Feasibility of inspiratory muscle training for patients with persistent dyspnea after COVID-19 infection

Objective: This study investigates the feasibility of delivering inspiratory muscle training as part of the physical therapy treatment for patients with post-COVID dyspnoea. Design: Mixed-methods pilot study. Subjects/patients: Patients with complaints of dyspnoea after COVID-19 infection and their physical therapists. Methods: The Amsterdam University of Applied Sciences and the Amsterdam University Medical Centers conducted this study. Participants performed daily inspiratory muscle training at home for 6 weeks, consisting of 30 repetitions against a pre-set resistance. The primary outcome was feasibility assessed as acceptability, safety, adherence and patient- and professional experience obtained through diaries and semi-structured interviews. The secondary outcome was maximal inspiratory pressure. Results: Sixteen patients participated. Nine patients and 2 physical therapists partook in semi-structured interviews. Two patients dropped out before initiating the training. Adherence was 73.7%, and no adverse events occurred. Protocol deviations occurred in 29.7% of the sessions. Maximal inspiratory pressure changed from 84.7% of predicted at baseline to 111.3% at follow-up. Qualitative analysis identified barriers to training: ‘Getting acquainted with the training material’ and ‘Finding the right schedule’. Facilitators were: ‘Support from physical therapists’ and ‘Experiencing improvements’. Conclusion:Delivering inspiratory muscle training to patients with post-COVID dyspnoea seems feasible. Patients valued the simplicity of the intervention and reported perceived improvements. However, the intervention should be carefully supervised, and training parameters adjusted to individual needs and capacity.