How does perioperative autonomic blockade affect hemodynamics?

• A. Causes increased systemic vascular resistance and hypertension.
• B. Causes decreased systemic vascular resistance and potential hypotension; may require fluids and/or vasopressors.
• C. Has no effect on hemodynamics.
• D. Increases heart rate due to reflex tachycardia.

Answer: (B)

Autonomic blockade during the perioperative period removes sympathetic tone to the vasculature. Without that tone, both arteries and veins dilate, leading to a drop in systemic vascular resistance and pooling of blood in the venous system. This reduces venous return (preload) and often lowers arterial pressure, producing hypotension. To counteract this, clinicians commonly administer IV fluids to improve preload and vasopressors to increase vascular tone and restore blood pressure.

The heart rate response to this blockade is variable and not reliably predictive of the hemodynamic effect; reflex tachycardia may occur if hypotension develops, but the autonomic blockade can blunt or alter normal reflexes, so a simple increase in heart rate is not the defining outcome.