Non rebreather mask

by thesix thesix (New) New

Hi everyone,

I have a question with 100% non-rebreather masks. I always see nurses going from 15L to 10L flow rate on a 100% non-rebreather mask but doesn't the non-rebreather mask still given 100% O2? Like does changing the flow rate even change anything? The bag is still inflated....and it's still 100% O2...?

MunoRN, RN

Specializes in Critical Care. Has 10 years experience. 8,019 Posts

There's no reason to turn down the flow rate to "wean" a patient off a NRB since you are correct, when used correctly a NRB provides near 100% FiO2 (less than that with air leaks and re-breathed air).

The amount of flow required to keep a NRB working correctly varies by the patient's lung volume and volume of dead space within the mask, but typically should be at least 10 L/min, although there's not really any downside to just always running it at 15L/min.

It should be noted that whomever decided to call a non-rebreather mask a "non-rebreather" mask was an idiot.

Even in the moist ideal conditions it's not really possible that a patient won't be inhaling any of their exhaled air (ie "rebreathing").  And a simple mask is actually more effective at flushing exhaled air from the mask than a non-breather mask since all the flow in between breaths is flushing the mask of exhaled air, whereas with an NRB only a small portion is flushing the mask, the rest is filling the reservoir bag.