Beta-adrenoceptor blockade and anaesthesia. Beta-adrenoceptor antagonism during anaesthesia for coronary artery surgery.

Twenty-six patients with severe coronary artery disease, receiving long term beta-adrenoceptor blocking drugs were anaesthetised for aorto-coronary bypass operations. Beta-adrenoceptor blocking drugs were withdrawn 2 to 8 days before surgery in ten patients only. In the remaining sixteen patients there were no serious complications due to the presence of a degree of beta-blockade during anaesthesia and surgery. The undesirable cardiovascular responses to laryngoscopy and tracheal intubation were diminished in these patients, and the rise in heart rate/systolic pressure product, and indicator of myocardial oxygen consumption, was less in this group. The need for peripheral vasodilators to treat systemic arterial pressure rises in response to surgery was also reduced. There appeared to be no contraindication to the continuation of beta-adrenoceptor blockade before operation in patients undergoing aorto-coronary bypass procedures when suitable anaesthetic agents were selected and when an appropriate blood volume was maintained.