Circulatory effects of anisodamine on cardiopulmonary bypass.

Anisodamine, a new M-cholinergic blocker discovered in China, was employed in experimental dogs on cardiopulmonary bypass (CPB) with a view to observing its hypotensive activities. Before bypass an intravenous bolus injection of anisodamine 5 mg/kg caused a transient fall of about 20 mmHg in arterial blood pressure for 10 to 15 minutes, with an increase of about 10 mmHg in pulse pressure, indicating lowering afterload. During bypass, a continuous intravenous drip of anisodamine brought about 27 to 37 mmHg fall in perfusion pressure (compared with the control group) while the perfusion flow rate was kept constant. Beneficial effects of anisodamine were manifested, post-bypass, by enhancement of cardiac output, lack of elevation of pulmonary arterial pressure, a speedy recovery of the ST segment to normal, and a decrease of the rate-pressure product, as results of circulatory improvement and myocardial protection.