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Clinical application of pulmonary function tests.pptm1
1.
2. Clinical Application of
Pulmonary Function Tests
Gamal Rabie Agmy, MD, FCCP
Professor of Chest Diseases,Assiut University
ERS National Delegate of Egypt
5. Weibel ER: Morphometry of the Human
Lung. Berlin and New York: Springer-
Verlag, 1963
The Airways
Conducting zone: no
gas exchange occurs
Anatomic dead
space
Transitional zone:
alveoli appear, but are
not great in number
Respiratory zone:
contain the alveolar
sacs
7. How does gas exchange occur?
• Numerous capillaries are wrapped around
alveoli.
• Gas diffuses across this alveolar-capillary
barrier.
• This barrier is as thin as 0.3 μm in some
places and has a surface area of 50-100
square meters!
10. Mechanics of Breathing
Inspiration
Active process
Expiration
Quiet breathing: passive
Can become active
11. Pulmonary Function Tests
Airway function
Simple spirometry
Forced vital capacity
maneuver
Maximal voluntary
ventilation
Maximal
inspiratory/expiratory
pressures
Airway resistance
Lung volumes and
ventilation
Functional residual
capacity
Total lung capacity,
residual volume
Minute ventilation,
alveolar ventilation,
dead space
Distribution of
ventilation
12. Pulmonary Function Tests
Diffusing capacity
tests
Blood gases and gas
exchange tests
Blood gas analysis
Pulse oximetry
Capnography
Cardiopulmonary
exercise tests
Metabolic
measurements
Resting energy
expenditure
Substrate utilization
Chemical analysis of
exhaled breath
13. Terminology
Forced vital capacity
(FVC):
Total volume of air that can
be exhaled forcefully from
TLC
The majority of FVC can be
exhaled in <3 seconds in
normal people, but often is
much more prolonged in
obstructive diseases
Measured in liters (L)
14. FVC
Interpretation of % predicted:
80-120% Normal
70-79% Mild reduction
50%-69% Moderate reduction
<50% Severe reduction
FVC
15. Terminology
Forced expiratory volume
in 1 second: (FEV1)
Volume of air forcefully
expired from full inflation
(TLC) in the first second
Measured in liters (L)
Normal people can exhale
more than 75-80% of their
FVC in the first second;
thus the FEV1/FVC can
be utilized to characterize
lung disease
16. FEV1
Interpretation of % predicted:
> 80% Mild
50-80% Moderate obstruction
30-50% severe obstruction
<30% Severe obstruction
FEV1 FVC
17. Terminology
Forced expiratory flow 25-
75% (FEF25-75)
Mean forced expiratory flow
during middle half of FVC
Measured in L/sec
May reflect effort
independent expiration and
the status of the small
airways
Highly variable
Depends heavily on FVC
18. FEF25-75
Interpretation of % predicted:
>60% Normal
40-60% Mild obstruction
20-40% Moderate obstruction
<20% Severe obstruction
19. Acceptability Criteria
Good start of test
No coughing
No variable flow
No early termination
Reproducibility
21. Changes in Lung Volumes in
Various Disease States
RuppelGL. ManualofPulmonary Function Testing, 8th ed., Mosby 2003
22. TLC
TLC < 80% of predicted value = restriction.
TLC > 120% of predicted value =
hyperinflation.
23.
24. 1-First Step, Check quality of the
test
1- Start:
*Good start: Extrapolated volume (EV) <
5% of FVC or 0.15 L
*Poor start: Extrapolated volume (EV)
≥5% of FVC or ≥ 0.15 L
2- Termination:
*No early termination :Tex ≥ 6 s
*Early termination : Tex < 6 s
25. 2- Look at …………FEV1/FVC
< N(70%)
Obstructive or Mixed
≥ N(70%)
Restrictive or Normal
3- Look at FEV1 To detect degree
Mild > 70%
Mod 50-69 %
Severe 35-49%
Very severe < 35%
27. 5- Reversibility test of FEV1
> 12%, 200 ml
Reversible (asthma)
< 12% ,200 ml
Ireversible (COPD)
6- Look at TLC
≥ 100% Pure obstruction
< 100% Mixed
28. 2- Look at …………FEV1/FVC
< N(70%)
Obstructive or Mixed
≥ N(70%)
Restrictive or Normal
3- Look at FVC
≥ N(80%) < N(80%)
Normal or SAWD
4-Look at FEF25/75
> 50% Normal < 50% SAWD
Restrictive
29. Patterns of Abnormality
Restriction low FEV1 & FVC, high FEV1%FVC
Recorded Predicted SR %Pred
FEV 1 1.49 2.52 -2.0 59
FVC 1.97 3.32 -2.2 59
FEV 1 %FVC 76 74 0.3 103
PEF 8.42 7.19 1.0 117
Obstructive low FEV1 relative to FVC, low PEF, low FEV1%FVC
Recorded Predicted SR %Pred
FEV 1 0.56 3.25 -5.3 17
FVC 1.65 4.04 -3.9 41
FEV 1 %FVC 34 78 -6.1 44
PEF 2.5 8.28 -4.8 30
high PEF early ILD
low PEF late ILD
30. Patterns of Abnormality
Upper AirwayObstruction low PEF relative to FEV1
Recorded Predicted SR %Pred
FEV 1 2.17 2.27 -0.3 96
FVC 2.68 2.70 0.0 99
FEV 1 %FVC 81 76 0.7 106
PEF 2.95 5.99 -3.4 49
FEV 1 /PEF 12.3
Discordant PEF and FEV1
High PEF versus FEV1 = early interstitial lung disease (ILD)
Low PEF versus FEV1 = upper airway obstruction
Concordant PEF and FEV1
Both low in airflow obstruction, myopathy, late ILD
52. Where is the pathology ???????
in the areas with increased density
meaning there is ground glass
in the areas with decreased density
meaning there is air trapping
53. Pathology in black areas
Airtrapping: Airway Disease
Bronchiolitis obliterans (constrictive bronchiolitis)
idiopathic, connective tissue diseases, drug reaction,
after transplantation, after infection
Hypersensitivity pneumonitis
granulomatous inflammation of bronchiolar wall
Sarcoidosis
granulomatous inflammation of bronchiolar wall
Asthma / Bronchiectasis / Airway diseases
54. Airway Disease
what you see……
In inspiration
sharply demarcated areas of seemingly increased
density (normal) and decreased density
demarcation by interlobular septa
In expiration
‘black’ areas remain in volume and density
‘white’ areas decrease in volume and increase in
density
INCREASE IN CONTRAST
DIFFERENCES AIRTRAPPING
62. Pathology in white Areas
Alveolitis / Pneumonitis
Ground glass
desquamative intertitial pneumoinia (DIP)
nonspecific interstitial pneumonia (NSIP)
organizing pneumonia
In expiration
both areas (white and black) decrease in
volume and increase in density
DECREASE IN CONTRAST
DIFFERENCES
68. PreoperativeAssessment
1- If FVC and FEV1>80% or 2L and DLco75%,
the patient can tolerate pneumonectomy.
2-If FVC,FEV1 and DLco< limits in step 1:
Predicted postoperative values of FEV1 and
DLco
69. Split Lung Function Studies
• Unilateral ventilation is measured by
inhalation Xe133 and perfusion is measured
by IV Tc99m albumin macroaggregates.
70. Split Lung Function Studies
• Postoperative FEV1= preoperative FEV1-
preoperative FEV1 x % of function of tumor-
containing lung X( no. of segments of resected
lobe/ total no. of segments of the lung )
E.g. preoperative FEV1= 2.0L
right lung function=40%
RUL lobectomy will be done.
Postoperative FEV1 = 2.0-2.0x40%x3/10=1.76L
71. Postoperative FEV1
• If radiospirometryis not done, then
Postoperative FEV1= preoperative FEV1-
preoperative FEV1 x 1/19x no. of resected
segments
E.g. preoperative FEV1= 2.0L
RUL lobectomy will be done.
Postoperative FEV1 = 2.0-2.0x1/19x3=1.684