Impact of Hypernatremia on Patients with Traumatic Brain Injury

Background: Hypernatremia is frequently encountered in the neurocritical intensive care units (ICUs) and its effect can badly affect the mortality. Objective: To verify whether the occurrence of hypernatremia during the ICU stay increases the risk of death in patients with severe traumatic brain injury (TBI). Methods: Randomized prospective study; 100 patients with TBI in Neurocritical care units at Cairo University Hospitals. Hypernatremia is defined as serum sodium above 145mmol/l. Logistic regression models were used to assess independent factors that could affect patients' mortality including hypernatremia, age, desmopressin and Glasgow Coma Score. Results: We included in the study 100 TBI patients (mean age 35.8±21.3 years); males 86%. Extradural hematoma (EDH) was documented in 27pts (27%), subarachnoid hemorrhage (SAH) in 20 pts (20%), intracerebral hemorrhage (ICH) in 19 pts (19%), cerebral contusion in 17 pts (17%), brain oedema in 15 pts (15%) & acute subdural hematoma in 2 pts (2%). Glasgow Coma Scores (range 3 to 10); 60 pts were mechanically ventilated; 10% were diabetic & 22% hypertensives. Hypernatremia was documented in 40 pts (40%) of total 100 pts with TBI. The total in-hospital mortality was 36 pts 100 (36%), 10 of them had normal sodium levels all over of their in hospital course and 26 pts were hypernatremic. After adjustment for the baseline risk, the incidence of hypernatremia over the course of the ICU stay was significantly related with increased mortality (hazard ratio 3.2 ( p :0.0001). However. there was positive correlation between serum sodium levels and duration of the ICU stay (Spearman correlation coefficient 0.5 and p value 0.002). Conclusions: Hypernatremia in patients with severe TBI is associated with an increased risk of death and a longer ICU stay. This association is independent of other outcome predictors including age and Glasgow Coma Score. Strategies to prevent hypernatremia in neurocritical ICUs should be encouraged.