Which of the following are disadvantages of the nasal cannula? 1. Pressure necrosis 2. Drying nasal ...

(Answer to Q. 1)  ANS: C
With straight prongs, oxygen flow is directed toward the superior aspects of the nasal cavity, thus promoting turbulent flow; with curved prongs, oxygen entering the nose is directed across the nasal turbinate, thus enhancing laminar flow as the gas flows through the nasal cavity. Thus, both types of prongs can cause the aforementioned disadvantages.

(Answer to Q. 2)  ANS: A
All of the choices are low-flow devices except for a Venturi mask. A Venturi mask is an air-entrainment device, all of which are considered to be high-flow devices. Therefore, Venturi masks deliver a precise FIO2.

(Answer to Q. 3)  ANS: A
Thorpe tubes are the most commonly used flowmeters in respiratory care.

(Answer to Q. 4)  ANS: B
This problem is usually detected when the flowmeter is turned off completely, but gas can be heard continuing to flow from the flowmeter outlet; in this case, the flowmeter should be re-placed. This problem can also occur because of constant wear and tear.