Oxygen Therapy

Abstract
Two types of Venturi masks claiming to deliver 24%, 28%, 35%, and 40% oxygen were studied with a new method employing ultrathin, large plastic bags, as well as by conventional methods. There were considerable variations between actual and claimed performance. Some masks delivered oxygen concentrations higher than the designated value. The masks were not truly "Venturi" in design. Their delivered oxygen concentrations vary somewhat depending on the stage of the patient's respiratory cycle. (JAMA228:474-478, 1974)