Effects of Expiratory Positive Airway Pressure on Exercise Tolerance, Dynamic Hyperinflation, and Dyspnea in COPD

• Published in: Respiratory care Vol. 62; no. 10; pp. 1298 - 1306
• Main Authors: Gass, Ricardo, Merola, Pietro, Monteiro, Mariane B, Cardoso, Dannuey M, Paiva, Dulciane N, Teixeira, Paulo Jz, Knorst, Marli M, Berton, Danilo C
• Format: Journal Article
• Language: English
• Published: United States Daedalus Enterprises, Inc 01.10.2017
• Subjects: Aged; Care and treatment; Chronic obstructive lung disease; Continuous positive airway pressure; Cross-Sectional Studies; Dyspnea - etiology; Dyspnea - physiopathology; Exercise Test - methods; Exercise Tolerance - physiology; Female; Humans; Inspiratory Capacity - physiology; Male; Middle Aged; Positive-Pressure Respiration - methods; Pulmonary Disease, Chronic Obstructive - complications; Pulmonary Disease, Chronic Obstructive - physiopathology; Pulmonary Disease, Chronic Obstructive - therapy; Risk factors; Tidal Volume - physiology; Treatment Outcome; Work of Breathing - physiology; positive-pressure respiration; inspiratory capacity; exercise; dyspnea; respiratory therapy; chronic obstructive pulmonary disease
• ISSN: 0020-1324; 1943-3654
• DOI: 10.4187/respcare.05556

The application of expiratory positive airway pressure (EPAP) in patients with COPD during exercise may reduce dynamic hyperinflation, while, on the other hand, it can increase the resistive work of breathing. Therefore, we evaluated the effects of 2 intensities of EPAP during exercise on tolerance, dynamic hyperinflation, and dyspnea in subjects with moderate to very severe COPD. We performed a cross-sectional, experimental, 4-visit study. In visit 1, subjects performed symptom-limited cycling incremental cardiopulmonary exercise test (CPET). In visits 2-4, at least 48 h apart, in a randomized order, subjects performed constant CPET without EPAP, EPAP with 5 cm H O (EPAP5), or EPAP with 10 cm H O (EPAP10). The study included 15 non-hypoxemic subjects ranging from moderate to very severe COPD (mean FEV = 35 ± 11% predicted). Increasing intensities of EPAP during constant CPET tended to cause progressive reduction in exercise tolerance ( = .11). Of note, 10 of 15 subjects demonstrated significantly shorter average exercise duration with EPAP10 compared to the test without EPAP (-151 ± 105 s, = .03 or -41 ± 26%). Minute ventilation increment was constrained by EPAP, secondary to a limited increase in tidal volume ( = .01). Finally, dyspnea sensation and serial measurements of inspiratory capacity during exercise were similar when comparing the three interventions at isotime and at end-constant CPETs. The application of EPAP5 or EPAP10 during exercise tended to cause a progressive reduction in exercise tolerance in subjects with COPD without improvement in dyspnea or dynamic hyperinflation at equivalent exercise duration.