The possible causes of post-operative pneumothorax after thoracotomy and esophagectomy include lung parenchymal leak/injury, bronchopleural fistula, ruptured bullae and malpositioned chest drains. When suction is applied to the chest drainage system, active and persistent bubbling may be seen. Although an anastomotic leak may produce a small pneumothorax, a large volume air leak is more indicative of lung injury.

Repair of an inguinal hernia under local anaesthesia has a short operative time, and patients are usually ambulant immediately after. Furthermore, the family history of this patient is unlikely to be significant and therefore, he is at a very low risk of developing a pulmonary embolism (PE).

Deep vein thrombosis (DVT) may develop insidiously in many surgical patients. If left untreated, it may progress to PE. The following surgical patients are at increased risk of developing DVT:

1. Surgery greater than 90 minutes at any site or greater than 60 minutes if the procedure involves lower limbs or pelvis
2. Acute admissions with inflammatory process involving the abdominal cavity
3. Expected significant reduction in mobility
4. Age over 60 years
5. Known malignancy
6. Thrombophilia
7. Previous thrombosis
8. BMI >30 kg/m2
9. Taking hormone replacement therapy or contraceptive pills
10. Varicose veins with phlebitis

Thromboprophylaxis can be mechanical or therapeutic. The former includes:
1. Early ambulation after surgery: cheap and effective
2. Compression stockings (contraindicated in peripheral arterial disease)
3. Intermittent pneumatic compression devices
4. Foot impulse devices

Therapeutic agents for thromboprophylaxis are:
1. Low-molecular-weight heparin (LMWH)
2. Unfractionated heparin
3. Dabigatran

Nasal injuries can be challenging to manage and where there is tissue loss, it can be difficult to primarily close them and obtain a satisfactory aesthetic result. Debridement together with a rotational skin flap would produce the best results.

A rotation flap is a semi-circular skin flap that is rotated into the defect on a fulcrum point. It provides the ability to mobilize large areas of tissue with a wide vascular base for reconstruction. Rotation flaps may be pedicled or free. Pedicled flaps are more reliable but are limited in the range of movement. Free flaps have increased range but carry greater risk of breakdown as they require vascular anastomosis.

The patient suffers from hyperkalaemia as an adverse effect of RBCs transfusion, which causes his ECG changes.
The potassium concentration of blood increases during storage, by as much as 5–10 mmol u−1. After the transfusion, the RBC membrane Na+–K+ ATPase pumping mechanism is re-established and cellular potassium reuptake occurs rapidly. Hyperkalaemia rarely occurs during massive transfusions unless the patient is also hypothermic and acidotic.
The total extracellular potassium load, which is <0.5 mmol for fresh RBC units and only 5-7 mmol for units at expiration, rarely causes problems in the recipient because of rapid dilution, redistribution into cells, and excretion. An abnormally high potassium level (>5 mmol/l or ≥1.5 mmol/l net increase) within an hour of transfusion is classified as transfusion-associated hyperkalaemia.
Irradiation enhances potassium leakage.

Answer: 6

Eye Opening Response
Spontaneous–open with blinking at baseline – 4 points
Opens to verbal command, speech, or shout – 3 points
Opens to pain, not applied to face – 2 point
None – 1 point

Verbal Response
Oriented – 5 points
Confused conversation, but able to answer questions – 4 points
Inappropriate responses, words discernible – 3 points
Incomprehensible speech – 2 points
None – 1 point

Motor Response
Obeys commands for movement – 6 points
Purposeful movement to painful stimulus – 5 points
Withdraws from pain – 4 points
Abnormal (spastic) flexion, decorticate posture – 3 points
Extensor (rigid) response, decerebrate posture – 2 points
None – 1 point

He opens his eyes to pain and groans or grunts. He extends his hands at the elbow on application of painful stimulus. This gives him a Glasgow score of 6: eye opening response of 2, verbal response 2 and motor response 2.

Perihepatic packing is a surgical procedure used in connection with surgery to the liver. In this procedure the liver is packed to stop non arterial bleeding, most often caused by liver injury.

During this surgery laparotomy pads are placed around the site of the bleeding. The main purpose of hepatic packing is to prevent the person from succumbing to the trauma triad of death. Under- or over-packing of the liver can cause adverse outcomes, and if the bleeding cannot be controlled through this surgical method, the Pringle manoeuvre is an alternate technique that can be utilized.

Rebleeding, constant decline of haemoglobin and increased transfusion requirement, as well as the failure of angioembolization of actively bleeding vessels are a few factors which indicate the need for laparotomy.

The operative approach has also evolved over the last two decades. Direct suture ligation of the parenchymal bleeding vessel, perihepatic packing, repair of venous injury under total vascular isolation and damage control surgery with utilization of preoperative and/or postoperative angioembolization are the preferred methods, compared to anatomical resection of the liver and use of the atriocaval shunt.

Answer: Yersinia enterocolitica

Yersinia enterocolitica (see the image below) is a bacterial species in the family Enterobacteriaceae that most often causes enterocolitis, acute diarrhoea, terminal ileitis, mesenteric lymphadenitis, and pseudo appendicitis but, if it spreads systemically, can also result in fatal sepsis. Symptoms of Y enterocolitica infection typically include the following:

Diarrhoea – The most common clinical manifestation of this infection; diarrhoea may be bloody in severe cases

Low-grade fever

Abdominal pain – May localize to the right lower quadrant

Vomiting – Present in approximately 15-40% of cases

Mesenteric adenitis, mesenteric ileitis, and acute pseudo appendicitis
These manifestations are characterized by the following symptoms (although nausea, vomiting, diarrhoea, and aphthous ulcers of the mouth can also occur):

Fever

Abdominal pain

Tenderness of the right lower quadrant

Leucocytosis

Pseudo appendicitis syndrome is more common in older children and young adults. Patients with Y enterocolitica infection often undergo appendectomy; several Scandinavian studies suggested a prevalence rate of 3.8-5.6% for infection with Y enterocolitica in patients with suspected appendicitis.

Analysis of several common-source outbreaks in the United States found that 10% of 444 patients with symptomatic, undiagnosed Y enterocolitica infection underwent laparotomy for suspected appendicitis.

Human clinical Y enterocolitica infections ensue after ingestion of the microorganisms in contaminated food or water or by direct inoculation through blood transfusion.

Y enterocolitica is potentially transmitted by contaminated unpasteurized milk and milk products, raw pork, tofu, meats, oysters, and fish. Outbreaks have been associated with raw vegetables; the surface of vegetables can become contaminated with pathogenic microorganisms through contact with soil, irrigation water, fertilizers, equipment, humans, and animals.

Pasteurized milk and dairy products can also cause outbreaks because Yersinia can proliferate at refrigerated temperatures.

Animal reservoirs of Y enterocolitica include swine (principle reservoir), dogs, cats, cows, sheep, goats, rodents, foxes, porcupines, and birds.

Reports of person-to-person spread are conflicting and are generally not observed in large outbreaks. Transmission via blood products has occurred, however, and infection can be transmitted from mother to new-born infant. Faecal-oral transmission among humans has not been proven.

Answer: Rupture of the aorta distal to the left subclavian artery

Aortic rupture is typically the result of a blunt aortic injury in the context of rapid deceleration. After traumatic brain injury, blunt aortic rupture is the second leading cause of death following blunt trauma. Thus, this condition is commonly fatal as blood in the aorta is under great pressure and can quickly escape the vessel through a tear, resulting in rapid haemorrhagic shock, exsanguination, and death.
Traumatic aortic transection or rupture is associated with a sudden and rapid deceleration of the heart and the aorta within the thoracic cavity. Anatomically, the heart and great vessels (superior vena cava, inferior vena cava, pulmonary arteries, pulmonary veins, and aorta) are mobile within the thoracic cavity and not fixed to the chest wall, unlike the descending abdominal aorta. Injury to the aorta during a sudden deceleration commonly originates near the terminal section of the aortic arch, also known as the isthmus. This portion lies just distal to the take-off of the left subclavian artery at the intersection of the mobile and fixed portions of the aorta.

In a surgical patient, hepatic dysfunction translates into an increased risk of infection, haemorrhage, thrombosis, and a prolonged half-life of numerous drugs (e.g., opioids and benzodiazepines). The associated imbalance of neuroendocrine mediators (e.g., vasopressin, renin-angiotensin-aldosterone system, and nitric oxide) also potentiates sodium and fluid retention, resulting in a background hyperdynamic circulation with splanchnic venous congestion and systemic vasodilation.
In emergency surgery, stress response to the underlying condition, anaesthesia, and surgical trauma increase the risk of hepatic decompensation and associated multi-system failure. Changes in hepatic perfusion with shock and fluid shifts further compromise hepatocellular synthetic and excretory functions. In addition, endotoxemia from gram-negative sepsis potentiates platelet aggregation and creates a state of low-grade disseminated intravascular coagulation.
Activation of the renin-angiotensin-aldosterone system with hypersecretion of vasopressin acts as compensatory mechanisms to preserve arterial pressure and replenish effective circulating volume when blood is pooled in the splanchnic territory. With the progression of cirrhosis, avidity for water and sodium increases, and dilutional hyponatremia results from water retention. In advanced cases, exacerbation of these abnormalities leads to hepatorenal syndrome (HRS). HRS is characterized by a rapid decline in renal function with low urinary excretion of sodium due to severe renal vasoconstriction and diminished or absent cortical perfusion. This syndrome is potentially reversible but carries an extremely poor prognosis.

Owing to raised intra-abdominal pressure due to ascites and muscle weakness from decreased muscle mass and malnutrition, umbilical and inguinal hernia incidence is higher in patients with cirrhosis.
If the patient with cirrhosis has umbilical hernia with obstructive symptoms such as intermittent incarceration or trophic skin changes, surgical repair should be considered.

Euvolemia and electrolyte homeostasis should be maintained under strict clinical and laboratory monitoring. Acute kidney injury in the absence of hemodynamic instability, use of nephrotoxic drugs, or parenchymal renal disease suggests the diagnosis of hepatorenal syndrome. Additional diagnostic criteria include no improvement in renal function after volume expansion with albumin and diuretic withdrawal. Treatment of hepatorenal syndrome requires the use of splanchnic vasoconstrictors (terlipressin, noradrenalin, or midodrine) and albumin infusion. Improved renal function has been demonstrated with medical treatment, but a mortality benefit is only ultimately achieved with liver transplantation. TIPS placement and renal and hepatic replacement therapies can be indicated as bridging strategies.

Since TPN solutions irritate the veins, they are best administered via a central line. The femoral route has a higher incidence of line-associated sepsis and is, thus, best avoided in this setting.

The National Institute for Health and Care Excellence (NICE) has laid down guidelines for identifying patients as malnourished or at risk of malnourishment, in order to start oral, enteral, or parenteral nutrition support, alone or in combination.

Following patients are identified as malnourished:
1. BMI <18.5 kg/m2
2. Unintentional weight loss of >10% within the last 3–6 months
3. BMI <20 kg/m2 and unintentional weight loss of >5% within the last 3–6 months

Following patients are at risk of malnutrition:
1. Eaten nothing or little for >5 days and/or likely to eat little or nothing for the next 5 days or longer
2. Poor absorptive capacity and/or
3. High nutrient loss and/or
4. High metabolic rate

Considering the method of parenteral nutrition:
1. For feeding <14 days, consider feeding via a peripheral venous catheter
2. For feeding >30 days, use a tunnelled subclavian line,
continuous administration in severely unwell patients
3. If feed needed for >2 weeks, consider changing from continuous to cyclical feeding
4. Do not give >50% of daily regime to unwell patients in the first 24–48 hours
5. In surgical patients, if malnourished with unsafe swallow or a non-functional GI tract or perforation, consider perioperative parenteral feeding.

Answer: Clostridium perfringens

Clostridium perfringens (C. perfringens) is a spore-forming gram-positive bacterium that is found in many environmental sources as well as in the intestines of humans and animals. C. perfringens is commonly found on raw meat and poultry. It prefers to grow in conditions with very little or no oxygen, and under ideal conditions can multiply very rapidly. Some strains of C. perfringens produce a toxin in the intestine that causes illness.
Beef, poultry, gravies, and dried or pre-cooked foods are common sources of C. perfringens infections. C. perfringens infection often occurs when foods are prepared in large quantities and kept warm for a long time before serving. Outbreaks often happen in institutions, such as hospitals, school cafeterias, prisons, and nursing homes, or at events with catered food.
People infected with C. perfringens develop diarrhoea and abdominal cramps within 6 to 24 hours (typically 8 to 12 hours). The illness usually begins suddenly and lasts for less than 24 hours. People infected with C. perfringens usually do not have fever or vomiting. The illness is not passed from one person to another.
Although C. perfringens may live normally in the human intestine, illness is caused by eating food contaminated with large numbers of C. perfringens bacteria that produce enough toxin in the intestines to cause illness.

C. perfringens can survive high temperatures. During cooling and holding of food at temperatures from 54°F–140°F (12°C–60°C), the bacteria grows. It can grow very rapidly between 109°F–117°F (43°C–47°C). If the food is served without reheating to kill the bacteria, live bacteria may be eaten. The bacteria produce a toxin inside the intestine that causes illness.

In 1–10% of all patients with acute middle cerebral artery occlusion, the subsequent ischemic stroke can be classified as “malignant,” defined by ischemic brain tissue large enough to cause a considerable increase of ICP and potential cerebral herniation.
Clinically, the patients present with severe hemispheric symptoms including hemiparesis or hemiplegia, loss of visual field, gaze deviation and, depending on the affected hemisphere, neglect or aphasia. Patients may also show an impaired level of consciousness, nausea, vomiting, papillary changes and papilledema as signs of increased ICP.
Decompressive craniectomy is the only therapeutic approach that is based on data of large randomized controlled trials in this condition. Decompressive craniectomy reduces the mortality rate in these patients, however leaving the majority of patients with at least some disability. Other treatment options like osmotherapy may be used in an individual risk-benefit-assessment, but evidence for these treatments and procedures is scarce.

Patient-controlled analgesia (PCA) is a delivery system with which patients self-administer predetermined doses of analgesic medication to relieve their pain. The use of PCA in hospitals has been increasing because of its proven advantages over conventional intramuscular injections. These include improved pain relief, greater patient satisfaction, less sedation and fewer postoperative complications.

Acute respiratory distress syndrome (ARDS) is an inflammatory process in the lungs that induces non-hydrostatic protein-rich pulmonary oedema. The immediate consequences are profound hypoxemia, decreased lung compliance, and increased intrapulmonary shunt and dead space. The clinicopathological aspects include severe inflammatory injury to the alveolar-capillary barrier, surfactant depletion, and loss of aerated lung tissue.

The most recent definition of ARDS, the Berlin definition, was proposed by a working group under the aegis of the European Society of Intensive Care Medicine. It defines ARDS by the presence within 7 days of a known clinical insult or new or worsening respiratory symptoms of a combination of acute hypoxemia (PaO2/FiO2 ≤ 300 mmHg), in a ventilated patient with a positive end-expiratory pressure (PEEP) of at least 5 cmH2O, and bilateral opacities not fully explained by heart failure or volume overload i.e. the heart pressure is norma. The Berlin definition uses the PaO2/FiO2 ratio to distinguish mild ARDS (200 < PaO2/FiO2 ≤ 300 mmHg), moderate ARDS (100 < PaO2/FiO2 ≤ 200 mmHg), and severe ARDS (PaO2/FiO2 ≤ 100 mmHg).
Most cases of ARDS in adults are associated with pulmonary sepsis (46 percent) or nonpulmonary sepsis (33 percent). Risk factors include those causing direct lung injury (e.g., pneumonia, inhalation injury, pulmonary contusion) and those causing indirect lung injury (e.g., nonpulmonary sepsis, burns, transfusion-related acute lung injury)

Most patients with ARDS need sedation, intubation, and ventilation while the underlying injury is treated. Any ventilator mode may be used, according to the Surviving Sepsis Clinical Practice Guideline and the National Heart, Lung, and Blood Institute’s ARDS Network (ARDSNet). Respiratory rate, expiratory time, positive end-expiratory pressure, and FiO2 are set following ARDSNet protocols. Settings are adjusted to maintain an oxygen saturation of 88 to 95 percent and a plateau pressure of 30 cm H2O or less to avoid barotrauma. Clinical practice guidelines recommend maintaining an arterial pH of 7.30 to 7.45, although patients in some research trials have tolerated permissive hypercapnia and a pH as low as 7.15

Airway obstruction: In the first 24 hours it is most likely from a compressive hematoma. After 24 hours consider laryngeal dysfunction secondary to hypocalcaemia.
In this patient, the most likely cause is a haematoma.
Definitive therapy is opening the surgical incision to evacuate the hematoma. Re-intubation may be lifesaving for persistent airway obstruction. Consider awake fibreoptic intubation.

Birds, with their broad geographic ranges and close association with humans, have historically played an important role as carriers of human disease and as reservoirs for drug-resistant bacteria.
The highest diversity of bacteria were found on birds in natural habitats. The most frequently reported bacteria were Escherichia coli, Salmonella enterica, and Campylobacter jejuni. Of the bacteria species reported, 54% have shown pathogenicity toward humans. Percentage-wise, more pathogens were found in tropical (vs. temperate) habitats and natural (vs. suburban, urban, or agricultural) habitats.

Campylobacter jejuni is usually the most common cause of community-acquired inflammatory enteritis.

The symptoms and severity of the gastroenteritis produced can vary.
Patients may have a history of ingestion of inadequately cooked poultry, unpasteurized milk, or untreated water. The incubation period is 1-7 days and is probably related to the dose of organisms ingested.
A brief prodrome of fever, headache, and myalgias lasting up to 24 hours is followed by crampy abdominal pain, fever as high as 40°C, and as many as 10 watery, frequently bloody, bowel movements per day. Fever, which develops in more than 90% of patients, maybe low or high grade and can persist for a week.
Patients with C jejuni infection who report vomiting, bloody diarrhoea, or both tend to have a long illness and require hospital admission.
Abdominal pain and tenderness may be localized. Pain in the right lower quadrant may mimic acute appendicitis (pseudo appendicitis).
Tenesmus occurs in approximately 25% of patients.

The diagnosis for this case is acute haemolytic transfusion reaction, due to ABO incompatibility. Haemolysis of the transfused cells can cause loin pain, shock, and hemoglobinemia, which may subsequently lead to disseminated intravascular coagulation. A direct Coombs test should confirm haemolysis. Other tests include unconjugated bilirubin, haptoglobin, serum and urine free haemoglobin.

Delayed haemolytic reactions, however, are normally associated with antibodies to the Rh system and occur 5–10 days after transfusion.

Acute transfusion reactions present during or within 24 hours of a blood transfusion. The most frequent clinical features are fever, chills, pruritus, or urticaria, which typically resolve, promptly, without specific treatment or complications. Other signs occurring in temporal relationship with a blood transfusion such as severe dyspnoea, pyrexia, or loss of consciousness may be the first indication of a more severe, potentially fatal reaction. Transfusion reactions may be immune-mediated or non-immune-mediated.

According to the ECS Guidelines 2019, Multidetector Computed tomographic pulmonary angiography (CTPA) is the method of choice for imaging the pulmonary vasculature in patients with suspected PE. It allows adequate visualization of the pulmonary arteries down to the subsegmental level.112–114 The Prospective Investigation On Pulmonary Embolism Diagnosis (PIOPED) II study observed a sensitivity of 83% and a specificity of 96% for (mainly four-detector) CTPA in PE diagnosis.

D-dimer levels are elevated in plasma in the presence of acute thrombosis because of simultaneous activation of coagulation and fibrinolysis. The negative predictive value of D-dimer testing is high, and a normal D-dimer level renders acute PE or DVT unlikely. On the other hand, the positive predictive value of elevated D-dimer levels is low and D-dimer testing is not useful for confirmation of PE.

A pressure of 10 mmHg should be set on the gas insufflation system.

Laparoscopic surgery may be performed in a number of body cavities. In some areas, irrigation solutions are preferred. In the abdomen, however, insufflation with carbon dioxide gas is commonly used. The amount of gas delivered is adjusted to maintain a constant intra-abdominal pressure of 12–15 mmHg. Excessive intra-abdominal pressure may reduce venous return and lead to hypotension. Too little insufflation will risk obscuring the surgical view.

Answer: Infection with Staphylococcus aureus

Surgical site infections (SSIs) are among the most common healthcare-associated infections, and contribute significantly to patient morbidity and healthcare costs. Staphylococcus aureus is the most common microbial cause. The epidemiology of S. aureus is changing with the dissemination of newer clones and the emergence of mupirocin resistance. Pre-operative screening, using culture- or molecular-based methods, and subsequent decolonization of patients who are positive for methicillin-susceptible S. aureus and methicillin-resistant S. aureus (MRSA) reduces SSIs and hospital stay. This applies especially to major clean surgery, such as cardiothoracic and orthopaedic, involving the insertion of implanted devices. However, it requires a multi-disciplinary approach coupled with patient education. Universal decolonization pre-operatively without screening for S. aureus may compromise the capacity to monitor for the emergence of new clones of S. aureus, contribute to mupirocin resistance, and prevent the adjustment of surgical prophylaxis for MRSA (i.e. replacement of a beta-lactam agent with a glycopeptide or alternative).

A surgical site infection is an infection that occurs after surgery in the part of the body where the surgery took place. Surgical site infections can sometimes be superficial infections involving the skin only. Other surgical site infections are more serious and can involve tissues under the skin, organs, or implanted material.

Symptoms include:
Redness and pain around the area where you had surgery
Drainage of cloudy fluid from your surgical wound
Fever

Answer: Escharotomy

Escharotomy is the surgical division of the nonviable eschar, which allows the cutaneous envelope to become more compliant. Hence, the underlying tissues have an increased available volume to expand into, preventing further tissue injury or functional compromise.

Full-thickness circumferential and near-circumferential skin burns result in the formation of a tough, inelastic mass of burnt tissue (eschar). The eschar, by virtue of this inelasticity, results in the burn-induced compartment syndrome. This is caused by the accumulation of extracellular and extravascular fluid within confined anatomic spaces of the extremities or digits. The excessive fluid causes the intracompartmental pressures to increase, resulting in collapse of the contained vascular and lymphatic structures and, hence, loss of tissue viability. The capillary closure pressure of 30 mm Hg, also measured as the compartment pressure, is accepted as that which requires intervention to prevent tissue death.

The circumferential eschar over the torso can lead to significant compromise of chest wall excursions and can hinder ventilation. Abdominal compartment syndrome with visceral hypoperfusion is associated with severe burns of the abdomen and torso. (A literature review by Strang et al found the prevalence of abdominal compartment syndrome in severely burned patients to be 4.1-16.6%, with the mean mortality rate for this condition in these patients to be 74.8%). Similarly, airway patency and venous return may be compromised by circumferential burns involving the neck.

Performing an escharotomy will therefore improve ventilation.

Twisting or rotational injuries to the knee in sports, followed by delayed onset of knee swelling and locking are strongly suggestive of a meniscal tear. Arthroscopic meniscectomy is the usual treatment.

Meniscal tear is one of the most common knee injuries, characterized by:
1. A popping sensation
2. Delayed swelling or stiffness of the affected knee
3. Pain, especially when twisting or rotating the knee
4. Difficulty straightening the knee fully
5. Locking of knee in place (patient may be able to unlock the knee)

In older adults, degenerative changes of the knee can also contribute to a torn meniscus with little or no trauma.

A torn meniscus may lead to knee instability, inability to move the knee normally, or persistent/recurrent knee pain. There is a strong likelihood of developing osteoarthritis in the injured knee.

Scalp wounds often bleed and the addition of adrenaline is, therefore, desirable. Lignocaine is fast acting and the preferred agent for local anaesthesia.

Lignocaine, also called lidocaine, is a local anaesthetic and a less commonly used antiarrhythmic. Its increased doses may be used when combined with adrenaline to limit systemic absorption. Adrenaline may be added to local anaesthetic drugs. It prolongs the duration of action at the site of injection and permits usage of higher doses. It is, however, contraindicated in patients taking monoamine oxidase inhibitors or tricyclic antidepressants.

Other listed options are ruled out in this case because:
1. Bupivacaine: has a much longer duration of action than lignocaine and, thus, may be used for topical wound infiltration at the conclusion of surgical procedures.
2. Prilocaine: the agent of choice for intravenous regional anaesthesia.

There is strong evidence to support haemostatic resuscitation in the setting of massive haemorrhage due to trauma. This advocates the use of 1:1:1 ratio.

Uncontrolled haemorrhage accounts for up to 39% of all trauma-related deaths. In the UK, approximately 2% of all trauma patients need massive transfusion. Massive transfusion is defined as the replacement of a patient’s total blood volume in less than 24 hours or the acute administration of more than half the patient’s estimated blood volume per hour. During acute bleeding, the practice of haemostatic resuscitation has been shown to reduce mortality rates. It is based on the principle of transfusion of blood components in fixed ratios. For example, packed red cells, FFP, and platelets are administered in a ratio of 1:1:1.

Bacteroides species are anaerobic bacteria that are predominant components of the bacterial florae of mucous membranes and are therefore a common cause of endogenous infections. Bacteroides infections can develop in all body sites, including the CNS, the head, the neck, the chest, the abdomen, the pelvis, the skin, and the soft tissues. Inadequate therapy against these anaerobic bacteria may lead to clinical failure.

These bacteria are resistant to penicillins, mostly through the production of beta-lactamase. Anaerobic bacteria can infect deep wounds, deep tissues, and internal organs where there is little oxygen. These infections are characterized by abscess formation, foul-smelling pus, and tissue destruction. Anaerobes outnumber aerobes by 1000:1 in the large intestine; thus, they play an important role in almost all intra-abdominal infections.

Secondary peritonitis and abdominal abscesses generally occur after entry of enteric organisms into the peritoneal cavity through perforation of the intestine or other viscus as a result of obstruction, infarction, or trauma.

Most visceral abscesses (e.g., hepatic), chronic cholecystitis, perforated and gangrenous appendicitis, postoperative wound infections and abscesses, diverticulitis, and any infection associated with faecal contamination of the abdominal cavity involve both aerobes and anaerobes.

Vomiting usually results in hypokalaemia, and hyponatremia would least likely occur as a result of it. Hyponatremia is a common postoperative finding among patients and hence serum sodium must be carefully monitored. Addison disease, SIADH, diuretic therapy can all cause hyponatremia.

Answer: They should be placed first on the operating list whenever possible

Patients with diet controlled diabetes are all
suitable for day case surgery if the procedure itself
is suitable for day surgery and all other criteria are
fulfilled.
People with diabetes controlled by oral or injected
medication are suitable for day case surgery if:
• They fulfil all day case criteria
• They can be first / early on a morning or afternoon
list.
Prioritise patients with diabetes on the list. This reduces the starvation time and hence the likelihood of the patient requiring a VRIII.

Insulin should never be stopped in people with Type 1 diabetes because this will lead to ketoacidosis. If the starvation period is expected to require omission of more than one meal, a variable rate intravenous insulin infusion (VRIII) with concomitant glucose and electrolyte infusion will be required. Insulin requirements are increased by:
• Obesity
• Prolonged or major surgery
• Infection
• Glucocorticoid treatment.
When a VRIII is used, insulin and substrate should be infused continuously. If the infusion is stopped, there will be no insulin present in the circulation after 3-5 minutes leading to immediate catabolism.

Ototoxicity is a recognised adverse reaction with the aminoglycoside antibiotics.

Gentamicin belongs to a class of drugs known as aminoglycoside antibiotics. It is a broad-spectrum antibiotic that is most affective against aerobic gram-negative rods. Gentamicin acts by inhibiting bacterial protein synthesis. This creates a pool of inactive bacterial ribosomes that can no longer re-initiate and translate new proteins.

The hearing loss produced by gentamicin is known as gentamycin-induced ototoxicity. The antibiotic itself is not dangerous. It becomes toxic when it binds to iron in the blood and produces destructive chemical agents known as free radicals.

For a rib fracture to cause pneumothorax, there must also be laceration to the underlying lung parenchyma. This has the risk of developing into a tension pneumothorax. Therefore, a chest drain should be inserted and the patient admitted.

Pneumothorax is a collection of free air in the chest cavity that causes the lung to collapse. The most common cause of pneumothorax is lung laceration with air leakage. In some instances, the lung continues to leak air into the chest cavity and results in compression of the chest structures, including vessels that return blood to the heart. This is known as a tension pneumothorax and can be fatal if not treated immediately. Blunt or penetrating chest trauma that creates a flap-type defect on the surface of the lung can result in this life-threatening condition.

The patient’s ECG indicates Inferior myocardial infarction. However, the tearing central chest pain is more suggestive of Aortic Dissection.
Patients with acute aortic dissection typically present with the sudden onset of severe chest pain, although this description is not universal.
The location of the pain may indicate where the dissection arises. Anterior chest pain and chest pain that mimics acute myocardial infarction usually are associated with the anterior arch or aortic root dissection. This is caused by the dissection interrupting flow to the coronary arteries, resulting in myocardial ischemia. Pain in the neck or jaw indicates that the dissection involves the aortic arch and extends into the great vessels.

High-probability ECG features of MI are the following:
ST-segment elevation greater than 1 mm in two anatomically contiguous leads
The presence of new Q waves

Intermediate-probability ECG features of MI are the following:
ST-segment depression
T-wave inversion
Other nonspecific ST-T wave abnormalities
Low-probability ECG features of MI are normal ECG findings. However, normal or nonspecific findings on ECGs do not exclude the possibility of MI.

Localization of the involved myocardium based on the distribution of ECG abnormalities in MI is as follows:
– Inferior wall – II, III, aVF
– Lateral wall – I, aVL, V4 through V6
– Anteroseptal – V1 through V3
– Anterolateral – V1 through V6
– Right ventricular – RV4, RV5
– Posterior wall – R/S ratio greater than 1 in V1 and V2, and – T-wave changes in V1, V8, and V9
– True posterior-wall MIs may cause precordial ST depressions, inverted and hyperacute T waves, or both. ST-segment elevation and upright hyperacute T waves may be evident with the use of right-sided chest leads.