Inhaled L-Epinephrine As a Rescue Therapy in Critical Bronchiolitis

Viral bronchiolitis is the leading cause of nonelective admission to the PICU. Guidelines recommend management that focuses on supportive care. Evidence suggests that inhaled epinephrine may reduce lower airways resistance and work of breathing in critical bronchiolitis. It has been demonstrated at one institution that it is feasible to administer continuous inhaled epinephrine (CIE) via heated high-flow nasal cannula (HFNC).

To describe the demographic and clinical characteristics of patients with bronchiolitis who received CIE and assess their physiologic response to treatment compared with patients who received conventional therapy.

We performed a single-center retrospective cohort study of previously healthy children 0-2 years old admitted to the PICU with diagnosis of bronchiolitis from 2017 to 2023.

Physiologic response to treatment was assessed via analysis of vital signs and use of respiratory rate, oxygenation, heart rate (ROX-HR) index.

One hundred ninety-three patients were included in the study. Patients who received CIE were younger (median age, 4 vs. 7 mo old; p = 0.01) and smaller (7.0 vs. 8.4 kg; p = 0.06), presented with higher initial peak respiratory rates (70 vs. 50 beats/min; p < 0.0001), and had longer ICU stays (3.4 vs. 1.8 d; p < 0.001). Patients treated with CIE exhibited overall higher respiratory rates and lower ROX-HR indices, indicating more severe illness. Within the first 48 hours of treatment, patients receiving CIE demonstrated a more rapid improvement in both respiratory rate and ROX-HR index compared with those receiving conventional therapy.

In this cohort, CIE was used as novel therapy for younger, smaller patients with more severe bronchiolitis on presentation to the PICU. The physiologic changes suggest potential benefit of this therapy for patients who are not improving with conventional HFNC therapy.