110714 spirometry

Question 1

transpulmonary pressure equals

Answer 1

Palv-Ppl

Question 2

what determines airflow, particularly during expiration?

Answer 2

flow = (Palv-Patm)/airway resistance

Question 3

where is resistance largest along the respiratory tract?

Answer 3

medium sized bronchi

Question 4

conductance and resistance relationship

Answer 4

inverse

Question 5

the only lung pressure we can measure i

Answer 5

pleural pressure

Question 6

how can we calculate lung compliance?

Answer 6

volume/pressure change for transpulmonary pressure

use points of zero alveolar pressure to find transpulmonary pressure

Question 7

in emphysema, compliance is

Answer 7

increased relative to normal subject

Question 8

in expiration, there are two phases called?

Answer 8

effort dependent

effort independent flow rate phase

Question 9

indications for PFTs

Answer 9

diagnostic (symptoms, signs, abnormal labs)

assess effects of diseases and therapies

screening (smokers, occupational exposures, preoperative risk, disability, prognosis)

Question 10

spirometry will never tell you the disease-true or false?

Answer 10

true

Question 11

what kind of graphs are there in spirometry?

Answer 11

volume time curve

flow volume loop

Question 12

what portion of flow volume loop is effort independent

Answer 12

btwn FEF25 and FEF75

Question 13

inspiratory flow rate on flow volume loop measures what?

Answer 13

how well upper airway is doing

upper airway=what’s outside of the chest wall

Question 14

expiratory flow rate on flow volume loops measures what?

Answer 14

what’s happening in the intrathoracic airways (anything affecting resp sys inside chest wall; not just lungs and airway)

Question 15

with asthma, what would you observe in the mid lung volume range and where on the flow volume loop?

Answer 15

in the expiratory flow rates, you would see decrease in expiratory flow rate in mid lung volume range

Question 16

FEF50 and FIF50 relationship in normal pts

Answer 16

normally equal

Question 17

hallmark of obstructive disease on flow volume loop

Answer 17

decreased flow rates

small airway–scalloping effect

Question 18

restrictive disease

Answer 18

you never get a lung capacity that goes out to normal because there’s scarring and not not expanding normally

total lung capacity is going to be too low

flow volume loop:
shape of curve is similar to normal curve

Question 19

FVC is expired in how many seconds normally

Answer 19

6

Question 20

keys to spirometry interpretation

Answer 20

FEV1/FVC ratio (must be close to 100% of predicted to be normal)
FEV1
FVC

Question 21

how do you interpret a NOT low ratio of FEV1/FVC?

Answer 21

normal ventilatory fxn and restrictive processes

Question 22

how do you interpret a LOW ratio of FEV1/FVC?

Answer 22

obstructive process

Question 23

what is normal FEV1/FVC ratio?

Answer 23

0.70-0.87, depending on demographics of pt

Question 24

what is considered normal spirometry result?

Answer 24

FEV1/FVC ratio is normal
AND
VC (FVC) is normal

Question 25

what is considered a normal FVC

Answer 25

greater than or equal to 80% of predicted (within the 95% confidence level)

Question 26

if FEV1/FVC ratio is low, how do you determine the degree of obstruction?

Answer 26

look at percent of predicted FEV1

see slide 20 for values

Question 27

when should you assess bronchodilator responsivity?

Answer 27

for all pts with spirometry showing low FEV1/FVC ratio

for all pts suspected of asthma or chronic obstructive lung dis

Question 28

bronchodilator respponsivity

Answer 28

significant response to a bronchodilator is shown when the FVC or FEV1 increases at least 12% AND 200mL

shows reversible obstruction–asthma

Question 29

ex of restrictive ventilatory defects

Answer 29

interstitial lung disease: sarcoidosis, collagen vascular dis, pulmonary fibrosis

penumonectomy

pleural disease: pleural effusion

chest wall dis: kyphosis, neuromuscular disorders

extrathoracic conditions: obesity

Question 30

true hallmark of restrictive ventilatory defect

Answer 30

reduced TLC

Question 31

how to determine if supports restrictive ventilatory defect?

Answer 31

normal FEV1/FVC ratio
reduced TLC–see slide 24 for values for degree of restrictive disease

if cannot obtain lung volumes, then grade FVC via the obstructive FEV1 criteria–see slide 25

Question 32

looking at shapes of flow volume loops-what to look for

Answer 32

beware of flattened inspiratory curve
check FEF50/FIF50 ratio
FEF50/FIF50 of 1 or less is normal
FEF50/FIF50 greater than 1 is variable extrathoracic airway obstruction

FEF50/FIF50 a little over 1 is fixed extrathoracic airway obsrtuction

Question 33

FEF50

Answer 33

forced expiratory flow of 50%–look at y axis and halve it to determine