Assessment of Acute Kidney Injury in Neurologically Injured Patients Receiving Hypertonic Sodium Chloride: Does Chloride Load Matter?

Background: Increasing evidence suggests that large-volume infusions of 0.9% sodium chloride (NaCl) for resuscitation are associated with hyperchloremic metabolic acidosis, renal vasoconstriction, and increased risk of acute kidney injury (AKI). Patients with neurological injury may require hypertonic NaCl for therapeutic hypernatremia, treatment of cerebral salt wasting, hyponatremia, or elevated intracranial pressure. Consequently, this increased exposure to chloride may result in an increased risk for development of AKI. Objective: The primary aim of this study was to describe the risk for development of AKI in neurologically injured patients receiving large volumes of intravenous hypertonic NaCl. Methods: This single-center, retrospective study looked at neurologically injured patients who received hypertonic NaCl and sodium acetate. Data were collected to assess renal function, hyperchloremia, and acidemia. Receiver operating characteristic (ROC) curve analysis was used to determine the predictive association between the amount of daily and overall chloride exposure and development of AKI. Results: A total of 301 patients were screened, and of those, 142 were included. Of the 142 patients included, 13% developed AKI, and 38% developed hyperchloremia. Additionally, 32% of patients were switched from NaCl to sodium acetate after an average of 3.4 ± 1.5 days of NaCl therapy. The ROC curve demonstrated that if patients received greater than 2055 mEq of chloride over 7 days, they were more likely to develop AKI (sensitivity 72%, specificity 70%; P = 0.002; area under the curve = 0.7). Conclusion and Relevance: Neurologically injured patients receiving hypertonic sodium therapy with a high chloride load are at risk of developing hyperchloremia and AKI.