Traumatic Brain Injury, Electrolyte Levels, and Associated Outcomes: A Systematic Review.

Introduction: Although it has been established that electrolyte abnormalities are a consequence of traumatic brain injury (TBI), the degree to which electrolyte imbalances impact patient outcomes has not been fully established. We aim to determine the impact of sodium, potassium, calcium, and magnesium abnormalities on outcomes in patients with TBI.

Methods: Four databases were searched for studies related to the impact of electrolyte abnormalities on outcomes for TBI patients. Outcomes of interest were rates of mortality, Glasgow Outcome Scale (GOS), and intensive care unit length of stay (ICU-LOS). The search included studies published up to July 21, 2022. Articles were then screened and included if they met inclusion and exclusion criteria.

Results: In total, fourteen studies met inclusion and exclusion criteria for analysis in this systematic review. In patients with TBI, an increased mortality rate was associated with hypernatremia, hypokalemia, and hypocalcemia in the majority of studies. Both hyponatremia and hypomagnesemia were associated with worse GOS at 6 months. Whereas, both hyponatremia and hypernatremia were associated with increased ICU-LOS. There was no evidence to suggest other electrolyte imbalances were associated with either GOS or ICU-LOS.

Conclusions: Hyponatremia and hypomagnesemia were associated with worse GOS. Hypernatremia was associated with increased mortality and ICU-LOS. Hypokalemia and hypocalcemia were associated with increased mortality. Given these findings, future practice guidelines should consider the effects of electrolytes' abnormalities on outcomes in TBI patients prior to establishing management strategies.