Which of the following factors cause the isothermic saturation boundary (ISB) to shift farther down into the airways?
1. Decreased ambient temperature
2. Increased tidal volume (VT)
3. Endotracheal intubation
a. 1 and 2 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2, and 3
ANS: D
The ISB shifts distally when a person breathes through the mouth rather than the nose; when he or she breathes cold, dry air; when the upper airway is bypassed (breathing through an artificial tracheal airway); or when the minute ventilation is higher than normal.
You might also like to view...
You are by the side of a patient who fell. He has a hematoma to his forehead as well as deformity of his left forearm. His daughter informs you that he has severe dementia and she cares for him at home. As you assess him, he continually screams out, "Mary, help me. I need help!" Which one of the following questions is MOST appropriate to ask the daughter?
A) "Was Mary his wife?" B) "Do you know what he means by this?" C) "Is this how he normally is?" D) "Isn't dementia is a terrible disease?"
The partial pressure of oxygen when there is 25% oxygen in a gas mixture at an atmospheric pressure of 760 mm Hg is ____ mm Hg
a. 190 c. 1900 b. 30.4 d. 159.6