In patients with COPD, why might a lower SpO2 target (e.g., 88–92%) be used?

• A. To prevent CO2 retention and respiratory acidosis in CO2 retainers.
• B. To maximize oxygen delivery by keeping SpO2 near 100%.
• C. To minimize oxygen use regardless of oxygenation.
• D. To avoid any oxygen administration.

Answer: (A)

In COPD patients who chronically retain CO2, oxygen therapy must balance correcting low oxygen with avoiding suppression of the natural drive to breathe. Giving too much oxygen can raise arterial oxygen levels enough to blunt the hypoxic drive and worsen CO2 retention, leading to respiratory acidosis. Using a lower SpO2 target of about 88–92% helps maintain adequate oxygenation while minimizing the risk of hypercapnia in these individuals. Clinically, oxygen is titrated to stay within that range, with monitoring (ABG or capnography as available) to ensure the patient remains well-oxygenated without tipping into CO2 retention. Aiming for near-normal saturation or avoiding oxygen altogether would either increase the risk of CO2 retention or leave hypoxemia untreated, respectively, so the 88–92% target represents a careful balance in this context.