PARIS – As an alternative to noninvasive ventilator devices (NIV), a battery-powered high-flow nasal cannula delivering heated air improves exercise tolerance as measured with the 6-minute walking distance (6MWD), according to a crossover trial presented at the annual congress of the European Respiratory Society.
Veronica Rossi
Not least important, these preliminary results show treatment with the device to be well tolerated, a potential advantage over NIV, according to Ms. Rossi, who cited published studies suggesting up to 35% of patients are intolerant to ambulatory NIV therapy.
In the study, 12 clinically stable COPD patients with a 6MWD of less than 300 m and dyspnea at a low level of exertion were enrolled. In random order on 2 consecutive days, patients were evaluated with the 6MWD test while fitted with the high-flow nasal cannula (HFNC) or while breathing room air.
The HFNC device delivers heated and humidified oxygen, which has been previously shown by the same group to improve oxygen saturation (Respir Med. 2016;118:128-32). In this study, the oxygen fraction (FiO2) of the air delivered by the proprietary HFNC device, marketed under the name AIRVO2 (Fisher & Paykel), was the same as the room air during the control exam.
In both tests, the patients performed the 6MWD while pushing a cart holding the device and the battery power source.
The mean 6MWD was 306 m using HFNC versus 267 m during the control test (P less than .05), even though the mean and nadir blood oxygenation (SpO2) levels were the same. However, the postexertion respiratory rate was significantly lower (P less than .05) when HFNC was used, Ms. Rossi reported. The inspiratory capacity was unchanged.
The improved levels of oxygen saturation (SaO2) demonstrated previously with high flows of humidified oxygen provided the basis for this preliminary crossover study, but a larger multicenter randomized trial was initiated last year. In that study with a planned enrollment of 160 COPD patients, the comparison will be between HFNC and usual oxygen delivered by a venturi mask. The primary outcome of the study, which will be completed early in 2019, is endurance improvement.
“COPD patients with severe dyspnea are frequently unable to achieve a workload that leads to improved exercise tolerance, with a result of reduced daily physical activities,” Ms. Rossi explained. She indicated that the HFNC, which is now being evaluated at several institutions, might be an important alternative to NIV in permitting patients to achieve adequate mobility.
The device is likely to be improved with technological advances, according to Ms. Rossi. She acknowledged that the current battery is heavy and the duration of the charge is relatively short, but she characterized this device as “good fit” for patients with very severe COPD. Only 8% of patients failed to complete this study.
Dr. Rossi reports no financial relationships relevant to this study.