The effectiveness of a mobile high‐frequency chest wall oscillation (HFCWO) device for airway clearance

INTRODUCTION: High-frequency chest wall oscillation (HFCWO) is a commonly prescribed airway clearance technique (ACT) for patients whose ability to expectorate sputum is compromised. This study aimed to assess the effectiveness of a newly developed mobile ACT device (mHFCWO-The Monarch Airway Clearance System) in patients with cystic fibrosis (CF). A standard nonmobile HFCWO device (sHFCWO) was used as a comparator. METHODOLOGY: This was a randomized, open-label, crossover pilot study. CF patients were treated with each device. Sputum was collected during and after each therapy session, while spirometry tests, Brody score assessment and functional respiratory imaging were performed before and after treatments. RESULTS: Wet weight of sputum collected during and after treatment was similar for mHFCWO and sHFCWO (6.53 ± 8.55 vs 5.80 ± 5.82; P = .777). Interestingly, the mHFCWO treatment led to a significant decrease in specific airway volume (9.55 ± 9.96 vs 8.74 ± 9.70 mL/L; P < .001), while increasing specific airway resistance (0.10 ± 0.16 vs 0.16 ± 0.23 KPA*S; P < .001). These changes were heterogeneously-distributed throughout the lung tissue and were greater in the distal areas, suggesting a shift of mucus. Changes were accompanied by an overall improvement in the Brody index (57.71 ± 16.55 vs 55.20 ± 16.98; P = .001). CONCLUSION: The newly developed mobile device provides airway clearance for CF patients comparable to a nonmobile sHFCWO device, yielding a change in airway geometry and patency by the shift of mucus from the more peripheral regions to the central airways.