The Effect of Clamping of Inferior Vena Cava and Portal Vein on Urine Output During Liver Transplantation

Background: Intraoperative hypotension, massive transfusion, liver disease, coexistent renal dysfunction, and decreased glomerular filtration rate during the anhepatic phase are major hazards for kidney function. We undertook this study to determine the change in urine output during clamping. Method: Twenty-four patients without preexistent renal disease, who were undergoing liver transplantation using the piggyback method, were enrolled in this study. Patients with a serum creatinine level >1.2 mg/dL were excluded. Urine output was monitored over 30 minutes before inferior vena cava and portal vein clamping, during clamping, and for 30 minutes after declamping. None of the patients had a clamping time >70 minutes. Our goal was to maintain mean arterial blood pressure and heart rate just by fluid administration diuretics were avoided. Results: Participants had a mean age of 39.12 ± 13.52 years (range, 15-67 years) with a male to female ratio of 1:4. Urine output 30 minutes before clamping was 3.64 ± 3.58 (range, 1.25-15.18) mL/kg/h, decreased to 1.28 ± 2.58 (range, 0-11.39) mL/kg/h during clamping (P = .00), and increased to 3.56 ± 3.64 (range, 0.51-15.18) mL/kg/h 30 minutes after declamping (P = .00). Conclusion: Urine output was significantly reduced in all patients after clamping of the IVC and portal veins. This observation may be explained by increased venous pressure leading to decreased renal perfusion pressure. It has been stated that one of the advantages of veno-veno bypass (VVB) is increased renal perfusion pressure. However, if the clamping time in the piggyback method is <70 minutes and patients have normal preoperative renal function, the decreased renal perfusion pressure will not cause postoperative kidney dysfunction.