Clancy J Dennis1, Collette Menadue2, Tessa Schneeberger3, Daniela Leitl3, Ursula Schoenheit-Kenn4, Camilla M Hoyos5, Alison R Harmer6, David J Barnes7, Andreas R Koczulla8, Klaus Kenn3, Jennifer A Alison9. 1. Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia. Electronic address: cden2754@uni.sydney.edu.au. 2. Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia. 3. Institute for Pulmonary Rehabilitation Research, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany; Department of Pulmonary Rehabilitation, Philipps-University of Marburg, German Centre for Lung Research (DZL), Marburg, Germany. 4. Institute for Pulmonary Rehabilitation Research, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany. 5. School of Psychology, University of Sydney, Sydney, NSW, Australia; Woolcock Institute of Medical Research, Centre for Sleep and Chronobiology, Sydney, NSW, Australia. 6. Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia. 7. Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia; Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia. 8. Institute for Pulmonary Rehabilitation Research, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany; Department of Pulmonary Rehabilitation, Philipps-University of Marburg, German Centre for Lung Research (DZL), Marburg, Germany; Teaching Hospital, Paracelsus Medical University, Salzburg, Austria. 9. Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia; Sydney Local Health District, Allied Health, Sydney, NSW, Australia.
Abstract
BACKGROUND: During exercise, dynamic hyperinflation (DH), measured by a reduction in inspiratory capacity (IC), increases exertional dyspnea and reduces functional capacity in many patients with severe COPD. Although noninvasive ventilation (NIV) during exercise can improve exercise duration, the effect on DH is unclear. RESEARCH QUESTIONS: In people with COPD, resting hyperinflation, and evidence of DH during exercise, does bilevel NIV during exercise reduce DH and increase endurance time compared with exercise with no NIV, and does NIV with an individually titrated expiratory positive airway pressure (T-EPAP) reduce DH and increase exercise endurance time more than NIV with standardized EPAP (S-EPAP) of 5 cm H2O? STUDY DESIGN AND METHODS: A randomized crossover trial in which investigators and participants were blinded between NIV interventions was performed. Participants (N = 19; FEV1 of 1.02 ± 0.24 L (39% ± 6% predicted) completed three constant work rate endurance cycle tests in random order-no NIV, NIV with S-EPAP, and NIV with T-EPAP-during exercise. Primary outcomes were isotime IC and exercise endurance time. Outcome measures from each intervention were compared at isotime and at end exercise by using a linear mixed-model analysis. RESULTS: Compared with no NIV, isotime IC and endurance time were greater with both NIV with S-EPAP (mean difference: 95% CI, 0.19 L [0.10-0.28]; 95% CI, 153 s [24-280], respectively) and T-EPAP (95% CI, 0.22 L [0.13-0.32]; 95% CI, 145 s [28-259], respectively). There was no difference between NIV with S-EPAP and NIV with T-EPAP. INTERPRETATION: In people with COPD and DH during exercise, NIV during exercise reduced DH and increased cycle endurance time. An S-EPAP of 5 cm H2O was adequate to obtain these benefits. TRIAL REGISTRY: Australian New Zealand Clinical Trials Registry; No.: ACTRN12613000804785; URL: http://www.anzctr.org.au.
BACKGROUND: During exercise, dynamic hyperinflation (DH), measured by a reduction in inspiratory capacity (IC), increases exertional dyspnea and reduces functional capacity in many patients with severe COPD. Although noninvasive ventilation (NIV) during exercise can improve exercise duration, the effect on DH is unclear. RESEARCH QUESTIONS: In people with COPD, resting hyperinflation, and evidence of DH during exercise, does bilevel NIV during exercise reduce DH and increase endurance time compared with exercise with no NIV, and does NIV with an individually titrated expiratory positive airway pressure (T-EPAP) reduce DH and increase exercise endurance time more than NIV with standardized EPAP (S-EPAP) of 5 cm H2O? STUDY DESIGN AND METHODS: A randomized crossover trial in which investigators and participants were blinded between NIV interventions was performed. Participants (N = 19; FEV1 of 1.02 ± 0.24 L (39% ± 6% predicted) completed three constant work rate endurance cycle tests in random order-no NIV, NIV with S-EPAP, and NIV with T-EPAP-during exercise. Primary outcomes were isotime IC and exercise endurance time. Outcome measures from each intervention were compared at isotime and at end exercise by using a linear mixed-model analysis. RESULTS: Compared with no NIV, isotime IC and endurance time were greater with both NIV with S-EPAP (mean difference: 95% CI, 0.19 L [0.10-0.28]; 95% CI, 153 s [24-280], respectively) and T-EPAP (95% CI, 0.22 L [0.13-0.32]; 95% CI, 145 s [28-259], respectively). There was no difference between NIV with S-EPAP and NIV with T-EPAP. INTERPRETATION: In people with COPD and DH during exercise, NIV during exercise reduced DH and increased cycle endurance time. An S-EPAP of 5 cm H2O was adequate to obtain these benefits. TRIAL REGISTRY: Australian New Zealand Clinical Trials Registry; No.: ACTRN12613000804785; URL: http://www.anzctr.org.au.