Physiologic Effects of an Ambulatory Ventilation System in Chronic Obstructive Pulmonary Disease

• Published in: American journal of respiratory and critical care medicine Vol. 188; no. 3; pp. 334 - 342
• Main Authors: PORSZASZ, Janos, CAO, Robert, MORISHIGE, Richard, VAN EYKERN, Leo A, STENZLER, Alex, CASABURI, Richard
• Format: Journal Article
• Language: English
• Published: New York, NY American Thoracic Society 01.08.2013
• Subjects: Aged; Ambulatory Care - methods; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Chronic obstructive pulmonary disease; Chronic obstructive pulmonary disease, asthma; Compressed air; Dyspnea; Electromyography; Equipment Design; Exercise Tolerance - physiology; Female; Humans; Intensive care medicine; Male; Medical sciences; Noninvasive Ventilation - instrumentation; Oxygen saturation; Pneumology; Pulmonary Disease, Chronic Obstructive - physiopathology; Pulmonary Disease, Chronic Obstructive - therapy; Pulmonary Gas Exchange; Pulse oximetry; Respiration; Respiratory Function Tests; Respiratory Muscles - physiopathology; United States > US; Physical exercise; Lung disease; Intensive care; noninvasive open ventilation system; Respiratory disease; respiratory muscle activation; Activation; exercise endurance; Respiratory muscle; Non invasive method; Open systems; Bronchus disease; Ventilation; Chronic obstructive pulmonary disease; Endurance; Ambulatory; Resuscitation
• ISSN: 1073-449X; 1535-4970
• DOI: 10.1164/rccm.201210-1773OC

Exercise intolerance limits the ability of patients with chronic obstructive pulmonary disease (COPD) to perform daily living activities. Noninvasive ventilation reduces dyspnea and improves exercise performance, but current systems are unsuitable for ambulatory use. In patients with COPD experiencing exercise-induced desaturation, we evaluated improvements in exercise tolerance facilitated by a wearable, 1-lb, noninvasive open ventilation (NIOV) system featuring a nasal pillow interface during constant work rate (CWR) cycle ergometer exercise and associated effects on dyspnea, respiratory muscle activation, and pulmonary gas exchange efficiency. Fifteen men with COPD (FEV₁ = 32.2 ± 12.0% predicted; FEV₁/FVC = 31.6 ± 7.1%; exercise oxygen saturation as measured by pulse oximetry [Spo₂] = 86.5 ± 2.9%) participated. After incremental testing establishing peak work rate, subjects completed three visits in which they performed CWR exercise to tolerance at 80% peak work rate: (1) unencumbered breathing room air, (2) using NIOV+compressed air, (3) using NIOV+compressed O₂, or (4) using O₂ via nasal cannula. Assessments included exercise duration, surface inspiratory muscle EMG, Spo₂, transcutaneous Pco₂, and Borg dyspnea scores. Exercise endurance was 17.6 ± 5.7 minutes using NIOV+O₂, greatly prolonged compared with unencumbered (5.6 ± 1.9 min), nasal O₂ (11.4 ± 6.8 min), and NIOV+Air (6.3 ± 4.1 min). Isotime Spo₂ was higher and intercostal, scalene, and diaphragmatic EMG activity was reduced using NIOV+O₂ compared with unencumbered, nasal O₂, and NIOV+Air, signifying respiratory muscle unloading. Isotime dyspnea reduction correlated with isotime EMG reduction (r = 0.42, P = 0.0053). There were no significant differences in isotime VD/VT or transcutaneous Pco₂ among treatments. NIOV+O₂ yielded substantial exercise endurance improvements accompanied by respiratory muscle unloading and dyspnea reductions in patients with severe hypoxemic COPD.