Initial serum electrolyte imbalances and mortality in patients with traumatic brain injury: a retrospective study

Electrolyte imbalance is common following traumatic brain injury (TBI) and can significantly impact patient outcomes. We aimed to explore the occurrence, patterns, and consequences of electrolyte imbalance in adult patients with TBI.

A retrospective study was conducted from 2016 to 2021 at a level 1 trauma center among hospitalized TBI patients. On admission, the levels of serum electrolytes, including sodium, potassium, calcium, magnesium, and phosphate, were analyzed. Demographics, injury characteristics, and interventions were assessed. The primary outcome was the in-hospital mortality. Multivariate logistic regression analysis was performed to identify independent predictors of mortality in TBI patients.

A total of 922 TBI patients were included in the analysis, of whom 902 (98%) had electrolyte imbalance. The mean age of patients with electrolyte imbalance was 32.0±15.0 years. Most patients were males (94%). The most common electrolyte abnormalities were hypocalcemia, hypophosphatemia, and hypokalemia. The overall in-hospital mortality rate was 22% in the entire cohort. In multivariate logistic analysis, the predictors of mortality included age (odds ratio [OR]=1.029, 95% confidence intervals [CI]: 1.013-1.046, P<0.001), low GCS (OR=0.883, 95%CI: 0.816-0.956, P=0.002), high Injury Severity Score (ISS) scale (OR=1.051, 95%CI: 1.026-1.078, P<0.001), hypernatremia (OR=2.175, 95%CI: 1.196-3.955, P=0.011), hyperkalemia (OR=4.862, 95%CI: 1.222-19.347; P=0.025), low serum bicarbonate levels (OR=0.926, 95%CI: 0.868-0.988, P=0.020), high serum lactate levels (OR=1.128, 95%CI: 1.022-1.244, P=0.017), high glucose levels (OR=1.072, 95%CI: 1.014-1.133, P=0.015), a longer activated partial thromboplastin time (OR=1.054, 95%CI: 1.024-1.084, P<0.001) and higer international normalized ratio (INR) (OR=3.825, 95%CI: 1.592-9.188, P=0.003).

Electrolyte imbalance is common in TBI patients, with the significant prevalence of hypocalcemia, hypophosphatemia, and hypokalemia. However, hypernatremia and hyperkalemia were associated with the risk of mortality, emphasizing the need for further research to comprehend electrolyte dynamics in TBI patients.