Sodium dysbalances in neurointensive care: results of a 5-year prospective study

Introduction

Sodium dysbalances represent important complications in neurointensive care. The aim of this study was to analyse sodium dysbalances and their relationship to outcome in the neurologic-neurosurgical care unit (NNICU) over a period of 5 years.

Methods

We prospectively evaluated patients with brain diseases, who developed serum sodium below 135 mmol/l (hyponatremia) or above 150 mmol/l (hypernatremia). We compared the incidence of cerebral complications, Glasgow Outcome Scale upon discharge from the NNICU and mortality in the NNICU between these two groups.

Results

In the 5-year observation period, serum sodium dysbalances occurred in 378 (24%) patients. The majority of them had hyponatremia (245 patients, 65%); hypernatremia was less frequent, in 133 (35%) patients. Hypernatremic patients stayed in the NNICU longer (P = 0.035), onset of hypernatremia arose in patients with significantly lower Glasgow Coma Scale (P = 0.001). These patients had more cerebral complications (P < 0.001), worse Glasgow Outcome Scale upon discharge from the NNICU (P < 0.001), higher mortality in the NNICU (P = 0.003) and higher incidence of pulmonary edema (P = 0.021). They received more antiedematic therapy (P < 0.001) and diuretics (P < 0.001). On the other hand, hyponatremia was more frequent upon entry to the NNICU (P < 0.001) and arose later after brain damage (P < 0.001) in comparison with hypernatremia.

Conclusions

In neurointensive care, hypernatremia was a prognostically more serious and less frequent sodium dysbalance than hyponatremia.