Background and objective Although long-term oxygen therapy is one of few treatments known to improve survival in COPD, no patient subgroup likely to derive benefit has been identified in over 30 years. We assessed the prognostic value of point measurement of PaO2 and proportion of ambulatory oximetry with saturations below 90% in this context. Methods Subjects were community-living patients with COPD and PaO2 56-70 mm Hg when stable. Baseline assessments included clinical, physiological and laboratory assessments, as well as 24-h ambulatory oximetry. Patients were followed to death from any cause, first exacerbation and first admission. Results Despite poor survival overall, there was no significant difference in prognosis between mildly hypoxaemic and moderately hypoxaemic patients. There were also no significant differences for secondary end-points (exacerbation and hospital admission). On multivariate analysis, trends were observed towards improved survival, with higher PaO2 and greater proportion of ambulatory oximetry below 90%. Conclusions Neither resting P aO2 nor proportion of ambulatory oximetry below 90% saturation effectively predicted survival in COPD. Long-term oxygen therapy improves survival in COPD, although the ability of oxygenation parameters to predict outcomes has not been studied. We studied subjects with mild-to-moderate resting hypoxaemia, failing to meet standard qualifying criteria for long-term oxygen therapy. Neither PaO2 nor partial 24-h oxygen saturations below 90% effectively predicted clinical outcomes.
- blood gas analysis
- blood gas monitoring
- chronic obstructive pulmonary disease
- oxygen inhalational therapy
- transcutaneous oximetry