Document Detail


Randomised controlled trial of high concentration versus titrated oxygen therapy in severe exacerbations of asthma.
MedLine Citation:
PMID:  21597111     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
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.
Authors:
Kyle Perrin; Meme Wijesinghe; Bridget Healy; Kirsten Wadsworth; Richard Bowditch; Susan Bibby; Tanya Baker; Mark Weatherall; Richard Beasley
Publication Detail:
Type:  Journal Article; Multicenter Study; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2011-05-19
Journal Detail:
Title:  Thorax     Volume:  66     ISSN:  1468-3296     ISO Abbreviation:  Thorax     Publication Date:  2011 Nov 
Date Detail:
Created Date:  2011-10-17     Completed Date:  2011-12-08     Revised Date:  2012-10-17    
Medline Journal Info:
Nlm Unique ID:  0417353     Medline TA:  Thorax     Country:  England    
Other Details:
Languages:  eng     Pagination:  937-41     Citation Subset:  IM    
Affiliation:
Medical Research Institute of New Zealand, Private Bag 7902, Wellington 6242, New Zealand.
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Aged
Asthma / blood,  physiopathology,  therapy*
Blood Gas Monitoring, Transcutaneous / methods
Carbon Dioxide / blood
Emergency Service, Hospital
Female
Forced Expiratory Volume / physiology
Hospitalization
Humans
Hypercapnia / blood,  etiology
Male
Middle Aged
Oxygen Inhalation Therapy / adverse effects,  methods*
Partial Pressure
Young Adult
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide
Comments/Corrections
Comment In:
Thorax. 2012 Sep;67(9):833-4; author reply 834   [PMID:  22188974 ]
Thorax. 2011 Nov;66(11):931-2   [PMID:  21685492 ]

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