Cardiac surgery is unique because blood exposed to nonendothelial cell surfaces is collected and continuously recirculated throughout the entire body. This contact with synthetic surfaces in the perfusion circuit and multiple tissues within the wound triggers a massive defense reaction that involves at least five plasma protein systems and five blood cells. This reaction—the inflammatory response to cardiopulmonary bypass—initiates a powerful thrombotic stimulus and the production, release, and circulation of a host of microemboli and vasoactive and cytotoxic substances that affect every organ and tissue within the body. Cardiopulmonary bypass and open heart surgery are simply not possible without heparin; thus the inflammatory response to cardiopulmonary bypass describes the consequences of exposing heparinized blood to nonendothelial cell–covered surfaces.

Much has been learned about the inflammatory response since early pioneers first described hemolysis, thrombocytopenia, and production of emboli during and after open heart surgery. Still much remains to be learned and the nirvana of a truly nonthrombogenic synthetic surface remains far beyond the horizon. This chapter summarizes applications of extracorporeal circulation as used in adult cardiac surgery. The presentation is divided into four sections. Section 11A describes the components and operation of perfusion systems and related special topics. The inflammatory response is separated into two middle sections (11B and 11C) for simplification and clarity; in reality the reactions of blood elements with each other are extensively intertwined and overlapping during cardiopulmonary bypass. The consequences of extracorporeal perfusion in terms of organ damage are summarized in section 11D.