Albumin mass balance and kinetics in liver transplantation

Abstract

Background: In major abdominal surgery albumin is shifted from the circulation, presumably leaking into the interstitial space, contributing to a 30-40% decrease in plasma albumin concentration. During and after liver transplantation exogenous albumin is infused for volume substitution and to maintain plasma albumin concentration. Here we used liver transplantation as a model procedure for the study of albumin mass balance and kinetics during major abdominal surgery with albumin substitution. Methods: Patients were studied during liver transplantation (n=16), and until postoperative day 3 (POD 3) (n=11). Cumulative perioperative albumin shift was assessed by mass balance of albumin and hemoglobin. Synthesis rates of albumin and fibrinogen were estimated by the flooding technique using deuterium-labeled phenylalanine. Albumin distribution was assessed by radioiodinated human serum albumin. Results: At the end of surgery, 37±17g of albumin (p<0.0001) had shifted from plasma, and this amount was stable until POD 3 (48±33g, p=0.0017 versus baseline). There was 91±37g exogenous albumin infused peroperatively and another 47±35g was infused postoperatively until POD 3. Absolute synthesis rates of albumin and fibrinogen on POD 3 were 239±84mg/kg body weight/day and 33mg/kg body weight/day (range 5-161), respectively. Conclusions: Albumin net leakage from plasma progressed until the end of surgery, and was then unaltered until POD 3. This is in contrast with the normalization of the cumulative albumin shift identified at day 3 after non-transplant major abdominal surgery. Liver synthesis of export proteins was high compared to reference values at the third postoperative day, suggesting rapid recovery of synthesis capacity.