Pulmonary Function Testing

Question 1

Forced vital capacity (FVC)

Answer 1

patient inhales as deeply as they can then exhales for as long and forcefully as possible.

Question 2

Forced expiratory volume in 1 second (FEV1)

Answer 2

amount of air exhaled during the first second of the FVC maneuver.

Question 3

FEV1/FVC ratio

Answer 3

normal is 80%

Question 4

Diffusing capacity

Answer 4

assesses the body’s ability to take up a gas

• Decreased when blood cannot bind gas diffusing (e.g., anemia)
• Conditions that reduce surface area for gas exchange (e.g., emphysema, pulmonary embolism)
• Conditions that alter membrane permeability or thickness (e.g., fibrosis)

Question 5

Determining Obstructive vs. Restrictive Patterns =

Answer 5

Is FEV1/FVC ratio less than the lower limit of normal?

• No => Normal or Restrictive
  - Is FVC less than lower limit of normal?
  - No - Normal; Yes - Restrictive
• Yes => Obstructive
  - Is FVC less than lower limit of normal?
  - No - Obstructive; Yes - Could be mixed