In suspected ACS, oxygen therapy should be administered?

• A. To all patients immediately
• B. Never
• C. Only if hypoxemic
• D. Only after nitrates

Answer: (C)

The main idea here is that oxygen is used only when the patient is actually hypoxemic. In suspected ACS, giving oxygen to everyone regardless of oxygen saturation isn’t recommended, because excess oxygen can be unnecessary or even harmful.

Oxygen should be started if there is low oxygen saturation (hypoxemia), typically defined as an SpO2 at or below about 90% on room air, or if there are signs of respiratory distress, shock, or heart failure. The goal is to improve oxygen delivery to ischemic heart tissue without causing hyperoxia. If the patient is not hypoxemic, supplemental oxygen is not routinely needed and should be avoided to prevent potential negative effects of hyperoxia.

Oxgen can be given when hypoxemia is present, and it is not a prerequisite to wait for nitrates. If needed, it can be started promptly alongside other ACS therapies to optimize oxygenation.

So the best approach is to administer oxygen only if hypoxemic.