The Impact of Timing of Maximal Crystalloid Hydration on Early Graft Function During Kidney Transplantation

Abstract

Early graft function is crucial for successful kidney transplantation. Maintaining adequate hydration is complicated by rapid movement of water to the extravascular space. We designed this study to test the effect of maximal hydration during graft ischemia time on early renal function. Forty adult patients with chronic renal failure underwent renal transplantation from related living donors. Study subjects were randomly assigned 1 of 2 regimens for intraoperative hydration. The constant infusion rate group received normal saline 0.9% at an infusion rate 10 to 12 mL . kg(-1) . h(-1) from the start of surgery until the renal vessels were unclamped after vascular anastomosis. The central venous pressure target (CVPT) group received normal saline 0.9% titrated to maintain a specific central venous pressure (CVP). The target CVP from the start of surgery until clamping of the donor renal vessels was 5 mm Hg except for the interval from clamping of the renal vessels until the end of renal vascular anastomosis, when the target CVP was 15 mm Hg. Perioperative hemodynamics, infused saline volumes, rate of infusion, onset of diuresis, graft turgidity, urine volume, and renal function during the first 5 postoperative days were recorded. At the end of renal ischemia time, both groups had received approximately 3 L crystalloid solution. The CVPT group achieved the highest peak of intravascular volume expansion with an average infusion rate of 48.3 mL . min(-1) during 48 +/- 12 minutes of renal ischemia. The CVPT group had better graft function, required fewer vasopressors and diuretics, and had less postoperative tissue edema than the constant infusion rate group. Hydration directed toward maintaining a given CVP during kidney transplantation produced a more stable hemodynamic profile and promoted diuresis. The calculated infusion rate of approximately 45 to 50 mL . min(-1), within an hour ischemia time, seems feasible to enhance early graft function. A larger trial with long-term follow-up of renal function is warranted to confirm the clinical benefit of titrating IV crystalloid administration to maintain a given CVP in this population.