Respiratory (Pulmonary Function Testing)

Front 1

what are the indications for performing pulmonary fxn tests

Back 1

- to eval pts with resp dz
- to assess resp involvement in pts with CV dz
- to evaluate impairment/response to therapy
- screen of high risk pts (ie. smokers)

Front 2

what is the forced FVC maneuver (using spirometry)?

Back 2

pt inspires maximally to total lung capacity, then exhales into spirometer as forcefully, as rapidly and as completely as possible

FVC = forced (expiratory) vital capacity

Front 3

what is the most important volume examined in a spirometry test? what's the second most important?

Back 3

#1 the volume that's exhaled in teh first second (FEV1)

#2 the total amt of air that pt can exhale (FVC)

Front 4

which loop -- expiratory or inspiratory -- do you usually look at for dz process with spirometry?

Back 4

expiratory loop

Front 5

a healthy FEV1/FVC ratio is greater than ___%.

Back 5

70%; basically, if you can exhale more than 70% of the air out in the first second, relative to the total amt of air you exhale...then you're a healthy person. if not, then you have an obstructive pathology that's keeping you from doing so.

Front 6

which is the best measure of severity of airflow obstruction?

a. FEV1
b. FVC
c. FEV1/FVC

Back 6

a. normal FEV1 > 80% of predicted for age, sex and height

Front 7

FEV1 indicates:

a. large and small airway function
b. degree of lung and chest expansion
c. amount of total lung capacity for a given patient
d. none of the above

Back 7

A

Front 8

FVC indicates:

a. large and small airway function
b. degree of lung and chest expansion
c. how much air patient can blow out very rapidly
d. two of these (name em)

Back 8

B,C

Front 9

if FEV1/FVC is less 70%, it's:

a. airway obstruction
b. airway restriction

Back 9

A. however, this is only true if FVC is not too small...otherwise you can't really distinguish b/w restrictive and obstructive lung dz

Front 10

a low FEF usually reflects:

Back 10

reflects small airway dz

Front 11

how do you dx obstruction on spirometry?

Back 11

- decreased FEV1, normal or slightly decreased FVC
** FEV1/FVC < 70% = obstruciton **
if FVC is decreased alot, may have combined restriction

Front 12

how do you dx restriction on spirometry?

Back 12

- reduced FVC and FEV1
** normal or INCREASED FEV1/FVC **

Front 13

what are some causes of restrictive lung dz?

Back 13

scarring, fibrosis of lung, chest wall problems (guillan-barre, myasthenia gravis)

Front 14

if a pt's FEV1 and/or FVC improve by >12% AND 200 mL from baseline after bronchodilator administration, what is this suggestive of?

Back 14

asthma (this tells us the airways are responsive to bronchodilators or not)

Front 15

when is the only time you look at inspiratory loop?

Back 15

to check for upper airway pathology

Front 16

truncation of expiratory loop =

truncation of inspiratory loop =

Back 16

intrathoracic obstruction (tracheal tumor above carina)

extrathoracic obstruction (vocal cord paralysis)

remember it's "E for I, and I for E"

Front 17

what if you have truncation of expiratory and inspiratory loop in spirometry?

Back 17

that means fixed obstruction (like in tracheal stenosis)

Front 18

hat 2 pts would you want to measure lung volume w/ body plethysmograph?

Back 18

- Pts with restrictive dz
- Pts with FVC so low that you can’t tell wther its obstructive or restrictive dz

Front 19

LARGE/SMALL lung volumes are caused by increase in compliance of lung (decrease in stiffness and elastic recoil)

Back 19

large (eg. emphysema)

Front 20

LARGE/SMALL lung volumes are caused by either a decrease in lung compliance or a decrease in chest wall compliance

Back 20

small (eg. parenchymal lung dz or chest wall disorders)

Front 21

in small volume lungs, you can have either a problem with decrease compliance of lung itself or a decreased chest wall compliance. how do you differentiate b/w lung problems or chest wall problems?

Back 21

diffusion capacity (DLCO) - which measures how well oxygen diffuses across alveolar-capillary membrane.

so if you have low DLCO, then you most likely have a lung problem bc most lung dz's decrease this diffusion capability by definition

Front 22

pt has normal FEV1/FVC ratio on spirometry. but the values for both FEV1 and FVC are below 80% of expected. patient is given lung volume and DLCO tests. what would you expect the results to be if pt had a chest wall problem? what would you expect if pt had a lung dz?

Back 22

In chest wall dz, you’ll have low lung volume and normal DLCO, whereas in lung dz, you’ll have both low lung volume and low DLCO.

Front 23

what is the mechanism for DLCO test?

Back 23

Single-breath technique for measurement of DLCO. The subject inhales a gas mixture containing a low concentration of CO and a tiny amount of helium. At end-inspiration the subject holds his or her breath for 10 seconds. During exhalation, the expired gas is analyzed for CO and helium concentration. During the breathhold period, some CO diffuses from the alveoli to the blood; the amount can be calculated from the measurements of the CO concentration in alveolar gas at the beginning and end of the 10-second interval

Front 24

pt has isolated low DLCO. possible dx?

Back 24

pulmonary vascular dz
anemia

Front 25

pt has reduced DLCO with abnormal spirometry (with obstructive pattern). dx?

Back 25

emphysema

Front 26

pt has reduced DLCO with abnormal spirometry (with restrictive pattern). dx?

Back 26

interstitial lung dz

Front 27

when and how do you do a bronchoprovocation test?

Back 27

do it when you want to support dx for asthma or hyperactive airway dz in the presence of normal spirometry(normal lung fxn)

You do spirometry, then you ask patient to inhale chemical, start with low dilution, then go up…then see at what point does pt’s FEV1 drop. Pts with asthma, once you start giving them even low dose methacholine, their FEV1 drops a lot. This doesn’t happen in normal people.