title: Pre-hospital oxygen therapy in acute exacerbations of chronic obstructive pulmonary disease.
abstract: BACKGROUND
  High concentration oxygen is commonly administered during acute exacerbations of chronic obstructive pulmonary disease (AECOPD). The aim of this study was to determine the association between oxygen, severity markers and poor outcomes in AECOPD.
  
  
  METHODS
  In an audit of patients with AECOPD arriving by ambulance to the Emergency Department of Wellington Hospital, details of oxygen administration, clinical outcomes and severity markers were documented. The main outcome measure was a composite of death, assisted ventilation, or respiratory failure. Associations between oxygen therapy, severity markers and poor clinical outcomes were assessed by logistic regression.
  
  
  RESULTS
  Of 250 patients 77 (31%) died, required assisted ventilation or were in respiratory failure. Increased oxygen flow was associated with increasing risk of death, assisted ventilation or respiratory failure with an odds ratio (OR) of 1.2 (95% CI 1.0-1.4) per 1 L/min oxygen flow. Increasing PaO(2) was associated with a greater risk of a poor outcome with an OR of 1.1 (95% CI 1.0-1.3) per 10 mmHg higher PaO(2). Home oxygen (OR 2.8, 95% CI 1.5-5.1), previous respiratory failure (OR 2.6, 95% CI 1.5-4.6), previous ventilation (OR 3.2, 95% CI 1.7-5.9) and home nebulizer use (OR 2.4, 95% CI 1.4-4.3) were associated with an increased risk of a poor outcome.
  
  
  CONCLUSIONS
  In AECOPD high flow oxygen in the ambulance is associated with poor clinical outcomes. A number of easily identified markers of chronic disease severity indicate an increased risk of a poor clinical outcome.
authors.affiliation: Medical Research Institute of New Zealand, University of Otago Wellington, New Zealand.
authors.forename: M
authors.initials: M
authors.lastname: Wijesinghe
authors.forename: K
authors.initials: K
authors.lastname: Perrin
authors.forename: B
authors.initials: B
authors.lastname: Healy
authors.forename: K
authors.initials: K
authors.lastname: Hart
authors.forename: J
authors.initials: J
authors.lastname: Clay
authors.forename: M
authors.initials: M
authors.lastname: Weatherall
authors.forename: R
authors.initials: R
authors.lastname: Beasley
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D004632:Emergency Medical Services / Q000379:methods* / Q000592:standards; D004636:Emergency Service, Hospital / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010102:Oxygen Inhalation Therapy / Q000009:adverse effects / Q000379:methods* / Q000592:standards; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology / Q000628:therapy*; D012189:Retrospective Studies; D016896:Treatment Outcome