Comparative Study of the Change in Liver Enzymes After General or Spinal Anesthetic Techniques in Patients With Preoperatively Elevated Liver Enzymes.

Overview

* To assess the changes in liver functions postoperatively in patients with preoperatively elevated liver enzymes. * To identify the most appropriate anesthesia technique for patients with preoperatively elevated liver enzymes. * To assess the effect of intraoperative event (bleeding, hypoxia, hypotension, prolonged operation) on liver functions in these patients.

Surgery and anesthesia are stressful events, thus there is a possibility that liver enzymes and bilirubin may increase postoperatively. Mild elevations of serum aminotransferase, alkaline phosphatase, or bilirubin levels are frequent after surgical procedures, whether performed under general or spinal anesthesia. Anesthesia causes an initial reduction in hepatic arterial blood flow of 35-42% in the first 30 min of induction of anesthesia. During surgery, The liver blood flow returns to baseline. It is possible that either the initial hypoperfusion or reperfusion injury, or both, may contribute to postoperative liver dysfunction when it occurs. The type of surgery is potentially an important factor of postoperative hepatic dysfunction. Intra-abdominal operations are more likely than extra-abdominal surgeries to cause reflex systemic hypotension and to subsequently reduce hepatic blood flow.This could be due to traction on abdominal viscera. Hypercarbia-induced splanchnic vasoconstriction is also a threat to hepatic perfusion in laparoscopic surgery. Surgeries that result in a large amount of blood loss increase the risk for ischemic hepatic injury, as can intraoperative hypotension. Liver disease is important to recognize preoperatively because the risk of surgery in patients with advanced disease can be grave.Patients with liver disease are more likely than patients without liver disease to experience hepatic decompensation with anesthesia. Measurement of serum Bilirubin levels is central to the evaluation of hepatobiliary disorders. Liver disease is a challenging condition for the anesthesiologist, However, the risk could be diminished by careful consideration of the patients' condition preoperatively and choosing suitable anesthetic procedure and drugs for these patients.Meanwhile, The effect of performing spinal anesthesia on patients with liver disease has not been investigated properly as most studies excluded patients with preoperatively elevated liver enzymes. Studies on patients undergoing general anesthesia with normal preoperative liver function tests showed a transient increase in the level of AST\& ALT, with a mild increase in postoperative bilirubin levels