Organ system response to cardiac function-splanchnic

The splanchnic circulation receives over 25% of the cardiac output and contains a similar percentage of the total blood volume under normal conditions. Thus the splanchnic circulation can act as a site of regulation of distribution of cardiac output and also as a blood reservoir. Multiple regulatory pathways are involved in the distribution of the splanchnic circulation. This chapter focuses on the intestinal and hepatic circulations because of their functional importance and in particular, because they are sites of dysregulation during pathologic conditions and surgical stresses, such as cardiopulmonary bypass. A review of the anatomy and physiology of both the intestinal and hepatic circulation is presented followed by the effects of cardiopulmonary bypass on this circulation. Splanchnic complications associated with cardiac surgical procedures will be reviewed. These include postcoarctectomy syndrome, protein-losing enteropathy, intestinal ischemia, necrotizing enterocolitis, ischemic hepatitis, acute hepatic failure, chronic hepatic dysfunction and cirrhosis, and pancreatitis.