In a patient with COPD exacerbation on oxygen therapy, what SpO2 target range should you aim for, and why?

• A. 92-94% SpO2 to maximize oxygenation.
• B. 88-92% SpO2 to prevent CO2 retention; titrate oxygen to maintain target while monitoring ABGs.
• C. 95-98% SpO2 to ensure complete tissue oxygenation.
• D. 85-89% SpO2 to minimize oxygen toxicity.

Answer: (B)

In COPD with an exacerbation, the goal of oxygen therapy is to balance enough oxygen delivery with avoiding CO2 retention. People with chronic CO2 retention often rely on hypoxemia to stimulate ventilation; giving too much oxygen can blunt their drive to breathe, raise arterial CO2, cause acidosis, and worsen respiratory failure. This is why the target is modest: about 88–92% SpO2. Keeping within this range helps ensure adequate tissue oxygenation (often corresponding to a PaO2 around 60–70 mmHg) while minimizing the risk of oxygen-induced hypercapnia. Oxygen should be titrated to maintain this target, with close ABG (or capnography) and clinical monitoring to adjust as needed. Higher targets (like 95–98%) can increase CO2 retention, while targets that are too low (85–89%) risk tissue hypoxia, and 92–94% is not consistently safe for all COPD patients.