RT Book, Section A1 Ramsay, Michael A2 Butterworth IV, John F. A2 Mackey, David C. A2 Wasnick, John D. SR Print(0) ID 1199412894 T1 Anesthesia for Patients with Liver Disease T2 Morgan & Mikhail’s Clinical Anesthesiology, 7e YR 2022 FD 2022 PB McGraw-Hill Education PP New York, NY SN 9781260473797 LK accessanesthesiology.mhmedical.com/content.aspx?aid=1199412894 RD 2024/03/29 AB KEY CONCEPTS Because of increased perioperative risk, patients with acute hepatitis should have elective surgery postponed until the acute hepatitis has resolved, as indicated by the normalization of liver tests. Isoflurane and sevoflurane are the volatile agents of choice for patients with significant liver disease because they preserve hepatic blood flow and oxygen delivery. Factors known to reduce hepatic blood flow, such as hypotension, excessive sympathetic activation, and high mean airway pressures during controlled ventilation, should be avoided. In evaluating patients for chronic hepatitis, laboratory test results may show only a mild elevation in serum aminotransferase activity and often correlate poorly with disease severity. Liver cirrhosis refers to the damaging effects to the liver of inflammation, hepatocellular injury, and the resulting fibrosis and regeneration of hepatocytes. Liver cirrhosis leads to portal hypertension, varices, and widespread endothelial damage from toxins not cleared by the liver that may cause multiorgan dysfunction. Massive bleeding from gastroesophageal varices is a major cause of morbidity and mortality in patients with liver disease, and, in addition to the cardiovascular effects of acute blood loss, the absorbed nitrogen load from the breakdown of blood in the gastrointestinal tract can precipitate hepatic encephalopathy. Cardiovascular changes observed in cirrhotic patients are usually those of hyperdynamic circulation, though clinically significant cirrhotic cardiomyopathy is often present and not recognized. A left ventricular ejection fraction of 50% is low for a patient with cirrhosis! The effects of hepatic cirrhosis on pulmonary arterioles may result in vasodilation, causing shunts and chronic hypoxemia, or conversely lead to pulmonary vasoconstriction and medial hyperplasia, causing an increase in vascular resistance and pulmonary hypertension. Hepatorenal syndrome is a functional renal defect in patients with cirrhosis that usually follows gastrointestinal bleeding, aggressive diuresis, sepsis, or major surgery. It is characterized by progressive oliguria with avid sodium retention, azotemia, intractable ascites, and a very high mortality rate. Factors known to precipitate hepatic encephalopathy in patients with cirrhosis include gastrointestinal bleeding, increased dietary protein intake, hypokalemic alkalosis from vomiting or diuresis, infections, worsening liver function, and drugs with central nervous system depressant activity. Following the removal of large amounts of ascitic fluid, aggressive intravenous fluid replacement is often necessary to prevent profound hypotension and acute kidney injury or failure.