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THE EFFECT OF SUPPLEMENTAL OXYGEN ON HYPERCAPNIA IN SUBJECTS WITH OBESITY-ASSOCIATED HYPOVENTILATION: A RANDOMIZED CROSS-OVER CLINICAL STUDY.
Chest. 2010 Oct 14;
Authors: Wijesinghe M, Williams M, Perrin K, Weatherall M, Beasley R
ABSTRACT BACKGROUND: It is unknown whether oxygen therapy causes worsening hypercapnia in obesity-associated hypoventilation, similar to the response observed in COPD. The objectives of this study were to investigate whether breathing 100% oxygen results in an increase in hypercapnia in obesity-associated hypoventilation, and the mechanisms of any effect. METHODS: In this double-blind randomized controlled cross-over trial 24 outpatient subjects with newly diagnosed obesity-associated hypoventilation inhaled 100% oxygen or room air for 20 minutes on two separate days. Transcutaneous carbon dioxide tension (PtCO(2)), minute ventilation (MV) and dead space to tidal volume ratio (Vd/Vt) were measured at baseline and at 20 minutes. A mixed linear model was used to determine differences between the two treatments. RESULTS: The study was terminated in 3 subjects breathing 100% oxygen due to a PtCO(2) increase ?10 mmHg, which occurred after 10:35, 13:20 and 15:51 minutes. The PtCO(2) increased by 5.0 mmHg (95% CI 3.1 to 6.8, P<0.001) with oxygen compared with room air. The MV decreased by 1.4 L/min (95% CI 0.11 to 2.6, P=0.03) and Vd/Vt increased by 0.067 (95% CI 0.035 to 0.10, P<0.001) with oxygen compared with room air. CONCLUSION: Breathing 100% oxygen causes worsening hypercapnia in stable subjects with obesity-associated hypoventilation. The study was registered with the Australia New Zealand Clinical Trials Registry (number ACTRN 12608000592347).
PMID: 20947648 [PubMed - as supplied by publisher]