A 60-year-old man with acute STEMI has an oxygen saturation of 96% on room air and is comfortable without dyspnoea. He is receiving aspirin, ticagrelor, and morphine. What is the correct approach to supplemental oxygen?
- A Give oxygen at 4 L/min for the first 24 hours in all MI patients
- B Give oxygen only if the patient is a current smoker
- C Give oxygen only if saturation falls below 90% or the patient is in respiratory distress ✓
- D Give high-flow oxygen until serial troponins peak
Correct answer: C. Give oxygen only if saturation falls below 90% or the patient is in respiratory distress
Explanation
Routine oxygen in normoxic patients with MI provides no mortality benefit and may cause harm through coronary vasoconstriction and increased oxidative stress. The DETO2X-AMI randomised trial showed no reduction in death or hospitalisation for infarction with routine oxygen in suspected MI with saturation of 90% or above. Current guidelines therefore reserve oxygen for saturation below 90% or clear respiratory distress.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.