This was a single center retrospective study of neurocritically ill adults (≥18 years of age) who received ≥2 boluses and/or continuous infusion of HTS at a level one trauma center. Exclusion criteria included vulnerable populations, preexisting hyponatremia (baseline sodium ≤135 mEq/L), or no sodium levels obtained following HTS administration. The primary outcome was the generation of a serum sodium prediction model using a Random Forest Model that was tuned to hyperparameters via grid search and used 5‑fold group‑vfold cross‑validation by patient to prevent leakage. Performance was assessed on a held‑out test set of patients using root mean squared error (RMSE), mean absolute error (MAE), R², calibration (slope/intercept), and residual diagnostics. Secondary safety outcomes included rates of hyperchloremia (>115 mEq/L), acute kidney injury, and the need for delayed neurosurgical intervention or renal replacement therapy.
