Elsevier

Respiratory Medicine

Volume 118, September 2016, Pages 128-132
Respiratory Medicine

Effects of heated and humidified high flow gases during high-intensity constant-load exercise on severe COPD patients with ventilatory limitation

https://doi.org/10.1016/j.rmed.2016.08.004Get rights and content
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Highlights

  • High flow nasal cannula (HFNC) may improve exercise capacity in COPD with ventilatory limitation.

  • During a constant load test HFNC allows higher oxygen saturation then Venturi mask at iso-FiO2.

  • A better oxygen saturation results also at a FiO2 of 0.21 during HFNC.

  • Dyspnea and leg fatigue are significantly reduced by HFNC application.

Abstract

Introduction

High flow nasal cannula (HFNC) was shown to washout the anatomical dead space, permitting a higher fraction of minute ventilation to participate in gas pulmonary exchanges. Moreover, it is able to guarantee the desired inhaled oxygen fraction (FiO2) even at high level of patient's minute ventilation by minimizing the room air entrainment. The effect of HFNC has never been investigated on stable severe COPD patients in term of endurance capacity with standardised laboratory tests.

Method/Design

We performed, in a randomized crossover study, two constant load exercise tests at the 75% of maximum workload achieved at a previous incremental exercise test on cycle-ergometer: with (HFNC-test) and without HFNC (Control-test). Both constant load tests were fulfilled at the same inhaled oxygen fraction (isoFiO2).

Results

The endurance time significantly increased in the HFNC-test compared to the Control-test (the mean difference between the two groups was 109 ± 104 s, p < 0.015). At iso-time, HFNC-test showed a better oxygen saturation (95 ± 3% vs 89 ± 3%, respectively, p < 0.005) either in the subgroup of patients who used supplemental oxygen and in the subgroup who did not. Moreover, a significantly lower dyspnea (median of 5.5 vs 10, respectively, p = 0.002) and leg fatigue score (median of 5 vs 9.5, p = 0.002) was recorded at iso-time during HFNC-test.

Conclusion

HFNC may improve the exercise performance in severe COPD patients with ventilatory limitation. This effect is associated to an improvement of SaO2 and perceived symptoms at iso-time. In a Pulmonary Rehabilitation program HFNC may allow a given high intensity load to be sustained for a longer time with less symptoms.

Keywords

Chronic obstructive pulmonary disease
High flow nasal cannula
Exercise training
Chronic respiratory failure
Oxygen therapy

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