الفهرس | Only 14 pages are availabe for public view |
Abstract In surgical patients with underlying chronic liver disease, surgical outcomes correlate with hepatocellular function. The risk of surgery in such patients should be assessed preoperatively using Child-Paughclassification or model for end-stage liver disease (MELD) severity scoring system. Patients with severe liver disease (e.g., Child-Paugh class - C) should not undergo any elective surgery and should be evaluated for liver transplantation. Patients with liver disease undergoing open heart surgery with cardiopulmonary bypass (CPB) are at especially high risk because of the effect on hepatic hemodynamic. This risk was demonstrated in a retrospective review of all patients with cirrhosis who underwent cardiac surgery with cardiopulmonary bypass at the Cleveland Clinic from 1992 to 2002. In coronary artery bypass graft surgery (CABG), various changes take place in different organs of the body because of the effect of bypass pumps and hemodilution.Dilutional anemia and hemodynamic changes can affect tissue oxygenation, and most studies state that a minimum hematocrit level of 22% is necessary for the on-pump technique. During CPB, the possibility of liver damage increases owing to the-non pulsatile perfusion, low-flow state, free radicals formation, and increased levels of catecholamines. Some studies have reported that CPB usually induces mild hepatocellular damage, whereas off-pump coronary bypass decreases the possibility of this damage. However, reports on CPB are conflicting because hypothermia decreases the oxygen demand of the splanchnic organs and, thus, hepatocellular oxygenation is preserved better during hypothermic CPB |