Which oxygen delivery method delivers about 40-60% oxygen and is used if hypoxemia does not improve with a nasal cannula?

• A. Nasal Cannula
• B. Simple Face Mask
• C. Venturi Mask
• D. Non-Rebreather

Answer: (B)

Oxygen delivery devices vary in the fraction of inspired oxygen (FiO2) they can provide, so when a patient remains hypoxemic on a nasal cannula, you escalate to a device that delivers a higher FiO2. A simple face mask delivers roughly 40-60% oxygen when used at moderate flow (about 5–8 liters per minute). This makes it the typical next step after a nasal cannula for patients whose oxygenation isn’t improving, because it boosts oxygenation significantly without the more complex setup of high-flow systems. It also requires the mask to fit well and the oxygen flow to be high enough to keep the reservoir bag inflated. By comparison, a Venturi mask offers precise, controlled FiO2 (often up to about 50% with COPD patients in mind), but is chosen when exact oxygen percentages are needed. A non-rebreather can provide very high FiO2, up to near 100%, and is reserved for severe hypoxemia or acute distress where maximal oxygen delivery is necessary. So the simple face mask is the best fit for increasing FiO2 to about 40-60% after nasal cannula has failed to correct hypoxemia.