High flow nasal cannula improves exercise capacity in COPD patients: crossover trial

Abstract

Introduction: The effects of high flow nasal cannula (HFNC) such as reducing of work of breathing could improve exercise tolerance in COPD patients, yet there is a strong lack of evidence supporting its use. Aims: To compare the exercise tolerance and comfort using HFNC or venturi mask (VM) in an incremental exercise test (IET) and on a constant work rate exercise test (CWRET). Methods: Clinically stable COPD patients who require oxygen during exercise. Each test (IET and CWRET) was conducted twice, once using HFNC (FiO2 40%, flow 50 L/m) and the other with VM (FiO2 40%). Patients were randomized to start the evaluations with HFNC or VM, and after 48-72 hours repeated the tests in the reverse order. We recorded maximum speed (MS) (km/h) in the IET, limit time (Tlim) (sec.) in the CWRET, and dyspnea, leg fatigue, oxygen saturation (SpO2), heart rate (HR), respiratory rate (RR), blood pressure (BP) and comfort in both tests for comparison between HFNC vs VM. A statistical significance of 0.05 was used for all analyses. Results: We enrolled 28 patients, 4 withdrew due to exacerbation. Patients were 56% male, age mean (SD) 69(10) yr. with FEV1 44(19)% predicted. Mean(SD) MS 5,9(0,9) vs 5,7(0,9) km/h; p Conclusions: HFNC improved exercise capacity in COPD patients increasing MS during IET and Tlim on CWRET with higher SpO2 and reduced dyspnea in comparison to VM. HFNC and VM were equally comfortable.