Mucous hypersecretion and plugging contribute to airway obstruction during asthma exacerbations. HFCWO may be a novel strategy for mechanical airway clearance to improve outcomes in patients with asthma exacerbations. The primary objective of this pilot study was to assess patient acceptability of HFCWO during asthma exacerbations.
Randomized, double-masked, controlled clinical trial comparing active and sham HFCWO (15 minute treatments, 3 treatments prescribed/day). Patients age >18 years hospitalized with physician-diagnosed asthma exacerbation were eligible. Patients with other chronic respiratory diseases were excluded. Inpatient asthma therapy was standardized across treatment groups. Outcomes were assessed at a follow-up visit after 4 treatments. The primary outcome was adherence to HFCWO ([# minutes used]/[# minutes prescribed] X 100%), and patient-reported comfort and perceived benefit. Secondary outcomes were: change in FEV1 % predicted (follow-up –pre-treatment), spontaneously expectorated sputum volume, and change in Borg dyspnea score.
Eight participants (N=4 per group) were enrolled. Baseline patient characteristics were similar between treatment groups: mean [SD] age 40.4 [12.7] years, 62% female, 75% African-American, median FEV1 = 45.3% [range 23.2-85.3%] and Borg dyspnea score = 4 [range 0-10]. Adherence to HFCWO was high (mean 98.1%; range 87% -100%), and 100% of participants agreed that the study vests were comfortable and 100% agreed that the study vests helped them feel better; differences between groups were not significant. Mean [SD] change in FEV1% predicted (1.8% [12.4%] vs. 3.7% [10.4%], p=0.82; active vs. sham) and median [range] sputum volume (20mL [15-35mL] vs. 20mL [10-45mL]; p=0.77) were similar between groups. There was a trend towards greater improvement in dyspnea in the active HFCWO treatment group (mean change [SD] in Borg dyspnea score, -3.6 [3.5] vs. 0 [0.8]; p=0.09).
HFCWO is feasible and may improve dyspnea during asthma exacerbations.
Further research is needed to evaluate the role of HFCWO in improving clinical outcomes in this population.
J.A. Krishnan, Advanced Respiratory, Inc.