The venturi inner mask is made according to the venturi principle, that is, when oxygen enters the mask through a narrow hole, a negative pressure is generated around the jet flow, and a certain amount of air is carried into the mask from the open edge. The size of the edge of the mask changes the air and oxygen The ratio.
Because the air flow injected into the mask is greater than the maximum flow rate and tidal volume of the patient during inhalation, the oxygen concentration is constant. Because the high flow rate of gas continuously flushes the inside of the mask, the exhaled breath is difficult to stay in the mask, so there is basically no repeated breathing. Patients with hypoxemia and hypercapnia need to choose a venturi inner cover, which can accurately control the aerobic concentr