Effects of inspiratory muscle training in patients with chronic obstructive pulmonary disease.

Rationale:

Respiratory muscle weakness is commonly observed in patients with COPD and contributes to reduced exercise capacity and dypnea. It is, however, still unclear if supplemental interventions to support exercise training programs such as inspiratory muscle training (IMTresult in clinically relevant improvements for patients. Meta-analyses of RCT¡¯s in patients with COPD revealed that IMT might have most beneficial effects on exercise capacity in patients with clearly reduced inspiratory muscle strength. However, the effectiveness of these interventions, when added to general exercise training programs, needs to be tested in randomized controlled trials (RCTs).



Objective:

In this project the effects of adding IMT to a 3-months general exercise training program will be compared with a regular 3-months general exercise training program on exercise capacity, HRQL and participation in daily physical activity in patients with COPD and inspiratory muscle weakness. The effects of IMT on breathing pattern and symptoms of dyspnea and leg fatigue during exercise will be assessed as secondary objectives.



Study design:

Randomized controlled trial, multicentre.



Study population:

All patients with spirometry-proven stable COPD that are referred for outpatient pulmonary rehabilitation will be screened for inclusion. Only patients with pronounced inspiratory muscle weakness (PI,max < 60cmH2O) will be eligible to participate in the study.



Intervention:

Patients agreeing to participate will be randomized into an intervention and a control group. Both groups will follow a general exercise training program. The intervention group will receive an additional inspiratory muscle training program at a high intensity (≥ 30% PI,max), whereas the control group will receive an inspiratory muscle training intervention at a low training intensity (¡Ü 10% PI,max).



Main study parameters/endpoints:

Improvement in the six-minute walking distance. A clinical relevant difference in improvement of the six minute walking distance between both groups is defined as 35m.

The addition of inspiratory muscle training to a general exercise training program improves inspiratory muscle strength, exercise capacity, health related quality of life and participation in daily physical activity in patients with COPD suffering from inspiratory muscle weakness.

At start and at end of rehabilatation (3 months).

Additional to general pulmonary rehabilatation prpgram: Inspiratory muscle training at a high intensity (≥ 30% PI,max), whereas the control group will receive an inspiratory muscle training intervention at a low training intensity (≤ 10% PI,max).