A frail 78-year-old woman with reduced preload receives an induction dose of propofol. Blood pressure falls sharply. Which combination best describes the haemodynamic mechanism?

• A Reduced systemic vascular resistance, direct negative inotropy, and impaired baroreflex compensation ✓
• B Increased systemic vascular resistance with reflex bradycardia
• C Tachycardia from sympathetic stimulation combined with increased contractility
• D Isolated decrease in cardiac output with unchanged vascular tone

Explanation

Propofol lowers arterial pressure mainly through venodilation and arteriolar dilation reducing systemic vascular resistance, compounded by direct myocardial depression. Unlike thiopentone, propofol markedly blunts the baroreceptor reflex, so the expected compensatory tachycardia is absent and bradycardia may occur. Sympathetic stimulation with increased contractility describes ketamine, the opposite profile.

Reference: Stoelting's Pharmacology and Physiology in Anesthetic Practice, 5th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.