Preoperative Evaluation & Risk Assessment Flashcards

A patient with obstructive sleep apnea (OSA) is scheduled for laparoscopic cholecystectomy. Which preoperative finding is most concerning for perioperative respiratory complications?

Answer: AHI >30 events/hour with daytime hypercapnia (PaCO2 >45 mmHg)

Severe OSA with daytime hypercapnia indicates obesity hypoventilation syndrome, conferring highest perioperative respiratory risk.

Which of the following best describes the concept of metabolic equivalents (METs) in preoperative cardiac risk stratification?

Answer: ≥4 METs functional capacity (e.g., climbing one flight of stairs) indicates acceptable perioperative cardiac risk

Patients who can achieve ≥4 METs (equivalent to climbing a flight of stairs or walking on level ground at 4 mph) have acceptable perioperative cardiac risk without further testing.

A patient with Child-Pugh Class C cirrhosis requires emergency appendectomy. What is the estimated perioperative mortality?

Answer: 50–85%

Child-Pugh Class C cirrhosis carries an estimated perioperative mortality of 50–85% for abdominal surgery due to coagulopathy, portal hypertension, and hepatic decompensation risk.

When assessing a patient for thoracic surgery, the 'stair-climbing test' is used because patients who can climb ≥ how many flights without stopping have acceptable pulmonary reserve?

Answer: 3 flights (≥12 m vertical height)

Climbing ≥3 flights (approximately 12 meters vertical) correlates with VO2 max ≥20 mL/kg/min, indicating sufficient pulmonary reserve for major thoracic resection.

A patient with myasthenia gravis is scheduled for thymectomy. Which preoperative feature most increases the risk of postoperative mechanical ventilation?

Answer: Duration of disease >6 years, pyridostigmine dose >750 mg/day, preoperative vital capacity <2.9 L, and presence of concurrent pulmonary disease

The Leventhal criteria predict need for postoperative ventilation: disease >6 years, pyridostigmine >750 mg/day, VC <2.9 L, and concurrent pulmonary disease.

Which preoperative laboratory test is most appropriate for a healthy 35-year-old woman scheduled for elective laparoscopic tubal ligation with no medical history?

Answer: Urine pregnancy test only

A urine pregnancy test is the only routinely indicated preoperative test for a healthy woman of childbearing age undergoing elective surgery.

A patient is found to have a preoperative serum potassium of 2.9 mEq/L before elective surgery. Which statement regarding perioperative management is most accurate?

Answer: Elective surgery should be postponed to correct hypokalemia to ≥3.5 mEq/L, as hypokalemia increases arrhythmia risk

For elective procedures, hypokalemia should be corrected to ≥3.5 mEq/L before surgery to reduce the risk of perioperative cardiac arrhythmias.