To assess the effects of dysnatremia following aneurysmal subarachnoid hemorrhage (aSAH) on patient outcomes.

Abnormalities in serum sodium are common in patients with aSAH but their potential effects on clinical outcomes are not completely understood.

The cohort consisted of 320 patients (mean age 57.8 years (SD 14.3), 61% female, 70% white). Hyponatremia occurred in 58% of cases, 5% of which were moderate-severe, for a median of 3 days [IQR 1-6]. Hypernatremia occurred in 49% of cases, 56% of which were moderate-severe, for a median of 5 days [IQR 2-8]. Hypertonic saline was administered for treatment of cerebral edema in 80% of hypernatremic patients. Patients with hypernatremia had a higher odds of vasospasm (OR 1.75, 95% CI 1.02-303, p=0.04), adjusted for Hunt and Hess grades, cerebral edema, and modified Fisher scales. Dysnatremia was not independently associated with mRS, DCI, or refractory hydrocephalus. Patients with hypernatremia had a longer hospital LOS (8.11 more days, 95% CI 5.4-10.8; p<0.001) independent of age, Hunt and Hess grades, modified Fisher scales, and complications including cerebral edema, vasospasm, DCI, and refractory hydrocephalus.

These findings may be used to inform the management of patients with aSAH, for whom cautious use of hypertonic saline and avoidance of hypernatremia is recommended.