You are examining the expiratory flow tracing during the ...

[CORALGRILL2014]

You are examining the expiratory flow tracing during the patient's forced vital capacity (FVC) maneuver. At what point during the exhalation can you generally begin to see flow from the bronchioles?
 
  a. Beyond 30
  b. Beyond 50
  c. Beyond 70
  d. Beyond 90

Question 2

What shape of the flow-volume loop is typical for the patient with a fixed upper airway obstruc-tion?
 
  a. Circular
  b. Box
  c. Elliptical
  d. Ramp

[phuda]

Answer to Question 1

ANS: B
Any flow measured in the first half of the FVC reflects on the bronchi; any flow measured be-yond 50 of the vital capacity reflects on the bronchioles.

Answer to Question 2

ANS: B
Compared with the normal flow-volume loop, a fixed upper airway obstruction produces a curve that appears box-shaped.