Frontiers in Medicine (Jul 2021)

Effect of Breathing Oxygen-Enriched Air on Exercise Performance in Patients With Pulmonary Hypertension Due to Heart Failure With Preserved Ejection Fraction: A Randomized, Placebo-Controlled, Crossover Trial

  • Julian Müller,
  • Julian Müller,
  • Mona Lichtblau,
  • Mona Lichtblau,
  • Stéphanie Saxer,
  • Stéphanie Saxer,
  • Luigi-Riccardo Calendo,
  • Luigi-Riccardo Calendo,
  • Arcangelo F. Carta,
  • Arcangelo F. Carta,
  • Simon R. Schneider,
  • Simon R. Schneider,
  • Charlotte Berlier,
  • Charlotte Berlier,
  • Michael Furian,
  • Michael Furian,
  • Konrad E. Bloch,
  • Konrad E. Bloch,
  • Konrad E. Bloch,
  • Esther I. Schwarz,
  • Esther I. Schwarz,
  • Silvia Ulrich,
  • Silvia Ulrich,
  • Silvia Ulrich

DOI
https://doi.org/10.3389/fmed.2021.692029
Journal volume & issue
Vol. 8

Abstract

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Objective: To evaluate the effects of breathing oxygen-enriched air (oxygen) on exercise performance in patients with pulmonary hypertension due to heart failure with preserved ejection fraction (PH-HFpEF).Methods: Ten patients with PH-HFpEF (five women, age 60 ± 9 y, mPAP 37 ± 14 mmHg, PAWP 18 ± 2 mmHg, PVR 3 ± 3 WU, resting SpO2 98 ± 2%) performed two-cycle incremental exercise tests (IET) and two constant-work-rate exercise test (CWRET) at 75% maximal work-rate (Wmax), each with ambient air (FiO2 0.21) and oxygen (FiO2 0.5) in a randomized, single-blinded, cross-over design. The main outcomes were the change in Wmax (IET) and cycling time (CWRET) with oxygen vs. air. Blood gases at rest and end-exercise, dyspnea by Borg CR10 score at end-exercise; continuous SpO2, minute ventilation (V'E), carbon dioxide output (V'CO2), and cerebral and quadricep muscle tissue oxygenation (CTO and QMTO) were measured.Results: With oxygen vs. air, Wmax (IET) increased from 94 ± 36 to 99 ± 36 W, mean difference (95% CI) 5.4 (0.9–9.8) W, p = 0.025, and cycling time (CWRET) from 532 ± 203 to 680 ± 76 s, +148 (31.8–264) s, p = 0.018. At end-exercise with oxygen, Borg dyspnea score and V'E/V'CO2 were lower, whereas PaO2 and end-tidal PaCO2 were higher. Other parameters were unchanged.Conclusion: Patients with PH-HFpEF not revealing resting hypoxemia significantly improved their exercise performance while breathing oxygen-enriched air along with less subjective dyspnea sensation, a better blood oxygenation, and an enhanced ventilatory efficiency. Future studies should investigate whether prolonged training with supplemental oxygen would increase the training effect and, potentially, daily activity for PH-HFpEF patients.Clinical Trial Registration: [clinicaltrials.gov], identifier [NCT04157660].

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