Non-rebreather (NRB) mask

A face mask device used to deliver oxygen therapy. When tightly fitted, an NRB mask can deliver oxygen concentrations up to 80-90% because air is drawn into the lungs from where it is collected in the reservoir bag, which is filled with 100% oxygen. Hence, there is minimal dilution from entrained room air. An NRB requires a patient to breathe unassisted. Therefore, it supports oxygenation but does nothing for the patient with ventilatory failure. (a.k.a. oxygen reservoir mask)