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Metabolic Problems During the Derioperative PeriodLiver transplantation is performed primarily in patients who have been ill for a lengthy period. Multisystemic ctTects of cirrhosis include a host of interrelated metabolic proccsscs ( Table 2). This review assunies that sonic o r all of these perturbations are present and focuses on issues of concern.
Acid-Base ConsiderationsAlthough both rcspiratory and metabolic acidosis occur during the course of cirrhosis$-" the handling of metabolic acids is often abnormal by the time patients present for transplantation. Because of its metabolism of orginic acid anions, primarily lactate and certain Jmino acids, the livcr has an important influence on normal acid-base homeostasis. The liver is also the primary source of urea production, a process that consumes bicarbonate (Fig. I), but the importance of this to acid-base balance is debated. Some have suggested that hcpatic urea synthesis has a role in acid-basc baliinrc similar to that of the kidneys and lungs,' leading to thc assertion that decreased urea synthesis is largely rcsponsible for the metabolic alkaosis often scen in cnd-stagc liver diseasc (ESLD This is more likely to occur in those patients administcred large amounts of blood producrs. which arc chelatcd with sodium citrate. When this citrate load is mct;ibolizcd by the transplanted liver. bicarbonate ion i s Rcnermd in the process (Fig. 2).Acidosis is uncommon in ESLL), but when it occurs, i t is typically associated with renal dysfunction andlor