During ventilation, how should FiO2 be titrated?

• A. Increase FiO2 to maintain SpO2 above 98% at all times.
• B. Maintain SpO2 about 92-96% and titrate FiO2 down to the lowest level that maintains target saturation.
• C. Keep FiO2 fixed at 0.5 regardless of saturation.
• D. Increase FiO2 only if the patient shows signs of distress.

Answer: (B)

Titrate FiO2 to achieve adequate oxygenation with the lowest feasible oxygen level. In most adults, aim for SpO2 around 92–96% and, once you reach that target, reduce FiO2 to the smallest value that keeps SpO2 in range. This approach avoids unnecessary oxygen exposure and potential oxygen toxicity while ensuring tissues stay well-oxygenated. Increasing FiO2 to push SpO2 above 98% can promote hyperoxia without added benefit and can be harmful over time. Keeping FiO2 fixed (e.g., at 0.5) ignores changing patient needs and may leave hypoxemia or unnecessary oxygen exposure if lung conditions improve. Waiting for distress to raise FiO2 risks prolonged periods of inadequate oxygenation. Special populations (like COPD) may have a lower SpO2 target (e.g., 88–92%), but the general strategy remains: titrate to the lowest FiO2 that maintains the appropriate saturation.