(871) Characteristics and Outcomes of Critical Bronchiolitis During the 2022 Surge Compared to Baseline

Introduction: Before COVID, PICU admission for viral bronchiolitis had predictable seasonal variability. Since 2020, patterns have differed markedly, with a historic “surge” in late 2022 that strained hospital capacity across the United States (US). Characteristics and outcomes of PICU bronchiolitis patients during the surge have not been described in a large multicenter database.

Methods: With local IRB and Virtual Pediatrics Systems (VPS) approval, data were obtained from the VPS “Virtual PICU” database for the surge (9/2022-12/2022) and a pre-COVD baseline period (1/2019-3/2020) for children < 2y of age with a primary diagnosis of bronchiolitis. Only centers with data from all study years were included. Categorical variables (including age per VPS policy) were compared with chi squared. Continuous variables (including average admissions per quarter for each center) were compared with Wilcoxon rank-sum and shown as median (IQR); p< 0.05 defined statistical significance.

Results: Among 5,510 surge and 21,628 baseline patients from 66 US PICUs, admissions per center per quarter were higher in the surge (57.5 [37.0-116.3] vs 21.7 [7.2-47.0], p< 0.001). The surge was associated with higher percentage of children aged < 28 days (7.3% vs 6.0%; p< 0.001), lower patient weight (6.9 [4.9-9.4] vs 7.5 [5.1-9.8] kg, p< 0.001), and a statistically significant but small decrease in use of high-flow nasal cannula (84.0% vs 85.4%, p< 0.01). Relative to baseline, use of non-invasive positive pressure increased 20% (36.5% vs 29.5%, p< 0.001) in the surge, intubation rates increased 20% (12.2% vs 10.2%, p< 0.001), cardiac arrest rates doubled (0.51% vs 0.20%; p < 0.001), and rate of a decline in pediatric cerebral performance category from PICU admission to discharge tripled (1.7% vs 0.6%; p< 0.01 [among 4329 children with data]).

Conclusions: Critical bronchiolitis patients during the 2022 surge were surprisingly younger and smaller, with similar use of high-flow nasal cannula. More concerningly, rates of intubation, cardiac arrest, and morbidity at PICU discharge were significantly increased from baseline. Contributing factors may include changes in host susceptibility, viral pathogenicity, provider behavior, and institutional practices regarding non-invasive support usage outside the PICU.