Preservation of renal function during liver transplantation is a gold standard. Intraoperative problems like hypotension, massive transfusion, liver disease, co-existing renal dysfunction, and decreased GFR during clamping of inferior vena cava (IVC) and portal vein (PV) are some major hazards for kidney function during liver transplantation. To determine the change in urine output during the clamping time, we undertook this study. 24 patients without preexisting renal disease, undergoing liver transplantation with piggyback method, were enrolled in this study. Patients with creatinine more than 1.2 mg/dl were excluded. Urine output was monitored 30 minutes before clamping of IVC and portal vein, during clamping, and 30 minutes after declamping. None of the patients had clamping time longer than 70 minutes. Our goal was to maintain mean arterial blood pressure and heart rate just by fluid administration and diuretics were avoided Participants had mean Age of 39.12 +/- 13.52 years (15-67) with male to female ratio of 1.4. Urine output 30 minutes before clamping was 1.53 ml/kg/hour, decreased to 0.37 ml/kg/hour during clamping and increased to 1.52 ml/kg/hour, 30 min after declamping.
Conclusion: Urine output reduced significantly in all patients, after clamping of IVC and portal vein (P<0.05). It can be explained by increased venous pressure and therefore decreased renal perfusion pressure. If clamping time is less than 70 minutes, the reduced perfusion pressure can be tolerated well by the kidneys, renal function will return to normal immediately after declamping, and no renal damage will occur. It has been stated that one of the advantages of veno-veno bypass (VVB) is increase of renal perfusion pressure. However, if the clamping time in piggyback method becomes shorter than 70 minutes and patients have normal preoperative renal function, the decreased renal perfusion pressure will not cause any kidney dysfunction post operatively.