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Publications

Journal Article Epublish

PubMed: 42688806 DOI: 10.1093/ehjopen/oeag125

Effect of low-flow oxygen therapy on 6 minute walk test in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: a randomized non-inferiority crossover trial.

Eur Heart J Open 6(5):oeag125

Authors: Carmen Wick, Mona Lichtblau, Anna Titz, Julian Müller, Alessandro Vella, Zoe Bousraou, Michael Furian, Stéphanie Saxer, Esther I Schwarz, Silvia Ulrich

Affiliations

  • Department of Pulmonology, University Hospital Zurich, Rämistrasse 100, 8091 Zurich, Switzerland.
  • Faculty of Medicine, University of Zurich, Rämistrasse 71, 8006 Zurich, Switzerland.
  • Department of Pulmonology, University Hospital Zurich, Rämistrasse 100, 8091 Zurich, Switzerland. Faculty of Medicine, University of Zurich, Rämistrasse 71, 8006 Zurich, Switzerland.
  • Eastern Switzerland University of Applied Sciences, Rosenbergstrasse 59, 9000 St. Gallen, Switzerland.

Abstract

AIMS

Patients with pulmonary arterial and distal chronic thromboembolic pulmonary hypertension (PAH/CTEPH) frequently experience exertional dyspnoea with desaturation. Although ambulatory low-flow supplemental oxygen therapy (SOT) is commonly prescribed, its effect via portable concentrators in daily life has not been studied. We investigated the effect of ambulatory SOT on six-minute walk distance (6MWD).

METHODS AND RESULTS

This was a randomized non-inferiority crossover study in patients with PAH or CTEPH desaturating by >3% during exercise. Patients performed two 6MWD tests in randomized order: one in ambient air and one with pulsed low-flow (1-2 L/min) nasal supplemental oxygen (SOT) by a portable back-packed concentrator. The primary outcome was 6MWD with a predefined non-inferiority margin of -35 m for ambient air vs. SOT. Forty patients (age 62 ± 15 years, 21 female, 20 PAH, 20 CTEPH) were included. The mean difference in 6MWD between ambient air and SOT was 0 m (95% CI: -15 to 14 m, P <0.001).Five patients exceeded the minimal clinically important difference of 35 m with SOT. At end-exercise, the cohort desaturated 2% less with SOT (95% CI -3 to -0.2%, P = 0.025) and reported 1 point less dyspnoea (95% CI 0.3 to 1, P < 0.002). These effects were also observed in PAH but not in CTEPH.

CONCLUSION

Walking on ambient air was non-inferior to low-flow SOT during 6MWD in treated PAH/CTEPH patients with exercise-induced desaturation and relatively preserved exercise capacity. SOT reduced dyspnoea in PAH. Future research should identify SOT responders and develop lighter, more effective devices tailored to patient needs.

REGISTRATION

ClinicalTrials.gov (NCT06384534).

MeSH

Exercise, Hypertension, Hypertension, Pulmonary, Air, Pulmonary Arterial Hypertension, Therapeutics, Walk Test