Effect of neuromuscular electrical nerve stimulation on quadriceps muscle strength and endurance in COPD patients. A randomised controlled trial

Abstract

Introduction: Neuromuscular Electric Nerve Stimulation (NMES) is a modality that is gaining interest as part of the management of participants with Chronic Obstructive Pulmonary Disease (COPD). Given the increased knowledge of how the muscle changes structurally as the respiratory condition deteriorates, treatment options are being investigated to help maintain and improve strength and endurance in patients who are limited due to poor exercise tolerance and increased dyspnoea and cannot part-take in rehabilitation.

Method: Using a randomised control trial design, 33 participants who required admission to hospital due to an acute exacerbation of COPD, with a moderate to severe classification based on the MRC score, were recruited and randomly allocated to an experimental (males: 83.33%, females: 16.67%) or control group (males: 60%, females: 40%). Isometric quadriceps strength was assessed using the hand-held dynamometer, and quadriceps endurance was evaluated with the quadriceps endurance test. Additionally, the rectus femoris cross-sectional area, width, and thickness were measured using an ultrasound. All outcome measures were measured at baseline and upon discharge from the hospital, following the intervention, in all participants. The experimental group received 30 minutes of NMES stimulation on the quadriceps muscles daily throughout their hospitalisation stay (mean days: Experimental – 7.78 days, Control–9.45 days), over and above the usual physiotherapy treatment provided to all participants by physiotherapists in the ward. The control group received only Physiotherapy treatment provided in the ward. All outcome measures were repeated before discharge.

Results: Statistically significant improvements in rectus femoris thickness (left and right: P<0.001) and rectus femoris width on the right side (P=0.017) were reported in the experimental group. In contrast, statistically significant declines in mean values for the left and right Rectus Femoris width were registered for the control group (left: P=0.006, right: P< 0.001).