Peak Serum Chloride and Hyperchloremia in Patients Undergoing Cardiac Surgery Is Not Explained by Chloride-Rich Intravenous Fluid Alone: A Post-Hoc Analysis of the LICRA Trial

Abstract

With the exception of 0.9% saline, little is known about factors that may contribute to increased serum chloride concentration (SCl-) in patients undergoing cardiac surgery. For the present study, the authors sought to characterize the association between administered chloride load from intravenous fluid and other perioperative variables, with peak perioperative SCl-. Secondary analysis of data from a previously published controlled clinical trial in which patients were assigned to a chloride-rich or chloride-limited perioperative fluid strategy (NCT02020538). Academic medical center. The study comprised 1,056 adult patients with normal preoperative SCl- undergoing cardiac surgery. None MEASUREMENTS AND MAIN RESULTS: Peak perioperative SCl- and hyperchloremia, defined as peak SCl- >110 mmol/L, were selected as co-primary endpoints. Regression modeling identified factors independently associated with these endpoints. Mean (standard deviation) peak perioperative SCl- was 114 (5) mmol/L, and hyperchloremia occurred in 824 (78.0%) of the cohort. In addition to administered volume of 0.9% saline, multivariate linear and logistic regression modeling consistently associated preoperative SCl- (regression coefficient 0.5; 95% confidence interval [CI] 0.4-0.6 mmol/L; odds ratio 1.60; 95% CI 1.41-1.82 per 1 mmol/L increase) and cardiopulmonary bypass duration (regression coefficient 0.1; 95% CI 0.1-0.2 mmol/L; odds ratio 1.12; 95% CI 1.06-1.19 per 10 minutes) with both co-primary outcomes. Multivariate modeling only explained approximately 50% of variability in peak SCl-. The present study's data identified an association for both 0.9% saline administration and other nonfluid variables with peak perioperative SCl- and hyperchloremia. Stand-alone strategies to limit administration of chloride-rich intravenous fluid may have limited ability to prevent hyperchloremia in this setting.