In the RDS case, what FiO2 was used for the patient on assist/control ventilation?

• A. 80%
• B. 85%
• C. 90%
• D. 100%

Answer: (C)

When a neonate with respiratory distress syndrome needs help from a ventilator, the main goal is to ensure enough oxygen gets into the blood despite poorly aerated lungs. In RDS, there’s alveolar collapse and a lot of shunting, so even with support from a ventilator, delivering adequate oxygen often requires a high fraction of inspired oxygen (FiO2) initially. On assist-control ventilation, FiO2 is adjusted to keep the baby’s oxygenation within a safe target range while the lungs are being recruited and surfactant helps improve gas exchange.

Using about 90% oxygen provides a strong driving force for oxygen transfer without necessarily pushing to the maximum, balancing the need to correct hypoxemia with the desire to limit oxygen toxicity. As the clinical picture improves and lung function increases, FiO2 is typically titrated downward with ongoing monitoring (SpO2 and arterial blood gases) to maintain adequate oxygenation while reducing exposure to high oxygen levels.