General Principles of Anaesthesia for Adult Cardiac Surgery

Abstract

Anesthesia in cardiac surgery is mainly focused on the hemodynamic management, which, in turn, depends on the complex interaction of patient’s pathophysiology, pharmacological agents and surgical techniques. A reduction in the sympathetic tone secondary to anesthetic drugs administration is associated with vasodilatation, reduction of cardiac contractility and relative hypovolemia. These factors, acting together, may lead to the “lethal triade” hypotension, ischemia and ventricular fibrillation. During the pre-cardiopulmonary bypass (CPB) period the maintenance of an optimal myocardial oxygen supply/consumption ratio can be achieved with adequate analgesia and the administration of short-acting agents. Avoidance of dysrhythmias and maintenance of sinus rhythm are of utmost importance before CPB institution to fulfill patients’ metabolic requirement averting low cardiac output syndrome. Since different cardiac defects have an underlying distinctive pathophysiology, specific considerations on preload, contractility and afterload are needed in order to guarantee a safe pre-bypass time, a straight CPB discontinuation and an optimal hemodynamic after chest closure. The use of transesophageal echocardiography (TEE) is essential throughout the surgery. An intraoperative anesthetic regimen including volatile agents is associated with a reduced postoperative cardiac dysfunction when compared to a total intravenous drug anesthesia, but no differences in survival is demonstrated.