In the described croup case, which of the following reflects the child’s oxygen status on room air?

• A. May remain normal
• B. Low oxygen saturation
• C. Frequent distressed breathing
• D. SpO2 99% on room air

Answer: (D)

The main idea here is how to judge oxygenation in a child with croup using a pulse oximetry reading on room air. In uncomplicated croup, enough oxygen is often delivered to the bloodstream despite the airway narrowing, so the oxygen saturation can stay normal without supplemental oxygen. A reading of 99% on room air shows the blood is well oxygenated without needing extra oxygen, which is exactly what you’d expect if the child isn’t hypoxic. The other options describe either general possibilities or related signs without giving a precise oxygenation value: low oxygen saturation would mean hypoxemia, frequent distressed breathing reflects work of breathing rather than oxygenation, and “may remain normal” is vague without a concrete SpO2 measurement. So the precise SpO2 of 99% on room air best reflects the child’s oxygen status in this scenario.