Effect of Home-base Exercise With Conical-PEP Device on Physical Performance and Quality of Life in COPD

The key pathophysiology of COPD is expiratory flow limit and hyperinflation that is a major factor related exertional dyspnea and exercise limitation. When expiratory minute volume( V ̇E) raise up while exercise, respiratory response by increase respiratory rate (RR) and tidal volume (VT), force exhalation occur lead to develop premature airway closer. These generate dynamic air tapping breath by breath and result in dynamic hyperinflation (DH). The DH limits VT expansion, increase respiratory muscle load, and it is a major cause related dyspnea and exercise termination. Furthermore, Pre-inflammatory products from the COPD lung contribute to another system, and provoke systemic inflammation lead to nutritional abnormalities, weight loss, skeletal muscle dysfunction, osteo-skeletal effect, cardiovascular effect and psychological effect. All of these affect the exercise tolerance and gradually affect physical activity and health-related quality of life (HRQL) as well. COPD GOLD guideline states that goal for treatments of stable COPD comprise of relive symptoms, improve exercise tolerance, improve health status, prevent disease progression and reduce mortality. Several evidences have suggested an effect of pulmonary rehabilitation (PR) in patient with stable COPD and following acute exacerbation. Strong evidences reported that the PR program could improve exercise tolerance, reduce dyspnea, decrease fatigue and improve health-related quality of life. The core stone of PR is an exercise program. Several types of exercise were published such as endurance exercise, interval exercise, strengthening exercise, respiratory muscle strengthening and breathing exercise. Most COPD patient stop exercise causes from dyspnea that related DH development during exercise. Previous studies reported various strategies to reduce DH development during exercise for extending exercise time or increase exercise capacity in immediate effect such as bronchodilators , hyperoxic breathing, heliox breathing, positive pressure therapy by non-invasive positive pressure ventilation (NIPPV), by pursed lip breathing (PLB) and by positive expiratory pressure (PEP) device. The PEP therapy have been conventionally using for reduce premature airway closer by moving equal pressure point from distal to proximal, improve gas exchange and improve secretion clearance. In the past decade, the knowledge of dynamic hyperinflation in COPD patient has rapidly glowed up. The PEP device and PLB have used to reduce DH development during exercise that reported in only 5 studies. They expected that delay DH development, it may delay exertional dyspnea, and may result in improve exercise capacity. Three studies reported DH parameter at pre and post exercise. Results indicated that using the PEP device can reduce DH when measuring immediate post exercise. However, effects of positive pressure therapy (PEP device and PLB) on exercise capacity were also inconclusive. But three studies showed positive effect of PEP therapy on exercise capacity. Training effect of PEP therapy on physical performance and quality of life was present in two studies. The first study showed the benefit of breathing retraining (including PLB, and other breathing techniques) that were integrated to all daily activities and exercise program, superior than control group in peak oxygen consumption after 7th week of exercise program. The second study applied PLB to reduce DH during exercise program. They found that after ten sessions (within 3 to 4 weeks) of program, both PLB and control groups significantly improve 6 minute walk distance and quality of life, but non-significant effect between groups. To date there was only two studies of PEP therapy applying to exercise program, and results were not conclusive. In spite of the PLB was wildly used, but positive pressure from this technique was reported about 5 cm H2O, it is lower boundary of therapeutic pressure range (5 to 20 cm H2O), this may result in a non-success of DH reduction. Consequently, The PEP device may be a convenient alternative way to generate positive pressure within therapeutic range for reduces DH during exercise or daily activities living. This may increase patient's physical performance and quality of life greater that exercise alone.