Hyperchloremia Is Not an Independent Risk Factor for Postoperative Acute Kidney Injury in Pediatric Cardiac Patients

Objective: Hyperchloremia recently has been shown to have an association with the development of acute kidney injury (AKI) in critically ill patients. However, there is little information about the prevalence of an abnormal chloride concentration after pediatric cardiac surgery and its association with postoperative AKI. The aim of this study was to determine the prevalence of hyperchloremia and its association with AKI in pediatric patients after cardiac surgery. Design: A retrospective single-center study. Setting: Referral high-volume pediatric cardiac center in a tertiary teaching hospital. Participants: Patients under 72 months of age with congenital heart disease who underwent cardiac surgery with the use of cardiopulmonary bypass. Interventions: None. Measurements and Main Results: The primary outcome was development of AKI diagnosed by Kidney Disease Improving Global Outcomes consensus criteria. The associations of outcomes with the highest serum chloride concentration ([Cl-]_max) and time-weighted average chloride concentration ([Cl-]_ave) within the first 48 hours after surgery were investigated. Of 521 patients included in the study, 463 patients (88.9%) had hyperchloremia at least 1 time within the first 48 hours after surgery. Postoperative AKI occurred in 205 patients (39.3%). [Cl-]_ave and [Cl-]_max in the AKI group were significantly higher than those in the non-AKI group (112 [110-114] mEq/L v 111 [109-113] mEq/L, p = 0.001 and 116 [113, 119] mEq/L v 114 [112-118] mEq/L, p = 0.002, respectively). After adjustment for other predictors of AKI by multivariable analyses, neither [Cl-]_ave nor [Cl-]_max was associated independently with the development of AKI (odds ratio [OR] = 1.040, 95% confidence interval [CI]: 0.885-1.220, p = 0.63; OR = 0.992, 95% CI: 0.874-1.130. p = 0.90). Conclusion: Postoperative hyperchloremia was common and was associated with the development of AKI in pediatric patients after congenital cardiac surgery in univariate analysis. After adjustment for predictors of AKI by multivariate analyses, there was no significant relationship between postoperative chloride concentration and AKI.