100+ Free General Surgery Board Practice Questions

Explanation: Refeeding syndrome is a potentially fatal condition characterized by severe electrolyte shifts (hypophosphatemia, hypokalemia, hypomagnesemia) and fluid retention following the reintroduction of nutrition in chronically malnourished patients. The hallmark is hypophosphatemia, driven by insulin release causing intracellular shifts of phosphate. Management requires immediate reduction of caloric intake (or holding TPN progress) and aggressive intravenous electrolyte replacement.

Explanation: To ensure maximum tissue concentrations of prophylactic antibiotics at the time of incision, the first dose should be administered within 60 minutes prior to the skin incision (or within 120 minutes for vancomycin or fluoroquinolones). Cefazolin is a first-generation cephalosporin with a half-life of about 2 hours, making the 60-minute window optimal.

Explanation: Transfusion-Related Acute Lung Injury (TRALI) is characterized by acute onset of dyspnea, hypoxemia, and bilateral pulmonary infiltrates within 6 hours of transfusion, in the absence of left atrial hypertension (normal PCWP). It is caused by donor antibodies against recipient HLA or neutrophil antigens, leading to leukocyte activation and pulmonary capillary leakage. Transfusion-Associated Circulatory Overload (TACO) would present with elevated PCWP, neck vein distention, and cardiogenic pulmonary edema.

Explanation: This presentation is highly suggestive of Heparin-Induced Thrombocytopenia (HIT) Type II, an immune-mediated disorder caused by antibodies to the heparin-platelet factor 4 (PF4) complex. It usually occurs 5-10 days after starting heparin and leads to thrombocytopenia and a paradoxically high risk of venous and arterial thrombosis (e.g., acute limb ischemia). Treatment requires immediate cessation of all heparin products and initiation of a non-heparin anticoagulant, typically a direct thrombin inhibitor like argatroban. Warfarin is contraindicated initially because it can worsen microvascular thrombosis (skin necrosis) by rapidly depleting protein C.

Explanation: Establishing CO2 pneumoperitoneum (typically at 12-15 mmHg) increases intra-abdominal pressure, causing compression of the vena cava (decreasing venous return/preload) and increasing SVR (afterload), which leads to a decrease in cardiac output. Diaphragmatic elevation increases peak airway pressures and decreases lung compliance. Renal blood flow and glomerular filtration rate decrease due to compression of renal parenchyma and veins. Absorption of CO2 causes hypercapnia and respiratory acidosis, not alkalosis.

Explanation: This patient is exhibiting signs of Local Anesthetic Systemic Toxicity (LAST), which starts with central nervous system excitation (numbness, metallic taste, seizures) and can progress to cardiovascular collapse (especially with bupivacaine). The definitive treatment for LAST-induced cardiac arrest or severe toxicity is immediate bolus and infusion of 20% lipid emulsion (intralipid), which acts as a 'lipid sink' to extract the lipophilic local anesthetic from cardiac tissue.

Explanation: The patient has a low pH (7.22, acidosis) and a low bicarbonate (12 mEq/L, metabolic). The pCO2 is low (28 mmHg) representing respiratory compensation (hyperventilation to blow off CO2). The elevated lactate (6.5 mmol/L) indicates anaerobic metabolism due to gut ischemia, which produces lactic acid, a cause of high anion gap metabolic acidosis (HAGMA). The formula for anion gap is Na - (Cl + HCO3). Lactic acidosis is a hallmark cause of HAGMA.

Explanation: According to CDC/NHSN definitions, a superficial incisional SSI involves only skin and subcutaneous tissue. A deep incisional SSI involves deep soft tissues, such as fascial and muscle layers. An organ/space SSI involves any part of the anatomy other than the incision (e.g., peritoneal cavity) that was opened or manipulated during surgery.

Explanation: The Revised Cardiac Risk Index (RCRI or Lee's Criteria) identifies six independent predictors of major cardiac complications: (1) high-risk surgery (intraperitoneal, intrathoracic, suprainguinal vascular), (2) history of ischemic heart disease, (3) history of congestive heart failure, (4) history of cerebrovascular disease, (5) preoperative treatment with insulin, and (6) preoperative serum creatinine > 2.0 mg/dL (177 micromol/L). Essential hypertension, age, and obesity are not among the six RCRI variables.

Explanation: The Surviving Sepsis Campaign guidelines recommend norepinephrine as the first-line vasopressor of choice for patients in septic shock who remain hypotensive despite adequate fluid resuscitation, targeting a MAP >= 65 mmHg. Dopamine is associated with higher rates of arrhythmias, and vasopressin is typically added as a second-line agent if MAP cannot be maintained with norepinephrine alone.