Association of chloride-rich fluids and medication diluents on the incidence of hyperchloremia and clinical consequences in aneurysmal subarachnoid hemorrhage

Background: Chloride-rich fluid administration is frequently employed in the management of aneurysmal subarachnoid hemorrhage (aSAH). However, the incidence and consequences of hyperchloremia in aSAH remain poorly defined. This study aimed to describe the incidence of hyperchloremia in aSAH, the contribution of fluid sources to chloride exposure, and the potential associations of hyperchloremia with patient outcomes. Methods: This was a single-center retrospective cohort study of patients admitted to a neurointensive care unit with aSAH. The primary outcome was incidence of hyperchloremia (chloride >109 mEq/L). Secondary outcomes included incidence of severe hyperchloremia (chloride >115 mEq/L), incidence of acute kidney injury (AKI), need for renal replacement therapy (RRT), intensive care unit (ICU) length of stay (LOS), hospital LOS, and in-hospital mortality. Results: Of the 234 patients included in the analysis, hyperchloremia occurred in 75% (n=175), and 58% (n=101) developed severe hyperchloremia. Median time to onset was 3 days (interquartile range, 1–5) after admission. Hyperchloremia was associated with prolonged ICU LOS (12 vs. 8 days, P<0.001), duration of mechanical ventilation (16 vs. 10 days, P<0.001), hospital LOS (15 vs. 9 days, P<0.001), and in-hospital mortality (14.3% vs. 0%, P=0.002) compared to no hyperchloremia. No significant difference was observed in the incidence of AKI or the need for RRT. Maintenance intravenous fluids accounted for the highest proportion of the cumulative chloride burden. Conclusion: Hyperchloremia occurs at a high frequency in aSAH and is associated with poor patient outcomes. Maintenance intravenous fluids accounted for the highest proportion of cumulative chloride burden.