETT is observed passing through the vocal cords. Another method is by checking for fogging in the ETT, which can indicate proper placement. Auscultation of bilateral equal breath sounds is also a reliable way to confirm correct ETT placement.
Additionally, the absence of borborygmi in the epigastrium is a positive sign that the ETT is in the correct position. Capnography or using a CO2 detector can provide further confirmation of proper ETT placement. Finally, chest radiography can be used to visually assess the placement of the endotracheal tube.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 9
Incorrect
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A 32-year-old man who has been in a car crash experiences symptoms of sudden airway blockage. You conclude that he needs to be intubated using a rapid sequence induction. You intend to use thiopental sodium as your induction medication.
What is the mechanism of action of thiopental sodium?Your Answer:
Correct Answer: Depressing postsynaptic sensitivity to neurotransmitters
Explanation:Thiopental sodium is a barbiturate with a very short duration of action. It is primarily used to induce anesthesia. Barbiturates are believed to primarily affect synapses by reducing the sensitivity of postsynaptic receptors to neurotransmitters and by interfering with the release of neurotransmitters from presynaptic neurons.
Thiopental sodium specifically binds to a unique site associated with a chloride ionophore at the GABAA receptor, which is responsible for the opening of chloride ion channels. This binding increases the length of time that the chloride ionophore remains open. As a result, the inhibitory effect of GABA on postsynaptic neurons in the thalamus is prolonged.
In summary, thiopental sodium acts as a short-acting barbiturate that is commonly used to induce anesthesia. It affects synapses by reducing postsynaptic receptor sensitivity and interfering with neurotransmitter release. By binding to a specific site at the GABAA receptor, thiopental sodium prolongs the inhibitory effect of GABA in the thalamus.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 10
Incorrect
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A 72 year old male patient is brought into the emergency department with suspected COVID-19 pneumonia and sepsis. It is decided to intubate him pending transfer to ITU. Your consultant requests you prepare propofol and suxamethonium for rapid sequence intubation. What class of drug is suxamethonium?
Your Answer:
Correct Answer: Depolarising neuromuscular blocker
Explanation:Suxamethonium, also called succinylcholine, is currently the sole depolarising neuromuscular blocking drug used in clinical settings. It functions by binding to acetylcholine (Ach) receptors as an agonist. Unlike acetylcholine, it is not broken down by acetylcholinesterase, leading to a longer duration of binding and prolonged inhibition of neuromuscular transmission. Eventually, it is metabolized by plasma cholinesterase (pseudocholinesterase).
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 11
Incorrect
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A 10 year old girl is brought to the emergency department by her parents after a fall while playing outside. The patient has a significant wound that needs to be cleaned and closed. You decide to examine and clean the wound under ketamine sedation as the patient is very upset. What type of sedation is typical of Ketamine?
Your Answer:
Correct Answer: Dissociative sedation
Explanation:Ketamine induces a distinct type of sedation known as dissociative sedation. This sedation state is unlike any other and is characterized by a trance-like, cataleptic condition. It provides deep pain relief and memory loss while still maintaining important protective reflexes for the airway, spontaneous breathing, and overall stability of the heart and lungs. Dissociative sedation with ketamine does not fit into the conventional categories of sedation.
Further Reading:
Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.
There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.
Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.
The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.
Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.
After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 12
Incorrect
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A 42 year old female is brought to the emergency department with a 15cm long laceration to her arm which occurred when she tripped and fell onto a sharp object. You are suturing the laceration under local anesthesia when the patient mentions experiencing numbness in her lips and feeling lightheaded. What is the probable diagnosis?
Your Answer:
Correct Answer: Local anaesthetic toxicity
Explanation:Early signs of local anaesthetic systemic toxicity (LAST) can include numbness around the mouth and tongue, a metallic taste in the mouth, feeling lightheaded or dizzy, and experiencing visual and auditory disturbances. LAST is a rare but serious complication that can occur when administering anesthesia. It is important for healthcare providers to be aware of the signs and symptoms of LAST, as early recognition can lead to better outcomes. Additionally, hyperventilation can temporarily lower calcium levels, which can cause numbness around the mouth.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 13
Incorrect
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A 15 year old male is brought to the emergency department by his parents after he fell while climbing over a fence and sustained a deep cut to the arm where the metal spike pierced the skin. An X-ray reveals no bone damage. You opt to examine and cleanse the wound under sedation as the patient is extremely upset. You choose to sedate the patient with Ketamine. What is the main way in which Ketamine works?
Your Answer:
Correct Answer: NMDA receptor antagonist
Explanation:Ketamine primarily works by blocking NMDA receptors, although its complete mechanism of action is not yet fully comprehended. Ongoing research is exploring its impact on various other receptors.
Further Reading:
Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.
There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.
Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.
The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.
Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.
After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 14
Incorrect
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A 42 year old woman comes to the emergency department with a dislocated finger. You intend to perform a reduction under local anesthesia. The patient mentions that she used Entonox® during childbirth a decade ago and found it to be extremely effective. She inquires if she can use Entonox® for this procedure. What exactly is Entonox®?
Your Answer:
Correct Answer: 50% nitrous oxide and 50% oxygen
Explanation:Entonox®, also known as ‘gas and air’ or ‘laughing gas’, is a combination of nitrous oxide and oxygen in equal proportions. It offers a mild sedative effect and helps reduce anxiety.
Further Reading:
Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.
There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.
Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.
The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.
Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.
After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 15
Incorrect
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A 35 year old male is brought to the emergency department with severe head and chest injuries. As his GCS continues to decline, it is determined that intubation is necessary. You begin preparing for rapid sequence induction (RSI). What is the appropriate dosage of sodium thiopentone for an adult undergoing RSI?
Your Answer:
Correct Answer: 3-5 mg/kg
Explanation:To perform rapid sequence induction in adults, it is recommended to administer a dose of sodium thiopentone ranging from 3 to 5 mg per kilogram of body weight.
Further Reading:
There are four commonly used induction agents in the UK: propofol, ketamine, thiopentone, and etomidate.
Propofol is a 1% solution that produces significant venodilation and myocardial depression. It can also reduce cerebral perfusion pressure. The typical dose for propofol is 1.5-2.5 mg/kg. However, it can cause side effects such as hypotension, respiratory depression, and pain at the site of injection.
Ketamine is another induction agent that produces a dissociative state. It does not display a dose-response continuum, meaning that the effects do not necessarily increase with higher doses. Ketamine can cause bronchodilation, which is useful in patients with asthma. The initial dose for ketamine is 0.5-2 mg/kg, with a typical IV dose of 1.5 mg/kg. Side effects of ketamine include tachycardia, hypertension, laryngospasm, unpleasant hallucinations, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, nystagmus and diplopia, abnormal movements, and skin reactions.
Thiopentone is an ultra-short acting barbiturate that acts on the GABA receptor complex. It decreases cerebral metabolic oxygen and reduces cerebral blood flow and intracranial pressure. The adult dose for thiopentone is 3-5 mg/kg, while the child dose is 5-8 mg/kg. However, these doses should be halved in patients with hypovolemia. Side effects of thiopentone include venodilation, myocardial depression, and hypotension. It is contraindicated in patients with acute porphyrias and myotonic dystrophy.
Etomidate is the most haemodynamically stable induction agent and is useful in patients with hypovolemia, anaphylaxis, and asthma. It has similar cerebral effects to thiopentone. The dose for etomidate is 0.15-0.3 mg/kg. Side effects of etomidate include injection site pain, movement disorders, adrenal insufficiency, and apnoea. It is contraindicated in patients with sepsis due to adrenal suppression.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 16
Incorrect
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You are summoned to aid a 67-year-old patient who is in resus and has experienced two defibrillation attempts for cardiac arrest. Unfortunately, there is no supply of amiodarone available, so your consultant requests you to prepare lidocaine for administration following the next shock. What is the mechanism of action of lidocaine in the context of cardiac arrest?
Your Answer:
Correct Answer: Blockade of sodium channels
Explanation:Lidocaine functions by inhibiting the activity of voltage-gated sodium channels, preventing the flow of sodium ions through these channels.
Further Reading:
In the management of respiratory and cardiac arrest, several drugs are commonly used to help restore normal function and improve outcomes. Adrenaline is a non-selective agonist of adrenergic receptors and is administered intravenously at a dose of 1 mg every 3-5 minutes. It works by causing vasoconstriction, increasing systemic vascular resistance (SVR), and improving cardiac output by increasing the force of heart contraction. Adrenaline also has bronchodilatory effects.
Amiodarone is another drug used in cardiac arrest situations. It blocks voltage-gated potassium channels, which prolongs repolarization and reduces myocardial excitability. The initial dose of amiodarone is 300 mg intravenously after 3 shocks, followed by a dose of 150 mg after 5 shocks.
Lidocaine is an alternative to amiodarone in cardiac arrest situations. It works by blocking sodium channels and decreasing heart rate. The recommended dose is 1 mg/kg by slow intravenous injection, with a repeat half of the initial dose after 5 minutes. The maximum total dose of lidocaine is 3 mg/kg.
Magnesium sulfate is used to reverse myocardial hyperexcitability associated with hypomagnesemia. It is administered intravenously at a dose of 2 g over 10-15 minutes. An additional dose may be given if necessary, but the maximum total dose should not exceed 3 g.
Atropine is an antagonist of muscarinic acetylcholine receptors and is used to counteract the slowing of heart rate caused by the parasympathetic nervous system. It is administered intravenously at a dose of 500 mcg every 3-5 minutes, with a maximum dose of 3 mg.
Naloxone is a competitive antagonist for opioid receptors and is used in cases of respiratory arrest caused by opioid overdose. It has a short duration of action, so careful monitoring is necessary. The initial dose of naloxone is 400 micrograms, followed by 800 mcg after 1 minute. The dose can be gradually escalated up to 2 mg per dose if there is no response to the preceding dose.
It is important for healthcare professionals to have knowledge of the pharmacology and dosing schedules of these drugs in order to effectively manage respiratory and cardiac arrest situations.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 17
Incorrect
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You are managing a 62-year-old woman who has suffered a displaced fracture of the distal radius. Your plan is to perform a reduction of the fracture using intravenous regional anesthesia (Bier's block). You opt to administer prilocaine 0.5% for the regional block. What would be the appropriate dosage for this patient?
Your Answer:
Correct Answer: 3 mg/kg
Explanation:The suggested amount of Prilocaine for Bier’s block is 3mg per kilogram of body weight. It is important to note that there is no available formulation of prilocaine combined with adrenaline, unlike other local anesthetics.
Further Reading:
Bier’s block is a regional intravenous anesthesia technique commonly used for minor surgical procedures of the forearm or for reducing distal radius fractures in the emergency department (ED). It is recommended by NICE as the preferred anesthesia block for adults requiring manipulation of distal forearm fractures in the ED.
Before performing the procedure, a pre-procedure checklist should be completed, including obtaining consent, recording the patient’s weight, ensuring the resuscitative equipment is available, and monitoring the patient’s vital signs throughout the procedure. The air cylinder should be checked if not using an electronic machine, and the cuff should be checked for leaks.
During the procedure, a double cuff tourniquet is placed on the upper arm, and the arm is elevated to exsanguinate the limb. The proximal cuff is inflated to a pressure 100 mmHg above the systolic blood pressure, up to a maximum of 300 mmHg. The time of inflation and pressure should be recorded, and the absence of the radial pulse should be confirmed. 0.5% plain prilocaine is then injected slowly, and the time of injection is recorded. The patient should be warned about the potential cold/hot sensation and mottled appearance of the arm. After injection, the cannula is removed and pressure is applied to the venipuncture site to prevent bleeding. After approximately 10 minutes, the patient should have anesthesia and should not feel pain during manipulation. If anesthesia is successful, the manipulation can be performed, and a plaster can be applied by a second staff member. A check x-ray should be obtained with the arm lowered onto a pillow. The tourniquet should be monitored at all times, and the cuff should be inflated for a minimum of 20 minutes and a maximum of 45 minutes. If rotation of the cuff is required, it should be done after the manipulation and plaster application. After the post-reduction x-ray is satisfactory, the cuff can be deflated while observing the patient and monitors. Limb circulation should be checked prior to discharge, and appropriate follow-up and analgesia should be arranged.
There are several contraindications to performing Bier’s block, including allergy to local anesthetic, hypertension over 200 mm Hg, infection in the limb, lymphedema, methemoglobinemia, morbid obesity, peripheral vascular disease, procedures needed in both arms, Raynaud’s phenomenon, scleroderma, severe hypertension and sickle cell disease.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 18
Incorrect
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A 45 year old male patient is brought into the emergency department with a suspected severe pulmonary embolism. It is decided to intubate him pending transfer to the intensive care unit. Your consultant requests you prepare the patient for rapid sequence intubation. You start pre-oxygenating the patient. What is the recommended minimum duration for sufficient pre-oxygenation?
Your Answer:
Correct Answer: 3 minutes
Explanation:Inspired oxygen primarily works by removing nitrogen from the lungs, which would otherwise take up a significant portion of the lung capacity. This nitrogen is replaced with oxygen, leading to improved oxygenation of the tissues and an increased oxygen reserve. As a result, the patient can safely hold their breath for a longer period of time. It is recommended to preoxygenate the patient for at least 3 minutes.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 19
Incorrect
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A 72-year-old female patient with a 10-day history of productive cough and fever is brought to the emergency department due to her condition worsening over the past 24 hours. Despite initial resuscitation measures, there is minimal improvement, and the decision is made to intubate the patient before transferring her to the intensive care unit for ventilatory and inotropic support. Your consultant requests you to preoxygenate the patient before rapid sequence induction. What is the primary mechanism through which pre-oxygenation exerts its effect?
Your Answer:
Correct Answer: Denitrogenation of the residual capacity of the lungs
Explanation:During pre-oxygenation, inspired Oxygen primarily works by removing Nitrogen and increasing the presence of Oxygen. Additionally, it helps to optimize the levels of oxygen in the alveolar, arterial, tissue, and venous areas.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 20
Incorrect
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A 14 year old male is brought into the emergency department with a dislocated shoulder following a fall from a skateboard. The patient has been receiving Entonox during ambulance transport. What is a contraindication to administering Entonox in this case?
Your Answer:
Correct Answer: Pneumothorax
Explanation:Nitrous oxide should not be used in cases where there is trapped air, such as pneumothorax. This is because nitrous oxide can diffuse into the trapped air and increase the pressure, which can be harmful. This can be particularly dangerous in conditions like pneumothorax, where the trapped air can expand and affect breathing, or in cases of intracranial air after a head injury, trapped air after a recent underwater dive, or recent injection of gas into the eye.
Further Reading:
Entonox® is a mixture of 50% nitrous oxide and 50% oxygen that can be used for self-administration to reduce anxiety. It can also be used alongside other anesthesia agents. However, its mechanism of action for anxiety reduction is not fully understood. The Entonox bottles are typically identified by blue and white color-coded collars, but a new standard will replace these with dark blue shoulders in the future. It is important to note that Entonox alone cannot be used as the sole maintenance agent in anesthesia.
One of the effects of nitrous oxide is the second-gas effect, where it speeds up the absorption of other inhaled anesthesia agents. Nitrous oxide enters the alveoli and diffuses into the blood, displacing nitrogen. This displacement causes the remaining alveolar gases to become more concentrated, increasing the fractional content of inhaled anesthesia gases and accelerating the uptake of volatile agents into the blood.
However, when nitrous oxide administration is stopped, it can cause diffusion hypoxia. Nitrous oxide exits the blood and diffuses back into the alveoli, while nitrogen diffuses in the opposite direction. Nitrous oxide enters the alveoli much faster than nitrogen leaves, resulting in the dilution of oxygen within the alveoli. This can lead to diffusion hypoxia, where the oxygen concentration in the alveoli is diluted, potentially causing oxygen deprivation in patients breathing air.
There are certain contraindications for using nitrous oxide, as it can expand in air-filled spaces. It should be avoided in conditions such as head injuries with intracranial air, pneumothorax, recent intraocular gas injection, and entrapped air following a recent underwater dive.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 21
Incorrect
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You have just performed rapid sequence induction using ketamine and rocuronium and placed an endotracheal tube under the guidance of a consultant. What category of medication does rocuronium belong to?
Your Answer:
Correct Answer: Non-depolarizing neuromuscular blocker
Explanation:Rocuronium is a type of neuromuscular blocker that does not cause depolarization.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 22
Incorrect
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A 68-year-old individual reports feeling unwell after having their dislocated shoulder reduced while under sedation. You decide to prescribe ondansetron. What is the mechanism of action of ondansetron?
Your Answer:
Correct Answer: 5-HT3 receptor antagonist
Explanation:Ondansetron is a medication that works by blocking serotonin receptors in the body. It is commonly used as a first-line treatment for postoperative nausea and vomiting (PONV), which can occur after procedures done under sedation or anesthesia.
Further Reading:
postoperative nausea and vomiting (PONV) is a common occurrence following procedures performed under sedation or anesthesia. It can be highly distressing for patients. Several risk factors have been identified for PONV, including female gender, a history of PONV or motion sickness, non-smoking status, patient age, use of volatile anesthetics, longer duration of anesthesia, perioperative opioid use, use of nitrous oxide, and certain types of surgery such as abdominal and gynecological procedures.
To manage PONV, antiemetics are commonly used. These medications work by targeting different receptors in the body. Cyclizine and promethazine are histamine H1-receptor antagonists, which block the action of histamine and help reduce nausea and vomiting. Ondansetron is a serotonin 5-HT3 receptor antagonist, which blocks the action of serotonin and is effective in preventing and treating PONV. Prochlorperazine is a dopamine D2 receptor antagonist, which blocks the action of dopamine and helps alleviate symptoms of nausea and vomiting. Metoclopramide is also a dopamine D2 receptor antagonist and a 5-HT3 receptor antagonist, providing dual action against PONV. It is also a 5-HT4 receptor agonist, which helps improve gastric emptying and reduces the risk of PONV.
Assessment and management of PONV involves a comprehensive approach. Healthcare professionals need to assess the patient’s risk factors for PONV and take appropriate measures to prevent its occurrence. This may include selecting the appropriate anesthesia technique, using antiemetics prophylactically, and providing adequate pain control. In cases where PONV does occur, prompt treatment with antiemetics should be initiated to alleviate symptoms and provide relief to the patient. Close monitoring of the patient’s condition and response to treatment is essential to ensure effective management of PONV.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 23
Incorrect
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You examine the X-ray of a 65 year old male who has tripped and landed on his extended right hand. The X-ray confirms a fracture of the distal radius with dorsal displacement. You intend to perform a reduction of the fracture using intravenous regional anesthesia (Bier's block). How many healthcare professionals should be present during the entire procedure?
Your Answer:
Correct Answer: 2
Explanation:Bier’s block is a regional intravenous anesthesia technique commonly used for minor surgical procedures of the forearm or for reducing distal radius fractures in the emergency department (ED). It is recommended by NICE as the preferred anesthesia block for adults requiring manipulation of distal forearm fractures in the ED.
Before performing the procedure, a pre-procedure checklist should be completed, including obtaining consent, recording the patient’s weight, ensuring the resuscitative equipment is available, and monitoring the patient’s vital signs throughout the procedure. The air cylinder should be checked if not using an electronic machine, and the cuff should be checked for leaks.
During the procedure, a double cuff tourniquet is placed on the upper arm, and the arm is elevated to exsanguinate the limb. The proximal cuff is inflated to a pressure 100 mmHg above the systolic blood pressure, up to a maximum of 300 mmHg. The time of inflation and pressure should be recorded, and the absence of the radial pulse should be confirmed. 0.5% plain prilocaine is then injected slowly, and the time of injection is recorded. The patient should be warned about the potential cold/hot sensation and mottled appearance of the arm. After injection, the cannula is removed and pressure is applied to the venipuncture site to prevent bleeding. After approximately 10 minutes, the patient should have anesthesia and should not feel pain during manipulation. If anesthesia is successful, the manipulation can be performed, and a plaster can be applied by a second staff member. A check x-ray should be obtained with the arm lowered onto a pillow. The tourniquet should be monitored at all times, and the cuff should be inflated for a minimum of 20 minutes and a maximum of 45 minutes. If rotation of the cuff is required, it should be done after the manipulation and plaster application. After the post-reduction x-ray is satisfactory, the cuff can be deflated while observing the patient and monitors. Limb circulation should be checked prior to discharge, and appropriate follow-up and analgesia should be arranged.
There are several contraindications to performing Bier’s block, including allergy to local anesthetic, hypertension over 200 mm Hg, infection in the limb, lymphedema, methemoglobinemia, morbid obesity, peripheral vascular disease, procedures needed in both arms, Raynaud’s phenomenon, scleroderma, severe hypertension and sickle cell disease.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 24
Incorrect
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A 32-year-old man that has been involved in a car crash develops symptoms of acute airway blockage. You determine that he needs intubation through a rapid sequence induction. You intend to use etomidate as your induction medication.
Etomidate functions by acting on what type of receptor?Your Answer:
Correct Answer: Gamma-aminobutyric acid (GABA)
Explanation:Etomidate is a derivative of imidazole that is commonly used to induce anesthesia due to its short-acting nature. Its main mechanism of action is believed to involve the modulation of fast inhibitory synaptic transmission within the central nervous system by acting on GABA type A receptors.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 25
Incorrect
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A 28 year old female presents at the emergency department with a circular saw laceration. You opt to examine the wound using local anesthesia. What is the maximum dosage of Prilocaine that can be administered?
Your Answer:
Correct Answer: 6 mg/Kg
Explanation:The highest amount of Prilocaine that can be administered without adrenaline is 6 mg per kilogram of body weight. However, if Prilocaine is used in combination with adrenaline, the maximum dose increases to 8mg per kilogram.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 26
Incorrect
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You are summoned to assist with a 72-year-old patient who is in the resuscitation bay and has experienced two defibrillation attempts following cardiac arrest. Unfortunately, there is no supply of amiodarone available, so your consultant instructs you to prepare lidocaine for administration after the next shock. What is the initial dosage of lidocaine to be given during cardiac arrest?
Your Answer:
Correct Answer: 1 mg/kg
Explanation:During cardiac arrest, Lidocaine is administered through a slow IV injection at an initial dose of 1 mg/kg when deemed suitable.
Further Reading:
In the management of respiratory and cardiac arrest, several drugs are commonly used to help restore normal function and improve outcomes. Adrenaline is a non-selective agonist of adrenergic receptors and is administered intravenously at a dose of 1 mg every 3-5 minutes. It works by causing vasoconstriction, increasing systemic vascular resistance (SVR), and improving cardiac output by increasing the force of heart contraction. Adrenaline also has bronchodilatory effects.
Amiodarone is another drug used in cardiac arrest situations. It blocks voltage-gated potassium channels, which prolongs repolarization and reduces myocardial excitability. The initial dose of amiodarone is 300 mg intravenously after 3 shocks, followed by a dose of 150 mg after 5 shocks.
Lidocaine is an alternative to amiodarone in cardiac arrest situations. It works by blocking sodium channels and decreasing heart rate. The recommended dose is 1 mg/kg by slow intravenous injection, with a repeat half of the initial dose after 5 minutes. The maximum total dose of lidocaine is 3 mg/kg.
Magnesium sulfate is used to reverse myocardial hyperexcitability associated with hypomagnesemia. It is administered intravenously at a dose of 2 g over 10-15 minutes. An additional dose may be given if necessary, but the maximum total dose should not exceed 3 g.
Atropine is an antagonist of muscarinic acetylcholine receptors and is used to counteract the slowing of heart rate caused by the parasympathetic nervous system. It is administered intravenously at a dose of 500 mcg every 3-5 minutes, with a maximum dose of 3 mg.
Naloxone is a competitive antagonist for opioid receptors and is used in cases of respiratory arrest caused by opioid overdose. It has a short duration of action, so careful monitoring is necessary. The initial dose of naloxone is 400 micrograms, followed by 800 mcg after 1 minute. The dose can be gradually escalated up to 2 mg per dose if there is no response to the preceding dose.
It is important for healthcare professionals to have knowledge of the pharmacology and dosing schedules of these drugs in order to effectively manage respiratory and cardiac arrest situations.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 27
Incorrect
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You are part of the resus team treating a 42-year-old female patient. Due to deteriorating GCS, your consultant advises you to prepare for rapid sequence induction. You contemplate which induction agent is most appropriate for this patient. What side effect of etomidate prevents its use in septic patients?
Your Answer:
Correct Answer: Adrenal suppression
Explanation:Etomidate is not recommended for use in septic patients because it can suppress adrenal cortisol production, leading to increased morbidity and mortality in sepsis cases. However, it is a suitable choice for haemodynamically unstable patients who are not experiencing sepsis, as it does not cause significant hypotension like other induction agents. Additionally, etomidate can be beneficial for patients with head injuries and elevated intracranial pressure, as it reduces cerebral blood flow and intracranial pressure.
Further Reading:
There are four commonly used induction agents in the UK: propofol, ketamine, thiopentone, and etomidate.
Propofol is a 1% solution that produces significant venodilation and myocardial depression. It can also reduce cerebral perfusion pressure. The typical dose for propofol is 1.5-2.5 mg/kg. However, it can cause side effects such as hypotension, respiratory depression, and pain at the site of injection.
Ketamine is another induction agent that produces a dissociative state. It does not display a dose-response continuum, meaning that the effects do not necessarily increase with higher doses. Ketamine can cause bronchodilation, which is useful in patients with asthma. The initial dose for ketamine is 0.5-2 mg/kg, with a typical IV dose of 1.5 mg/kg. Side effects of ketamine include tachycardia, hypertension, laryngospasm, unpleasant hallucinations, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, nystagmus and diplopia, abnormal movements, and skin reactions.
Thiopentone is an ultra-short acting barbiturate that acts on the GABA receptor complex. It decreases cerebral metabolic oxygen and reduces cerebral blood flow and intracranial pressure. The adult dose for thiopentone is 3-5 mg/kg, while the child dose is 5-8 mg/kg. However, these doses should be halved in patients with hypovolemia. Side effects of thiopentone include venodilation, myocardial depression, and hypotension. It is contraindicated in patients with acute porphyrias and myotonic dystrophy.
Etomidate is the most haemodynamically stable induction agent and is useful in patients with hypovolemia, anaphylaxis, and asthma. It has similar cerebral effects to thiopentone. The dose for etomidate is 0.15-0.3 mg/kg. Side effects of etomidate include injection site pain, movement disorders, adrenal insufficiency, and apnoea. It is contraindicated in patients with sepsis due to adrenal suppression.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 28
Incorrect
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A 65 year old female patient has been brought into the department after being hit by a car in a vehicle-pedestrian accident. The patient needs CT imaging to evaluate the complete scope of her injuries. What are the minimum monitoring requirements for transferring a critically ill patient?
Your Answer:
Correct Answer: ECG, oxygen saturations, blood pressure and temperature monitoring
Explanation:It is crucial to continuously monitor the oxygen saturation, blood pressure, ECG, and temperature of critically ill patients during transfers. If the patient is intubated, monitoring of end-tidal CO2 is also necessary. The minimum standard monitoring requirements for any critically ill patient during transfers include ECG, oxygen saturation, blood pressure, and temperature. Additionally, if the patient is intubated, monitoring of end-tidal CO2 is mandatory. It is important to note that the guidance from ICS/FICM suggests that monitoring protocols for intra-hospital transfers should be similar to those for interhospital transfers.
Further Reading:
Transfer of critically ill patients in the emergency department is a common occurrence and can involve intra-hospital transfers or transfers to another hospital. However, there are several risks associated with these transfers that doctors need to be aware of and manage effectively.
Technical risks include equipment failure or inadequate equipment, unreliable power or oxygen supply, incompatible equipment, restricted positioning, and restricted monitoring equipment. These technical issues can hinder the ability to detect and treat problems with ventilation, blood pressure control, and arrhythmias during the transfer.
Non-technical risks involve limited personal and medical team during the transfer, isolation and lack of resources in the receiving hospital, and problems with communication and liaison between the origin and destination sites.
Organizational risks can be mitigated by having a dedicated consultant lead for transfers who is responsible for producing guidelines, training staff, standardizing protocols, equipment, and documentation, as well as capturing data and conducting audits.
To optimize the patient’s clinical condition before transfer, several key steps should be taken. These include ensuring a low threshold for intubation and anticipating airway and ventilation problems, securing the endotracheal tube (ETT) and verifying its position, calculating oxygen requirements and ensuring an adequate supply, monitoring for circulatory issues and inserting at least two IV accesses, providing ongoing analgesia and sedation, controlling seizures, and addressing any fractures or temperature changes.
It is also important to have the necessary equipment and personnel for the transfer. Standard monitoring equipment should include ECG, oxygen saturation, blood pressure, temperature, and capnographic monitoring for ventilated patients. Additional monitoring may be required depending on the level of care needed by the patient.
In terms of oxygen supply, it is standard practice to calculate the expected oxygen consumption during transfer and multiply it by two to ensure an additional supply in case of delays. The suggested oxygen supply for transfer can be calculated using the minute volume, fraction of inspired oxygen, and estimated transfer time.
Overall, managing the risks associated with patient transfers requires careful planning, communication, and coordination to ensure the safety and well-being of critically ill patients.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 29
Incorrect
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A 32 year old male presents to the emergency department with a laceration to the distal third of his finger caused by a box cutter. You intend to clean and examine the wound under local anesthesia. You gather the necessary equipment to administer a digital (ring) nerve block and prepare to inject the anesthetic at the base of the finger. How are the digital nerves arranged within the finger?
Your Answer:
Correct Answer: 2 palmar and 2 dorsal digital nerves
Explanation:The finger has a total of four digital nerves. Two of these nerves, known as the palmar digital nerves, run along the palm side of each finger. The other two nerves, called the dorsal digital nerves, are located on the back side of the finger. However, the dorsal nerve supply changes slightly at the level of the proximal IP joint. Beyond this point, the dorsal nerve supply comes from the dorsal branch of the palmar digital nerve.
Further Reading:
Digital nerve blocks are commonly used to numb the finger for various procedures such as foreign body removal, dislocation reduction, and suturing. Sensation to the finger is primarily provided by the proper digital nerves, which arise from the common digital nerve. Each common digital nerve divides into two proper digital nerves, which run along the palmar aspect of the finger. These proper digital nerves give off a dorsal branch that supplies the dorsal aspect of the finger.
The most common technique for digital nerve blocks is the digital (ring) block. The hand is cleaned and the injection sites are cleansed with an alcohol swab. A syringe containing 1% lidocaine is prepared, and the needle is inserted at the base of the finger from a dorsal approach. Lidocaine is infiltrated under the skin, and the needle is then advanced towards the palmar aspect of the finger to inject more lidocaine. This process is repeated on the opposite side of the finger.
It is important not to use lidocaine with adrenaline for this procedure, as it may cause constriction and ischemia of the digital artery. Lidocaine 1% is the preferred local anesthetic, and the maximum dose is 3 ml/kg up to 200 mg. Contraindications for digital nerve blocks include compromised circulation to the finger, infection at the planned injection site, contraindication to local anesthetic (e.g. allergy), and suspected compartment syndrome (which is rare in the finger).
Complications of digital nerve blocks can include vascular injury to the digital artery or vein, injury to the digital nerve, infection, pain, allergic reaction, intravascular injection (which can be avoided by aspirating prior to injection), and systemic local anesthetic toxicity (which is uncommon with typical doses of lidocaine).
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This question is part of the following fields:
- Basic Anaesthetics
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Question 30
Incorrect
-
You are managing a 62-year-old woman with a dorsally displaced fracture of the distal radius. Your plan is to perform a reduction of the fracture using intravenous regional anesthesia (Bier's block). Following the administration of the local anesthetic, you observe a change in the patient's skin color to a grayish-blue hue. What complication is most likely to have occurred?
Your Answer:
Correct Answer: Methaemoglobinaemia
Explanation:In this case, the administration of the local anesthetic used for the Bier’s block may have caused the patient’s blood to convert hemoglobin into methemoglobin, resulting in the observed skin color change.
Further Reading:
Bier’s block is a regional intravenous anesthesia technique commonly used for minor surgical procedures of the forearm or for reducing distal radius fractures in the emergency department (ED). It is recommended by NICE as the preferred anesthesia block for adults requiring manipulation of distal forearm fractures in the ED.
Before performing the procedure, a pre-procedure checklist should be completed, including obtaining consent, recording the patient’s weight, ensuring the resuscitative equipment is available, and monitoring the patient’s vital signs throughout the procedure. The air cylinder should be checked if not using an electronic machine, and the cuff should be checked for leaks.
During the procedure, a double cuff tourniquet is placed on the upper arm, and the arm is elevated to exsanguinate the limb. The proximal cuff is inflated to a pressure 100 mmHg above the systolic blood pressure, up to a maximum of 300 mmHg. The time of inflation and pressure should be recorded, and the absence of the radial pulse should be confirmed. 0.5% plain prilocaine is then injected slowly, and the time of injection is recorded. The patient should be warned about the potential cold/hot sensation and mottled appearance of the arm. After injection, the cannula is removed and pressure is applied to the venipuncture site to prevent bleeding. After approximately 10 minutes, the patient should have anesthesia and should not feel pain during manipulation. If anesthesia is successful, the manipulation can be performed, and a plaster can be applied by a second staff member. A check x-ray should be obtained with the arm lowered onto a pillow. The tourniquet should be monitored at all times, and the cuff should be inflated for a minimum of 20 minutes and a maximum of 45 minutes. If rotation of the cuff is required, it should be done after the manipulation and plaster application. After the post-reduction x-ray is satisfactory, the cuff can be deflated while observing the patient and monitors. Limb circulation should be checked prior to discharge, and appropriate follow-up and analgesia should be arranged.
There are several contraindications to performing Bier’s block, including allergy to local anesthetic, hypertension over 200 mm Hg, infection in the limb, lymphedema, methemoglobinemia, morbid obesity, peripheral vascular disease, procedures needed in both arms, Raynaud’s phenomenon, scleroderma, severe hypertension and sickle cell disease.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 31
Incorrect
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You have a debrief session with your mentor after a case involving a patient who experienced systemic toxicity from local anesthesia. Towards the end of the conversation, your mentor emphasizes the importance of reporting such episodes. In the UK, which of the following organizations should be notified about incidents of local anesthetic systemic toxicity?
Your Answer:
Correct Answer: National Patient Safety Agency
Explanation:Instances of local anaesthetic systemic toxicity (LAST) should be promptly reported to the National Patient Safety Agency (NPSA). Additionally, it is advisable to report any adverse drug reactions to the Medicines and Healthcare products Regulatory Agency (MHRA) through their yellow card scheme. Please refer to the follow-up section in the notes for further details.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 32
Incorrect
-
A 45 year old male patient is brought into the emergency department with a suspected massive pulmonary embolism. It is decided to intubate him pending transfer to ITU. Your consultant requests you prepare the patient for rapid sequence intubation. You start pre-oxygenating the patient. What is the gold standard evaluation for ensuring sufficient pre-oxygenation?
Your Answer:
Correct Answer: End tidal O2 > 85%
Explanation:The blood gas measurement of pO2 should be equal to or greater than 18 kilopascals (kPa) at a level of 10.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 33
Incorrect
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A 25 year old college student is brought into the ER after being discovered in a collapsed state with decreased consciousness in the early morning hours. You have concerns about the patient's airway and opt to insert an oropharyngeal airway. How would you determine the appropriate size for an oropharyngeal airway?
Your Answer:
Correct Answer: Distance between the patient's incisors and the angle of their mandible
Explanation:The size of an oropharyngeal airway (OPA or Guedel) can be determined by measuring the distance between the patient’s incisors and the angle of their mandible. To ensure proper fit, the OPA should be approximately the same length as this measurement. Please refer to the image in the notes for visual guidance.
Further Reading:
Techniques to keep the airway open:
1. Suction: Used to remove obstructing material such as blood, vomit, secretions, and food debris from the oral cavity.
2. Chin lift manoeuvres: Involves lifting the head off the floor and lifting the chin to extend the head in relation to the neck. Improves alignment of the pharyngeal, laryngeal, and oral axes.
3. Jaw thrust: Used in trauma patients with cervical spine injury concerns. Fingers are placed under the mandible and gently pushed upward.
Airway adjuncts:
1. Oropharyngeal airway (OPA): Prevents the tongue from occluding the airway. Sized according to the patient by measuring from the incisor teeth to the angle of the mandible. Inserted with the tip facing backwards and rotated 180 degrees once it touches the back of the palate or oropharynx.
2. Nasopharyngeal airway (NPA): Useful when it is difficult to open the mouth or in semi-conscious patients. Sized by length (distance between nostril and tragus of the ear) and diameter (roughly that of the patient’s little finger). Contraindicated in basal skull and midface fractures.
Laryngeal mask airway (LMA):
– Supraglottic airway device used as a first line or rescue airway.
– Easy to insert, sized according to patient’s bodyweight.
– Advantages: Easy insertion, effective ventilation, some protection from aspiration.
– Disadvantages: Risk of hypoventilation, greater gastric inflation than endotracheal tube (ETT), risk of aspiration and laryngospasm.Note: Proper training and assessment of the patient’s condition are essential for airway management.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 34
Incorrect
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You are part of the team managing a conscious patient in the emergency room. You decide to insert a nasopharyngeal airway adjunct. How should you determine the appropriate size of the nasopharyngeal airway?
Your Answer:
Correct Answer: Sized according to the distance between the nostril and the tragus of the ear
Explanation:Nasopharyngeal airway adjuncts (NPAs) are selected based on their length, which should match the distance between the nostril and the tragus of the ear.
Further Reading:
Techniques to keep the airway open:
1. Suction: Used to remove obstructing material such as blood, vomit, secretions, and food debris from the oral cavity.
2. Chin lift manoeuvres: Involves lifting the head off the floor and lifting the chin to extend the head in relation to the neck. Improves alignment of the pharyngeal, laryngeal, and oral axes.
3. Jaw thrust: Used in trauma patients with cervical spine injury concerns. Fingers are placed under the mandible and gently pushed upward.
Airway adjuncts:
1. Oropharyngeal airway (OPA): Prevents the tongue from occluding the airway. Sized according to the patient by measuring from the incisor teeth to the angle of the mandible. Inserted with the tip facing backwards and rotated 180 degrees once it touches the back of the palate or oropharynx.
2. Nasopharyngeal airway (NPA): Useful when it is difficult to open the mouth or in semi-conscious patients. Sized by length (distance between nostril and tragus of the ear) and diameter (roughly that of the patient’s little finger). Contraindicated in basal skull and midface fractures.
Laryngeal mask airway (LMA):
– Supraglottic airway device used as a first line or rescue airway.
– Easy to insert, sized according to patient’s bodyweight.
– Advantages: Easy insertion, effective ventilation, some protection from aspiration.
– Disadvantages: Risk of hypoventilation, greater gastric inflation than endotracheal tube (ETT), risk of aspiration and laryngospasm.Note: Proper training and assessment of the patient’s condition are essential for airway management.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 35
Incorrect
-
A 28-year-old patient has arrived at the emergency department following an accident at a construction site. The skin has been lacerated by a dropped piece of stainless steel sheeting with a sharp edge. The plan is to suture the wound after infiltrating the area with local anesthesia. In the suture room, you find Lidocaine 1% with Adrenaline (Epinephrine) 1:200,000 and Bupivacaine 0.5% available. What is a contraindication to using local anesthesia combined with adrenaline?
Your Answer:
Correct Answer: Area to be infiltrated is in periphery
Explanation:Adrenaline is known to cause vasoconstriction, which is the narrowing of blood vessels. As a result, it is not recommended to use adrenaline in areas such as the peripheries, end arteries, and flap lacerations because it can increase the risk of ischemia, which is a lack of blood supply to tissues. Additionally, there are certain contraindications to using adrenaline locally, including conditions like pheochromocytoma, hypertension, and arteriosclerosis. It is important to be cautious of these factors as adrenaline’s vasoconstrictive effects can also lead to an elevation in blood pressure.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 36
Incorrect
-
A 32-year-old patient presents to the emergency department with a 6 cm leg laceration. After assessing the wound, it is determined that suturing under anesthesia is necessary. You intend to supervise one of the medical students in closing the wound. Before beginning the procedure, you have a discussion about the risks associated with local anesthesia. Methemoglobinemia is primarily associated with which type of anesthetic agent?
Your Answer:
Correct Answer: Prilocaine
Explanation:Methaemoglobinaemia is a condition that can occur when prilocaine is used, particularly when administered at doses higher than 16 mg/kg.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 37
Incorrect
-
A 45 year old female patient has been brought to the emergency department with multiple injuries following a fall while hiking in the mountains. You observe significant injuries to the face. There is also bruising to the chest wall and a fracture dislocation to the ankle. The patient has undergone rapid sequence induction with Propofol and Suxamethonium. A chest X-ray shows multiple rib fractures but no pneumothorax or visible pulmonary contusion. You notice that the patient's end tidal CO2 has steadily increased since being intubated from 4.5 KPa to 7.4 KPa. You observe esophageal temperature is 39.3ºC. What is the likely cause of these readings?
Your Answer:
Correct Answer: Malignant hyperthermia
Explanation:The earliest and most frequent clinical indication of malignant hyperthermia is typically an increase in end tidal CO2. An unexplained elevation in end tidal CO2 is often the initial and most reliable sign of this condition.
Further Reading:
Malignant hyperthermia is a rare and life-threatening syndrome that can be triggered by certain medications in individuals who are genetically susceptible. The most common triggers are suxamethonium and inhalational anaesthetic agents. The syndrome is caused by the release of stored calcium ions from skeletal muscle cells, leading to uncontrolled muscle contraction and excessive heat production. This results in symptoms such as high fever, sweating, flushed skin, rapid heartbeat, and muscle rigidity. It can also lead to complications such as acute kidney injury, rhabdomyolysis, and metabolic acidosis. Treatment involves discontinuing the trigger medication, administering dantrolene to inhibit calcium release and promote muscle relaxation, and managing any associated complications such as hyperkalemia and acidosis. Referral to a malignant hyperthermia center for further investigation is also recommended.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 38
Incorrect
-
You are getting ready to administer local anesthesia to the skin of a patient's groin before inserting a femoral venous catheter. You opt for lidocaine as the choice of medication. What is the mechanism of action of lidocaine?
Your Answer:
Correct Answer:
Explanation:Lidocaine works by blocking voltage-gated sodium channels. These channels are responsible for the propagation of action potentials in nerve fibers. By blocking these channels, lidocaine prevents the influx of sodium ions into the nerve cells, thereby inhibiting the generation and conduction of nerve impulses. This results in local anesthesia, as the transmission of pain signals from the skin to the brain is effectively blocked.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 39
Incorrect
-
You are a member of the team assisting with the intubation of a pediatric patient. The initial intubation attempt is unsuccessful. Your attending physician instructs you to apply pressure on the larynx during the second attempt. With the patient positioned in a semi-recumbent position, which direction should pressure be applied to aid in intubation?
Your Answer:
Correct Answer: Backwards, upwards and rightwards
Explanation:The BURP maneuver is a technique used to assist with intubation. It involves applying pressure in a specific direction on the larynx. The acronym BURP stands for backwards (B), upwards (U), rightwards (R), and pressure (P). To perform the maneuver correctly, the thyroid cartilage is moved backwards, 2 cm upwards, and 0.5cm – 2 cm to the right in relation to the anatomical position.
Further Reading:
A difficult airway refers to a situation where factors have been identified that make airway management more challenging. These factors can include body habitus, head and neck anatomy, mouth characteristics, jaw abnormalities, and neck mobility. The LEMON criteria can be used to predict difficult intubation by assessing these factors. The criteria include looking externally at these factors, evaluating the 3-3-2 rule which assesses the space in the mouth and neck, assessing the Mallampati score which measures the distance between the tongue base and roof of the mouth, and considering any upper airway obstructions or reduced neck mobility.
Direct laryngoscopy is a method used to visualize the larynx and assess the size of the tracheal opening. The Cormack-Lehane grading system can be used to classify the tracheal opening, with higher grades indicating more difficult access. In cases of a failed airway, where intubation attempts are unsuccessful and oxygenation cannot be maintained, the immediate priority is to oxygenate the patient and prevent hypoxic brain injury. This can be done through various measures such as using a bag-valve-mask ventilation, high flow oxygen, suctioning, and optimizing head positioning.
If oxygenation cannot be maintained, it is important to call for help from senior medical professionals and obtain a difficult airway trolley if not already available. If basic airway management techniques do not improve oxygenation, further intubation attempts may be considered using different equipment or techniques. If oxygen saturations remain below 90%, a surgical airway such as a cricothyroidotomy may be necessary.
Post-intubation hypoxia can occur for various reasons, and the mnemonic DOPES can be used to identify and address potential problems. DOPES stands for displacement of the endotracheal tube, obstruction, pneumothorax, equipment failure, and stacked breaths. If intubation attempts fail, a maximum of three attempts should be made before moving to an alternative plan, such as using a laryngeal mask airway or considering a cricothyroidotomy.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 40
Incorrect
-
You are part of the team working on a child with severe burns. The child has a suspected inhalation injury and needs to be intubated before being transferred to the local burns unit. During direct laryngoscopy, which classification system is used to evaluate the glottic opening?
Your Answer:
Correct Answer: Cormack and Lehane classification
Explanation:The tracheal opening can be classified using the Cormack-Lehane grading system. This system categorizes the views obtained through direct laryngoscopy based on the structures that are visible. More information about this classification system can be found in the notes provided below.
Further Reading:
A difficult airway refers to a situation where factors have been identified that make airway management more challenging. These factors can include body habitus, head and neck anatomy, mouth characteristics, jaw abnormalities, and neck mobility. The LEMON criteria can be used to predict difficult intubation by assessing these factors. The criteria include looking externally at these factors, evaluating the 3-3-2 rule which assesses the space in the mouth and neck, assessing the Mallampati score which measures the distance between the tongue base and roof of the mouth, and considering any upper airway obstructions or reduced neck mobility.
Direct laryngoscopy is a method used to visualize the larynx and assess the size of the tracheal opening. The Cormack-Lehane grading system can be used to classify the tracheal opening, with higher grades indicating more difficult access. In cases of a failed airway, where intubation attempts are unsuccessful and oxygenation cannot be maintained, the immediate priority is to oxygenate the patient and prevent hypoxic brain injury. This can be done through various measures such as using a bag-valve-mask ventilation, high flow oxygen, suctioning, and optimizing head positioning.
If oxygenation cannot be maintained, it is important to call for help from senior medical professionals and obtain a difficult airway trolley if not already available. If basic airway management techniques do not improve oxygenation, further intubation attempts may be considered using different equipment or techniques. If oxygen saturations remain below 90%, a surgical airway such as a cricothyroidotomy may be necessary.
Post-intubation hypoxia can occur for various reasons, and the mnemonic DOPES can be used to identify and address potential problems. DOPES stands for displacement of the endotracheal tube, obstruction, pneumothorax, equipment failure, and stacked breaths. If intubation attempts fail, a maximum of three attempts should be made before moving to an alternative plan, such as using a laryngeal mask airway or considering a cricothyroidotomy.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 41
Incorrect
-
You are part of the team managing a 60 year old patient who has experienced cardiac arrest. What is the appropriate dosage of adrenaline to administer to this patient?
Your Answer:
Correct Answer: 1 mg IV
Explanation:In cases of cardiac arrest, it is recommended to administer 1 mg of adrenaline intravenously (IV) every 3-5 minutes. According to the 2021 resus council guidelines for adult advanced life support (ALS), the administration of vasopressors should follow these guidelines:
– For adult patients in cardiac arrest with a non-shockable rhythm, administer 1 mg of adrenaline IV (or intraosseous) as soon as possible.
– For adult patients in cardiac arrest with a shockable rhythm, administer 1 mg of adrenaline IV (or intraosseous) after the third shock.
– Continuously repeat the administration of 1 mg of adrenaline IV (or intraosseous) every 3-5 minutes throughout the ALS procedure.Further Reading:
In the management of respiratory and cardiac arrest, several drugs are commonly used to help restore normal function and improve outcomes. Adrenaline is a non-selective agonist of adrenergic receptors and is administered intravenously at a dose of 1 mg every 3-5 minutes. It works by causing vasoconstriction, increasing systemic vascular resistance (SVR), and improving cardiac output by increasing the force of heart contraction. Adrenaline also has bronchodilatory effects.
Amiodarone is another drug used in cardiac arrest situations. It blocks voltage-gated potassium channels, which prolongs repolarization and reduces myocardial excitability. The initial dose of amiodarone is 300 mg intravenously after 3 shocks, followed by a dose of 150 mg after 5 shocks.
Lidocaine is an alternative to amiodarone in cardiac arrest situations. It works by blocking sodium channels and decreasing heart rate. The recommended dose is 1 mg/kg by slow intravenous injection, with a repeat half of the initial dose after 5 minutes. The maximum total dose of lidocaine is 3 mg/kg.
Magnesium sulfate is used to reverse myocardial hyperexcitability associated with hypomagnesemia. It is administered intravenously at a dose of 2 g over 10-15 minutes. An additional dose may be given if necessary, but the maximum total dose should not exceed 3 g.
Atropine is an antagonist of muscarinic acetylcholine receptors and is used to counteract the slowing of heart rate caused by the parasympathetic nervous system. It is administered intravenously at a dose of 500 mcg every 3-5 minutes, with a maximum dose of 3 mg.
Naloxone is a competitive antagonist for opioid receptors and is used in cases of respiratory arrest caused by opioid overdose. It has a short duration of action, so careful monitoring is necessary. The initial dose of naloxone is 400 micrograms, followed by 800 mcg after 1 minute. The dose can be gradually escalated up to 2 mg per dose if there is no response to the preceding dose.
It is important for healthcare professionals to have knowledge of the pharmacology and dosing schedules of these drugs in order to effectively manage respiratory and cardiac arrest situations.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 42
Incorrect
-
A 52 year old male is brought to the emergency department with severe head and chest injuries. As his Glasgow Coma Scale (GCS) continues to decline, it is determined that intubation is necessary. You begin preparing for rapid sequence induction (RSI). Before administering sodium thiopentone, the patient's blood pressure is measured and found to be 88/58 mmHg. What is the most suitable course of action?
Your Answer:
Correct Answer: Use half normal dose
Explanation:In patients with pre-existing hypovolaemia, the amount of sodium thiopentone administered should be reduced by half. This is because sodium thiopentone can cause venodilation and myocardial depression, which can result in significant hypovolaemia. Alternatively, an induction agent that does not cause hypotension, such as Etomidate, can be used instead. It is important to note that both propofol and thiopentone are known to cause hypotension.
Further Reading:
There are four commonly used induction agents in the UK: propofol, ketamine, thiopentone, and etomidate.
Propofol is a 1% solution that produces significant venodilation and myocardial depression. It can also reduce cerebral perfusion pressure. The typical dose for propofol is 1.5-2.5 mg/kg. However, it can cause side effects such as hypotension, respiratory depression, and pain at the site of injection.
Ketamine is another induction agent that produces a dissociative state. It does not display a dose-response continuum, meaning that the effects do not necessarily increase with higher doses. Ketamine can cause bronchodilation, which is useful in patients with asthma. The initial dose for ketamine is 0.5-2 mg/kg, with a typical IV dose of 1.5 mg/kg. Side effects of ketamine include tachycardia, hypertension, laryngospasm, unpleasant hallucinations, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, nystagmus and diplopia, abnormal movements, and skin reactions.
Thiopentone is an ultra-short acting barbiturate that acts on the GABA receptor complex. It decreases cerebral metabolic oxygen and reduces cerebral blood flow and intracranial pressure. The adult dose for thiopentone is 3-5 mg/kg, while the child dose is 5-8 mg/kg. However, these doses should be halved in patients with hypovolemia. Side effects of thiopentone include venodilation, myocardial depression, and hypotension. It is contraindicated in patients with acute porphyrias and myotonic dystrophy.
Etomidate is the most haemodynamically stable induction agent and is useful in patients with hypovolemia, anaphylaxis, and asthma. It has similar cerebral effects to thiopentone. The dose for etomidate is 0.15-0.3 mg/kg. Side effects of etomidate include injection site pain, movement disorders, adrenal insufficiency, and apnoea. It is contraindicated in patients with sepsis due to adrenal suppression.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 43
Incorrect
-
A 25-year-old individual who was attacked with a baseball bat returns from the radiology department after undergoing a CT head scan. The CT images show the presence of intracranial bleeding, and after consulting with the on-call neurosurgical registrar, it is decided that the patient will be transferred to the nearby neurosurgical unit after intubation. How can you determine the amount of oxygen that will be required during the transfer?
Your Answer:
Correct Answer: 2 x Minute Volume (MV) x FiO2 x transfer time in minutes
Explanation:To determine the amount of oxygen needed for a transfer, you can use the formula: 2 x Minute Volume (MV) x FiO2 x transfer time in minutes. This formula calculates the volume of oxygen that should be taken on the transfer. The Minute Volume (MV) represents the expected oxygen consumption. It is recommended to double the expected consumption to account for any unforeseen delays or increased oxygen demand during the transfer. Therefore, the second equation is used to calculate the volume of oxygen that will be taken on the transfer.
Further Reading:
Transfer of critically ill patients in the emergency department is a common occurrence and can involve intra-hospital transfers or transfers to another hospital. However, there are several risks associated with these transfers that doctors need to be aware of and manage effectively.
Technical risks include equipment failure or inadequate equipment, unreliable power or oxygen supply, incompatible equipment, restricted positioning, and restricted monitoring equipment. These technical issues can hinder the ability to detect and treat problems with ventilation, blood pressure control, and arrhythmias during the transfer.
Non-technical risks involve limited personal and medical team during the transfer, isolation and lack of resources in the receiving hospital, and problems with communication and liaison between the origin and destination sites.
Organizational risks can be mitigated by having a dedicated consultant lead for transfers who is responsible for producing guidelines, training staff, standardizing protocols, equipment, and documentation, as well as capturing data and conducting audits.
To optimize the patient’s clinical condition before transfer, several key steps should be taken. These include ensuring a low threshold for intubation and anticipating airway and ventilation problems, securing the endotracheal tube (ETT) and verifying its position, calculating oxygen requirements and ensuring an adequate supply, monitoring for circulatory issues and inserting at least two IV accesses, providing ongoing analgesia and sedation, controlling seizures, and addressing any fractures or temperature changes.
It is also important to have the necessary equipment and personnel for the transfer. Standard monitoring equipment should include ECG, oxygen saturation, blood pressure, temperature, and capnographic monitoring for ventilated patients. Additional monitoring may be required depending on the level of care needed by the patient.
In terms of oxygen supply, it is standard practice to calculate the expected oxygen consumption during transfer and multiply it by two to ensure an additional supply in case of delays. The suggested oxygen supply for transfer can be calculated using the minute volume, fraction of inspired oxygen, and estimated transfer time.
Overall, managing the risks associated with patient transfers requires careful planning, communication, and coordination to ensure the safety and well-being of critically ill patients.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 44
Incorrect
-
You are preparing to conduct rapid sequence induction. What clinical observation, typically seen after administering suxamethonium, is not present when rocuronium is used for neuromuscular blockade?
Your Answer:
Correct Answer: Muscle fasciculations
Explanation:When suxamethonium is administered for neuromuscular blockade during rapid sequence induction, one of the clinical observations typically seen is muscle fasciculations. However, when rocuronium is used instead, muscle fasciculations are not present.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 45
Incorrect
-
You are overseeing the care of a 72-year-old patient who is experiencing a peri-arrest arrhythmia. Laboratory results indicate that the patient has a significant deficiency of magnesium in their blood. After careful consideration, you determine that administering magnesium sulfate is necessary. What is the appropriate dosage regimen for this treatment?
Your Answer:
Correct Answer: 2g IV given over 10-15 minutes
Explanation:To treat serious arrhythmia caused by hypomagnesaemia, it is recommended to administer 2 g of magnesium sulphate intravenously over a period of 10-15 minutes.
Further Reading:
In the management of respiratory and cardiac arrest, several drugs are commonly used to help restore normal function and improve outcomes. Adrenaline is a non-selective agonist of adrenergic receptors and is administered intravenously at a dose of 1 mg every 3-5 minutes. It works by causing vasoconstriction, increasing systemic vascular resistance (SVR), and improving cardiac output by increasing the force of heart contraction. Adrenaline also has bronchodilatory effects.
Amiodarone is another drug used in cardiac arrest situations. It blocks voltage-gated potassium channels, which prolongs repolarization and reduces myocardial excitability. The initial dose of amiodarone is 300 mg intravenously after 3 shocks, followed by a dose of 150 mg after 5 shocks.
Lidocaine is an alternative to amiodarone in cardiac arrest situations. It works by blocking sodium channels and decreasing heart rate. The recommended dose is 1 mg/kg by slow intravenous injection, with a repeat half of the initial dose after 5 minutes. The maximum total dose of lidocaine is 3 mg/kg.
Magnesium sulfate is used to reverse myocardial hyperexcitability associated with hypomagnesemia. It is administered intravenously at a dose of 2 g over 10-15 minutes. An additional dose may be given if necessary, but the maximum total dose should not exceed 3 g.
Atropine is an antagonist of muscarinic acetylcholine receptors and is used to counteract the slowing of heart rate caused by the parasympathetic nervous system. It is administered intravenously at a dose of 500 mcg every 3-5 minutes, with a maximum dose of 3 mg.
Naloxone is a competitive antagonist for opioid receptors and is used in cases of respiratory arrest caused by opioid overdose. It has a short duration of action, so careful monitoring is necessary. The initial dose of naloxone is 400 micrograms, followed by 800 mcg after 1 minute. The dose can be gradually escalated up to 2 mg per dose if there is no response to the preceding dose.
It is important for healthcare professionals to have knowledge of the pharmacology and dosing schedules of these drugs in order to effectively manage respiratory and cardiac arrest situations.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 46
Incorrect
-
A 15-year-old presents to the emergency department with facial swelling and respiratory distress. Despite attempts at ventilation, it is determined that a cricothyroidotomy procedure is necessary. Which of the following statements about cricothyroidotomy is correct?
Your Answer:
Correct Answer: Involves creating an airway via the space between thyroid and cricoid cartilages
Explanation:Jet ventilation through a needle cricothyroidotomy typically involves using a 1 bar (100 Kpa) oxygen source.
Further Reading:
Cricothyroidotomy, also known as cricothyrotomy, is a procedure used to create an airway by making an incision between the thyroid and cricoid cartilages. This can be done surgically with a scalpel or using a needle method. It is typically used as a short-term solution for establishing an airway in emergency situations where traditional intubation is not possible.
The surgical technique involves dividing the cricothyroid membrane transversely, while some recommend making a longitudinal skin incision first to identify the structures below. Complications of this procedure can include bleeding, infection, incorrect placement resulting in a false passage, fistula formation, cartilage fracture, subcutaneous emphysema, scarring leading to stenosis, and injury to the vocal cords or larynx. There is also a risk of damage to the recurrent laryngeal nerve, and failure to perform the procedure successfully can lead to hypoxia and death.
There are certain contraindications to surgical cricothyroidotomy, such as the availability of less invasive airway securing methods, patients under 12 years old (although a needle technique may be used), laryngeal fracture, pre-existing or acute laryngeal pathology, tracheal transection with retraction into the mediastinum, and obscured anatomical landmarks.
The needle (cannula) cricothyroidotomy involves inserting a cannula through the cricothyroid membrane to access the trachea. This method is mainly used in children in scenarios where ENT assistance is not available. However, there are drawbacks to this approach, including the need for high-pressure oxygen delivery, which can risk barotrauma and may not always be readily available. The cannula is also prone to kinking and displacement, and there is limited evacuation of expiratory gases, making it suitable for only a short period of time before CO2 retention becomes problematic.
In children, the cannula cricothyroidotomy and ventilation procedure involves extending the neck and stabilizing the larynx, inserting a 14g or 16g cannula at a 45-degree angle aiming caudally, confirming the position by aspirating air through a saline-filled syringe, and connecting it to an insufflation device or following specific oxygen pressure and flow settings for jet ventilation.
If a longer-term airway is needed, a cricothyroidotomy may be converted to
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This question is part of the following fields:
- Basic Anaesthetics
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Question 47
Incorrect
-
A 52 year old male is brought into the emergency room after an accident at a construction site resulting in a severe blunt abdominal injury. The patient is experiencing hypotension. The surgical team is preparing for immediate transfer to the operating room. The consultant requests you to prepare intravenous ketamine for rapid sequence induction. What would be the appropriate initial dose of IV ketamine for this patient?
Your Answer:
Correct Answer: 1.5 mg/kg IV
Explanation:The recommended dose of ketamine for rapid sequence intubation (RSI) is typically 1.5 mg/kg administered intravenously. This dosage is commonly used in UK medical centers. According to the British National Formulary (BNF), intravenous induction doses of ketamine range from 0.5 to 2 mg/kg for longer procedures and 1 to 4.5 mg/kg for shorter procedures. Ketamine is known to cause an increase in blood pressure, making it a suitable option for individuals with hemodynamic compromise.
Further Reading:
There are four commonly used induction agents in the UK: propofol, ketamine, thiopentone, and etomidate.
Propofol is a 1% solution that produces significant venodilation and myocardial depression. It can also reduce cerebral perfusion pressure. The typical dose for propofol is 1.5-2.5 mg/kg. However, it can cause side effects such as hypotension, respiratory depression, and pain at the site of injection.
Ketamine is another induction agent that produces a dissociative state. It does not display a dose-response continuum, meaning that the effects do not necessarily increase with higher doses. Ketamine can cause bronchodilation, which is useful in patients with asthma. The initial dose for ketamine is 0.5-2 mg/kg, with a typical IV dose of 1.5 mg/kg. Side effects of ketamine include tachycardia, hypertension, laryngospasm, unpleasant hallucinations, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, nystagmus and diplopia, abnormal movements, and skin reactions.
Thiopentone is an ultra-short acting barbiturate that acts on the GABA receptor complex. It decreases cerebral metabolic oxygen and reduces cerebral blood flow and intracranial pressure. The adult dose for thiopentone is 3-5 mg/kg, while the child dose is 5-8 mg/kg. However, these doses should be halved in patients with hypovolemia. Side effects of thiopentone include venodilation, myocardial depression, and hypotension. It is contraindicated in patients with acute porphyrias and myotonic dystrophy.
Etomidate is the most haemodynamically stable induction agent and is useful in patients with hypovolemia, anaphylaxis, and asthma. It has similar cerebral effects to thiopentone. The dose for etomidate is 0.15-0.3 mg/kg. Side effects of etomidate include injection site pain, movement disorders, adrenal insufficiency, and apnoea. It is contraindicated in patients with sepsis due to adrenal suppression.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 48
Incorrect
-
You have been requested to arrange a teaching session on regional anesthesia for the recently inducted foundation doctors. Your task is to educate them about the application of Bier's block. What is the shortest duration for tourniquet placement during a Bier's block procedure?
Your Answer:
Correct Answer: 20 minutes
Explanation:The minimum cuff inflation time for Bier’s block is set at 20 minutes, while the maximum time is 45 minutes. Similarly, the minimum tourniquet time is also 20 minutes, with a maximum of 45 minutes. The purpose of the minimum tourniquet time is to allow enough time for the local anaesthetic to bind to the local tissue and prevent it from being absorbed into the bloodstream. This helps reduce the risk of systemic toxicity from the anaesthetic. After 20 minutes, the chances of experiencing this toxicity should be significantly reduced. On the other hand, the maximum tourniquet time is set at 45 minutes to minimize the risk of complications such as distal ischaemia, nerve compression, and compartment syndrome.
Further Reading:
Bier’s block is a regional intravenous anesthesia technique commonly used for minor surgical procedures of the forearm or for reducing distal radius fractures in the emergency department (ED). It is recommended by NICE as the preferred anesthesia block for adults requiring manipulation of distal forearm fractures in the ED.
Before performing the procedure, a pre-procedure checklist should be completed, including obtaining consent, recording the patient’s weight, ensuring the resuscitative equipment is available, and monitoring the patient’s vital signs throughout the procedure. The air cylinder should be checked if not using an electronic machine, and the cuff should be checked for leaks.
During the procedure, a double cuff tourniquet is placed on the upper arm, and the arm is elevated to exsanguinate the limb. The proximal cuff is inflated to a pressure 100 mmHg above the systolic blood pressure, up to a maximum of 300 mmHg. The time of inflation and pressure should be recorded, and the absence of the radial pulse should be confirmed. 0.5% plain prilocaine is then injected slowly, and the time of injection is recorded. The patient should be warned about the potential cold/hot sensation and mottled appearance of the arm. After injection, the cannula is removed and pressure is applied to the venipuncture site to prevent bleeding. After approximately 10 minutes, the patient should have anesthesia and should not feel pain during manipulation. If anesthesia is successful, the manipulation can be performed, and a plaster can be applied by a second staff member. A check x-ray should be obtained with the arm lowered onto a pillow. The tourniquet should be monitored at all times, and the cuff should be inflated for a minimum of 20 minutes and a maximum of 45 minutes. If rotation of the cuff is required, it should be done after the manipulation and plaster application. After the post-reduction x-ray is satisfactory, the cuff can be deflated while observing the patient and monitors. Limb circulation should be checked prior to discharge, and appropriate follow-up and analgesia should be arranged.
There are several contraindications to performing Bier’s block, including allergy to local anesthetic, hypertension over 200 mm Hg, infection in the limb, lymphedema, methemoglobinemia, morbid obesity, peripheral vascular disease, procedures needed in both arms, Raynaud’s phenomenon, scleroderma, severe hypertension and sickle cell disease.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 49
Incorrect
-
A 55 year old female patient is brought into the emergency department with urosepsis. It is decided to intubate her pending transfer to ITU. Your consultant requests you prepare propofol and suxamethonium for rapid sequence intubation (RSI). What is the recommended dose of suxamethonium for RSI in adults?
Your Answer:
Correct Answer: 1.5 mg/kg
Explanation:The appropriate dosage of suxamethonium for rapid sequence intubation (RSI) in adults is between 1 and 1.5 milligrams per kilogram of body weight.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 50
Incorrect
-
A 25 year old male presents to the emergency department with a significant laceration on his right forearm. You suggest that the wound can be stitched under local anesthesia. You opt to use 1% lidocaine for the procedure. The patient has a weight of 70kg. Determine the maximum amount of lidocaine 1% that can be administered.
Your Answer:
Correct Answer: 18 ml
Explanation:Lidocaine is a medication that is available in a concentration of 10 mg per milliliter. The maximum recommended dose of lidocaine is 18 milliliters.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 51
Incorrect
-
A 72 year old male presents to the emergency department after a fall on his outstretched arm. X-ray results confirm a dislocated shoulder. Your consultant recommends reducing it under sedation. What are the four essential elements for successful procedural sedation?
Your Answer:
Correct Answer: Analgesia, anxiolysis, sedation and amnesia
Explanation:The four essential elements for effective procedural sedation are analgesia, anxiolysis, sedation, and amnesia. According to the Royal College of Emergency Medicine (RCEM), it is important to prioritize pain management before sedation, using appropriate analgesics based on the patient’s pain level. Non-pharmacological methods should be considered to reduce anxiety, such as creating a comfortable environment and involving supportive family members. The level of sedation required should be determined in advance, with most procedures in the emergency department requiring moderate to deep sedation. Lastly, providing a degree of amnesia will help minimize any unpleasant memories associated with the procedure.
Further Reading:
Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.
There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.
Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.
The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.
Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.
After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 52
Incorrect
-
You are part of the team managing a pediatric trauma patient in the resuscitation room. You are assisting the attending physician who is performing rapid sequence induction. The attending physician asks you to apply cricoid pressure. What is the recommended amount of pressure that should be applied to the cricoid?
Your Answer:
Correct Answer: 30-40 Newtons
Explanation:To prevent the aspiration of gastric contents, it is recommended to apply a force of 30-40 Newtons to the cricoid cartilage during cricoid pressure.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 53
Incorrect
-
You intend to administer Midazolam to sedate a patient before reducing a dislocated shoulder. Where does the metabolism of Midazolam occur?
Your Answer:
Correct Answer: Liver
Explanation:When administering treatment to patients with hepatic impairment, it is crucial to consider that midazolam is metabolized in the liver.
Further Reading:
Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.
There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.
Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.
The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.
Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.
After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 54
Incorrect
-
You are part of the team managing a pediatric patient, your consultant asks you what the patient's Mallampati score is. What criteria is utilized to assess the Mallampati score?
Your Answer:
Correct Answer: The distance between the tongue base and the roof of the mouth
Explanation:The Mallampati score is a measure that assesses the distance between the base of the tongue and the roof of the mouth. This score is used to classify the level of airway obstruction during certain medical procedures. Please refer to the notes below for the complete classification.
Further Reading:
A difficult airway refers to a situation where factors have been identified that make airway management more challenging. These factors can include body habitus, head and neck anatomy, mouth characteristics, jaw abnormalities, and neck mobility. The LEMON criteria can be used to predict difficult intubation by assessing these factors. The criteria include looking externally at these factors, evaluating the 3-3-2 rule which assesses the space in the mouth and neck, assessing the Mallampati score which measures the distance between the tongue base and roof of the mouth, and considering any upper airway obstructions or reduced neck mobility.
Direct laryngoscopy is a method used to visualize the larynx and assess the size of the tracheal opening. The Cormack-Lehane grading system can be used to classify the tracheal opening, with higher grades indicating more difficult access. In cases of a failed airway, where intubation attempts are unsuccessful and oxygenation cannot be maintained, the immediate priority is to oxygenate the patient and prevent hypoxic brain injury. This can be done through various measures such as using a bag-valve-mask ventilation, high flow oxygen, suctioning, and optimizing head positioning.
If oxygenation cannot be maintained, it is important to call for help from senior medical professionals and obtain a difficult airway trolley if not already available. If basic airway management techniques do not improve oxygenation, further intubation attempts may be considered using different equipment or techniques. If oxygen saturations remain below 90%, a surgical airway such as a cricothyroidotomy may be necessary.
Post-intubation hypoxia can occur for various reasons, and the mnemonic DOPES can be used to identify and address potential problems. DOPES stands for displacement of the endotracheal tube, obstruction, pneumothorax, equipment failure, and stacked breaths. If intubation attempts fail, a maximum of three attempts should be made before moving to an alternative plan, such as using a laryngeal mask airway or considering a cricothyroidotomy.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 55
Incorrect
-
You are managing a 42 year old female who has been brought into the emergency department with burns and suspected inhalation injury following a house fire. Due to concerns about the patient's ability to maintain their airway it is decided to proceed with intubation and ventilation. Your initial attempt to intubate the patient fails. What is the maximum number of intubation attempts that should be made?
Your Answer:
Correct Answer: 3
Explanation:According to the guidelines of the Difficult Airway Society, it is recommended to limit intubation attempts to a maximum of three. However, if the first three attempts are unsuccessful, a more experienced colleague may make a fourth attempt. If all four attempts are unsuccessful, the intubation should be declared as a failure.
Further Reading:
A difficult airway refers to a situation where factors have been identified that make airway management more challenging. These factors can include body habitus, head and neck anatomy, mouth characteristics, jaw abnormalities, and neck mobility. The LEMON criteria can be used to predict difficult intubation by assessing these factors. The criteria include looking externally at these factors, evaluating the 3-3-2 rule which assesses the space in the mouth and neck, assessing the Mallampati score which measures the distance between the tongue base and roof of the mouth, and considering any upper airway obstructions or reduced neck mobility.
Direct laryngoscopy is a method used to visualize the larynx and assess the size of the tracheal opening. The Cormack-Lehane grading system can be used to classify the tracheal opening, with higher grades indicating more difficult access. In cases of a failed airway, where intubation attempts are unsuccessful and oxygenation cannot be maintained, the immediate priority is to oxygenate the patient and prevent hypoxic brain injury. This can be done through various measures such as using a bag-valve-mask ventilation, high flow oxygen, suctioning, and optimizing head positioning.
If oxygenation cannot be maintained, it is important to call for help from senior medical professionals and obtain a difficult airway trolley if not already available. If basic airway management techniques do not improve oxygenation, further intubation attempts may be considered using different equipment or techniques. If oxygen saturations remain below 90%, a surgical airway such as a cricothyroidotomy may be necessary.
Post-intubation hypoxia can occur for various reasons, and the mnemonic DOPES can be used to identify and address potential problems. DOPES stands for displacement of the endotracheal tube, obstruction, pneumothorax, equipment failure, and stacked breaths. If intubation attempts fail, a maximum of three attempts should be made before moving to an alternative plan, such as using a laryngeal mask airway or considering a cricothyroidotomy.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 56
Incorrect
-
A 27 year old woman is brought into the emergency department with a suspected wrist fracture after tripping at a concert. The patient has been receiving nitrous oxide during ambulance transport. The patient is informed that they can cease inhaling nitrous oxide after receiving opioid pain medication. What is the recommended course of action upon discontinuing nitrous oxide?
Your Answer:
Correct Answer: The patient should have oxygen administered for 5 minutes
Explanation:To prevent diffusion hypoxia, it is recommended to administer supplemental oxygen to patients for about 5 minutes after discontinuing nitrous oxide. This is important because there is a risk of developing diffusion hypoxia after the termination of nitrous oxide.
Further Reading:
Entonox® is a mixture of 50% nitrous oxide and 50% oxygen that can be used for self-administration to reduce anxiety. It can also be used alongside other anesthesia agents. However, its mechanism of action for anxiety reduction is not fully understood. The Entonox bottles are typically identified by blue and white color-coded collars, but a new standard will replace these with dark blue shoulders in the future. It is important to note that Entonox alone cannot be used as the sole maintenance agent in anesthesia.
One of the effects of nitrous oxide is the second-gas effect, where it speeds up the absorption of other inhaled anesthesia agents. Nitrous oxide enters the alveoli and diffuses into the blood, displacing nitrogen. This displacement causes the remaining alveolar gases to become more concentrated, increasing the fractional content of inhaled anesthesia gases and accelerating the uptake of volatile agents into the blood.
However, when nitrous oxide administration is stopped, it can cause diffusion hypoxia. Nitrous oxide exits the blood and diffuses back into the alveoli, while nitrogen diffuses in the opposite direction. Nitrous oxide enters the alveoli much faster than nitrogen leaves, resulting in the dilution of oxygen within the alveoli. This can lead to diffusion hypoxia, where the oxygen concentration in the alveoli is diluted, potentially causing oxygen deprivation in patients breathing air.
There are certain contraindications for using nitrous oxide, as it can expand in air-filled spaces. It should be avoided in conditions such as head injuries with intracranial air, pneumothorax, recent intraocular gas injection, and entrapped air following a recent underwater dive.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 57
Incorrect
-
A 28-year-old with a past of opioid misuse is brought into the ER after being discovered in a collapsed state with decreased level of consciousness. You are worried about the patient's airway. Your consultant recommends using a nasopharyngeal airway adjunct instead of an oropharyngeal airway adjunct. Why is a nasopharyngeal airway preferred in this scenario?
Your Answer:
Correct Answer: Less likely to provoke the gag reflex
Explanation:When a patient is semi-conscious, it is less likely for the nasopharyngeal airway adjuncts (NPA’s) to trigger the gag reflex compared to oropharyngeal airways. Therefore, NPA’s are typically the preferred option in these cases.
Further Reading:
Techniques to keep the airway open:
1. Suction: Used to remove obstructing material such as blood, vomit, secretions, and food debris from the oral cavity.
2. Chin lift manoeuvres: Involves lifting the head off the floor and lifting the chin to extend the head in relation to the neck. Improves alignment of the pharyngeal, laryngeal, and oral axes.
3. Jaw thrust: Used in trauma patients with cervical spine injury concerns. Fingers are placed under the mandible and gently pushed upward.
Airway adjuncts:
1. Oropharyngeal airway (OPA): Prevents the tongue from occluding the airway. Sized according to the patient by measuring from the incisor teeth to the angle of the mandible. Inserted with the tip facing backwards and rotated 180 degrees once it touches the back of the palate or oropharynx.
2. Nasopharyngeal airway (NPA): Useful when it is difficult to open the mouth or in semi-conscious patients. Sized by length (distance between nostril and tragus of the ear) and diameter (roughly that of the patient’s little finger). Contraindicated in basal skull and midface fractures.
Laryngeal mask airway (LMA):
– Supraglottic airway device used as a first line or rescue airway.
– Easy to insert, sized according to patient’s bodyweight.
– Advantages: Easy insertion, effective ventilation, some protection from aspiration.
– Disadvantages: Risk of hypoventilation, greater gastric inflation than endotracheal tube (ETT), risk of aspiration and laryngospasm.Note: Proper training and assessment of the patient’s condition are essential for airway management.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 58
Incorrect
-
A 42 year old male patient is brought into the emergency department due to a recent onset of high fever and feeling unwell that has worsened over the past day, with the patient becoming increasingly drowsy. Despite initial resuscitation efforts, there is minimal response and it is decided to intubate the patient before transferring to the intensive care unit for ventilatory and inotropic support. Your consultant requests that you apply pressure over the cricoid during the procedure. What is the reason for this?
Your Answer:
Correct Answer: Prevent aspiration of gastric contents
Explanation:Cricoid pressure is applied during intubation to compress the oesophagus and prevent the backflow of stomach contents, reducing the risk of aspiration.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 59
Incorrect
-
You are getting ready to administer Propofol to a patient for cardioversion and anticipate a potential side effect. What is a common adverse reaction associated with Propofol?
Your Answer:
Correct Answer: Hypotension
Explanation:Propofol often leads to hypotension as a common side effect. Other common side effects of Propofol include apnoea, arrhythmias, headache, and nausea with vomiting.
Further Reading:
Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.
There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.
Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.
The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.
Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.
After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 60
Incorrect
-
A 45 year old presents to the emergency department after a fall onto their outstretched left hand. An X-ray confirms a displaced fracture of the distal radius. Your consultant recommends reducing it under conscious sedation. What is the best description of conscious sedation?
Your Answer:
Correct Answer: Level of sedation where patient responds purposefully to verbal commands
Explanation:Conscious sedation involves a patient who can respond purposefully to verbal commands. It is different from deeper levels of sedation where the patient may only respond to painful stimuli or not respond at all. In conscious sedation, the patient can usually maintain their own airway and does not need assistance with breathing or cardiovascular support.
Further Reading:
Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.
There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.
Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.
The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.
Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.
After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 61
Incorrect
-
You are overseeing a patient who has been administered ketamine. You have concerns about restlessness and emergence phenomena during the recovery process. Which class of medication is commonly employed to manage emergence phenomena?
Your Answer:
Correct Answer: Benzodiazepines
Explanation:Benzodiazepines are medications that are utilized to address emergence phenomena, which are characterized by restlessness and distressing hallucinations experienced upon awakening from ketamine sedation or induction. These phenomena are more frequently observed in older children and adults, affecting approximately one out of every three adults. To manage emergence phenomena, benzodiazepines may be administered. It is important to note that the RCEM does not recommend preventive treatment and suggests addressing emergence phenomena as they arise.
Further Reading:
There are four commonly used induction agents in the UK: propofol, ketamine, thiopentone, and etomidate.
Propofol is a 1% solution that produces significant venodilation and myocardial depression. It can also reduce cerebral perfusion pressure. The typical dose for propofol is 1.5-2.5 mg/kg. However, it can cause side effects such as hypotension, respiratory depression, and pain at the site of injection.
Ketamine is another induction agent that produces a dissociative state. It does not display a dose-response continuum, meaning that the effects do not necessarily increase with higher doses. Ketamine can cause bronchodilation, which is useful in patients with asthma. The initial dose for ketamine is 0.5-2 mg/kg, with a typical IV dose of 1.5 mg/kg. Side effects of ketamine include tachycardia, hypertension, laryngospasm, unpleasant hallucinations, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, nystagmus and diplopia, abnormal movements, and skin reactions.
Thiopentone is an ultra-short acting barbiturate that acts on the GABA receptor complex. It decreases cerebral metabolic oxygen and reduces cerebral blood flow and intracranial pressure. The adult dose for thiopentone is 3-5 mg/kg, while the child dose is 5-8 mg/kg. However, these doses should be halved in patients with hypovolemia. Side effects of thiopentone include venodilation, myocardial depression, and hypotension. It is contraindicated in patients with acute porphyrias and myotonic dystrophy.
Etomidate is the most haemodynamically stable induction agent and is useful in patients with hypovolemia, anaphylaxis, and asthma. It has similar cerebral effects to thiopentone. The dose for etomidate is 0.15-0.3 mg/kg. Side effects of etomidate include injection site pain, movement disorders, adrenal insufficiency, and apnoea. It is contraindicated in patients with sepsis due to adrenal suppression.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 62
Incorrect
-
You are summoned to the resuscitation bay to provide assistance for a patient experiencing cardiac arrest. Concerning medications administered during cardiac arrest in adults, which of the following statements is accurate?
Your Answer:
Correct Answer: Adrenaline is a non-selective agonist of adrenergic receptors
Explanation:Adrenaline acts on all types of adrenergic receptors without preference. It is administered in doses of 1 mg every 3-5 minutes during cardiac arrest. On the other hand, Amiodarone functions by blocking voltage-gated potassium channels and is typically administered after the third shock.
Further Reading:
In the management of respiratory and cardiac arrest, several drugs are commonly used to help restore normal function and improve outcomes. Adrenaline is a non-selective agonist of adrenergic receptors and is administered intravenously at a dose of 1 mg every 3-5 minutes. It works by causing vasoconstriction, increasing systemic vascular resistance (SVR), and improving cardiac output by increasing the force of heart contraction. Adrenaline also has bronchodilatory effects.
Amiodarone is another drug used in cardiac arrest situations. It blocks voltage-gated potassium channels, which prolongs repolarization and reduces myocardial excitability. The initial dose of amiodarone is 300 mg intravenously after 3 shocks, followed by a dose of 150 mg after 5 shocks.
Lidocaine is an alternative to amiodarone in cardiac arrest situations. It works by blocking sodium channels and decreasing heart rate. The recommended dose is 1 mg/kg by slow intravenous injection, with a repeat half of the initial dose after 5 minutes. The maximum total dose of lidocaine is 3 mg/kg.
Magnesium sulfate is used to reverse myocardial hyperexcitability associated with hypomagnesemia. It is administered intravenously at a dose of 2 g over 10-15 minutes. An additional dose may be given if necessary, but the maximum total dose should not exceed 3 g.
Atropine is an antagonist of muscarinic acetylcholine receptors and is used to counteract the slowing of heart rate caused by the parasympathetic nervous system. It is administered intravenously at a dose of 500 mcg every 3-5 minutes, with a maximum dose of 3 mg.
Naloxone is a competitive antagonist for opioid receptors and is used in cases of respiratory arrest caused by opioid overdose. It has a short duration of action, so careful monitoring is necessary. The initial dose of naloxone is 400 micrograms, followed by 800 mcg after 1 minute. The dose can be gradually escalated up to 2 mg per dose if there is no response to the preceding dose.
It is important for healthcare professionals to have knowledge of the pharmacology and dosing schedules of these drugs in order to effectively manage respiratory and cardiac arrest situations.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 63
Incorrect
-
A 65-year-old male patient is brought into the emergency department with suspected sepsis. It is decided to intubate the patient pending transfer to the intensive care unit (ICU). Your consultant requests you to prepare propofol and suxamethonium for rapid sequence intubation. What is the mechanism of action of suxamethonium?
Your Answer:
Correct Answer: Non-competitive agonist of acetylcholine receptors at the neuromuscular junction
Explanation:Suxamethonium, also called succinylcholine, is a type of drug used to block neuromuscular transmission. It acts as an agonist by binding to acetylcholine receptors at the neuromuscular junction. Unlike acetylcholine, suxamethonium is not broken down by acetylcholinesterase, which means it stays bound to the receptors for a longer time, leading to prolonged inhibition of neuromuscular transmission. Eventually, suxamethonium is metabolized by plasma cholinesterase.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 64
Incorrect
-
You are caring for a patient with a declining Glasgow Coma Scale (GCS) that you expect will need rapid sequence induction (RSI). You observe that the patient has a history of asthma. Which of the following induction medications is recognized for its bronchodilatory effects and would be appropriate for use in an asthmatic patient?
Your Answer:
Correct Answer: Ketamine
Explanation:When caring for a patient with a declining Glasgow Coma Scale (GCS) who may require rapid sequence induction (RSI), it is important to consider their medical history. In this case, the patient has a history of asthma. One of the induction medications that is recognized for its bronchodilatory effects and would be appropriate for use in an asthmatic patient is Ketamine.
Further Reading:
There are four commonly used induction agents in the UK: propofol, ketamine, thiopentone, and etomidate.
Propofol is a 1% solution that produces significant venodilation and myocardial depression. It can also reduce cerebral perfusion pressure. The typical dose for propofol is 1.5-2.5 mg/kg. However, it can cause side effects such as hypotension, respiratory depression, and pain at the site of injection.
Ketamine is another induction agent that produces a dissociative state. It does not display a dose-response continuum, meaning that the effects do not necessarily increase with higher doses. Ketamine can cause bronchodilation, which is useful in patients with asthma. The initial dose for ketamine is 0.5-2 mg/kg, with a typical IV dose of 1.5 mg/kg. Side effects of ketamine include tachycardia, hypertension, laryngospasm, unpleasant hallucinations, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, nystagmus and diplopia, abnormal movements, and skin reactions.
Thiopentone is an ultra-short acting barbiturate that acts on the GABA receptor complex. It decreases cerebral metabolic oxygen and reduces cerebral blood flow and intracranial pressure. The adult dose for thiopentone is 3-5 mg/kg, while the child dose is 5-8 mg/kg. However, these doses should be halved in patients with hypovolemia. Side effects of thiopentone include venodilation, myocardial depression, and hypotension. It is contraindicated in patients with acute porphyrias and myotonic dystrophy.
Etomidate is the most haemodynamically stable induction agent and is useful in patients with hypovolemia, anaphylaxis, and asthma. It has similar cerebral effects to thiopentone. The dose for etomidate is 0.15-0.3 mg/kg. Side effects of etomidate include injection site pain, movement disorders, adrenal insufficiency, and apnoea. It is contraindicated in patients with sepsis due to adrenal suppression.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 65
Incorrect
-
A 35-year-old male is brought to the emergency department with a severe head injury. Due to a decreasing Glasgow Coma Scale (GCS), it is decided to intubate him. You prepare for rapid sequence induction (RSI) and plan to use propofol as the induction agent. Which of the following statements about propofol and its impact on blood pressure is accurate?
Your Answer:
Correct Answer: Propofol causes hypotension via venodilation
Explanation:The administration of propofol can result in venodilation, leading to a significant drop in blood pressure. This effect is particularly significant in patients who are already experiencing unstable blood flow.
Further Reading:
There are four commonly used induction agents in the UK: propofol, ketamine, thiopentone, and etomidate.
Propofol is a 1% solution that produces significant venodilation and myocardial depression. It can also reduce cerebral perfusion pressure. The typical dose for propofol is 1.5-2.5 mg/kg. However, it can cause side effects such as hypotension, respiratory depression, and pain at the site of injection.
Ketamine is another induction agent that produces a dissociative state. It does not display a dose-response continuum, meaning that the effects do not necessarily increase with higher doses. Ketamine can cause bronchodilation, which is useful in patients with asthma. The initial dose for ketamine is 0.5-2 mg/kg, with a typical IV dose of 1.5 mg/kg. Side effects of ketamine include tachycardia, hypertension, laryngospasm, unpleasant hallucinations, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, nystagmus and diplopia, abnormal movements, and skin reactions.
Thiopentone is an ultra-short acting barbiturate that acts on the GABA receptor complex. It decreases cerebral metabolic oxygen and reduces cerebral blood flow and intracranial pressure. The adult dose for thiopentone is 3-5 mg/kg, while the child dose is 5-8 mg/kg. However, these doses should be halved in patients with hypovolemia. Side effects of thiopentone include venodilation, myocardial depression, and hypotension. It is contraindicated in patients with acute porphyrias and myotonic dystrophy.
Etomidate is the most haemodynamically stable induction agent and is useful in patients with hypovolemia, anaphylaxis, and asthma. It has similar cerebral effects to thiopentone. The dose for etomidate is 0.15-0.3 mg/kg. Side effects of etomidate include injection site pain, movement disorders, adrenal insufficiency, and apnoea. It is contraindicated in patients with sepsis due to adrenal suppression.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 66
Incorrect
-
You review the X-ray of a 70 year old male who has fallen onto his outstretched right hand. The X-ray confirms a dorsally displaced fracture of the distal radius. You plan to reduce the fracture using intravenous regional anesthesia (Bier's block). Which local anesthetic is first choice for this procedure?
Your Answer:
Correct Answer: Prilocaine
Explanation:According to the Royal College of Emergency Medicine (RCEM), Prilocaine is the preferred choice for intravenous regional anesthesia. This is because Bupivacaine and lidocaine have a higher risk of causing harmful side effects.
Further Reading:
Bier’s block is a regional intravenous anesthesia technique commonly used for minor surgical procedures of the forearm or for reducing distal radius fractures in the emergency department (ED). It is recommended by NICE as the preferred anesthesia block for adults requiring manipulation of distal forearm fractures in the ED.
Before performing the procedure, a pre-procedure checklist should be completed, including obtaining consent, recording the patient’s weight, ensuring the resuscitative equipment is available, and monitoring the patient’s vital signs throughout the procedure. The air cylinder should be checked if not using an electronic machine, and the cuff should be checked for leaks.
During the procedure, a double cuff tourniquet is placed on the upper arm, and the arm is elevated to exsanguinate the limb. The proximal cuff is inflated to a pressure 100 mmHg above the systolic blood pressure, up to a maximum of 300 mmHg. The time of inflation and pressure should be recorded, and the absence of the radial pulse should be confirmed. 0.5% plain prilocaine is then injected slowly, and the time of injection is recorded. The patient should be warned about the potential cold/hot sensation and mottled appearance of the arm. After injection, the cannula is removed and pressure is applied to the venipuncture site to prevent bleeding. After approximately 10 minutes, the patient should have anesthesia and should not feel pain during manipulation. If anesthesia is successful, the manipulation can be performed, and a plaster can be applied by a second staff member. A check x-ray should be obtained with the arm lowered onto a pillow. The tourniquet should be monitored at all times, and the cuff should be inflated for a minimum of 20 minutes and a maximum of 45 minutes. If rotation of the cuff is required, it should be done after the manipulation and plaster application. After the post-reduction x-ray is satisfactory, the cuff can be deflated while observing the patient and monitors. Limb circulation should be checked prior to discharge, and appropriate follow-up and analgesia should be arranged.
There are several contraindications to performing Bier’s block, including allergy to local anesthetic, hypertension over 200 mm Hg, infection in the limb, lymphedema, methemoglobinemia, morbid obesity, peripheral vascular disease, procedures needed in both arms, Raynaud’s phenomenon, scleroderma, severe hypertension and sickle cell disease.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 67
Incorrect
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A 42 year old male is brought into the resuscitation bay with multiple injuries after a roof collapse. The patient has extensive bruising on the neck and a fractured femur caused by a beam that fell and crushed his right thigh. Your consultant intends to perform rapid sequence induction (RSI) and intubation. Which of the following medications would be inappropriate for this patient?
Your Answer:
Correct Answer: Suxamethonium
Explanation:Suxamethonium is a medication that can cause an increase in serum potassium levels by causing potassium to leave muscle cells. This can be a problem in patients who already have high levels of potassium, such as those with crush injuries. Therefore, suxamethonium should not be used in these cases.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 68
Incorrect
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A 32-year-old man that has been involved in a car crash develops symptoms of acute airway blockage. You conclude that he needs to be intubated using a rapid sequence induction. You intend to use thiopental sodium as your induction medication.
What type of receptor does thiopental sodium act on to produce its effects?Your Answer:
Correct Answer: Gamma-aminobutyric acid (GABA)
Explanation:Thiopental sodium is a barbiturate with a very short duration of action. It is primarily used to induce anesthesia. Barbiturates are believed to primarily affect synapses by reducing the sensitivity of postsynaptic receptors to neurotransmitters and by interfering with the release of neurotransmitters from presynaptic neurons.
Thiopental sodium specifically binds to a unique site associated with a chloride ionophore at the GABAA receptor, which is responsible for the opening of chloride ion channels. This binding increases the length of time that the chloride ionophore remains open. As a result, the inhibitory effect of GABA on postsynaptic neurons in the thalamus is prolonged.
In summary, thiopental sodium acts as a short-acting barbiturate that is commonly used to induce anesthesia. It affects synapses by reducing postsynaptic receptor sensitivity and interfering with neurotransmitter release. By binding to a specific site at the GABAA receptor, thiopental sodium prolongs the inhibitory effect of GABA in the thalamus.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 69
Incorrect
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You are part of the resus team treating a 42-year-old female patient with a severe head injury after falling from a ladder. As the patient's GCS continues to decline, your consultant instructs you to prepare for rapid sequence induction. You gather the necessary supplies and prepare etomidate as the induction agent. Upon reviewing the patient's details, you observe that she weighs 65kg. What would be the appropriate dose of etomidate for this patient during RSI?
Your Answer:
Correct Answer: 21mg
Explanation:The recommended dose of etomidate for rapid sequence intubation (RSI) is typically 0.3mg per kilogram of body weight. For example, a patient weighing 70 kilograms would receive a dose of 21mg (70 x 0.3 = 21mg). This dosage falls within the accepted range of 0.15-0.3 mg/kg as suggested by the British National Formulary (BNF). Therefore, the only option within this range is the fourth option.
Further Reading:
There are four commonly used induction agents in the UK: propofol, ketamine, thiopentone, and etomidate.
Propofol is a 1% solution that produces significant venodilation and myocardial depression. It can also reduce cerebral perfusion pressure. The typical dose for propofol is 1.5-2.5 mg/kg. However, it can cause side effects such as hypotension, respiratory depression, and pain at the site of injection.
Ketamine is another induction agent that produces a dissociative state. It does not display a dose-response continuum, meaning that the effects do not necessarily increase with higher doses. Ketamine can cause bronchodilation, which is useful in patients with asthma. The initial dose for ketamine is 0.5-2 mg/kg, with a typical IV dose of 1.5 mg/kg. Side effects of ketamine include tachycardia, hypertension, laryngospasm, unpleasant hallucinations, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, nystagmus and diplopia, abnormal movements, and skin reactions.
Thiopentone is an ultra-short acting barbiturate that acts on the GABA receptor complex. It decreases cerebral metabolic oxygen and reduces cerebral blood flow and intracranial pressure. The adult dose for thiopentone is 3-5 mg/kg, while the child dose is 5-8 mg/kg. However, these doses should be halved in patients with hypovolemia. Side effects of thiopentone include venodilation, myocardial depression, and hypotension. It is contraindicated in patients with acute porphyrias and myotonic dystrophy.
Etomidate is the most haemodynamically stable induction agent and is useful in patients with hypovolemia, anaphylaxis, and asthma. It has similar cerebral effects to thiopentone. The dose for etomidate is 0.15-0.3 mg/kg. Side effects of etomidate include injection site pain, movement disorders, adrenal insufficiency, and apnoea. It is contraindicated in patients with sepsis due to adrenal suppression.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 70
Incorrect
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A 30-year-old woman is brought in by ambulance following a car accident where her car was struck by a truck. She has suffered severe facial injuries and shows signs of airway obstruction. Her C-spine is triple immobilized. You perform a LEMON assessment for difficult intubation.
Which of the following factors indicates a difficult intubation?Your Answer:
Correct Answer: Mallampati score of 4
Explanation:Trauma patients who require a definitively secured airway include those who are apnoeic, have a Glasgow Coma Scale score of less than 9, experience sustained seizure activity, have unstable midface trauma or airway injuries, have a large flail segment or respiratory failure, have a high risk of aspiration, or are unable to maintain an airway or oxygenation through other means.
To predict difficult intubations, the LEMON assessment can be utilized. The LEMON mnemonic provides a systematic approach to assess potential challenges in intubation. It stands for the following:
– Look externally: Examine for any characteristics that are known to cause difficult intubation or ventilation.
– Evaluate the 3-3-2 rule: Measure the incisor distance, hyoid/mental distance, and thyroid-to-mouth distance. If any of these measurements are less than the specified number of fingerbreadths, it may indicate a difficult intubation.
– Mallampati: Assess the Mallampati score, which is a classification system based on the visibility of certain structures in the mouth and throat. A score of 3 or higher suggests a difficult intubation.
– Obstruction: Check for the presence of any conditions that could potentially obstruct the airway.
– Neck mobility: Evaluate the mobility of the patient’s neck, as limited mobility may make intubation more challenging.By utilizing the LEMON assessment, healthcare providers can identify potential difficulties in securing the airway and make appropriate interventions to ensure patient safety.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 71
Incorrect
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You examine the X-ray of a 55-year-old male who has fallen onto his extended right hand. The X-ray confirms a fracture of the distal radius with dorsal displacement. Your plan is to perform a reduction of the fracture using intravenous regional anesthesia (Bier's block). While conducting the procedure, you take note of the duration of cuff inflation. What is the maximum duration the cuff should remain inflated?
Your Answer:
Correct Answer: 45 minutes
Explanation:According to the RCEM, the minimum time for cuff inflation during Bier’s block is 20 minutes, while the maximum time is 45 minutes.
Further Reading:
Bier’s block is a regional intravenous anesthesia technique commonly used for minor surgical procedures of the forearm or for reducing distal radius fractures in the emergency department (ED). It is recommended by NICE as the preferred anesthesia block for adults requiring manipulation of distal forearm fractures in the ED.
Before performing the procedure, a pre-procedure checklist should be completed, including obtaining consent, recording the patient’s weight, ensuring the resuscitative equipment is available, and monitoring the patient’s vital signs throughout the procedure. The air cylinder should be checked if not using an electronic machine, and the cuff should be checked for leaks.
During the procedure, a double cuff tourniquet is placed on the upper arm, and the arm is elevated to exsanguinate the limb. The proximal cuff is inflated to a pressure 100 mmHg above the systolic blood pressure, up to a maximum of 300 mmHg. The time of inflation and pressure should be recorded, and the absence of the radial pulse should be confirmed. 0.5% plain prilocaine is then injected slowly, and the time of injection is recorded. The patient should be warned about the potential cold/hot sensation and mottled appearance of the arm. After injection, the cannula is removed and pressure is applied to the venipuncture site to prevent bleeding. After approximately 10 minutes, the patient should have anesthesia and should not feel pain during manipulation. If anesthesia is successful, the manipulation can be performed, and a plaster can be applied by a second staff member. A check x-ray should be obtained with the arm lowered onto a pillow. The tourniquet should be monitored at all times, and the cuff should be inflated for a minimum of 20 minutes and a maximum of 45 minutes. If rotation of the cuff is required, it should be done after the manipulation and plaster application. After the post-reduction x-ray is satisfactory, the cuff can be deflated while observing the patient and monitors. Limb circulation should be checked prior to discharge, and appropriate follow-up and analgesia should be arranged.
There are several contraindications to performing Bier’s block, including allergy to local anesthetic, hypertension over 200 mm Hg, infection in the limb, lymphedema, methemoglobinemia, morbid obesity, peripheral vascular disease, procedures needed in both arms, Raynaud’s phenomenon, scleroderma, severe hypertension and sickle cell disease.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 72
Incorrect
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You assess a 16 year old with an open fracture dislocation of the ankle after a motorcycle accident. The patient has been given nitrous oxide during transportation in the ambulance. The orthopedic surgeon on call is currently in the emergency department and recommends that the injury be promptly treated in the operating room. Which of the following statements about nitrous oxide is correct?
Your Answer:
Correct Answer: Nitrous oxide administration increases the fractional content of inhaled anaesthetic gases
Explanation:The administration of nitrous oxide increases the amount of inhaled anaesthetic gases in the body through a phenomenon called the ‘second gas effect’. Nitrous oxide is much more soluble than nitrogen, with a solubility that is 20 to 30 times higher. When nitrous oxide is given, it causes a decrease in the volume of air in the alveoli. Additionally, nitrous oxide can enhance the absorption of other inhaled anaesthetic agents through the second gas effect. However, it is important to note that nitrous oxide alone cannot be used as the sole maintenance agent in anaesthesia.
Further Reading:
Entonox® is a mixture of 50% nitrous oxide and 50% oxygen that can be used for self-administration to reduce anxiety. It can also be used alongside other anesthesia agents. However, its mechanism of action for anxiety reduction is not fully understood. The Entonox bottles are typically identified by blue and white color-coded collars, but a new standard will replace these with dark blue shoulders in the future. It is important to note that Entonox alone cannot be used as the sole maintenance agent in anesthesia.
One of the effects of nitrous oxide is the second-gas effect, where it speeds up the absorption of other inhaled anesthesia agents. Nitrous oxide enters the alveoli and diffuses into the blood, displacing nitrogen. This displacement causes the remaining alveolar gases to become more concentrated, increasing the fractional content of inhaled anesthesia gases and accelerating the uptake of volatile agents into the blood.
However, when nitrous oxide administration is stopped, it can cause diffusion hypoxia. Nitrous oxide exits the blood and diffuses back into the alveoli, while nitrogen diffuses in the opposite direction. Nitrous oxide enters the alveoli much faster than nitrogen leaves, resulting in the dilution of oxygen within the alveoli. This can lead to diffusion hypoxia, where the oxygen concentration in the alveoli is diluted, potentially causing oxygen deprivation in patients breathing air.
There are certain contraindications for using nitrous oxide, as it can expand in air-filled spaces. It should be avoided in conditions such as head injuries with intracranial air, pneumothorax, recent intraocular gas injection, and entrapped air following a recent underwater dive.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 73
Incorrect
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You are managing a pediatric patient in the emergency department who needs sedation for suturing. You are considering using ketamine. What is an absolute contraindication to using ketamine in this case?
Your Answer:
Correct Answer: Aged less than 12 months
Explanation:Ketamine should not be used in children under 12 months old due to the increased risk of laryngospasm and airway complications. The Royal College of Emergency Medicine advises against using ketamine in children under 1 year old in the emergency department, and it should only be administered by experienced clinicians in children aged 5 and under. Ketamine may cause a slight increase in blood pressure and heart rate, making it a suitable option for those with low blood pressure. However, it is contraindicated in individuals with malignant hypertension (blood pressure above 180 mmHg). Please refer to the notes below for additional contraindications.
Further Reading:
Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.
There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.
Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.
The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.
Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.
After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 74
Incorrect
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A 68 year old has been brought to the emergency department by ambulance with a history of collapsing shortly after complaining of severe chest pain and difficulty breathing. It has been determined that the patient needs rapid sequence induction after pre-oxygenation. What is the best position for the patient to be in during pre-oxygenation?
Your Answer:
Correct Answer: 20-30 degrees head up tilt
Explanation:Several studies have shown that elevating the head by 20-30 degrees is beneficial for increasing oxygen levels compared to lying flat on the back.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 75
Incorrect
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You are requested to assess a 52-year-old individual who has experienced cyanosis and a severe headache after receiving a local anesthetic injection for a regional block. The junior doctor is currently collecting a venous blood sample for analysis. What would be the most suitable course of treatment in this case?
Your Answer:
Correct Answer: IV methylene blue 1-2 mg/kg over 5 mins
Explanation:If a patient is critically ill and shows symptoms highly indicative of methemoglobinemia, treatment may be started before the blood results are available.
Bier’s block is a regional intravenous anesthesia technique commonly used for minor surgical procedures of the forearm or for reducing distal radius fractures in the emergency department (ED). It is recommended by NICE as the preferred anesthesia block for adults requiring manipulation of distal forearm fractures in the ED.
Before performing the procedure, a pre-procedure checklist should be completed, including obtaining consent, recording the patient’s weight, ensuring the resuscitative equipment is available, and monitoring the patient’s vital signs throughout the procedure. The air cylinder should be checked if not using an electronic machine, and the cuff should be checked for leaks.
During the procedure, a double cuff tourniquet is placed on the upper arm, and the arm is elevated to exsanguinate the limb. The proximal cuff is inflated to a pressure 100 mmHg above the systolic blood pressure, up to a maximum of 300 mmHg. The time of inflation and pressure should be recorded, and the absence of the radial pulse should be confirmed. 0.5% plain prilocaine is then injected slowly, and the time of injection is recorded. The patient should be warned about the potential cold/hot sensation and mottled appearance of the arm. After injection, the cannula is removed and pressure is applied to the venipuncture site to prevent bleeding. After approximately 10 minutes, the patient should have anesthesia and should not feel pain during manipulation. If anesthesia is successful, the manipulation can be performed, and a plaster can be applied by a second staff member. A check x-ray should be obtained with the arm lowered onto a pillow. The tourniquet should be monitored at all times, and the cuff should be inflated for a minimum of 20 minutes and a maximum of 45 minutes. If rotation of the cuff is required, it should be done after the manipulation and plaster application. After the post-reduction x-ray is satisfactory, the cuff can be deflated while observing the patient and monitors. Limb circulation should be checked prior to discharge, and appropriate follow-up and analgesia should be arranged.
There are several contraindications to performing Bier’s block, including allergy to local anesthetic, hypertension over 200 mm Hg, infection in the limb, lymphedema, methemoglobinemia, morbid obesity, peripheral vascular disease, procedures needed in both arms, Raynaud’s phenomenon, scleroderma, severe hypertension and sickle cell disease.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 76
Incorrect
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What is the main pharmacological factor that influences the speed of onset for local anaesthetic agents, resulting in a rapid onset of action?
Your Answer:
Correct Answer: Lipid Solubility
Explanation:The speed at which local anesthetics take effect is primarily determined by their lipid solubility. The onset of action is directly influenced by how well the anesthetic can dissolve in lipids, which is in turn related to its pKa value. A higher lipid solubility leads to a faster onset of action. The pKa value, which represents the acid-dissociation constant, is an indicator of lipid solubility. An anesthetic agent with a pKa value closer to 7.4 is more likely to be highly lipid soluble.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 77
Incorrect
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A 35 year old female trauma patient is being treated in the resus. It is decided to administer intravenous ketamine for rapid sequence induction, and your consultant requests you to prepare the medication. What is a frequently observed side effect of ketamine?
Your Answer:
Correct Answer: Nystagmus
Explanation:Ketamine administration can lead to various side effects, including nystagmus and diplopia. Other potential side effects include tachycardia, hypertension, laryngospasm, unpleasant hallucinations or emergence phenomena, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, and abnormal tonic-clonic movements.
Further Reading:
There are four commonly used induction agents in the UK: propofol, ketamine, thiopentone, and etomidate.
Propofol is a 1% solution that produces significant venodilation and myocardial depression. It can also reduce cerebral perfusion pressure. The typical dose for propofol is 1.5-2.5 mg/kg. However, it can cause side effects such as hypotension, respiratory depression, and pain at the site of injection.
Ketamine is another induction agent that produces a dissociative state. It does not display a dose-response continuum, meaning that the effects do not necessarily increase with higher doses. Ketamine can cause bronchodilation, which is useful in patients with asthma. The initial dose for ketamine is 0.5-2 mg/kg, with a typical IV dose of 1.5 mg/kg. Side effects of ketamine include tachycardia, hypertension, laryngospasm, unpleasant hallucinations, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, nystagmus and diplopia, abnormal movements, and skin reactions.
Thiopentone is an ultra-short acting barbiturate that acts on the GABA receptor complex. It decreases cerebral metabolic oxygen and reduces cerebral blood flow and intracranial pressure. The adult dose for thiopentone is 3-5 mg/kg, while the child dose is 5-8 mg/kg. However, these doses should be halved in patients with hypovolemia. Side effects of thiopentone include venodilation, myocardial depression, and hypotension. It is contraindicated in patients with acute porphyrias and myotonic dystrophy.
Etomidate is the most haemodynamically stable induction agent and is useful in patients with hypovolemia, anaphylaxis, and asthma. It has similar cerebral effects to thiopentone. The dose for etomidate is 0.15-0.3 mg/kg. Side effects of etomidate include injection site pain, movement disorders, adrenal insufficiency, and apnoea. It is contraindicated in patients with sepsis due to adrenal suppression.
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This question is part of the following fields:
- Basic Anaesthetics
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Question 78
Incorrect
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You have just performed rapid sequence induction using ketamine and rocuronium and placed an endotracheal tube under consultant supervision. What is the time interval from administration of rocuronium to the onset of paralysis?
Your Answer:
Correct Answer: 45-60 seconds
Explanation:Both suxamethonium and rocuronium take approximately 45-60 seconds to induce paralysis. The time it takes for rocuronium to cause paralysis is similar to that of suxamethonium, which is also around 45-60 seconds.
Further Reading:
Rapid sequence induction (RSI) is a method used to place an endotracheal tube (ETT) in the trachea while minimizing the risk of aspiration. It involves inducing loss of consciousness while applying cricoid pressure, followed by intubation without face mask ventilation. The steps of RSI can be remembered using the 7 P’s: preparation, pre-oxygenation, pre-treatment, paralysis and induction, protection and positioning, placement with proof, and post-intubation management.
Preparation involves preparing the patient, equipment, team, and anticipating any difficulties that may arise during the procedure. Pre-oxygenation is important to ensure the patient has an adequate oxygen reserve and prolongs the time before desaturation. This is typically done by breathing 100% oxygen for 3 minutes. Pre-treatment involves administering drugs to counter expected side effects of the procedure and anesthesia agents used.
Paralysis and induction involve administering a rapid-acting induction agent followed by a neuromuscular blocking agent. Commonly used induction agents include propofol, ketamine, thiopentone, and etomidate. The neuromuscular blocking agents can be depolarizing (such as suxamethonium) or non-depolarizing (such as rocuronium). Depolarizing agents bind to acetylcholine receptors and generate an action potential, while non-depolarizing agents act as competitive antagonists.
Protection and positioning involve applying cricoid pressure to prevent regurgitation of gastric contents and positioning the patient’s neck appropriately. Tube placement is confirmed by visualizing the tube passing between the vocal cords, auscultation of the chest and stomach, end-tidal CO2 measurement, and visualizing misting of the tube. Post-intubation management includes standard care such as monitoring ECG, SpO2, NIBP, capnography, and maintaining sedation and neuromuscular blockade.
Overall, RSI is a technique used to quickly and safely secure the airway in patients who may be at risk of aspiration. It involves a series of steps to ensure proper preparation, oxygenation, drug administration, and tube placement. Monitoring and post-intubation care are also important aspects of RSI.
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This question is part of the following fields:
- Basic Anaesthetics
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