Techniques for avoiding neurologic injury during adult cardiac surgery.

The mechanisms and pathophysiology of perioperative neurologic injury are reviewed. The principle mechanisms of the ischemic injury are gaseous and particulate emboli and hypoperfusion caused by cerebrovascular occlusive disease. The contribution of the cardiopulmonary bypass circuit to the development of ischemic injury is discussed. The important role of the surgeon in preventing particulate and gaseous microemboli and macroemboli is described and techniques for avoiding hypoperfusion in the presence of occlusive cerebrovascular disease are presented. Patients at greatest risk of perioperative neurologic injury are elderly patients with atherosclerotic aorta, cerebrovascular disease, and previous neurologic abnormalities. The pump oxygenator may be the cause of neurologic injury by generation of emboli, hypoperfusion, and perfusion accidents. The principles of perfusion safety are presented. Massive air embolization may occur from the heart-lung machine or from the heart. Methods of preventing massive air embolus including techniques of bypass and air removal from the heart are discussed. The management of massive air embolus is thoroughly described. The detection of cerebrovascular disease is discussed and the management of the patient with cerebrovascular disease described. Atherosclerosis of the ascending aorta is a major risk factor for perioperative neurologic injury. Methods of detection and management are thoroughly described. Prevention of embolization from intracardiac debris and clot is described.