Bronchiolitis trends in out-of-hospital urgent care services in the Community of Madrid: Observational study, 2016-2023.

Introduction: Bronchiolitis poses a considerable challenge during its seasonal peak, overwhelming the material and human resources available to care for affected patients. As a result, interhospital transfers increase exponentially. We did not find any studies analysing the characteristics of patients with bronchiolitis managed in out-of-hospital urgent care (OHUC) services and the impact of the COVID-19 pandemic on the epidemiology of bronchiolitis.

Objective: To establish the characteristics of paediatric and neonatal patients with acute bronchiolitis (AB) managed in OHUC services in the Community of Madrid and to analyse the impact of the COVID-19 pandemic on the epidemiology of bronchiolitis.

Methods: Retrospective cross-sectional observational and descriptive study carried out in OHUC settings in the Community of Madrid between 2016 and 2023. We included patients with a diagnosis of acute bronchiolitis based on the ICD-10 codes documented in the electronic records of urgent care visits and interhospital transports. We collected data on sociodemographic, clinical and treatment (ventilation and medication) variables.

Results: The sample included 630 patients with AB: 343 managed in non-neonatal OHUC (non-neo) services and 287 by the mobile neonatal intensive care unit transport team (NTT). The median age was 3.7 months (IQR, 2.8-4.7) in patients in the non-neo OHUC group and 19 days (IQR, 14.2-23.7) in the NTT group. There was a statistically significant increase in age in the 2020/2021 season in the non-neo OHUC group. The severity score was significantly higher in the NTT group. There was an unusual peak in bronchiolitis cases in June 2021, coinciding with the end of the 4th wave of the COVID-19 pandemic. The incidence of bronchiolitis was highest after the 6th wave of the pandemic (13.5 cases per 10 000 children aged < 2 years).

Conclusions: The median age of paediatric patients with AB managed in OHUC services increased following the end of the lockdown imposed due to the COVID-19 pandemic, which was probably associated with the lack of exposure to the viruses that cause it. This also may explain why the incidence of bronchiolitis was highest in the season following the 6th wave of the pandemic. The severity score was higher in neonatal patients. Epidemiological surveillance, the introduction of protocols and the implementation of an ongoing training programme for non-specialized health care staff involved in the transport of these patients could improve their management.