Which step confirms POB function during use?

• A. Squeeze the bag at mid-point to observe inflation
• B. Verify oxygen is colorless and odorless
• C. Turn the POB on
• D. Put mask over mouth

Answer: (A)

When you’re using a portable oxygen bottle, you confirm that oxygen is actually flowing by checking the reservoir bag. Squeezing the bag at its mid-point and watching it inflate shows that oxygen is being delivered through the system to the mask. This quick visual cue is the best way to verify the POB is functioning during use because it directly demonstrates flow.

The other ideas don’t serve as a flow check: oxygen being colorless and odorless is a physical property, not a function check of the device; turning the POB on is a setup step, not a real-time confirmation of flow once in use; and placing the mask on the face is part of using the system, not a diagnostic method to confirm that oxygen is actually delivering.