For a patient with chronic obstructive pulmonary disease, the oxygen flow should be set to no more than how many liters per minute?

• A. 1-2
• B. 2-4
• C. 4-6
• D. 6-8

Answer: (B)

In COPD with chronic CO2 retention, oxygen must be titrated carefully because the drive to breathe can depend on low oxygen levels. Giving too much oxygen can blunt ventilation, raise arterial CO2, and worsen acidosis. The goal is to achieve adequate oxygenation without overshooting, typically targeting an SpO2 of about 88–92%. To do this safely with a nasal cannula, the flow is kept low and adjusted as needed, usually not exceeding about two to four liters per minute. Starting around 1–2 L/min and increasing only to maintain the target saturation helps avoid suppressing the respiratory drive while correcting hypoxemia; if higher oxygen is truly required, other delivery methods or escalation of support would be considered.