Effect of ambulatory oxygen on exertional dyspnea in IPF patients without resting hypoxemia

Summary

Background and objective

The effects of ambulatory oxygen for idiopathic pulmonary fibrosis (IPF) patients without resting hypoxemia have not been elucidated. The purpose of this study was to assess the effect of ambulatory oxygen on dyspnea in IPF patients without resting hypoxemia but with desaturation on exertion.

Methods

This was a double-blind, placebo-controlled, randomized crossover trial of ambulatory oxygen versus ambulatory air. Patients with IPF who had a partial pressure of arterial oxygen (PaO₂) between 60 mm Hg and 80 mm Hg at rest, and desaturation of 88% or less in a room-air 6-min walk test were eligible. Patients underwent a standardized 6-min walk test and a 6-min free walk test under each ambulatory gas. Oxygen and air were provided at 4 L/min intranasally. Dyspnea was evaluated immediately, 1, and 2 min after the tests.

Results

Twenty patients (16 men), with a mean age of 73.5 (SD 4.1) years, % predicted forced vital capacity (FVC) of 71.0 (13.3) %, % predicted diffusion capacity for carbon monoxide (DLco) of 57.0 (13.3) %, and PaO₂ of 72.5 (5.4) mm Hg were recruited. No significant differences in dyspnea were observed between ambulatory oxygen and air at each time point. However, some patients showed improvement in dyspnea with oxygen on an individual basis.

Conclusions

Since oxygen provides no additional benefit over air in terms of exertional dyspnea for IPF patients without resting hypoxemia, routine prescription of ambulatory oxygen is not recommended. However, assessment on an individual basis is necessary.

Trial registration. UMIN Clinical Trial Registry; No.:UMIN000005098; URL:http://www.umin.ac.jp/ctr/.