Functional Electrical Stimulation-A New Therapeutic Approach to Enhance Exercise Intensity in Chronic Obstructive Pulmonary Disease Patients: A Randomized, Controlled Crossover Trial

Objective: To evaluate the effect of quadriceps functional electrical stimulation (FES)-cycling on exertional oxygen uptake (V˙o₂) compared with placebo FES-cycling in patients with chronic obstructive pulmonary disease (COPD).

Design: A randomized, single-blind, placebo-controlled crossover trial.

Setting: Pulmonary rehabilitation department.

Participants: Consecutive patients (N=23) with COPD Global Initiative for Chronic Obstructive Lung Disease stage 2, 3, or 4 (mean forced expiratory volume during the first second, 1.4±0.4L [50.3% predicted]) who had recently begun a respiratory rehabilitation program.

Intervention: Two consecutive 30-minute sessions were carried out at a constant load with active and placebo FES-cycling.

Main outcome measures: The primary outcome was mean V˙o₂ during the 30-minute exercise session. The secondary outcomes were respiratory gas exchange and hemodynamic parameters averaged over the 30-minute endurance session. Lactate values, dyspnea, and perceived muscle fatigue were evaluated at the end of the sessions.

Results: FES-cycling increased the physiological response more than the placebo, with a greater V˙o₂ achieved of 36.6mL/min (95% confidence interval [CI], 8.9-64.3mL/min) (P=.01). There was also a greater increase in lactate after FES-cycling (+1.5mmol/L [95% CI, .05-2.9mmol/L]; P=.01). FES-cycling did not change dyspnea or muscle fatigue compared with the placebo condition.

Conclusions: FES-cycling effectively increased exercise intensity in patients with COPD. Further studies should evaluate longer-term FES-cycling rehabilitation programs.