Which statement best describes oxygen titration for long-term therapy?

• A. Use highest FiO2 possible at all times.
• B. Use fixed FiO2 regardless of SpO2.
• C. Never reassess oxygen needs after initial prescription.
• D. Use the lowest FiO2 to maintain target SpO2, monitor periodically with ABGs, and adjust as needed.

Answer: (D)

The essential idea is to tailor oxygen delivery to the patient’s actual needs, giving just enough to keep oxygenation within a safe target range. For long-term therapy, you want to use the lowest FiO2 that achieves the target SpO2, rather than continuously pushing more oxygen. This minimizes risks from excessive oxygen, such as oxygen toxicity or CO2 retention in susceptible individuals, while ensuring tissues receive adequate oxygen.

Monitoring periodically with arterial blood gases helps confirm that the chosen FiO2 is truly meeting the patient’s oxygen needs and not causing problems with gas exchange or acid-base balance. Adjustments are made as the patient’s condition changes—during infections, rehabilitation, or other factors that affect lung function or oxygen requirements. This ongoing titration and reassessment is what keeps long-term therapy both safe and effective.

The other options go against this approach: using the highest possible oxygen at all times can cause harm; locking in a fixed FiO2 ignores fluctuations in needs; and never reassessing after the initial prescription fails to account for evolving health status.