Combination of inspiratory and expiratory muscle training in same respiratory cycle versus different cycles in COPD patients: a randomized trial

Wenhui Xu,Rui Li,Rongchang Chen,Yuhe Hu,Xin Chen,Luqian Zhou,Limei Xu,Kai Wang,Lili Guan

doi:10.1186/s12931-018-0917-6

Abstract

BackgroundDifference between combined inspiratory and expiratory muscle training in same respiratory cycle or different cycles remained unclarified. We explored the difference between both patterns of combined trainings in patients with COPD.MethodsIn this randomized, open-label, controlled trial, stable COPD subjects trained for 48 minutes daily, for 8 weeks, using a monitoring device for quality control. Ninety-two subjects were randomly and equally assigned for sham training, inspiratory muscle training(IMT), combined inspiratory and expiratory muscle training in same cycle(CTSC) or combined inspiratory and expiratory muscle training in different cycles(CTDC). Respiratory muscle strength, as the primary endpoint, was measured before and after training. Registry: ClinicalTrials.gov (identifier: NCT02326181).ResultsRespiratory muscle training improved maximal inspiratory pressure(PImax), while no significant difference was found in PImax among IMT, CTSC and CTDC. Maximal expiratory pressure(PEmax) in CTSC and CTDC was greater than IMT(P = 0.026, and P=0.04, respectively) and sham training (P = 0.001). IMT, CTSC, and CTDC shortened inhalation and prolonged exhalation(P < 0.01). Subjects with respiratory muscle weakness in IMT and CTDC exhibited greater increase in PImax than those without. IMT, CTSC and CTDC showed no difference in symptoms and quality of life scales among themselves(P > 0.05).ConclusionBoth patterns of CTSC and CTDC improved inspiratory and expiratory muscle strength, while IMT alone only raised PImax. Respiratory muscle training might change the respiratory cycles, and be more beneficial for COPD patients with inspiratory muscle weakness.

Highlights

Patients with Chronic obstructive pulmonary disease (COPD) generally suffer from respiratory muscle dysfunction [1]
Two subjects in Inspiratory muscle training (IMT) discontinued due Spirometry and exercise capacity No significant changes were observed in ΔFVC, ΔFEV1, ΔFEV1%pred, ΔFEV1/forced vital capacity (FVC), and Δ 6MWD among groups (P > 0.05) (Table 2)
The ΔSGRQ and ΔCAT of IMT, CTSC, and CTDC were notably lower than Sham training (P < 0.05), but no significant difference among groups was found (P > 0.05)

Summary

Introduction

Patients with COPD generally suffer from respiratory muscle dysfunction [1]. Severe respiratory muscle dysfunction can lead to problems such as dyspnea, hypoxemia, and decreased exercise capacity. IMT has been suggested as an important solution to decreased respiratory muscle function [4]. It has shown that IMT in patients with COPD can delay deterioration of lung function via increasing inspiratory muscle strength and endurance, which relieves dyspnea, and improves quality of life [5, 6]. It is known that expiratory muscles are usually activated at the end of expiration in COPD patients during rest, or weight-bearing breathing [9]. This helps to maintain respiratory function [10]. Difference between combined inspiratory and expiratory muscle training in same respiratory cycle or different cycles remained unclarified. We explored the difference between both patterns of combined trainings in patients with COPD

Methods

Results

Discussion

Conclusion