B4.037 Evaluating Pulmonary Function Tests

Question 1

what are some indications for pulmonary function testing

Answer 1

screening
evaluation of a respiratory symptom or sign
grading severity of disease
following progression of disease
monitoring response to therapy
monitoring occupational, drug or radiation toxicity
predicting prognosis
predicting post-operative pulmonary risk
assessing disability/impairment

Question 2

what is the basic function of spirometry

Answer 2

measures how fast and how much air you breathe out

Question 3

what are the 3 ATS acceptability criteria for FVC

Answer 3

good start of test
smooth continuous curve
satisfactory exhalation

Question 4

what is the optimal amount of exhalation

Answer 4

10 s

minimum of 6 s

Question 5

what are the ATS reproducibility criteria?

Answer 5

after 3 acceptable maneuvers, if the 2 largest FEV1 are within 150 mL and the 2 largest FVC are within 150 mL, the session is complete

Question 6

if you can’t meet the reproducibility criteria, what should you do?

Answer 6

continue until both criteria are met OR
a total of 8 trials OR
the subject cannot or should not continue

Question 7

what should be features of the final spirometry report

Answer 7

FEV1 and FVC should be the largest from any acceptable trial (not necessarily the same)
“best test” curve should come from the trial with the largest sum of FEV1 and FVC

Question 8

hesitating start

Answer 8

small peak in the middle of initial upward trend

Question 9

submaximal effort

Answer 9

less steep and less tall curve

Question 10

rainbow curve

Answer 10

less steep and less tall curve, slightly more rounded out than submaximal effort
normal in young, non-smoking females

Question 11

early termination

Answer 11

sudden vertical drop in downward trend

Question 12

coughing

Answer 12

sharp spikes in trend line

Question 13

subject briefly stopped exhaling

Answer 13

flow momentarily hits zero and then goes back to where it should be

Question 14

“knee”

Answer 14

downward trend initially flat-ish and then gets steeper

normal in young, non-smokers

Question 15

low TLC

Answer 15

restrictive process

Question 16

low FEV1/FVC

Answer 16

obstructive process

Question 17

what is the gas dilution method used for

Answer 17

measurement of lung volume

Question 18

how is the gas dilution method done

Answer 18

nitrogen washout and helium dilution

takes advantage of inert, poorly soluble gas of known concentration

Question 19

downsides of gas dilution method

Answer 19

unable to measure gas in poor communication with airways

cannot be immediately repeated

Question 20

what is plethysmography used for

Answer 20

measurement of lung volume

Question 21

what does the lung volume measured by plethysmography/gas dilution correspond to?

Answer 21

FRC; end expiration point on the spirogram
so
TLC = FRC + IC

Question 22

normal predicted range of FEV1, as % of predicted

Answer 22

80-120%

Question 23

normal predicted range of FVC, as % of predicted

Answer 23

80-120%

Question 24

normal predicted range of FEV1/FVC, as % of predicted

Answer 24

+/- 0.05 of predicted ratio

Question 25

normal predicted range of TLC, as % of predicted

Answer 25

80-120%

Question 26

normal predicted range of FRC, as % of predicted

Answer 26

75-120%

Question 27

normal predicted range of RV, as % of predicted

Answer 27

75-120%

Question 28

normal predicted range of DLCO, as % of predicted

Answer 28

75-120%

Question 29

what is an obstructive pulmonary defect

Answer 29

disproportionate reduction of max airflow from the lung with respect to the FVC that can be displaced from the lung indicates EXPIRATORY airflow limitation

Question 30

cutoff for chronic obstructive lung disease FEV1/FVC

Answer 30

< 0.7

Question 31

causes of obstructive pulmonary defect

Answer 31

``` asthma COPD bronchiectasis obliterative bronchiolitis lymphangioleiomyomatosis (LAM) diffuse panbronchiolitis ```

Question 32

what is a restrictive pulmonary defect

Answer 32

characterizes by a reduction in TLC below the 5th percentile of normal distribution possible indictor when FVC is reduced by FEV1/FVC is normal or increased

Question 33

what is a pseudorestriction

Answer 33

reduced FVC normal FEV1/FVC normal TLC

Question 34

what are some causes of restrictive defects within the lungs

Answer 34

``` resection atelectasis stiff lung CHF thickened pleura tumor ```

Question 35

what are some causes of restrictive defects within the pleural cavity

Answer 35

effusion enlarged heart tumor

Question 36

what are some causes of restrictive defects within the chest wall

Answer 36

``` scleroderma ascites pregnancy obesity kyphoscoliosis splinting due to back pain ```

Question 37

what are some causes of restrictive defects within the muscle

Answer 37

neuromuscular disease old polio paralyzed diaphragm

Question 38

what is a bronchodilator response

Answer 38

when flow volume loops improve after administration of a bronchodilator >12% and 200 mL increase in FEV1 or FVC

Question 39

extrathoracic airway obstruction

Answer 39

above suprasternal notch

Question 40

intrathoracic airway obstruction

Answer 40

between suprasternal notch and carina

Question 41

variable airway obstruction

Answer 41

lesion narrow and decreases flow excessively during one phase of respiration

Question 42

fixed airway obstruction

Answer 42

narrowing causes decreased flow equally during both phases of respiration

Question 43

variable extrathoracic lesions

Answer 43

vocal chord paralysis or dysfunction tracheomalacia goiter

Question 44

variable intrathoracic lesions

Answer 44

tracheomalacia malignant tracheal lesions tracheal stricture

Question 45

fixed lesions

Answer 45

tracheal stenosis vocal chord paralysis vocal chord malignancy

Question 46

what is the DLCO

Answer 46

single breath carbon monoxide diffusing capacity | normal = 30 mL CO/min/mmHg

Question 47

how is DLCO measured

Answer 47

from RV, inhale low concentration CO plus inert/insoluble gas to TLC 10 second breath hold then exhale completely exhaled gas analyzed for CO to calculate DLCO

Question 48

what are some reasons for a decreased DLCO

Answer 48

``` Valsalva maneuver pulmonary resection emphysema insterstitial lung disease pulmonary vascular disease pregnancy CO smoking anemia ```