Electrostimulation, Skeletal Muscle Function, and Exercise Capacity in Chronic Obstructive Pulmonary Disease (COPD)

Background: Because it has little impact on ventilatory requirements and dyspnea, muscle electrostimulation appears as a promising alternative to general physical reconditioning in advanced COPD and its feasibility has been confirmed in this population. However, the physiological mechanisms underlying the proposed benefits of electrostimulation training have not been explored.

Objective: To evaluate in COPD patients the physiological mechanisms of changes in exercise tolerance after electrostimulation training.

Method: We propose to conduct a controlled, randomized and double blind clinical trial comparing the efficacy of muscle electrostimulation training of the lower limbs to sham training in 24 patients with COPD. Patients are included in either 6 weeks of electrostimulation training (active treatment group) or 6 weeks of sham electrostimulation. Before and after training, patients perform endurance shuttle walking test, muscle function testing, muscle biopsy, blood sampling and health-related quality of life questionnaire.

Planning analysis: The main outcome will be change in the strength of the quadriceps over the 6-week electrostimulation program. The other end-points will be mid-thigh and calf muscle cross-sectional area, lower limb muscle endurance, ventilation, dyspnea, leg fatigue, operational lung volumes at iso-time and walking time during an endurance shuttle walk, muscle hypertrophying/atrophying pathways and muscle aerobic capacity. For each group, pre- and post-training comparisons will be made using a repeated measures design. The magnitude of the pre- and post-training changes will also compared between both groups with a two-way ANOVA (group, training effect) with repeated measures on the second factor (training effect). A p value < 0.05 will be considered statistically significant.

Inclusion criteria

• COPD
• FEV1 < 60% predicted value and FEV1/ FVC < 70%
• 6-minute walking distance < 400 m

Exclusion criteria

• Patients suffering from cardiovascular, neurological, skeletal muscle, or any other condition that could alter their capacity to perform the exercise test
• Patients taking systemic corticosteroids on a daily basis (patients having received systemic steroids for the treatment of up to two exacerbations in the preceding year and those on inhaled steroids will be allowed)
• Patients with room air PaO2 < 60 mm Hg will be excluded.