Comparison of two different preload targets of stroke volume variation during kidney transplantation: a randomised controlled trial

Introduction: Maintaining adequate preload during kidney transplantation (KT) is important for graft function. We evaluated whether a high or low normal target for a dynamic preload index of stroke volume variation (SVV) would impact graft function during living donor KT.

Methods: We compared haemodynamic management algorithms using two different targets of SVV: SVV6% group (n = 30) versus SVV12% group (n = 30). Crystalloids were administered to achieve SVV less than the assigned target. Neutrophil gelatinase-associated lipocalin (NGAL) level at the end of surgery was compared. We also compared the incidence of delayed graft function (DGF), daily serum creatinine level and glomerular filtration rate (GFR) until 2 weeks postoperatively.

Results: The total amount of crystalloids administered was significantly different between the SVV6% and SVV12% groups (median [interquartile range] 2,250 [1,700-3,600] vs. 1,350 [1,050-1,900], P < 0.001). There was no significant difference in NGAL level at the end of the operation between the SVV6% and SVV12% groups (395 [234-560] vs. 518 [346-654], P = 0.115). The incidence of DGF was not significantly different, and there was no significant difference in the postoperative serum creatinine levels or GFR between the groups.

Conclusions: Our randomised trial demonstrated that an SVV target of either 6% or 12% could be adequate as a preload management target for postoperative graft function during living donor KT. However, given the low incidence of DGF in living donor KT and type II error, our study should be interpreted carefully and further studies for deceased donor KT are required.