Respiratory muscle training in restrictive thoracic disease: a randomized controlled trial.

Objective: To investigate the effects of respiratory muscle training (RMT) in patients with restrictive thoracic disorders and intermittent noninvasive positive-pressure ventilation (NPPV).

Design: Prospective randomized controlled trial.

Setting: Home-based RMT, with assessment in a primary care pulmonary center.

Participants: Thirty patients with restrictive thoracic disorders; 28 patients completed the trial.

Intervention: Three months of RMT by isocapnic hyperpnea or sham training.

Main Outcome Measures: Respiratory muscle strength and endurance, lung function, exercise performance, and health-related quality of life (HRQOL).

Results: After RMT, maximal inspiratory mouth pressure was increased (27.6%+/-36.5%, P=.013). In patients who could perform cycle ergometer testing (n=17), peak oxygen consumption (2.24+/-3.39mLxkg(-1).min(-1) vs -1.71+/-2.54mLxkg(-1).min(-1), P=.014) and maximal work rate (9.4+/-14.8W vs -5.1+/-10.8W, P=.043) increased relative to a control group. Similar differences occurred regarding changes of HRQOL (physical performance, 3.3+/-11.4 score vs -6.6+/-9.0 score; P=.012) and time of ventilator use (-0.6+/-1.2h/d vs 0.4+/-0.5h/d, P=.010). Lung volumes, 12-second maximum voluntary ventilation, 6-minute walking distance, and blood gases were unchanged.

Conclusions: In patients with restrictive thoracic disorders and NPPV, RMT improved inspiratory muscle strength. Exercise performance and HRQOL were improved when the 2 groups were compared. RMT was practicable and safe despite severe respiratory impairment. Further evaluation, including different training intensities and modalities, seems warranted.