Normal saline versus lower-chloride solutions for kidney transplantation.

Abstract

The ideal intravenous fluid for kidney transplantation has not been defined, despite the common use of normal saline during the peri-operative period. The high chloride content of normal saline is associated with an increased risk of hyperchloraemic metabolic acidosis, which may in turn increase the risk of hyperkalaemia and delayed graft function. Balanced electrolyte solutions have a lower chloride content which may decrease this risk and avoid the need for dialysis due to hyperkalaemia in the immediate post-transplant period. Randomised controlled trials (RCTs) addressing this issue have used biochemical outcomes to compare fluids and have been underpowered to address patient-centred outcomes such as delayed graft function. To examine the effect of lower-chloride solutions versus normal saline on delayed graft function, hyperkalaemia and acid-base status in kidney transplant recipients. We searched the Cochrane Kidney and Transplant's Specialised Register to 26 November 2015 through contact with the Information Specialist using search terms relevant to this review. RCTs of kidney transplant recipients that compared peri-operative intravenous lower-chloride solutions to normal saline were included. Two independent investigators assessed studies for eligibility and risk of bias. Data from individual studies were extracted using standardised forms and pooled according to a published protocol. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes. Six studies (477 participants) were included in the review. All participants were adult kidney transplant recipients and 70% of participants underwent live-donor kidney transplantation. The overall risk of bias was low for selection bias and unclear for remaining domains. There was no difference in the risk of delayed graft function (3 studies, 298 participants: RR 1.03, 95% CI 0.62 to 1.70) or hyperkalaemia (2 studies, 199 participants: RR 0.48, 95% CI 0.04 to 6.10) for participants who received balanced electrolyte solutions compared to normal saline. Intraoperative balanced electrolyte solutions compared to normal saline were associated with higher blood pH (3 studies, 193 participants: MD 0.07, 95% CI 0.05 to 0.09), higher serum bicarbonate (3 studies, 215 participants: MD 3.02 mEq/L, 95% CI 2.00 to 4.05) and lower serum chloride (3 studies, 215 participants: MD -9.93 mmol/L, 95% CI -19.96 to 0.11). There were four cases of graft loss in the normal saline group and one in the balanced electrolyte solution group, and four cases of acute rejection in the normal saline group compared to two cases in the balanced electrolyte solution group. Balanced electrolyte solutions are associated with less hyperchloraemic metabolic acidosis compared to normal saline, however it remains uncertain whether lower-chloride solutions lead to improved graft outcomes compared to normal saline.