Electrolyte Testing Variability Among Critically Ill Children With Viral Bronchiolitis.

Background Viral bronchiolitis is the most common indication for pediatric hospitalization for children under 12 months, and admissions for critical bronchiolitis and associated hospital charges continue to rise. Despite this, electrolyte testing practices among children admitted to pediatric intensive care units with bronchiolitis are not well described. This study evaluates the frequency of electrolyte testing and the extent of variation in testing practices across U.S. pediatric ICUs (PICUs). Methods We conducted a multicenter, retrospective cohort study of children admitted to PICUs with viral bronchiolitis between January 1, 2017, and December 31, 2021, using the Pediatric Health Information System database. The primary outcomes were (1) the rate of any electrolyte testing and (2) the rate of multiple electrolyte testing during each PICU hospitalization. Results Among 23,776 patient encounters, 79% (18,825/23,776) received at least one electrolyte test. Substantial between-hospital variation was observed in the rates of both initial and repeat testing. Hospital-level differences accounted for 32% of the overall variation in any electrolyte testing and 44% of the variation in multiple testing. Among patients who received at least one test (n = 18,825), 80% (15,016) underwent multiple electrolyte tests, while 20% (3,809) received only a single test. Conclusion Significant national variation exists in electrolyte testing practices among PICU patients with viral bronchiolitis. These findings highlight substantial heterogeneity in current practice and underscore the need for future studies incorporating clinical context to better define when electrolyte testing is most informative and how testing practices relate to patient characteristics and outcomes.