Clinical experience in continuous graft monitoring with microdialysis early after liver transplantation

Background: Early detection of impaired graft function after transplantation is essential. Microdialysis permits continuous monitoring of metabolic changes by mimicking the passive function of a capillary blood vessel by perfusion of a tubular semipermeable membrane introduced into the tissue. Based on the results of animal experiments, a clinical pilot study was undertaken. Methods: Ten consecutive patients undergoing whole-organ orthotopic liver transplantation were studied. Intrahepatic implantation of a microdialysis catheter was performed at the end of the operation. A reference catheter was placed in the subcutaneous tissue over the right pectoral area immediately after abdominal closure. Consecutive serial samples were collected at 1-h intervals for 3 days after the operation. Glucose, lactate, pyruvate and glycerol concentrations were measured. Results: During the first 24 h, the glucose level was higher in the liver than in reference tissue. Initially, increased mean(s.e.m.) levels of lactate (7.0(1.9) mmol/l) were observed in the liver, with a rapid decrease (to 2.7(0.3) mmol/l) over 24 h. A decrease in, and later stabilization of, the lactate : pyruvate ratio in the liver, from 18.7(4.2) to 10.0(1.1), was observed within 24 h after transplantation. Liver glycerol levels decreased from 62.3(7.4) to 24.3(7.5) mumol/l within the first 16 h after reperfusion and remained stable thereafter. Conclusion: Microdialysis allows continuous monitoring of tissue metabolism in the transplanted liver. The procedure is easy to perform and safe. The specific detection and monitoring of pathological changes in the liver graft (e.g. arterial and portal vein thrombosis, or early rejection) with microdialysis should be addressed in further studies.