Effect of high flow oxygen on mortality in chronic obstructive pulmonary disease patients in prehospital setting: randomised controlled trial.
OBJECTIVE
To compare standard high flow oxygen treatment with titrated oxygen treatment for patients with an acute exacerbation of chronic obstructive pulmonary disease in the prehospital setting.


METHODS
Cluster randomised controlled parallel group trial.


METHODS
Ambulance service in Hobart, Tasmania, Australia.


METHODS
405 patients with a presumed acute exacerbation of chronic obstructive pulmonary disease who were treated by paramedics, transported, and admitted to the Royal Hobart Hospital during the trial period; 214 had a diagnosis of chronic obstructive pulmonary disease confirmed by lung function tests in the previous five years.


METHODS
High flow oxygen treatment compared with titrated oxygen treatment in the prehospital (ambulance/paramedic) setting.


METHODS
Prehospital or in-hospital mortality.


RESULTS
In an intention to treat analysis, the risk of death was significantly lower in the titrated oxygen arm compared with the high flow oxygen arm for all patients (high flow oxygen n=226; titrated oxygen n=179) and for the subgroup of patients with confirmed chronic obstructive pulmonary disease (high flow n=117; titrated n=97). Overall mortality was 9% (21 deaths) in the high flow oxygen arm compared with 4% (7 deaths) in the titrated oxygen arm; mortality in the subgroup with confirmed chronic obstructive pulmonary disease was 9% (11 deaths) in the high flow arm compared with 2% (2 deaths) in the titrated oxygen arm. Titrated oxygen treatment reduced mortality compared with high flow oxygen by 58% for all patients (relative risk 0.42, 95% confidence interval 0.20 to 0.89; P=0.02) and by 78% for the patients with confirmed chronic obstructive pulmonary disease (0.22, 0.05 to 0.91; P=0.04). Patients with chronic obstructive pulmonary disease who received titrated oxygen according to the protocol were significantly less likely to have respiratory acidosis (mean difference in pH 0.12 (SE 0.05); P=0.01; n=28) or hypercapnia (mean difference in arterial carbon dioxide pressure -33.6 (16.3) mm Hg; P=0.02; n=29) than were patients who received high flow oxygen.


CONCLUSIONS
Titrated oxygen treatment significantly reduced mortality, hypercapnia, and respiratory acidosis compared with high flow oxygen in acute exacerbations of chronic obstructive pulmonary disease. These results provide strong evidence to recommend the routine use of titrated oxygen treatment in patients with breathlessness and a history or clinical likelihood of chronic obstructive pulmonary disease in the prehospital setting.


BACKGROUND
Australian New Zealand Clinical Trials Register ACTRN12609000236291.
Austin
Michael A
MA
Menzies Research Institute, University of Tasmania, Hobart, Tasmania, 7001 Australia. maaustin@utas.edu.au
Wills
Karen E
KE
Blizzard
Leigh
L
Walters
Eugene H
EH
Wood-Baker
Richard
R
D000328:Adult; D000368:Aged; D016000:Cluster Analysis; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000008:administration & dosage*; D029424:Pulmonary Disease, Chronic Obstructive / Q000401:mortality / Q000628:therapy*; D012423:Rural Health; D013648:Tasmania / Q000453:epidemiology; D014504:Urban Health
D010100:Oxygen