RT Journal Article
SR Electronic
T1 Randomised controlled trial of high concentration versus titrated oxygen therapy in severe exacerbations of asthma
JF Thorax
JO Thorax
FD BMJ Publishing Group Ltd and British Thoracic Society
SP 937
OP 941
DO 10.1136/thx.2010.155259
VO 66
IS 11
A1 Kyle Perrin
A1 Meme Wijesinghe
A1 Bridget Healy
A1 Kirsten Wadsworth
A1 Richard Bowditch
A1 Susan Bibby
A1 Tanya Baker
A1 Mark Weatherall
A1 Richard Beasley
YR 2011
UL http://thorax.bmj.com/content/66/11/937.abstract
AB Background The effect on Paco2 of high concentration oxygen therapy when administered to patients with severe exacerbations of asthma is uncertain.Methods 106 patients with severe exacerbations of asthma presenting to the Emergency Department were randomised to high concentration oxygen (8 l/min via medium concentration mask) or titrated oxygen (to achieve oxygen saturations between 93% and 95%) for 60 min. Patients with chronic obstructive pulmonary disease or disorders associated with hypercapnic respiratory failure were excluded. The transcutaneous partial pressure of carbon dioxide (Ptco2) was measured at 0, 20, 40 and 60 min. The primary outcome variable was the proportion of patients with a rise in Ptco2 ≥4 mm Hg at 60 min.Results The proportion of patients with a rise in Ptco2 ≥4 mm Hg at 60 min was significantly higher in the high concentration oxygen group, 22/50 (44%) vs 10/53 (19%), RR 2.3 (95% CI 1.2 to 4.4, p<0.006). The high concentration group had a higher proportion of patients with a rise in Ptco2 ≥8 mm Hg, 11/50 (22%) vs 3/53 (6%), RR 3.9 (95% CI 1.2 to 13.1, p=0.016). All 10 patients with a final Ptco2 ≥45 mm Hg received high concentration oxygen therapy, and in five there was an increase in Ptco2 ≥10 mm Hg.Conclusion High concentration oxygen therapy causes a clinically significant increase in Ptco2 in patients presenting with severe exacerbations of asthma. A titrated oxygen regime is recommended in the treatment of severe asthma, in which oxygen is administered only to patients with hypoxaemia, in a dose that relieves hypoxaemia without causing hyperoxaemia.Clinical trial number ACTRN12607000131459.