3 - PFTs

Question 1

3 main spirometry values

Answer 1

FEV1
FVC
FEV1/FVC

Question 2

which loop in the flow volume loop gives you more information usually?

Answer 2

expiratory

Question 3

what is FEV1 good for assessing?

Answer 3

best measure of severity of airflow obstruction

indicates large and small airway function

Question 4

what is FVC good for assessing?

Answer 4

indicates degree of lung and chest expansion

Question 5

what does the FEV1/FVC ratio tell you?

Answer 5

distinguishes obstruction from restriction:

<70% = obstruction

Question 6

what does the FEF(25-75) indicate?

Answer 6

small airway obstruction

Question 7

spirometry results for obstruction

Answer 7

dec FEV1, normal or dec FVC

FEV1/FVC < 70%

Question 8

spirometry results for restriction

Answer 8

dec FVC and FEV1

normal or inc FEV1/FVC

Question 9

what happens to the shape of the expiratory flow volume curve as obstructive dz worsens?

Answer 9

becomes more concave

Question 10

if pt shows major improvement in spirometry after a bronchodilator is given, what do they probably have?

Answer 10

asthma

Question 11

what does upper airway obstruction look like on flow volume loop, and how do you tell if its intrathoracic or extrathoracic or fixed?

Answer 11

clipping

variable intrathoracic - in expiratory loop
variable extrathoracic - in inspiratory loop (Letters are switched - i’s go w/ e’s)
fixed - both loops

Question 12

when do you measure lung volume?

Answer 12

airway obstruction w/ low FVC (rule out concomitant restrictive)
restrictive disorders (pulm fibrosis, chest wall / neuromuscular disorders)

Question 13

2 methods for lung volume measurement

Answer 13

plethysmography (body box)

helium dilution