A 62-year-old man with severe aortic stenosis (valve area 0.7 cm²) requires urgent laparotomy for perforated viscus. Which haemodynamic goal is MOST critical during induction of anaesthesia?

• A Allow systemic vascular resistance to fall to facilitate forward flow
• B Increase heart rate to >100 bpm to improve cardiac output
• C Maintain heart rate between 80–100 bpm with tachycardia avoided ✓
• D Induce mild hypovolaemia to reduce LV preload and wall stress

Explanation

Severe aortic stenosis produces fixed cardiac output; the hypertrophied LV is preload-dependent and extremely sensitive to tachycardia, which shortens diastolic filling time and precipitates ischaemia. SVR must be maintained (not reduced) to preserve coronary perfusion pressure. Bradycardia is also hazardous as it reduces output in the setting of a fixed stroke volume, hence the narrow target of 60–80 bpm, but the key principle is avoidance of tachycardia and hypotension.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.