(1203) A Matched Analysis of the Use of High-Flow Nasal Cannula for Pediatric Severe Acute Asthma

Introduction: The high flow nasal cannula (HFNC) device is commonly used to treat pediatric severe acute asthma. However, there is little evidence for its effectiveness in real-world practice. We sought to compare the physiologic effects and clinical outcomes for children treated for severe acute asthma with HFNC vs. matched controls.

Methods: This was a single center retrospective matched cohort study at a quaternary care children’s hospital. Children ages 2-18 hospitalized for severe acute asthma from 2015-2022 were included. Encounters receiving treatment with HFNC within the first 24 hours of hospitalization were included as cases. Controls were treated with oxygen facemask. Logistic regression 1:1 propensity score matching was done using demographics, initial vital signs, and medications. The primary outcome was improvement in clinical asthma symptoms in the first 24 hours of hospitalization measured as percent change from initial.

Results: Of 693 eligible cases, 451 were matched to eligible controls. Propensity scores were closely aligned between the cohorts, with the only significant difference in characteristics being a higher percentage of patients of Black race in the control group (54.3% vs. 46.6%; p=0.02). Compared to the matched controls, the HFNC cohort had smaller improvements in heart rate (-11.5% [-20.9;-0.9] vs. -14.7% [-22.6;-5.7]; p< 0.01), respiratory rate (-14.3% [-27.9;5.4] vs. -16.7% [-31.5;0.0]; p=0.03), and pediatric asthma severity score (-14.3% [-28.6;0.0] vs. -20.0% [-33.3;0.0]; p< 0.01) after 24 hours of hospitalization. The HFNC cohort also had longer pediatric intensive care unit (PICU) length of stay (LOS) (1.5 days [1.1;2.1] vs. 1.2 days [0.9;1.8]; p< 0.01) and hospital LOS (2.8 days [2.1;3.8] vs. 2.5 days [1.9;3.4]; p< 0.01). When subgrouping to younger patients (2-3 years old), or those with the highest severity (PASS>9), those treated with HFNC had no difference in symptom improvements but maintained a longer PICU LOS.

Conclusions: Encounters using HFNC for severe acute pediatric asthma had decreased clinical improvement in 24 hours of hospitalization compared to matched controls, and increased LOS. Specific subgroups of younger patients, and those with the highest severity scores showed no differences in clinical symptom improvement and may benefit from HFNC therapy.