Postoperative considerations of cardiopulmonary bypass in adult cardiac surgery

Abstract

Development of the cardiopulmonary bypass (CPB) technology in the second half of the twentieth century was one of the most important medical advances and has been the main part of cardiac surgery as a routine procedure. Providing a completely motionless, bloodless heart is the main goal of CPB. CPB fulfills the role of the heart (and lungs) by preserving the systemic circulation and gas exchange. Since the first initial machine, evolution from cross-sectional technique till to minimal extracorporeal circulation continues. The practice of cardiac surgery with CPB is safe and effective (but not perfect). CPB is a non-physiologic state and could cause multi-organ dysfunction. Although it simplifies cardiac surgery, CPB by itself induces a systemic inflammatory response syndrome, mostly due to blood contact with artificial surfaces. It activates complement, leukocyte, coagulation and fibrinolytic cascade, upregulation of proinflammatory cytokines, and production of oxygen free radicals and alters nitric oxide metabolism. Nearly all organs can be affected by these inflammatory mediators. In majority of patients these changes are asymptomatic due to adequate physiologic reserve. With improved knowledge in pathophysiology of CPB effects, efforts led to make new extracorporeal technology with less side effects. The first section describes the structural parts of CPB. The second section discusses about the CPB effects on vital organs.