Intraoperative Hypotension

Abstract

Intraoperative hypotension is usually defined as a mean arterial pressure less than 25% of the patient’s usual value. Untreated, it may result in inadequate organ perfusion. Hypotension may be due to a low cardiac output, low systemic vascular resistance or a combination of both. Risk factors include chronic hypertension and advanced age. The most common causes of intraoperative hypotension are anaesthetic drugs (including regional anaesthesia) and hypovolaemia. Initial management usually involves fluid bolus to optimise preload, and use of drugs to increase contractility and provide vasoconstriction. Thorough evaluation of the patient is required to identify specific underlying causes.