Anesthetic Concerns for the Patient with Liver Disease

Advanced hepatic disease should really be considered a systemic disease process, affecting multiple organ systems. Like kidney failure, it reflects a fundamental defect in protein metabolism, i.e., nitrogen elimination after deamination of amino acids. In renal failure, ammonia is converted to urea, which accumulates as BUN. In liver failure, the arginine cycle fails to convert ammonia to urea, so that ammonia accumulates and blood urea nitrogen (BUN) remains very low. In fact, hyperammonemia is a marker for other circulating byproducts of protein metabolism that cause defective ion transport across cell membranes, resulting in intracellular sodium and water accumulation. Every organ system is affected. Patients with advanced hepatic disease present a challenge to anesthesiologists because liver failure implies abnormal handling of anesthetic agents, as well as multiorgan system dysfunction, general debility and specific problems associated with replacement therapy and transplantation. Moreover, when hepatic insufficiency is severe, anesthesia and surgery may themselves precipitate acute failure. This outline will address an approach to the patient with severe hepatic disease undergoing non-liver transplant surgery. It will focus on the manifestations of organ dysfunction, pharmacology of anesthetic agents and selected aspects of anesthetic preparation and perioperative management.