Hypernatremia severity and the risk of death after traumatic brain injury.

PURPOSE: To investigate the relationship between severity of hypernatremia and the risk of death for patients with traumatic brain injury (TBI) who have been admitted to the neurosurgical intensive care unit (NICU).

METHODS: A total of 1044 patients with TBI were admitted to our NICU from January 2005 to January 2010. Of these patients, 881 were included in this study. Based on blood serum sodium level in the NICU the 881 patients were divided into four groups: 614 had normal serum sodium (Na<150mmol/L), 34 had mild hypernatremia (Na 150-<155mmol/L), 66 had moderate hypernatremia (Na 155-160mmol/L) and 167 had severe hypernatremia (Na≥160mmol/L).

RESULTS: The mortality rates for the mild, moderate, and severe hypernatremia groups were 20.6%, 42.4%, and 86.8%, respectively; the mortality rate for the normal group was 2.0%. In multivariable analysis, mild, moderate, and severe hypernatremia were independent risk factors for mortality; compared with the normal group the odds ratios of mild, moderate, and severe hypernatremia were 9.50, 4.34, and 29.35, respectively.

CONCLUSIONS: Severe hypernatremia is an independent risk factor with extremely high odds ratio for death in patients with TBI who are admitted to the NICU.