Perioperative monitoring of indocyanine green clearance and plasma disappearance rate in patients undergoing liver transplantation

Abstract

Introduction: Indocyanine green (ICG) elimination tests have been repeatedly suggested as an early predictor of graft function in patients with liver transplantation. Conventionally, ICG clearance (ClICG) is measured by a series of blood samples with subsequent laboratory analysis. More recently bedside techniques have become available to measure ICG concentrations in vivo and in addition to ClICG, the plasma disappearance rate of ICG (PDRICG) is increasingly being used. The aim of this study was to assess and to compare the normal time courses of ClICG and PDRICG in liver transplant recipients.

Methods: ClICG and PDRICG were measured perioperatively and at various times up to 24 h after liver transplantation. The bedside transpulmonary indicator dilution technique with an arterial fiberoptic-thermistor catheter was used to assess the ICG concentration time curve together with total circulating blood volume (Vd circ).

Results: Similar patterns of the time courses of ClICG and PDRICG with a fast recovery of ICG elimination in the early reperfusion period were observed. Compared to healthy subjects, ClICG was supranormal and PDRICG was slightly subnormal. In this study, Vd circ was increased at baseline and remained increased during surgery.

Conclusions: PDRICG and ClICG are well suited to monitor onset and maintenance of graft function in patients undergoing liver transplantation. The PDRICG values measured tend to be relatively lower than ClICG because of an increased blood volume in these patients. By knowing these differences it is justified to monitor liver function in a very simple manner with PDRICG.