Downsizing: What have we learned from rodent models of cardiopulmonary bypass?

Major cardiovascular surgery employing cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) represents a unique biologic stimulus leading to profound pertubations in inflammatory, hemostatic, and oxidative stress pathways, all implicated in the pathogenesis of perioperative organ injury. Organ injury following cardiac surgery and associated morbidity concerns a number of organs including brain, heart, kidneys, liver, and lung. Despite significant advances in surgical, anesthetic, and organ protective strategies, the incidence of perioperative organ injury remains high. The clinical and financial implications of these problems can be profound, with prolonged hospitalization, reduced quality of life, and increased health care resource utilization having been associated with minor and major organ injuries. Preventing or treating these organ injuries remains difficult because the underlying mechanisms associated with ischemic reperfusion injury and the generalized inflammatory response introduced by CPB and DHCA are incompletely understood. The use of appropriate disease models of CPB and DHCA to study these injury mechanisms together with the testing of pharmaceutical treatments and other strategies should first occur in suitable animal models before applying them in costly multi-center trials.