Pulmonology: PFT's

Question 1

What FEV value would you expect to see in an obstructive and restrictive dx?

Answer 1

Decreased in BOTH restrictive and obstructive

Question 2

Is forced vital capacity (FVC) increased or decreased in obstructive and restrictive dx?

Answer 2

decreased in BOTH

Question 3

Why is obtaining a FEV/FVC ratio important in the diagnosis of restrictive vs obstructive px?

Answer 3

Because in obstructive disease the FVC is smaller and the FEV is MUCH smaller so the RATIO IS DECREASED. Whereas in restrictive disease, the ratio is increased or normal; hence spirometry is diagnostic.

Question 4

in obstructive disease what would the peak expiratory flow be?

Answer 4

Decreased

Question 5

in restrictive disease, what would the peak expiratory flow be?

Answer 5

increased or normal

Question 6

What would the residual volume be in obstructive and restrictive disease?

Answer 6

Decrease in RESTRICTIVE

Increase in OBSTRUCTIVE

Question 7

What are the indications to not use spirometry or PFT’s?

Answer 7

Severe asthma, respiratory distress, angina, PTX, hemoptysis, active TB; if the patient cannot give maximal effort, don’t use the test.

Question 8

How do predictive values of pulmonary function test vary?

Answer 8

They vary with age, gender, height and to a lesser extent-weight and ethnicity. *all PFT’s are measured against predicted values**

Question 9

What is body plethysmography used for?

Answer 9

Used to calculate lung volumes; pt is placed in sealed box and breathes through a one way valve