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Respiratory Therapist/Venturi Mask Settings


I have been searching for some kind of chart for the Venturi Mask and concentrator settings.  I understand that the Orange percentage is 50% at 12 lpm, but is the lpm the end result or what the concentrator should be set on.  So if I were to have the concentrator set to 2 lpm, using a 50%, (orange) diluter, what is the end result for the patient?  And, then for the rest what would be the end results, and CONCENTRATOR setting?

Any Venturi is based off of 100% oxygen and the set flow going into it. So in your example you must have 12 lpm of 100% oxygen going into the venturi to get 50%. Any less flow and your concentration will be off.

A venturi works by having the driving gas pull in ambient air to give you the set percentage you have for that dial. Any change in the flow or driving gas concentration will change the output concentration.

In your example the lower flow would most likely make your output less then 50% if your concentrator is truly putting out 100%, which I know some have trouble doing.

Respiratory Therapist

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Rob Trusty


Pediatric respiratory care, Anything CPR related


20 years working in a childrens hospital. Clinical Educator.


Respiratory Care

RRT-NPS, AHA Training center faculty

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