The effects of threshold inspiratory muscle training in patients with chronic obstructive pulmonary disease: A randomised experimental study

Abstract

Aims and objectives: To investigate the effects of threshold inspiratory muscle training in patients with stages II through IV chronic obstructive pulmonary disease using maximum inspiratory pressure, baseline dyspnoea index, 6-minute walk test and quality of life.

Background: A threshold inspiratory muscle training device provides pressure for inspiratory muscle strength, but there is limited information on the effects of threshold inspiratory muscle training starting at low pressure training.

Design: Randomised experimental design.

Methods: A total of 55 patients completed this study between September 2013-April 2014. The experimental group (n = 27) was provided medical treatment and routine care, along with five sessions of threshold inspiratory muscle training per week (21-30 min per session), accompanied by a progressive increase in the pressure threshold over a period of 8 weeks. The control group (n = 28) was provided medical treatment and routine care only, without intervention. In the inferential analysis, p values <.05 were considered to indicate statistical significance.

Results: After 8 weeks in the experimental group, mean maximum inspiratory pressure improved by -17.6 ± 0.18 cmH₂ O, mean 6-minute walk test improved by 47.8 ± 1.46 m, and the baseline dyspnoea index increased from 4.48 ± 2.12 points to 9.0 ± 2.27 points. These data and quality of life were statistically different between the experimental and the control groups (p < .05).

Conclusions: The threshold inspiratory muscle training can reduce patients' difficulties with respect to daily activities, thereby reducing the burden on the family, and improving prognosis in patients with moderate-to-very severe chronic obstructive pulmonary disease.

Keywords: chronic obstructive pulmonary disease; experimental design; inspiratory muscle training; respiratory nursing.