Hepatic microcirculation during human orthotopic liver transplantation

Laser Doppler flowmetry (LDF) can measure blood flow in the hepatic microcirculation. Adequate graft perfusion is essential to the outcome of organ transplantation and has not previously been measured during operation in liver transplant recipients.

LDF was carried out during operation in 22 human liver grafts after restoring portal vein and hepatic artery inflow. LDF readings were validated against liver blood flow with an electromagnetic flowmeter. Intraoperative haemodynamics and donor organ parameters known to influence graft function were correlated with LDF.

There was a significant correlation (r = 0.96, P < 0.001) between hepatic perfusion determined with LDF and total liver blood flow measured by electromagnetic flowmetry. The perfusion measurements were reproducible with a coefficient of variation of 4 per cent. Mean(s.d.) hepatic perfusion increased significantly from baseline following venous reperfusion (17(6) versus 114(37) flux units, P < 0.001). Arterial revascularization resulted in a significant increase in mean(s.d.) perfusion (32(4)per cent, P = 0.02). There was a significant negative correlation between cold ischaemia time and graft perfusion (r = 0.48, P = 0.02; n = 22).

LDF provides a reliable non-invasive method of monitoring liver graft blood flow perfusion during transplantation.