Prevention of major perioperative neurological dysfunction—a personal perspective

Abstract

Neurological dysfunction following cardiac surgical procedures has many causes. We have reduced perioperative neurological dysfunction to very low levels with protocols related to five potential causes of perioperative stroke. The five areas we have concentrated upon are: 1) components and use of the heart-lung machine; 2) air embolization; 3) intrinsic cerebrovascular disease; 4) atheroemboli from the ascending aorta and; 5) clot emboli from the left ventricle. We have employed methods of operation of the heart-lung machine which minimize the risk of microemboli or air emboli. Air evacuation manoeuvres are employed in every patient at the termination of cardiopulmonary bypass. A brain protection protocol which employs pharmacological brain protection, as well as increased oxygen-carrying capacity and perfusion pressure, is used in patients with cerebrovascular disease and patients with atheromatous ascending aorta. Applying these protocols, we have performed 690 consecutive cardiac surgical procedures with strokes occurring in three patients (0-4%). There was one stroke in 558 patients (0.2%) having coronary artery bypass grafting. Stroke occurred in one of 48 high risk patients (2%) in whom the brain protection protocol was used. There were no apparent episodes of air embolization or embolization of clot from the left ventricle.