High-concentration versus titrated oxygen therapy in ST-elevation myocardial infarction: a pilot randomized controlled trial.
BACKGROUND
The optimal approach to oxygen therapy in ST-elevation myocardial infarction (STEMI) is uncertain.


METHODS
A randomized controlled trial was undertaken in which 136 patients presenting with their first STEMI uncomplicated by cardiogenic shock or marked hypoxia were randomized to receive high-concentration (6 L/min via medium concentration mask) or titrated oxygen (to achieve oxygen saturation 93%-96%) for 6 hours after presentation. The main outcome variables were 30-day mortality and infarct size assessed by troponin T level at 72 hours. Secondary outcomes included a meta-analysis of mortality data from this study and previous randomized controlled trials, and infarct size was assessed by magnetic resonance imaging at 4 to 6 weeks.


RESULTS
There were 1 of 68 and 2 of 68 deaths in the high-concentration and titrated oxygen groups, respectively; a meta-analysis including these data with those from the 2 previous studies showed an odds ratio for mortality of high-concentration oxygen compared with room air or titrated oxygen of 2.2 (95% CI 0.8-6.0). There was no significant difference between high-concentration versus titrated oxygen in troponin T (ratio of mean levels 0.74, 95% CI 0.50-1.1, P = .14), infarct mass (mean difference -0.8 g, 95% CI -7.6 to 6.1, P = .82), or percent infarct mass (mean difference -0.6%, 95% CI -5.6 to 4.5, P = .83).


CONCLUSIONS
This study found no evidence of benefit or harm from high-concentration compared with titrated oxygen in initially uncomplicated STEMI. However, our estimates have wide CIs, and as a result, large randomized controlled trials are required to resolve the clinical uncertainty.
Capital & Coast District Health Board, Wellington, New Zealand.
Anil M
AM
Ranchord
Rachel
R
Argyle
Rhys
R
Beynon
Kyle
K
Perrin
Vishal
V
Sharma
Mark
M
Weatherall
Mark
M
Simmonds
Grant
G
Heatlie
Nicholas
N
Brooks
Richard
R
Beasley
D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D010100:Oxygen / Q000008:administration & dosage* / Q000627:therapeutic use; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D010865:Pilot Projects; D011446:Prospective Studies; D015996:Survival Rate / Q000639:trends; D016896:Treatment Outcome
D010100:Oxygen