Characteristics and Outcomes of Critical Bronchiolitis During the 2022 Surge Compared With Baseline

Before COVID-19, pediatric intensive care unit (PICU) admissions for bronchiolitis had a predictable seasonal variability. Since 2020, patterns have differed markedly, with a historic "surge" in late 2022 that strained hospitals nationwide. We aimed to compare patient characteristics and outcomes of critical bronchiolitis during the surge to baseline periods.

Data were obtained from the Virtual Pediatric Systems database for patients younger than 2 years with a primary diagnosis of bronchiolitis admitted to a PICU between July 2015 and December 2022. The surge period was defined as October 2022 to December 2022. The COVID-19 period was excluded. Categorical variables were compared with chi-square tests. Continuous variables were compared with Wilcoxon rank-sum tests.

Data were analyzed on 63 838 patients. Admissions per center per quarter were nearly 3-fold higher in the surge compared with baseline (60.0 [41.8-132.5] vs 21.0 [9.0-44.2], P < .001). The surge was associated with large increases in noninvasive continuous positive airway pressure (22.2% vs 15.3%, P < .001) and noninvasive bilevel positive airway pressure (21.0% vs 18.6%; P < .001), with no change in intubation rates (13.3% vs 12.6%, P = .091). Relative to baseline, cardiac arrest rates doubled (0.9% vs 0.5%; P < .001) and there was an increase in acquired morbidity (decline in Pediatric Cerebral Performance Categories or Pediatric Overall Performance Category score). In a secondary analysis, including the peak period of each year, similar trends were noted.

The 2022 surge was characterized by historically large PICU patient volumes and increased rates of noninvasive respiratory support, cardiac arrest, and acquired morbidity. Contributing factors may include changes in host susceptibility, illness severity, clinician behavior, and institutional practices regarding noninvasive support outside the PICU.