Supplemental oxygen use for suspected myocardial infarction without hypoxemia


Background: Clinical guidelines recommend supplemental oxygen in patients with suspected acute myocardial infarction but data to support its use in patients without hypoxemia are limited.
Study design: Open-label, registry based randomized clinical trial.
Setting: Thirty-five hospitals in Sweden with acute cardiac care facilities.
Synopsis: Authors included 6,629 patients aged 30 and older who presented with symptoms suggestive of myocardial infarction. Patients with oxygen saturations 90% or greater were enrolled in the study and randomly assigned to either 6 liters per minute of face mask oxygen for 6-12 hours or ambient air. Median oxygen saturation was 99% in the treatment group and 97% in the ambient air group (P less than .0001). In an intention-to-treat model, 1 year after randomization there was no significant difference in all-cause mortality between the oxygen (5.0%) and ambient air (5.1%) groups (P = .80). There was no difference in the rate of rehospitalization with myocardial infarction or the composite endpoint of all-cause mortality and rehospitalizations for myocardial infarction at 30 days and 1 year. Limitations of this study include lower power than anticipated since calculations were based on a higher mortality rate than observed in this study, and the open-label protocol.
Bottom line: In patients who present with a suspected myocardial infarction without hypoxemia, oxygen therapy is not associated with improved all-cause mortality or decreased rehospitalizations for myocardial infarction.
Citation: Hofmann R, Jernberg T, Erlinge D, et al. Oxygen therapy in suspected acute myocardial infarction. N Engl J Med. 2017;377:1240-9.

Dr. Gala is a hospitalist, Beth Israel Deaconess Medical Center, and instructor in medicine, Harvard Medical School, Boston.

Recommended Reading

VIDEO: New stroke guideline embraces imaging-guided thrombectomy
The Hospitalist
Heart attacks bring 12 weeks of higher stroke risk
The Hospitalist
Rivaroxaban versus warfarin in mild acute ischemic stroke secondary to atrial fibrillation
The Hospitalist
CPR decision support videos can serve as a supplement to CPR preference discussions for inpatients
The Hospitalist
Anticoagulation use in new-onset secondary atrial fibrillation
The Hospitalist
   Comments ()