Effect of high- versus low-volume saline administration on acute kidney injury after cardiac surgery

Methods: In this retrospective study, we evaluated 1,740 consecutive patients who underwent cardiac surgery over a 2-year period. The patients were divided into high-volume saline (n=328, 18.8%) and low-volume saline (n=1,412, 81.2%) groups based on the amount of saline (>1 or ≤1 L, respectively) administered during the first 48 postoperative hours.

Results: AKI, the primary outcome, was defined according to the Risk, Injury, Failure, Loss, End Stage classification. There were no significant differences in the incidence of AKI (P=0.46), new renal replacement therapy (RRT) (P=0.39), and early mortality (P=0.52) between the 2 groups. Adjustment of baseline characteristics using propensity score matching showed that high-volume of saline administration was not significantly associated with an increased risk of AKI (OR, 1.22; 95% CI, 0.77–1.93; P=0.38), new RRT (OR, 1.25; 95% CI, 0.68–2.28; P=0.45), or early mortality (HR, 0.98; 95% CI, 0.48–2.02; P=0.97). These results were validated by further adjustments for significant covariates.

Conclusions: High-volume administration of saline in the period following cardiac surgery was not associated with a significant increase in the risk of AKI.