['Osmotherapy has been the cornerstone in the management of patients with elevated intracranial pressure (ICP) following traumatic brain injury (TBI). Several studies have demonstrated that hypertonic saline (HTS) is a safe and effective osmotherapy agent. This study evaluated the effectiveness of HTS in reducing intracranial hypertension in the presence of a wide range of serum and cerebrospinal fluid (CSF) osmolalities.', 'Forty-two doses of 23.4% saline boluses for treatment of refractory intracranial hypertension were reviewed retrospectively. Thirty milliliters of 23.4% NaCl was infused over 15\xa0min for intracranial hypertension, defined as ICP\xa0>20\xa0mmHg. The CSF and serum osmolalities from frozen stored samples were measured with an osmometer. The values of serum sodium, hourly ICP, blood urea nitrogen (BUN), and creatinine were obtained directly from the medical records.', 'The serum and CSF osmolalities correlated very closely to serum sodium (r\xa0>\xa00.9, P\xa0<\xa00.0001). The reduction in ICP from the baseline (measured from either the mean ICP or the lowest ICP measurement in the first 6\xa0h after bolus HTS treatment) was statistically significant regardless of serum osmolality. The mean reduction from baseline to follow-up values was 8.8\xa0mm Hg (P\xa0<\xa00.0001). The decrease in ICP was as evident with serum osmolalities\xa0>320 as it was at\xa0≤320.'] Does hypertonic saline reduce intracranial hypertension in the presence of high serum and cerebrospinal fluid osmolalities?