Answer: Aspirin

Aspirin increases bleeding time when taken orally. Aspirin causes several different effects in the body, mainly the reduction of inflammation, analgesia (relief of pain), the prevention of clotting, and the reduction of fever. Much of this is believed to be due to decreased production of prostaglandins and TXA2. Aspirin’s ability to suppress the production of prostaglandins and thromboxanes is due to its irreversible inactivation of the cyclooxygenase (COX) enzyme. Cyclooxygenase is required for prostaglandin and thromboxane synthesis. Prostaglandins are local chemical messengers that exert multiple effects including but not limited to the transmission of pain information to the brain, modulation of the hypothalamic thermostat, and inflammation. They are produced in response to the stimulation of phospholipids within the plasma membrane of cells resulting in the release of arachidonic acid (prostaglandin precursor). Thromboxanes are responsible for the aggregation of platelets that form blood clots.
Low-dose, long-term aspirin use irreversibly blocks the formation of thromboxane A2 in platelets, producing an inhibitory effect on platelet aggregation.

Antihypertensive and antidiabetic medications do not need to be stopped when a patient is undergoing local anaesthesia. Steroid (Prednisolone) use cannot be stopped abruptly; tapering the drug gives the adrenal glands time to return to their normal patterns of secretion. Withdrawal symptoms and signs (weakness, fatigue, decreased appetite, weight loss, nausea, vomiting, diarrhoea, abdominal pain) can mimic many other medical problems. Some may be life-threatening.

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.

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

Answer: Allow the wound to heal by secondary intention

A perianal abscess is a type of anorectal abscess that is confined to the perianal space. Other causes can include inflammatory bowel diseases such as Crohn’s disease, as well as trauma, or cancerous origins. Patients with recurrent or complex abscesses should be evaluated for Crohn’s disease. Perianal abscesses are the most common type of anorectal abscesses. These abscesses can cause significant discomfort for patients. They are located at the anal verge and if left untreated can extend into the ischioanal space or intersphincteric space since these areas are continuous with the perianal space. They can also cause systemic infection if left untreated. Patients will complain of anal pain which may be dull, sharp, aching, or throbbing. This may be accompanied by fever, chills, constipation, or diarrhoea. Patients with perianal abscess typically present with pain around the anus, which may or may not be associated with bowel movements, but is usually constant. Purulent discharge may be reported if the abscess is spontaneously draining, and blood per rectum may be reported in a spontaneously draining abscess.

A physical exam can typically rule out other causes of anal pain, such as haemorrhoids, and will yield an area of fluctuance or an area of erythema and induration in the skin around the perianal area. Cellulitis should be noted and marked if extending beyond the fluctuant area.

Perianal abscesses are an indication for timely incision and drainage. Antibiotic administration alone is inadequate and inappropriate. Once incision and drainage are performed, there is no need for antibiotic administration unless certain medical issues necessitate the use. Such conditions include valvular heart disease, immunocompromised patients, diabetic patients, or in the setting of sepsis. Antibiotics are also considered in these patients or cases with signs of systemic infection or significant surrounding cellulitis.

Incision and drainage are typically performed in an office setting, or immediately in the emergency department. Local anaesthesia with 1% lidocaine may be administered to the surrounding tissues. A cruciate incision is made as close to the anal verge as possible to shorten any potential fistula formation. Blunt palpation is used to ensure no other septation or abscess pocket is missed. It is useful before completion of procedure to excise a skin flap of the cruciate incision or the tips of the four skin flaps to ensure adequate drainage and prevent premature healing of the skin over the abscess pocket. Packing may be placed initially for haemostasis. Continual packing may be further utilized for healing by secondary intention. Patients are encouraged to keep the incision and drainage site clean. Sitz baths may assist in pain relief.

More extensive abscesses may require the operating room for the adequate exam under anaesthesia to ensure adequate drainage, as well as inspect for other diseases such as fistula in ano.

The complications of central vein catheterization (CVC) include infection, thrombosis, occlusion, and, in particular, mechanical complications which usually occur during insertion and are closely related to the anatomic location of the central veins. Infectious complications are reported to occur in 5% to 26% of patients, mechanical complications in 5% to 19%, and thrombotic complications in 2% to 26%. Mechanical complications associated with the insertion of central lines include arterial puncture, hematoma, haemothorax, pneumothorax, arterial-venous fistula, venous air embolism, nerve injury, thoracic duct injury (left side only), intraluminal dissection, and puncture of the aorta
Pneumothorax is one of the most common CVC insertion complications, reportedly representing up to 30% of all mechanical adverse events of CVC insertion.
Clinician-performed bedside US allows the diagnosis of pneumothorax to be made immediately, with a high degree of sensitivity and with better accuracy than supine chest films and equal to that of CT scan.
Tension pneumothorax is classically characterized by hypotension and hypoxia. On examination, breath sounds are absent on the affected haemothorax and the trachea deviates away from the affected side. The thorax may also be hyper resonant; jugular venous distention and tachycardia may be present.
If a pneumothorax is diagnosed the treatment strategy should be determined by the following factors: (I) size; (II) symptoms; (III) spontaneous breathing or use of mechanical ventilation; (IV) clinical diagnosis of a tension pneumothorax.

Treatment consisted of: (I) observation; (II) outpatient insertion of a Heimlich valve; (III) inpatient tube thoracostomy.

Chemotherapy for acute myeloid leukaemia (AML) requires long-term therapy and multiple blood tests. Therefore, an indwelling device, such as Groshong line, is preferable.

Tunnelled lines such as Groshong and Hickman lines are popular devices for patients with long-term therapeutic requirements. These devices are usually inserted, using ultrasound guidance, into the internal jugular vein and then tunnelled under the skin. A cuff of woven material is sited near the end and helps to anchor the device into the tissues. These cuffs require formal dissection to allow the device to be removed.

Because of the substantial risk of thromboembolism early after valve replacement, perioperative initiation of anticoagulation is necessary, despite the increased risk for bleeding. Anticoagulation should be initiated within 24 h after the procedure with unfractionated heparin or low-molecular-weight heparin (LMWH).
Heparin is monitored by checking the activated partial thromboplastin time or anti-Xa activity.
Oral anticoagulants are monitored by INR.

Answer: Myofibroblasts

Fibroblasts are a type of cell which have mesenchymal origin and can exhibit either non-contractile or highly contractile phenotype. Under normal conditions, fibroblasts function to maintain tissue homeostasis by regulating the turnover of extracellular matrix (ECM). When tissues are injured, however, fibroblasts around the injured region differentiate into myofibroblasts, a type of highly contractile cells that produce abundant ECM proteins. While the mechanisms of wound healing are not completely understood, it has become clear that both fibroblasts and myofibroblasts play a critical role in the wound healing process. Specifically, the traction forces of fibroblasts and coordinated contraction of myofibroblasts are believed to be responsible for wound contraction and closure. However, excessive myofibroblast activity, accompanied by elevated levels of mechanical stress in the healing region, often causes scar tissue formation, and in the worst case, contracture of tissues (e.g. Dupuytren’s contracture), leading to local immobilization and loss of function.

Chyle leakage is one of the most challenging complications following an esophagectomy and can lead to hypovolemia, metabolic and nutritional depletion, infection, and even death. The leakage occurs in 1.1 to 3.7% of esophagectomy patients; mortality occurs in excess of 50% of patients. Surgeons administer a lipid rich material prior to surgery to facilitate its identification if it occurs.

Answer: Loss of fat emulsification will result in the malabsorption of vitamins A, C, D, and K

Vitamins are classified as either fat soluble (vitamins A, D, E and K) or water soluble (vitamins B and C). This difference between the two groups is very important. It determines how each vitamin acts within the body. The fat soluble vitamins are soluble in lipids (fats). These vitamins are usually absorbed in fat globules (called chylomicrons) that travel through the lymphatic system of the small intestines and into the general blood circulation within the body. These fat soluble vitamins, especially vitamins A and E, are then stored in body tissues.
Vitamin C is a water soluble vitamin which makes the statement false.
Primary pancreatic maldigestion of carbohydrate, protein, and fat is caused by decreased activity of amylase, trypsin, and lipase. Pancreatic lipase is an enzyme secreted from the pancreas. As the primary lipase enzyme that hydrolyses dietary fat molecules in the human digestive system, it is one of the main digestive enzymes, converting triglyceride substrates found in ingested oils to monoglycerides and free fatty acids.
The duodenum plays a key role in absorption of vitamins and minerals, and is removed in PD resections. This, in combination with malabsorption and increased metabolic demand, results in increased risk of micronutrient deficiencies. Routine supplementation of fat soluble vitamin and trace elements are recommended following resection.

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.

Management of Acute Pancreatitis revolves around supportive care, adequate nutrition, and intravenous hydration. The rationale for hydration is based on the need to resolve the hypovolemia that occurs secondary to vomiting, reduced oral intake, third space extravasation, respiratory losses and diaphoresis. Besides, early hydration provides macrocirculatory and microcirculatory support to prevent the cascade of events leading to pancreatic necrosis.
There is a lack of high level evidence to guide the choice of fluid in AP. Crystalloids are recommended by the American Gastroenterological Association, and colloids (packed red blood cells) are considered in cases of low haematocrit (< 25%) and low serum albumin (< 2 g/dL). Among the crystalloids, Ringer's lactate solution is preferred over Normal saline. However, there is an urgent need of studies on this issue.

Gaining venous access in small children is challenging most of the times especially in cases of trauma. Therefore, intraosseous infusions should be preferred in this setting. Broviac lines are long-term IV access systems with narrow lumens and, hence, would be unsuitable.

Intraosseous access is typically undertaken at the anteromedial aspect of the proximal tibia and provides access to the marrow cavity and circulatory system. Although traditionally preferred in paediatric practice, it may be used in adults as well, and a wide range of fluids can be infused using this approach.

Pyrexia is a very common post operative finding and can most likely result from an infection. However, it is highly unlikely to occur as a result of ileus. Anastomotic leaks are uncommon after right sided colonic surgery. In this scenario atelectasis would be the most likely underlying cause, as open extended right hemicolectomies will necessitate a long midline incision.

Postoperative hypertension, arrhythmias, and heart failure commonly occur in the first 2 days after surgery, but the risk of myocardial infarction persists for at least 5 or 6 days after surgery.
ECG should be done to exclude it.

Dextran 40 and 70 have a higher rate of causing anaphylaxis than either gelatins or starches.

Dextrans are branched polysaccharide molecules, with dextran 40 and 70 available. The high-molecular-weight dextran 70 may persist for up to eight hours. They inhibit platelet aggregation and leucocyte plugging in the microcirculation, thereby, improving flow through the microcirculation. They are primarily used in sepsis.
Unlike many other intravenous fluids, dextrans are a recognised cause of anaphylaxis.

Answer: Serum phosphate

Refeeding syndrome can be defined as the potentially fatal shifts in fluids and electrolytes that may occur in malnourished patients receiving artificial refeeding (whether enterally or parenterally. These shifts result from hormonal and metabolic changes and may cause serious clinical complications. The hallmark biochemical feature of refeeding syndrome is hypophosphatemia. However, the syndrome is complex and may also feature abnormal sodium and fluid balance; changes in glucose, protein, and fat metabolism; thiamine deficiency; hypokalaemia; and hypomagnesaemia.
During refeeding, glycaemia leads to increased insulin and decreased secretion of glucagon. Insulin stimulates glycogen, fat, and protein synthesis. This process requires minerals such as phosphate and magnesium and cofactors such as thiamine. Insulin stimulates the absorption of potassium into the cells through the sodium-potassium ATPase symporter, which also transports glucose into the cells. Magnesium and phosphate are also taken up into the cells. Water follows by osmosis. These processes result in a decrease in the serum levels of phosphate, potassium, and magnesium, all of which are already depleted. The clinical features of the refeeding syndrome occur as a result of the functional deficits of these electrolytes and the rapid change in basal metabolic rate.

Symptoms of hypophosphatemia include:

confusion or hesitation
seizures
muscle breakdown
neuromuscular problems
acute heart failure

Deficiency in thiamine can lead to Korsakoff’s syndrome (retrograde and anterograde amnesia, confabulation) and Wernicke’s encephalopathy (ocular abnormalities, ataxia, confusional state, hypothermia, coma). These symptoms are not present in the patient so Thiamine deficiency can be ruled out and there is no need to do tests for Serum vitamin B.

Jejunostomy feeding (enteral feeding) is now the standard of care in most feeding protocols after esophagectomy. The feeding regimen consists of a gradually increasing volume of feeds in the first five to seven days. Patients should resume oral intake as soon as possible after surgery. In hospital, all forms of enteral access appear to be safe. Out of hospital, the ability to provide home feeding by feeding jejunostomy is likely where meaningful nutritional improvements can be made. Improving nutrition and related quality of life in the early months might improve the long-term outcome

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.

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.

Open haemorrhoidectomy is traditionally viewed as a painful procedure. Most operations are performed under general or regional anaesthesia. Following excisional haemorrhoidectomy, severe pain is not unusual, a well placed caudal anaesthetic will counter this. A pudendal nerve block is an alternative but is less effective than a caudal.

Answer: Bradycardia

Prolonged bed rest and immobilization inevitably lead to complications. Such complications are much easier to prevent than to treat. Musculoskeletal complications include loss of muscle strength and endurance, contractures and soft tissue changes, disuse osteoporosis, and degenerative joint disease. Cardiovascular complications include an increased heart rate (tachycardia), decreased cardiac reserve, orthostatic hypotension, and venous thromboembolism.

If patients need IV fluids for routine maintenance alone, restrict the initial prescription to:
25–30 ml/kg/day of water and
approximately 1 mmol/kg/day of potassium, sodium and chloride and
approximately 50–100 g/day of glucose to limit starvation ketosis.
Weight-based potassium prescriptions should be rounded to the nearest common fluids available (for example, a 67 kg person should have fluids containing 20 mmol and 40 mmol of potassium in 24 hours). Potassium should not be added to intravenous fluid bags as this is dangerous.

Sodium chloride 0.9%, with or without additional potassium, is one of the most commonly used IV fluids in UK practice.

Glucose 5% solution provides a useful means of giving free water for, once the glucose is metabolised, the fluid is distributed throughout total body water. It is, therefore, a potentially useful means of correcting or preventing simple dehydration and the glucose content will also help to prevent starvation ketosis, although it is important to recognize that it will not make much of a contribution to covering patients overall nutritional needs. The use of 5% glucose, will increase risks of significant hyponatraemia, particularly in children, the elderly, patients on diuretics and those with excess ADH due to osmotic and non-osmotic stimuli (a problem is seen quite frequently in hospitalized patients). Nevertheless, hyponatremia is likely to be avoided by not exceeding recommended volumes of maintenance IV fluids and by careful monitoring of patients’ clinical volume status and electrolyte measurements.

Portacaths are usually inserted when there is a need for long term access to a vein. This might be to provide medication, special intravenous feeding, fluids, blood and blood product transfusion and blood tests. Broviacs would pose the same core problems as a Hickman.

Bowel preparation is a significant aspect of the flexible sigmoidoscopy procedure. Clear visibility of the bowel mucosa is critical for a thorough examination. The combination of a light breakfast in the morning and the application of 1 or 2 phosphate enemas a few hours before the examination is a safe and commonly used method of preparing a patient for a flexible sigmoidoscopy procedure.

Complications of Transurethral Resection: TURP
T URP syndrome
U rethral stricture/UTI
R etrograde ejaculation
P erforation of the prostate

TURP syndrome can cause a wide variety of symptoms that include asymptomatic hyponatremia, ECG changes, fatigue, vomiting, confusion, visual loss, coma and death. In a conscious and alert patient, changes in the mental state of may be the first sign of TURP syndrome and bladder perforation.

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.

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.

The immediate treatment of hypercalcaemia involves intravenous fluid resuscitation. This may be complemented with the use of bisphosphonates and sometimes, diuretics. However, fluids are administered first. Normal saline is usually preferred for this over other solutions.

Urgent management in hypercalcaemia is indicated if:
1. Serum calcium level >3.5 mmol/L
2. Reduced consciousness
3. Severe abdominal pain
4. Pre-renal failure

Management options include:
1. Intravenous fluid resuscitation with 3–6 litres of 0.9% normal saline in 24 hours
2. Concurrent administration of calcitonin to help lower calcium levels
3. Medical therapy (usually if corrected calcium >3.0mmol/L)

Absence of comorbidities and a small procedure with no likelihood of systemic compromise will equate to an ASA score of 1.

The ASA physical status classification system is a system for assessing the fitness of patients before surgery. It has six grades, as described below:

ASA 1: No physiological, biochemical, or psychiatric disturbance. The surgical pathology is localised and has not invoked systemic disturbance.

ASA 2: Mild or moderate systemic disruption caused either by the surgical disease process or through an underlying pre-existing disease.

ASA 3: Severe systemic disruption, not life-threatening, caused either by the surgical pathology or a pre-existing disease.

ASA 4: Patient has severe systemic disease that is a constant threat to life.

ASA 5: Patient is moribund and will not survive without surgery.

ASA 6: A brain-dead patient whose organs are being removed with the intention of transplanting them into another patient.