Vivodtzev I, Pe[spacing acute]pin J-L, Vottero G, Mayer V, Porsin B, Le[spacing acute]vy P, Wuyam B
Chest. 2006;129:1540-1548.
Study Objectives
Low body weight in COPD patients is associated with worsening dyspnea, reduced leg strength, and poor prognosis. Classical rehabilitation strategies are then limited by reduced exercise tolerance. Thus, we proposed to evaluate whether electrostimulation (ES) was a beneficial technique in the rehabilitation programs for severely deconditioned COPD patients after an acute exacerbation.
Design.
Randomized, controlled study.
Setting.
Pulmonary rehabilitation center.
Patients.
Seventeen patients with severe COPD (mean +/- [SD] FEV1, 30 +/- 3% predicted) and low body mass index (BMI) [18 +/- 2.5 kg/m2].
Methods.
Patients were randomly assigned either to usual rehabilitation (UR) alone or to a UR-plus-ES program for 4 weeks. Quadriceps muscle strength, total muscle mass (MM), exercise capacity, and health-related quality of life were measured before and after rehabilitation.
Results.
The training with ES plus UR induced a significant twofold improvement in the mean number of maximal voluntary contraction (MVC) compared to UR alone (97 +/- 71 vs 36 +/- 34 contractions, respectively; p < 0.03) and resulted in a more significant improvement in dyspnea when performing daily tasks (decrease in the dyspnea domain score of the 28-item Maugeri Foundation Respiratory Failure questionnaire, 1.7 +/- 1.0 vs 0.2 +/- 1.2 points, respectively; p < 0.05). There was also a significant increase in walking distance (63 +/- 40 m; p < 0.01) and BMI (0.6 +/- 0.5 kg/m2; p < 0.02) after training in the ES UR group. A significant relationship was found between changes in MVC and changes in MM after training in the ES UR group (r = 0.94; p < 0.03).
Conclusions.
The combination of ES and UR was associated with greater improvement in quadriceps strength and dyspnea during the performance of daily tasks than UR alone in severely disabled COPD patients with low BMI. In this population, ES has been revealed as a useful procedure, complementing the usual pulmonary rehabilitation.
Comment.
Pulmonary rehabilitation (PR) has established value in improving effort tolerance and related quality-of-life indices in chronic obstructive pulmonary disease. This improvement is primarily a function of the exercise training, strengthening and endurance, that is central to PR. However, patients at the extreme end of the severity spectrum have been shown to derive less benefit, and this may reflect their relative inability to perform sufficient levels of exercise. This trial attempts to address that deficiency by an alternate form of muscle strengthening using electrostimulation of the quadriceps in severely deconditioned and malnourished patients with severe chronic obstructive pulmonary disease. The intervention was well tolerated, and at the end of the treatment period, subjects showed significant gains in muscle strength and exercise tolerance, as measured by maximum voluntary contraction force and 6-minute walk distance, respectively, in comparison with controls who received only usual rehabilitation. This technique merits consideration and further evaluation especially in patients who have a marked reduction in muscle mass as a consequence of exacerbation-related inactivity often compounded by the myopathic effects of prolonged or high-dose corticosteroid therapy. Issues with adequate blinding of study personnel are a concern, and therefore, this should be considered as preliminary rather than definitive data.
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