Electrically stimulated ventilation feedback improves the ventilation pattern in patients with COPD

[Purpose] We aimed to determine the effects of ventilation feedback using electrical stimulation on ventilation pattern during exercise in patients with chronic obstructive pulmonary disease (COPD), and develop new rehabilitation methods. [Subjects] This randomized double-blind placebo-controlled trial included 24 patients with COPD. [Methods] Phasic electrical stimulation during expiration (PESE) or a placebo was given to all the cases. Minute ventilation (VE), tidal volume (TV), respiratory rate (RR), expiratory time (Te), total respiratory time (Ttot), dead-space gas volume to tidal gas volume (VD/VT), oxygen uptake (VO(2)), carbon dioxide output (VCO(2)), Borg scale (Borg), and percutaneous oxygen saturation (SpO(2)) during rest and exercise were assessed. [Results] The placebo group showed no obvious change in ventilation measurements at rest or during exercise. However, in the PESE group, TV, Te, and Ttot significantly increased, while RR and VD/VT significantly decreased during exercise compared with the baseline measurements. Borg scores, SpO(2), VO(2), or VCO(2) did not differ significantly. [Conclusion] PESE improves the ventilation pattern during rest and exercise. Furthermore, PESE does not increase VO(2), which may indicate an increased workload. Biofeedback may contribute to PESE effects. Stimulation applied during expiration may evoke sensations increasing prolonged expiration awareness, facilitating prolongation.