Neuromuscular Electrical Stimulation in Chronic Obstructive Pulmonary Disease (COPD)

Combination of Pulmonary Rehabilitation and Neuromuscular Electrical Stimulation and in COPD Patients: a Randomized Clinical Trial of Efficacy

The purpose of this study is to elucidate whether combination of usual pulmonary rehabilitation and neuromuscular electrical stimulation of quadriceps may improve exercise capacity in patients affected by chronic obstructive pulmonary disease (COPD).

Neuromuscular electrical stimulation (NMES) has been extensively used as technique to improve muscle function in different areas of rehabilitation, however it seems to be more appropriate in critical care situation, while its use in more able patients is of uncertain benefit. In other words, NMES seems to be particularly effective in severely deconditioned and bed ridden patients. We therefore carried out a randomised trial to compare the efficacy of combination of NMES and PR (NM+PR) with combination of sham stimulation and PR (SS+PR) in a large population of moderately impaired COPD patients. Primary outcome was evaluation of effect of NMES on quadriceps strength and on exercise capacity. Secondary outcome was evaluation of effect of NMES on symptoms (dyspnoea) and quality of life.

NMES was applied by means of a commercially available four channel electrostimulator which generated a symmetrical biphasic pulsed current. Each session lasted 30 minutes and was performed 5 days/week for 5 weeks.

Quadriceps strength was assessed by means of Sit to Stand Test (STST). The subjects held their arms stationary by putting their hands on their hips. The subjects were asked to complete the sitting and standing positions without using the arms for support while rising and sitting. Once instructed, subjects stand upright and without delay sit down again, repeating the procedure as many times as possible in a 1 min period. The number of completed repetitions was recorded. The subjects were permitted to use rest periods to complete 1 min.

The modified Medical Research Council (MMRC) scale was used for rating dyspnoea. MMRC is a five-point scale based on degrees of various physical activities that precipitate breathlessness. Scores on the MMRC dyspnoea scale can range from 0 (normal) to 4.

St. George's respiratory questionnaire is a standardized self-administered airways disease-specific questionnaire divided into three subscales: symptoms (eight items), activity (16 items), and impacts (26 items). For each subscale and for the overall questionnaire, scores range from zero (no impairment) to 100 (maximum impairment).

Inclusion Criteria: Clinical diagnosis of COPD Must be able to walk Exclusion Criteria: Previous or current diagnosis of chronic respiratory failure A history of diseases other than COPD, in particular neurological disease Need for treatment with systemic steroids during the rehabilitation period