Interactions of anaesthesia and high pre-operative doses of beta-receptor antagonists.

Haemodynamic responses to anaesthesia and surgery were observed in 13 patients with severe renovascular hypertension treated with high doses of beta-receptor antagonists (equivalent to 10-37 mg/kg/day of propranolol) and 24 patients receiving moderate doses of beta-receptor antagonists (equivalent to 120-480 mg propranolol per day). Chronotropic and inotropic responses to the noxious stimuli of laryngoscopy or surgical stimulation were effectively suppressed by beta-receptor blockade thus increasing arterial pressure due to these stimuli or aortic cross-clamping which indicated a purely resistive load for the left ventricle. In no patient was evidence found that myocardial performance, and its effect on left ventricular ejection, was seriously compromised.