Impact of Hypertonic Saline on Outcomes after Decompressive Hemicraniectomy for Malignant Edema

Background Hypertonic saline (HTS) is widely used to control malignant cerebral edema (MCE) around decompressive hemicraniectomy (DHC), but its impact on clinical outcomes remains uncertain. We hypothesized that higher HTS exposure does not improve outcomes among patients undergoing DHC. Methods We retrospectively identified consecutive adults with ischemic stroke and MCE admitted to a tertiary stroke center (years: 2017‐2021). Patients were grouped by DHC status, with a prespecified primary analysis restricted to the DHC cohort. Exposures included total sodium dose from osmotic agents and serum sodium metrics (peak/mean where available). Outcomes were in‐hospital mortality, discharge modified Rankin Scale (mRS), acute kidney injury (AKI), and adverse events. Multivariable logistic/ordinal regression adjusted for age, stroke severity, infarct territory, midline shift, and timing of DHC. Results Ninety‐six patients met criteria (DHC n=46; non‐DHC n=50). Compared with non‐DHC, the DHC group received higher cumulative sodium dosing and more mannitol (both p <0.01), reflecting greater illness severity. Within the DHC cohort, higher HTS exposure (by total sodium dose and by serum sodium concentration) was not associated with lower mortality, better functional outcome at discharge, or improved ICP control after adjustment. Higher HTS exposure did not increase the frequency of AKI. In exploratory analyses, greater pre‐operative HTS use predicted subsequent performance of DHC, suggesting it functions as a marker of refractory edema rather than a modifier of outcome. Conclusions Among patients undergoing DHC for MCE, greater HTS exposure and higher serum sodium levels were not associated with improved survival, functional outcomes, or ICP control, and were not linked to excess renal complications. HTS remains useful for short‐term physiologic management, but our findings suggest it should not be expected to alter clinical outcomes in patients who progress to DHC. Prospective studies are needed to define optimal peri‐DHC osmotherapy strategies.