Is inspiratory muscle training (IMT) an acceptable treatment option for people with chronic obstructive pulmonary disease (COPD) who have declined pulmonary rehabilitation (PR) and can IMT enhance PR uptake? A single-group prepost feasibility study in a home-based setting

Abstract

Objectives: This feasibility study aimed to assess the acceptability of inspiratory muscle training (IMT) in people with chronic obstructive pulmonary disease (COPD) who declined pulmonary rehabilitation (PR) as a potential treatment option or precursor to PR. Objectives were to assess attitudes to IMT, PR and alternatives to PR; factors influencing adherence with IMT and acceptability of outcome measures, research tools and study protocol.

Design: A pragmatic, mixed methods, prepost feasibility study was conducted. Recruitment took place over a 4-month period. Participants were followed up for a period of 6 months.

Settings: IMT sessions and assessments were conducted in the domiciliary setting.

Participants: Inclusion criteria: people over the age of 35, stable COPD, Medical Research Council Dyspnoea scale of 3 or above, declined PR.

Exclusion criteria: history of spontaneous pneumothorax, incomplete recovery from a traumatic pneumothorax, asthma, known recently perforated eardrum, unstable angina, ventricular dysrhythmias, cerebrovascular event or myocardial infarction within the last 2 months. Participants were selected from a purposive sample. Of the 22 potential participants screened, 11 were recruited and interviewed. Ten participants commenced IMT. Seven participants completed the follow-up assessment.

Intervention: Eight weeks of IMT twice a day, 5 days a week with visits once weekly by a physiotherapist. Unsupervised IMT twice a day three times a week until follow-up at 6 months.

Outcomes: Acceptability of IMT and the study process was explored via semi-structured interviews. Adherence with IMT was assessed by the Powerbreathe K3 device and participant diaries. Uptake of PR was identified.

Results: IMT was found to be acceptable. Adherence was explored. Four people went on to participate in PR.

Conclusions: Feasibility was established. A randomised controlled trial is warranted to establish efficacy and cost-effectiveness of IMT in those who decline PR and IMT as an intervention to promote uptake of PR.

Trial registration number: NCT01956565; Post-results.

Keywords: adherence; chronic airways disease; inspiratory muscle training; pulmonary rehabilitation; rehabilitation medicine; uptake.

Figure 1

Consort diagram. IMT, inspiratory muscle training; n, number; URTI, upper respiratory tract infection.

Figure 2

Training progression: load (weeks 1–8). P, participant.

Figure 3

Training intensity: average load, volume and power (weeks 1–8). PiMax, maximal inspiratory pressure; VC, vital capacity.

Figure 4

Training intensity: average load, volume and power (weeks 9–26). PiMax, maximal inspiratory pressure; VC, vital capacity.

Figure 5

PR uptake, adherence (weeks 9–26) and change in PiMax at 6 months. n/a, not appropriate; PiMax, maximal inspiratory pressure; PR, pulmonary rehabilitation.

Figure 6

PR uptake, T-Index (weeks 9–26) and change in PiMax at 6 months. n/a, not appropriate; PiMax, maximal inspiratory pressure; PR, pulmonary rehabilitation; T-Index, amount of work achieved during a session expressed as a percentage of the maximal potentially achievable work.

Figure 7

PR uptake, training load (weeks 9–26) and change in PiMax at 6 months. n/a, not appropriate; PiMax, maximal inspiratory pressure; PR, pulmonary rehabilitation.