A 62-year-old man with hypertension, hepatitis C, and hepatocellular carcinoma presented for right liver partial lobectomy. The patient did not appear to have cirrhosis, and laboratory studies were within normal limits. He underwent an inguinal hernia repair under general anesthesia 13 years ago without difficulty. General anesthesia was induced with propofol and fentanyl. Muscle relaxation was achieved with vecuronium. General anesthesia was maintained with isoflurane and fentanyl. An intraarterial catheter and two large-bore peripheral intravenous catheters were placed.
During the case, the surgeon asks you to limit fluid administration and avoid transfusion, if possible. Before resection of the tumor, the surgeon announces the “Pringle is on,” and the patient becomes hypotensive and tachycardic.
Describe liver cirrhosis and its systemic effects.
Cirrhosis of the liver affects approximately 3 million Americans and is the 12th leading cause of death in the United States. Chronic hepatitis refers to liver disease in which inflammation and necrosis are present for at least 6 months and is most commonly due to hepatitis C virus infection or alcohol abuse. The disease can be divided into two major categories: cholestatic disease and hepatocellular disease. Cholestatic diseases (e.g., primary biliary cirrhosis, primary sclerosing cholangitis) are uncommon causes of chronic hepatitis, whereas hepatocellular causes (e.g., infectious, autoimmune, steatohepatitis, or alcoholic) predominate and more often lead to hepatic resection or transplantation.
Cirrhosis of the liver is a major challenge to the anesthesiologist because it leads to problems in nearly every organ system. Most patients with long-standing liver disease are functionally unwell and have poor nutritional status and exercise tolerance on presentation. Table 33-1 outlines common problems related to chronic liver disease that must be considered by the anesthesiologist.
|Central nervous system||Hepatic encephalopathy||Variable manifestations—confusion, personality changes, sleep disorder, coma|
|Can be precipitated by anesthesia or surgery if hepatic perfusion is impaired (e.g., hypotension, hypoxemia)|
|Cardiovascular system||Hyperdynamic state||Patients have profoundly reduced systemic vascular resistance with resultant high cardiac output, low to normal blood pressure, mildly elevated heart rate (probable nitric oxide effects)|
|Cardiomyopathy||Signs and symptoms of congestive heart failure|
|Altered blood flow||Increased splanchnic blood flow with resultant central hypovolemia|
|Arteriovenous collateralization with increased mixed venous oxygen saturation|
|Portal hypertension||Increased portal venous pressure leads to increased portosystemic collateral development and plays a role in ascites and encephalopathy|
|Resultant esophageal varices are at a high risk for bleeding if traumatized|
|Pulmonary system||Hypoxemia||True pulmonary shunting can occur from increased atelectasis (from fluid retention as ascites or pleural effusions), impaired hypoxic pulmonary vasoconstriction|
|Hepatopulmonary syndrome with intrapulmonary vascular dilation and shunting|
|Pulmonary hypertension||Portopulmonary hypertension is pulmonary and portal hypertension existing simultaneously as a result of long-standing liver disease|
|Renal system||Hepatorenal syndrome||Develops as a result of prerenal failure from advanced cirrhosis often precipitated by sudden decreases in cardiac output (e.g., various anesthetic agents)|
|Generally, disease is responsive to albumin and vasopressin analogues|
|Edema and ascites||Major factors in development of ascites are portal hypertension and sodium and water retention|
|Patients are often on salt-restricted diets and diuretic therapy|
|Electrolyte abnormalities are common|
|Albumin therapy is the mainstay of treatment. Infection of ascitic fluid (spontaneous bacterial peritonitis) may lead to sepsis and renal failure|
|Hematologic system||Coagulopathy/hypercoagulability||Variable impairment in clotting and fibrinolysis despite results of “synthetic” liver function test (i.e., PT, INR)|
|Patients may be coagulopathic or prothrombotic with expectant complications of either state occurring in an unpredictable fashion|
|Thrombocytopenia||Portal hypertension induces splenomegaly and platelet sequestration (main cause of thrombocytopenia), but bone marrow suppression and immune-mediated destruction of platelets also play a role|
|Endocrine system||Abnormal glucose use||Multifactorial insulin resistance can lead to hyperglycemia|
|Loss of glycogen stores can lead to hypoglycemia|
|Gastrointestinal system||Esophageal varices||Long-term portal hypertension can lead to varices that if ruptured (during NG tube placement, TEE placement) can prove fatal|
How do you evaluate a patient with severe liver disease, and how does the liver disease affect the choice of anesthetic agents?
In addition to the usual directed history and physical examination of surgical patients, patients with cirrhosis of the liver require a thorough assessment regarding the severity of disease and recognition of the risk it entails. The urgency of surgery dictates the time allowed to optimize coexisting medical problems. In acute hepatitis, elective surgery is generally contraindicated, and emergency surgery carries a very high degree of risk. Common signs and symptoms of liver disease should be sought to assess overall well-being. Jaundice, ascites, petechiae, and ecchymoses are easy to assess quickly on first encountering the patient. Figure 33-1 presents a rational approach to a patient with suspected liver disease.
A well-accepted method by which the severity of liver disease can be assessed is the Child-Pugh score ( Table 33-2 ). Although the Child-Pugh score has been used for more than 30 years as a prognostic indicator for cirrhosis, it has several limitations, including two subjective variables of the five variables used, lack of a renal function correlate to survival, and overemphasis on measures of synthetic function (i.e., albumin and prothrombin time). Child-Pugh scores are considered a good, although not perfect, predictor of severity and subsequent mortality in these patients. The Model for End-Stage Liver Disease (MELD) score is a more useful model for population comparison and for use in transplant selection because it does not rely on subjective data. Instead, MELD scores involve nonempirically derived objective variables: bilirubin, creatinine, international normalized ratio, and cause of cirrhosis. However, the MELD score is less useful in stratifying risk in cirrhotic patients for nontransplant procedures.
|Encephalopathy||None||Mild to moderate||Severe|
|Ascites||None||Mild to moderate||Severe|
|International normalized ratio||<1.7||1.7–2.3||>2.3|