For most ACS patients without hypoxemia, what oxygen strategy is recommended?

• A. Provide routine high-flow oxygen to all patients
• B. Avoid routine high-flow oxygen; supplement if SpO2 < 90%; target SpO2 94–99%
• C. Provide oxygen only if the patient is dyspneic
• D. Maintain SpO2 at 100% at all times

Answer: (B)

Maintaining oxygen delivery in ACS is about avoiding both hypoxemia and hyperoxia. For most ACS patients who aren’t hypoxemic, giving routine high-flow oxygen doesn’t improve outcomes and can actually worsen them by causing coronary vasoconstriction, increased oxidative stress, and potential myocardial injury. The best approach is to monitor SpO2 and supplement oxygen only if it drops below 90%, with a target SpO2 of about 94–99%. This keeps oxygen delivery sufficient without the risks of hyperoxia. Maintaining SpO2 at 100% isn’t necessary and can be harmful. If a patient is dyspneic, that prompts closer assessment, but the guiding target remains the SpO2 range above.