The effects of oxygen supplementation during exercise in patients with non-hypoxemic chronic obstructive pulmonary disease

Abstract

Introduction: Oxygen therapy consists in a modality of treatment in patients with chronic obstructive pulmonary disease (COPD) for the mainteance of oxygen arterial saturation (SpO2) above 90%. In patients with a reduction in SpO2 during exercise, oxygen supplementation during the effort improves exercise tolerance. Objective: The purpose of this study is to evaluate, through a literature review, the effects of oxygen supplementation in patients with non-hypoxemic COPD during rest on exercise tolerance, SpO2 and dyspnea. Materials and Methods: We have searched the data bank Medline/Pubmed and Scielo and selected randomized, controlled trials, from 1996 to 2007, written in Portuguese or English. All papers where the keywords COPD, oxygen, exercise and rehabilitation were present in the title or the abstract were selected. Results: From 10 studies that have used oxygen during effort in non-hypoxemic patients in rest situation, 7 papers showed beneficial effects, which indicates that oxygen during exercise can help patients with COPD in improving their performance during exercise and contribute to the maintenance or improvement of the SpO2. There was no significant improvement when dyspnea was analyzed. The use of O2 after and/or before exercise or during a pulmonary rehabilitation program seems not to cause any additional effescts. Conclusions: Oxygen supplementation during exercise in rest non-hypoxemic COPD patients promotes the maintenance or improvement of SpO2, as well as improves performance during exercise.