The effects of serotonin-receptor blockade after cardiopulmonary by-pass. A pilot study.

Ketanserin (R 41468) blocks selectively the 5HT2 receptors. We studied the effects of 10 mg of Ketanserin i.v. in 11 patients after cardiopulmonary by-pass. A sudden decrease in arterial blood pressure and in filling pressures way observed. The heart rate stayed unchanged and the rate pressure product decreased significantly. Cardiac output increased. The observed effects were essentially those of vasodilation without increases in heart rate. This pilot study showed that the 5HT2 receptors blockade may be of clinical value in the quick reversal of hemodynamic instability after cardiopulmonary by-pass.