Lecture 3: Pulmonary Function Testing

Question 1

List 6 indications for pulmonary function testing (PFT)

Answer 1

• Evaluate sx’s and signs of lung disease (i.e., cough, dyspnea, wheezing, hyperinflation, etc.
• Assess progression of lung disease
• Monitor effectiveness of therapy
• Evaluate preoperative patients in selected situation
• Screen people at risk for pulmonary disease such as smokers or people with occupational exposure
• Monitor for potentially toxic effects of certain drugs/chemicals

Question 2

Pulmonary function tests are not indicated in which patients; may be confusing when what is present?

Answer 2

• Not indicated in pt’s without sx’s
• May be confusing when non-pulmonary diseases that effect the pulmonary system are active (i.e., CHF); pt may appear to have pulmonary disease

Question 3

What are the 3 most important values measured during pulmonary function testing?

Answer 3

• FVC
• FEV₁
• FEV₁/FVC ratio

Question 4

What is the FEV₁/FVC ratio used to determine?

Answer 4

If pattern is obstructive, restrictive, or normal

Question 5

Which gas is used to assess the diffusion capacity of the lungs?

Answer 5

Carbon monoxide

Question 6

For obstructive disease, measurement of the RV and TLC can be used to demonstrate what?

Answer 6

• Air trapping
• Hyperinflation

Question 7

What value is needed to confirm true restriction and to better quantitate the degree of restriction in a restrictive lung disease?

Answer 7

TLC

Question 8

If the FEV₁/FVC ratio is either normal or increased this may indicate restrictive disease or normal study, how can the FVC value be used for further interpretation?

Answer 8

• If the FVC is NOT less than the lower limit of normal = normal study
• If FVC is less than the lower limit of normal = restrictive pattern

Question 9

What is the FVC like in an obstructive vs. restrictive pattern of disease?

Answer 9

• Obstructive = decreased or normal
• Restrictive = decreased

Question 10

What is the FEV₁ like in an obstructive vs. restricitve pattern of disease?

Answer 10

• Obstructive = decreased
• Restrictive = decreased or normal

Question 11

What is the TLC like in an obstructive vs. restricitve pattern of disease?

Answer 11

• Obstructive = normal or increased
• Restrictive = decreased

Question 12

Using the FEV₁ as % of predicted value for classifying the severity of an obstruction which value indicates mild, moderate, moderately severe, severe, and very severe?

Answer 12

• Mild = >70%
• Moderate = 60-69%
• Moderately severe = 50-59%
• Severe = 35-49%
• Very severe = <35%

Question 13

If the FVC is less than normal, how can using the TLC and RV determine if there is a mixed pattern of obstructive/restrictive or if there is obstruction with air trapping?

Answer 13

• If there is mixed pattern, the TLC will be decreased
• If air trapping is occurring then the TLC will be normal or elevated and the RV will be significantly increased

Question 14

Air trapping will lead to an increase in which value of lung volume?

Answer 14

RV

Question 15

What are 4 extra-parenchymal causes of restrictive lung disease?

Answer 15

• Obesity
• Neuromuscular disease
• Chest wall deformities
• Large pleural effusions

Question 16

Which value can be used to distinguish between parenchymal vs. extraparenchymal causes of restrictive lung diseases?

Answer 16

• Diffusing capacity of the lung
• If below lower limit of normal after correcting for lung volumes = parenchymal disease likely

Question 17

What will FVC be in restrictive lung disease?

What will the FEV1/FVC ratio be in restrictive lung disease?

Will TLC and RV be increased or decreased?

Will DLCO be high, normal or low?

Answer 17

<80% predicted

normal to >.70

Decreased

Could be normal or low

Question 18

What will FEV1/FVC ratio be in obstructive lung disease?

What will the graph look like?

Is TLC and RV high or low?

Will DLCO be high, normal or low?

Answer 18

<.70

Concave, scooped, “Chair”

TLC and RV are high from air trapping

DLCO can be normal or low

Question 19

In patients with obstruction, you need to determine if there is any improvement in FEV1 or FVC after bronchodilator therapy

If there is >12% increase in FEV1 or FVC AND an absolute volume increase of >200ml then ?

if not?

Answer 19

the patient has asthma

if not then the patient has COPD or another obstructive lung disease