Artificial Circulatory Support

Abstract

Extracorporeal cardiopulmonary bypass (CPB) is the most common type of artificial circulatory support. The evolution of cardiac surgery is inextricably linked with the success of cardiopulmonary bypass. It facilitates surgery both on the surface and within the chambers of the heart providing the function of the heart and lungs, giving the blood momentum, and performing gas exchange, respectively. This allows the heart and lungs to be isolated from the patient's systemic circulation. CPB was first used by John Gibbon on the May 6, 1953, to close an atrial septal defect in 18-year-old Cecilia Bavolek. Since then improvements in technology, management and understanding of CPB have significantly contributed to a reduction in patient morbidity and mortality. It has also enabled a shift toward an older more complicated patient population. This chapter examines the cannulation sites necessary for CPB, their importance, and the options available. The in-depth description of the extracorporeal circuit focuses on the materials used and the properties of the various components. The non-physiological aspects of these components are highlighted and the importance of full patient anticoagulation for extracorporeal support is explained. The roles of the various associated CPB techniques are discussed, including myocardial protection during cross-clamping of the aorta and deep hypothermic arrest. The chapter also gives an insight into many of the acute and long-term complications of CPB and finally gives background information on the support devices allied with cardiac surgery, from intra-aortic balloon counterpulsation to the components of long-term extracorporeal membrane oxygenation (ECMO).