During clipping of a large basilar apex aneurysm, the surgeon finds the neck thin-walled and friable and asks for a brief bloodless, flaccid sac because proximal temporary clips cannot be applied safely. Which intervention provides a short period of deliberate circulatory arrest suitable for clip placement?

• A Adenosine bolus producing transient ventricular asystole ✓
• B Deepened sevoflurane to 2 MAC for controlled hypotension
• C Esmolol infusion targeting a systolic pressure of 70 mmHg
• D Sodium nitroprusside bolus of 1 mcg/kg

Explanation

An adenosine bolus of roughly 0.3 to 0.6 mg/kg produces 15 to 45 seconds of ventricular asystole, creating a slack, bloodless aneurysm sac for definitive clip placement when temporary clips are anatomically impossible, as at the basilar apex. Beta-blockers and vasodilators lower pressure but never produce a truly empty sac, and 2 MAC volatile agent risks prolonged hypotension without reliable arrest and impairs neurophysiological monitoring.

Reference: Miller's Anesthesia, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.