<Tr> <Th> Related items </Th> <Td> Nasal cannula </Td> </Tr> <Tr> <Td_colspan="2"> (edit on Wikidata) </Td> </Tr> <P> A non-rebreather mask (NRB, non-rebreather, non-rebreather facemask, etc .) is a device used in medicine to assist in the delivery of oxygen therapy . An NRB requires that the patient can breathe unassisted, but unlike low flow nasal cannula, the NRB allows for the delivery of higher concentrations of oxygen . </P> <P> The non-rebreather mask covers both the nose and mouth of the patient and attaches with the use of an elastic cord around the patient's head . The NRB has an attached reservoir bag, typically 1 liter, that connects to an external oxygen tank or Bulk Oxygen Supply system . Before an NRB is placed on the patient, the reservoir bag is inflated to greater than two - thirds full of oxygen, at a rate of 15 liters per minute (lpm). Approximately 1 ⁄ 3 of the air from the reservoir is depleted as the patient inhales, and it is then replaced by the flow from the O supply . If the bag becomes completely deflated, the patient will no longer have a source of air to breathe . </P>

When do you use a non rebreather mask
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