Oxygen Therapy Devices Practice Test

Nasal prongs deliver FiO2 that rises in roughly 4% increments for each additional liter per minute of flow, starting near room air (about 21%). At 1 L/min, you’d expect about 25% oxygen (0.25), which clinicians often approximate as 24–26%. Among common choices, 0.24 best matches this 1 L/min estimate. The other values are not consistent with the typical 1 L/min delivery: 0.20 would be too low for nasal prongs at this flow, while 0.28 and 0.32 correspond to higher flows (around 2–3 L/min) rather than 1 L/min.