Initial dysnatremia and clinical outcomes in pediatric traumatic brain injury: a multicenter observational study

Purpose: We aimed to investigate the association between initial dysnatremia (hyponatremia and hypernatremia) and in-hospital mortality, as well as between initial dysnatremia and functional outcomes, among children with traumatic brain injury (TBI). Method: We performed a multicenter observational study among 26 pediatric intensive care units from January 2014 to August 2022. We recruited children with TBI under 18 years of age who presented to participating sites within 24 h of injury. We compared demographics and clinical characteristics between children with initial hyponatremia and eu-natremia and between those with initial hypernatremia and eu-natremia. We defined poor functional outcome as a discharge Pediatric Cerebral Performance Category (PCPC) score of moderate, severe disability, coma, and death, or an increase of at least 2 categories from baseline. We performed multivariable logistic regression for mortality and poor PCPC outcome. Results: Among 648 children, 84 (13.0%) and 42 (6.5%) presented with hyponatremia and hypernatremia, respectively. We observed fewer 14-day ventilation-free days between those with initial hyponatremia [7.0 (interquartile range (IQR) = 0.0–11.0)] and initial hypernatremia [0.0 (IQR = 0.0–10.0)], compared to eu-natremia [9.0 (IQR = 4.0–12.0); p = 0.006 and p < 0.001]. We observed fewer 14-day ICU-free days between those with initial hyponatremia [3.0 (IQR = 0.0–9.0)] and initial hypernatremia [0.0 (IQR = 0.0–3.0)], compared to eu-natremia [7.0 (IQR = 0.0–11.0); p = 0.006 and p < 0.001]. After adjusting for age, severity, and sex, presenting hyponatremia was associated with in-hospital mortality [adjusted odds ratio (aOR) = 2.47, 95% confidence interval (CI) = 1.31–4.66, p = 0.005] and poor outcome (aOR = 1.67, 95% CI = 1.01–2.76, p = 0.045). After adjustment, initial hypernatremia was associated with mortality (aOR = 5.91, 95% CI = 2.85–12.25, p < 0.001) and poor outcome (aOR = 3.00, 95% CI = 1.50–5.98, p = 0.002). Conclusion: Among children with TBI, presenting dysnatremia was associated with in-hospital mortality and poor functional outcome, particularly hypernatremia. Future research should investigate longitudinal sodium measurements in pediatric TBI and their association with clinical outcomes.