These masks, sometimes called High Air Flow Oxygen Enrichment
(HAFOE) masks incorporate a Venturi Barrel and use the Bernoulli
principle to deliver a predetermined and fixed concentration of
oxygen to the patient, regardless of the patients respiratory
pattern, providing a higher gas flow than the peak
inspiratory flow rate.
The performance of small venturi
masks are not considered as accurate as large volume masks. The
concentration is very much dependent on patients breathing rate and
minute volume.