Neuromuscular electrical stimulation appears to be useful in people with severe chronic obstructive pulmonary disease.

Abstract

In patients with chronic obstructive pulmonary disease (COPD), what effect does neuromuscular electrical stimulation (NMES) have on muscle function and walking endurance? Randomised, controlled trial in which the patients and those who collected outcome measures were blinded to group allocation. Home-based intervention with outcomes collected at a hospital in Quebec City, Canada. Patients who were clinically stable, sedentary and able to travel to the hospital with: (a) a smoking history >20 pack-years, (b) severe airflow obstruction, and (c) a 6-minute walk distance <400m. Exclusion criteria comprised any co-morbid condition associated with muscle wasting. Randomisation of 22 patients allocated 13 to the intervention group and 9 to the control group. Both groups received electrical stimulation 5 times a week for 6 weeks. Each session comprised 35min of bilateral stimulation for the quadriceps and 25min of bilateral stimulation for the calf. Stimulation was applied with the patient in sitting. They were encouraged to increase the intensity to the maximum they could tolerate. Patients were visited weekly at home by a research nurse to monitor progress. Parameters used by the intervention group were 50Hz frequency, 400μs pulse duration, and 6sec/16sec duty cycle. Parameters used by the control/sham group were 5Hz frequency, 100μs pulse duration, applied continuously. The primary outcome was quadriceps strength. The secondary outcomes included quadriceps endurance and performance during the endurance shuttle walk test. Data were available on 12 and 8 patients in the intervention and control groups, respectively. Current intensity increased over the training period in the intervention group from 20±4mA to 31±10mA (p <0.001). Compared with the control group, the intervention group conferred greater gains in quadriceps force (difference in mean percent change from baseline 14%, 95% CI 1% to 26%) and endurance (42%, 95% CI 4% to 80%), but not walking endurance. In patients with severe COPD, NMES delivered at home enhanced muscle function but not walking endurance.