Chapter 11 - Organ damage during cardiopulmonary bypass

Summary

Organ damage during cardiac surgery has been primarily attributed to the use of cardiopulmonary bypass (CPB). Cerebral and renal dysfunctions are perceived to be the frequent and debilitating consequences of CPB. Transition from physiological circulation to CPB results in contact between blood and a number of non-biological surfaces that form the extracorporeal circuit. The plasma levels of endotoxins increase during CPB. Endotoxins are lipopolysaccharides (LPS) derived from the cell membranes of gram-negative bacteria. The source of the endotoxins is widely believed to primarily be the gastrointestinal (GI) tract. Clinical reports have shown that oxidative stress and markers of inflammation are significantly reduced during OPCAB when compared to CABG performed on CPB. CPB causes profound reductions in blood flow in the splanchnic circulation and thus leads to reduced perfusion to the GI tract and associated organs. Hepatic metabolism is reduced during CPB in conjunction with the reduction in splanchnic blood flow.