Chapter 33. Anesthesia for Patients with Liver Disease

• 
  Because of the increased risk of perioperative morbidity and mortality, patients with acute hepatitis should have any 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 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.
• 
  Approximately 10% of patients with cirrhosis also develop at least one episode of spontaneous bacterial peritonitis, and some patients may eventually develop hepatocellular carcinoma.
• 
  Massive bleeding from gastroesophageal varices is a major cause of morbidity and mortality, and, in addition to the cardiovascular effects of acute blood loss, the absorbed nitrogen load from the breakdown of blood in the intestinal tract can precipitate hepatic encephalopathy.
• 
  The cardiovascular changes observed in the patient with hepatic cirrhosis are usually that of a hyperdynamic circulation, although clinically significant cirrhotic cardiomyopathy is often present and not recognized.
• 
  The effects of hepatic cirrhosis on pulmonary vascular resistance vessels may result in chronic hypoxemia.
• 
  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, and worsening liver function.
• 
  Following the removal of large amounts of ascitic fluid, aggressive intravenous fluid replacement is often necessary to prevent profound hypotension and kidney failure.

The prevalence of liver disease is increasing in the United States. Cirrhosis, the terminal pathology in the majority of liver diseases, has a general population incidence as high as 5% in some autopsy series. It is a major cause of death in men in their fourth and fifth decades of life, and mortality rates are increasing. Ten percent of the patients with liver disease undergo operative procedures during the final 2 years of their lives. The liver has remarkable functional reserve, and thus overt clinical manifestations of hepatic disease are often absent until extensive damage has occurred. When patients with little hepatic reserve come to the operating room, effects from anesthesia and the surgical procedure can precipitate further hepatic decompensation, leading to frank hepatic failure.

Coagulation in Liver Disease

In stable chronic liver disease, the causes of excessive bleeding primarily involve severe thrombocytopenia, endothelial dysfunction, portal hypertension, renal failure, and sepsis (see Chapters 32 and 51). However, the hemostatic changes that occur with liver disease may cause hypercoagulation and thrombosis, as well as an increased risk of bleeding. Clot breakdown may be enhanced by ...