ABA Perioperative Patient Management 3 — Questions and Answers
Question 1: A 58-year-old patient with a recent drug-eluting coronary stent (placed 4 months ago) requires semi-urgent colon resection. What is the best antiplatelet management strategy?
- Continue aspirin; consider continuing P2Y12 inhibitor or bridge with cangrelor/tirofiban after multidisciplinary discussion (Correct answer)
- Stop all antiplatelets 10 days before surgery to minimize bleeding
- Proceed with surgery immediately; stent thrombosis risk is low after 4 months
- Switch to clopidogrel monotherapy only and stop aspirin
Correct answer: Continue aspirin; consider continuing P2Y12 inhibitor or bridge with cangrelor/tirofiban after multidisciplinary discussion
Drug-eluting stents require dual antiplatelet therapy for at least 12 months; semi-urgent surgery within that window requires cardiology input, continuation of aspirin, and individualized P2Y12 management.
Question 2: Which parameter BEST predicts fluid responsiveness in a mechanically ventilated patient without arrhythmia?
- Pulse pressure variation (PPV) > 13% (Correct answer)
- Central venous pressure < 8 mmHg
- Urine output < 0.5 mL/kg/hr
- Mixed venous oxygen saturation < 65%
Correct answer: Pulse pressure variation (PPV) > 13%
PPV > 13% in a fully mechanically ventilated patient without arrhythmia or right heart failure is the most validated dynamic predictor of fluid responsiveness.
Question 3: A patient undergoing spine surgery in the prone position develops sudden hypotension and bradycardia after a previously stable 3-hour course. The MOST likely cause is:
- Venous air embolism (Correct answer)
- Tension pneumothorax
- Anaphylaxis
- Massive hemorrhage with reflex bradycardia
Correct answer: Venous air embolism
Venous air embolism can occur in prone spine surgery due to the elevated operative field creating negative venous pressure; it presents with sudden cardiovascular collapse and mill-wheel murmur.
Question 4: In a patient with morbid obesity (BMI 52) undergoing bariatric surgery, which ventilation strategy reduces postoperative pulmonary complications MOST effectively?
- Low tidal volume (6–8 mL/kg IBW) with PEEP 8–10 cmH₂O and recruitment maneuvers (Correct answer)
- High tidal volume (10–12 mL/kg actual body weight) with low PEEP
- Pressure-controlled ventilation targeting tidal volume based on actual body weight
- Spontaneous ventilation with a laryngeal mask airway
Correct answer: Low tidal volume (6–8 mL/kg IBW) with PEEP 8–10 cmH₂O and recruitment maneuvers
Lung-protective ventilation using IBW-based tidal volumes, moderate PEEP, and periodic recruitment maneuvers reduces atelectasis and PPCs in obese patients.
Question 5: Postoperative nausea and vomiting (PONV) prophylaxis with ondansetron works primarily by:
- Blocking 5-HT₃ receptors in the chemoreceptor trigger zone and vagal afferents (Correct answer)
- Antagonizing dopamine D₂ receptors in the area postrema
- Inhibiting histamine H₁ receptors in the vestibular nucleus
- Blocking muscarinic receptors in the vomiting center
Correct answer: Blocking 5-HT₃ receptors in the chemoreceptor trigger zone and vagal afferents
Ondansetron is a selective 5-HT₃ antagonist that blocks serotonin-mediated signaling in the CTZ and peripheral vagal afferents responsible for nausea.
Question 6: A 65-year-old patient with ESRD on hemodialysis requires a parathyroidectomy. Which muscle relaxant is SAFEST to use?
- Cisatracurium (Correct answer)
- Vecuronium
- Rocuronium
- Pancuronium
Correct answer: Cisatracurium
Cisatracurium undergoes Hofmann elimination and ester hydrolysis independent of renal or hepatic function, making it the safest NMBD in ESRD.
Question 7: Which criterion is part of the modified Aldrete score used to determine PACU discharge readiness?
- Activity, respiration, circulation, consciousness, and SpO₂ (Correct answer)
- Pain score < 4, ability to void, and tolerating oral fluids
- GCS ≥ 15 and heart rate within 20% of baseline
- PONV score ≤ 1 and adequate analgesia
Correct answer: Activity, respiration, circulation, consciousness, and SpO₂
The modified Aldrete score evaluates five criteria (activity, respiration, circulation, consciousness, oxygen saturation), each scored 0–2, with discharge at ≥ 9.
ABA Perioperative Patient Management 3
A 58-year-old patient with a recent drug-eluting coronary stent (placed 4 months ago) requires semi-urgent colon resection.
What is the best antiplatelet management strategy?