By Rae Allain, MD
The addition of vibratory therapy to routine pulmonary rehabilitation for patients with moderate or worse COPD may result in meaningful improvement in exercise capacity and should be considered in patients who can tolerate it.
Dyspnea (shortness of breath) is an uncomfortable and very prevalent symptom in patients with COPD, causing major disability, anxiety, and adverse effects on quality of life (QOL). Etiology of dyspnea in advanced COPD is multifactorial and often difficult to treat. Pulmonary rehabilitation is recommended for patients with significant symptom burden and risk for exacerbation. Vibration devices have been incorporated into pulmonary rehabilitation due to purported improvements in respiratory muscle force, delayed fatigue, reduced pain, and airway secretion clearance. Indeed, the 2023 GOLD (Global Initiative for Chronic Obstructive Lung Disease) Report notes that “exercise capacity may also be improved by whole-body vibration training.”(1)
This prospective, single-center, randomized, single-blind, controlled trial enrolled 40 patients with moderate or worse COPD who were referred to a pulmonary rehabilitation program. All patients were assigned to 4 weeks training consisting of both aerobic and resistance exercise as well as airway clearance techniques. Additionally, they were randomly divided into three groups. As an adjunct to the training, they were randomly assigned to 1) receive continuous chest wall vibration during cycle ergometry; 2) receive sham (no vibration delivered) chest wall vibration during cycle ergometry; or 3) perform cycle ergometry without enhancement (control group). The primary outcome was functional exercise capacity (measured by 6-minute walk distance) and dyspnea (measured by Barthel Index-dyspnea). The Barthel Index dyspnea quantitates dyspnea on a scale of 0 (best) to 100 (worst) in the context of activities of daily living (ADLs). Secondary outcomes were maximal inspiratory and expiratory pressures, QOL, and risk of death (BODE index).
36/40 patients completed the study protocol. There was no significant difference between groups between the primary outcome of functional exercise capacity and dyspnea. However, patients who had vibration therapy had a statistically significant improvement in 6-minute walk distance when this parameter alone was analyzed. The mean walk distances of those who received vibration therapy were 14 and 23 meters greater than the sham vibration and control groups, respectively. The effect size on 6-minute walk distance was statistically judged as “moderate” for the vibration group whereas there was no difference within or between the other groups. The study failed to show a difference with the vibration intervention on dyspnea, respiratory muscle function, quality of life, or mortality (BODE index).
This study shows that patients with COPD who participate in pulmonary rehabilitation with added vibration therapy may benefit from improved exercise capacity. The distances gained in the 6-minute walk data can translate into clinically meaningful improvements for patients, perhaps allowing greater independence in ADLs. However, the improvements in exercise capacity were disappointingly not accompanied by diminished symptoms of dyspnea. Vibration therapy is postulated to act by increasing afferent feedback from intercostal muscles, thereby modulating dyspnea via central respiratory drive, delayed respiratory muscle fatigue or disconnecting efferent output from afferent inputs. However, etiology of dyspnea is complex and expectations that a single intervention can diminish dyspnea in all patients with COPD are likely unrealistic. Rather, a “bundled” approach of treatments may be more efficacious to treating COPD related dyspnea. Future research should be multi-institutional and likely should include a multifaceted approach, including vibratory therapy, to treat dyspnea.
References: 1. 2023 Gold Report - Global Initiative for Chronic Obstructive Lung Disease. GOLD. (2023, April 28). https://goldcopd.org/2023-gold-report-2/
Source: Pancera S, Buraschi R, Bianchi LN, Porta R, Negrini S, Arienti C. (2021). Effectiveness of continuous chest wall vibration with concurrent aerobic training on dyspnea and functional exercise capacity in patients with chronic obstructive pulmonary disease: A randomized controlled trial. Arch Phys Med Rehabil. 2021; 102(8), 1457–1464. doi.org/10.1016/j.apmr.2021.03.006