BCA Preoperative Evaluation & Risk Assessment 3 — Questions and Answers
Question 1: A patient with obstructive sleep apnea (OSA) is scheduled for laparoscopic cholecystectomy. Which preoperative finding is most concerning for perioperative respiratory complications?
- AHI >30 events/hour with daytime hypercapnia (PaCO2 >45 mmHg) (Correct answer)
- BMI 35 with AHI of 15 events/hour
- Neck circumference >40 cm with loud snoring
- Epworth Sleepiness Scale score of 14
Correct 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.
Question 2: Which of the following best describes the concept of metabolic equivalents (METs) in preoperative cardiac risk stratification?
- ≥4 METs functional capacity (e.g., climbing one flight of stairs) indicates acceptable perioperative cardiac risk (Correct answer)
- ≥7 METs is required to safely proceed with high-risk surgery without further testing
- MET assessment is only valid when confirmed by formal exercise stress testing
- METs below 2 indicate high risk only in patients over 70 years old
Correct 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.
Question 3: A patient with Child-Pugh Class C cirrhosis requires emergency appendectomy. What is the estimated perioperative mortality?
- 50–85% (Correct answer)
- 10–20%
- 25–35%
- 5–10%
Correct 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.
Question 4: 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?
- 3 flights (≥12 m vertical height) (Correct answer)
- 1 flight
- 5 flights
- 2 flights
Correct 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.
Question 5: A patient with myasthenia gravis is scheduled for thymectomy. Which preoperative feature most increases the risk of postoperative mechanical ventilation?
- Duration of disease >6 years, pyridostigmine dose >750 mg/day, preoperative vital capacity <2.9 L, and presence of concurrent pulmonary disease (Correct answer)
- Ocular-only disease with normal vital capacity
- Anti-AChR antibody titer >1.0 nmol/L
- Age >60 with disease onset after menopause
Correct 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.
Question 6: Which preoperative laboratory test is most appropriate for a healthy 35-year-old woman scheduled for elective laparoscopic tubal ligation with no medical history?
- Urine pregnancy test only (Correct answer)
- CBC, BMP, coagulation studies, and ECG
- No laboratory tests are required
- CBC and type-and-screen only
Correct 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.
Question 7: 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?
- Elective surgery should be postponed to correct hypokalemia to ≥3.5 mEq/L, as hypokalemia increases arrhythmia risk (Correct answer)
- Proceed with surgery since mild hypokalemia rarely causes clinical problems
- Administer IV potassium 40 mEq rapidly and recheck before proceeding
- The threshold for postponing surgery is K+ <2.5 mEq/L
Correct 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.
BCA Preoperative Evaluation & Risk Assessment 3
A patient with obstructive sleep apnea (OSA) is scheduled for laparoscopic cholecystectomy.
Which preoperative finding is most concerning for perioperative respiratory complications?