Mechanisms of non-pharmacologic adjunct therapies used during exercise in COPD

Abstract

Individuals with chronic obstructive pulmonary disease (COPD) are often limited in their ability to perform exercise due to a heightened sense of dyspnea and/or the occurrence of leg fatigue associated with a reduced ventilatory capacity and peripheral skeletal muscle dysfunction, respectively. Pulmonary rehabilitation programs have been shown to improve exercise tolerance and health related quality of life. Additional therapeutic approaches such as non-invasive ventilatory support (NIVS), heliox (He-O(2)) and supplemental oxygen have been used as non-pharmacologic adjuncts to exercise to enhance the ability of patients with COPD to exercise at a higher exercise-intensity and thus improve the physiological benefits of exercise. The purpose of the current review is to examine the pathophysiology of exercise limitation in COPD and to explore the physiological mechanisms underlying the effect of the adjunct therapies on exercise in patients with COPD. This review indicates that strategies that aim to unload the respiratory muscles and enhance oxygen saturation during exercise alleviate exercise limiting factors and improve exercise performance in patients with COPD. However, available data shows significant variability in the effectiveness across patients. Further research is needed to identify the most appropriate candidates for these forms of therapies.

Normativa SEPAR sobre disfunción muscular de los pacientes con enfermedad pulmonar obstructiva crónica

“…Aunque escasos, algunos estudios han asociado el uso de VMNI a una mejor función de los músculos periféricos, puesta de manifiesto mediante un incremento en la fuerza y resistencia del cuádriceps 165 , probablemente como consecuencia de un mayor aporte de oxí-geno a los músculos periféricos, fruto de la reducción en el trabajo respiratorio 166 . Este mismo mecanismo se ha invocado para explicar el efecto de la respiración con heliox (mezcla de helio y oxígeno) sobre la función de los músculos periféricos.…”

Use of positive expiratory pressure during six minute walk test: results in patients with moderate to severe chronic obstructive pulmonary disease

“…Patients with COPD typically experience dyspnea during exercise and stop exercising because of dyspnea or leg fatigue or a combination of both. Patients with mild COPD usually perceive dyspnea more intensely than leg fatigue [6,7]. In this group the breathing pattern is more rapid and shallow and is the cause of dynamic hyperinflation which generates an inspiratory threshold due to positive end-expiratory pressure which results in a reduction of inspiratory capacity strictly related to dyspnea and in respiratory effort [7].…”

“…Patients with mild COPD usually perceive dyspnea more intensely than leg fatigue [6,7]. In this group the breathing pattern is more rapid and shallow and is the cause of dynamic hyperinflation which generates an inspiratory threshold due to positive end-expiratory pressure which results in a reduction of inspiratory capacity strictly related to dyspnea and in respiratory effort [7]. Dynamic hyperinflation is the result of expiratory flow limitation: most people with COPD are able to maintain a stable end expiratory lung volume (EELV) and inspiratory capacity (IC) at rest.…”

“…This leads to increased EELV and reduced IC.These two parameters have been identified as major contributory factors to dispnea in COPD patients [8]. Treatments to reduce airflow obstruction and/or dynamic hyperinflation include pursed lip breathing (PLB) [9], several non-pharmacological therapies that include supplemental oxygen, heliox, breathing helium-oxygen mixtures, and non-invasive ventilation [7,9]. There is evidence that non-invasive ventilation reduces the work of breathing during exercise which in turn decreases dyspnea and increases endurance time in patients with moderate to severe COPD.…”

“…There is evidence that non-invasive ventilation reduces the work of breathing during exercise which in turn decreases dyspnea and increases endurance time in patients with moderate to severe COPD. Several studies have demonstrated a relationship between decreased dyspnea and reduced work of breathing [7,10-12]. Only few evidences exist concerning the use of positive expiratory devices: these devices should permit a reduction in lung hyperinflation and an increasing in exercise duration (endurance) [13].…”