Supplementary oxygen efficacy for chronic pulmonary disorders and exertion desaturation

Abstract

Introduction: Exertion-induced desaturation (EID) is a common complication of numerous pulmonary disorders and often treated with supplementary oxygen during exertion. We performed a systematic review and meta-analysis of randomised clinical trials (RCTs) to evaluate the efficacy of supplementary oxygen for EID in pulmonary disorders.

Material and methods: Medline and Embase were systematically searched from July 2022 to June 2023 following PRISMA guidelines. RCTs that met predefined inclusion criteria were included. Means and standard deviations were extracted and standardised mean differences (SMDs), the difference in means between groups divided by the standard deviation, and 95% confidence intervals were calculated. Exercise capacity was the primary outcome; exercise dyspnoea, baseline dyspnoea and quality of life were secondary objectives. The immediate, post-rehabilitation, short-term and ambulatory effects of oxygen supplementation were evaluated.

Results: We included 15 studies in our analysis. Oxygen supplementation to treat adult EID had been investigated for COPD and idiopathic pulmonary fibrosis (IPF) only. Oxygen supplementation was superior to placebo for its immediate effect on exercise capacity for COPD (SMD 0.42, 95% CI 0.15-0.69, I²=3%) and IPF (SMD 0.41, 95% CI 0.08-0.75, I²=57%) and exercise dyspnoea for COPD (SMD -0.40, 95% CI -0.76--0.04, I²=31%). Sensitivity analysis revealed similar results.

Conclusions: Our study revealed the efficacy of supplemental oxygen for EID and only a positive immediate effect on exercise capacity and dyspnoea, but no improvement in other short-term or long-term measures.

FIGURE 1

PRISMA flowchart.

FIGURE 2

Effect of oxygen versus placebo supplementation on immediate exercise capacity for patients with COPD. Corresponding references for the studies cited in the figure are available in the supplementary material. 6MWT: 6-min walk test; CPCT: constant power cycle test; DL: DerSimonian and Laird; ESWT: endurance shuttle walk test; O₂: number of patients on oxygen; Pl: number of patients on placebo; RCT: randomised control trial; RoB: risk of bias; SMD: standardised mean difference.

FIGURE 3

Effect of oxygen versus placebo supplementation on immediate exercise capacity for patients with idiopathic pulmonary fibrosis. Corresponding references for the studies cited in the figure are available in the supplementary material. 6MWT: 6-min walk test; CPCT: constant power cycle test; DL: DerSimonian and Laird; IMCT: incremental maximal cycle test; O₂: number of patients on oxygen; Pl: number of patients on placebo; RCT: randomised control trial; RoB: risk of bias; SMD: standardised mean difference

FIGURE 4

Effect of oxygen versus placebo supplementation on post-rehabilitation exercise capacity for patients with COPD. Corresponding references for the studies cited in the figure are available in the supplementary material. 6MWT: 6-min walk test; DL: DerSimonian and Laird; ESWT: endurance shuttle walk test; O₂: number of patients on oxygen; Pl: number of patients on placebo; RCT: randomised control trial; RoB: risk of bias; SMD: standardised mean difference.

FIGURE 5

Effect of oxygen versus placebo supplementation on short-term ambulatory exercise capacity for patients with COPD. Corresponding references for the studies cited in the figure are available in the supplementary material. 6MWT: 6-min walk test; A5MWT: Ambulatory 5-min walk test; DL: DerSimonian and Laird; ESWT: endurance shuttle walk test; O₂: number of patients on oxygen; Pl: number of patients on placebo; RCT: randomised control trial; RoB: risk of bias; SMD: standardised mean difference.