The point on a static pressure-volume curve (SPV) where the ...

[clmills979]

The point on a static pressure-volume curve (SPV) where the alveoli begin to open is referred to as which of the following?
 
  a. Lower inflection point on the inflation limb
  b. Upper inflection point on the inflation limb
  c. Upper inflection point on the deflation limb
  d. Lower inflection point on the deflation limb

Question 2

The sigmoid shape of the static pressure-volume lung recruitment maneuver indicates which of the following?
 
  a. All parts of the lungs open with the same pressure.
  b. Independent portions of the lungs open with the same pressure.
  c. Dependent portions of the lungs open with different pressures.
  d. Lung units open at different times with different pressures.

[T4T]

Answer to Question 1

ANS: A
At the lower inflection point on the inflation limb, the slope of the line changes significantly. It originally was believed that this point represents the opening of most of the collapsed alveoli. However, it is the point at which the alveoli begin to open. Even at the upper inflection point on the inflation limb, the alveoli are still being recruited in some parts of the lungs.

Answer to Question 2

ANS: D
The shape of the pressure-volume curve suggests that different areas of the lung open at different pressures during the recruitment maneuver. As pressure is exerted every few seconds, different areas of the lungs are recruited. This occurs between the lower inflection point on the inspiratory limb up to the upper inflection point on the inspiratory limb.

[clmills979]

TYSM

[Dnite]

Excellent