Vasomotor waves during cardiopulmonary bypass.

Vasomotor waves (VMW) were observed in nine cardiac patients during cardiopulmonary bypass. The period and amplitude of the waves were described together with their consistency and other pertinent data. Effects of several pharmacologic agents on these waves were tested. These VMW are likely to be caused by spontaneous oscillation of presso-regulatory feedback systems. Cerebral ischemic response is suspected to be the most likely candidate. However, no patients showed any gross neurological symptoms in the postoperative period.