2. Clinical Application of
Pulmonary Function Tests
Gamal Rabie Agmy, MD, FCCP
Professor of Chest Diseases,Assiut University
ERS National Delegate of Egypt

4. Anatomy
 Lungs comprised of
 Airways
 Alveoli
http://www.aduk.org.uk/gfx/lungs.jpg

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

6. From Netter Atlas of Human Anatomy, 1989

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!

8. Gas Exchange
From Netter
Atlas of
Human
Anatomy,
1989

9. The Alveoli
 Approximately 300
million alveoli
 1/3 mm diameter
 Total surface area if
they were complete
spheres 85 sq.
meters (size of a
tennis court)
Murray & Nadel: Textbook of Respiratory
Medicine, 3rd ed., Copyright © 2000 W. B.
Saunders Company

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

20. Acceptable and Unacceptable
Spirograms (from ATS, 1994)

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.

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%

26. 4- Postbronchodilator FEV1/FVC
> 70%
asthma
< 70%
COPD

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

31. Common FVL Shapes
Volume
Flow
Normal Young or quitter Poor effort
Hesitation Knee Coughing

32. Asthma
0 1 2 3 4 5 6
0
2
4
6
8
10
12
FlowinL/s
Litres
concave FV curve
intrapulmonary airflow obstruction

33. Restrictive
0 1 2 3 4 5 6
-8
-6
-4
-2
0
2
4
6
8
10
12 F 19 yrs 1.64m
FVC 2.41 L -3.42 SR
FEV 2.41 L -2.62 SR
FEV% 100 +2.23 SR
PEF 5.55L/s -2.00 SR
F/P 7.2 RT 116 ms
FlowinL/s
Litres

34. COPD
0 1 2 3 4 5
-6
-4
-2
0
2
4
6
8
10
FlowinL/s
Litres
pressure dependent airways collapse

35. Poorly co-ordinated start
0 1 2 3 4 5 6
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
FlowinL/s
Litres
EV = large
Rise Time = 496 ms
Irregular shape
Poorly repeatable

36. Upper Airway Obstruction
0 1 2 3 4 5 6
-6
-4
-2
0
2
4
6 Age 40 yrs
FVC 3.52 L 0.84 SR
FEV1
3.0 L 0.74 SR
PEF 4.57 L/s -2.18 SR
FEV/PEF = 10.9
Inspiratory
Expiratory
FlowinL/s
Volume in Litres
FEV1 in mls
PEF in L/min
> 8

37. Upper Airway Obstruction
0 1 2 3 4 5 6
-6
-4
-2
0
2
4
6
8
10
12
FlowinL/s
Volume in Litres
Male aged 62 Height 1.68m
Recorded Predicted Range SR
FEV1 2.23 2.94 2.1 to 3.8 -1.4
FVC 3.40 3.71 2.7 to 4.7 -0.5
FEV1%FVC 66 76 64 to 88 -1.5
PEF 2.85 7.81 5.8 to 9.8 -4.1
FEV1/PEF 13.1

38. Inspiration
-ve
-ve
Expiration
+ve
+ve
Extra-thoracic UAO
worse on insp.
Intra-thoracic UAO
worse on exp.
Variable UAO

39. Intra-thoracic UAO
0 1 2 3 4 5 6
-8
-6
-4
-2
0
2
4
6
8
10
12
FlowinL/s
Liters
Age 65 Female
FVC 2.97 L 1.3 SR
FEV1 2.26 L 0.6 SR
FEV1% 76% -0.1 SR
PEF 3.4 L·s-1 -2.5 SR
F/P 11.1 RT 455 ms

40. Variable Extrathoracic Upper
Airway Obstruction

41. Fixed Upper Airway Obstruction

42. Upper Airway Obstruction
• Variable extrathoracic obstructions
1. vocal cord paralysis,
2. thyromegaly,
3. tracheomalacia, or
4. Neoplasm
• Large airways variable intrathoracic obstructions
1. tracheomalacia or
2. neoplasm
• Fixed obstruction
1. tracheal stenosis,
2. foreign body, or
3. neoplasm.

43. *If FIVC /FEVC >90, FIF50 <80% predicted and
FEF50/FIF50 <0.8 variable intrathoracic
large and upper airway obstruction.
*If FIVC /FEVC >90, FIF50 <80% predicted and
FEF50/FIF50>1.2 Variable extrathoracic
obstruction.
*If FIVC /FEVC >90, FIF50 <80% predicted and
FEF50/FIF50 = 0.8 – 1.2  Fixed upper
airway obstruction.

44. Obstruction, Restriction, Mixed

45. True Restrictive Disorders
Intraparenchymal
Interstitial Infilterative Diffuse alveolar
Chest Wall
Pleural Skeletal
Reduced TLC.FRC,RV,VC and normal to high FEV1/FVC
In 50% DLco/VA>80% The other half had low DLco/VA

46. Pseudorestrictive Disorders
Normally: IC/ERV=2-3/1
True restrictive: IC/ERV=<2/1
Pseudorestrictive: IC/ERV=6/1

47. Pseudorestrictive Disorders
Obesity:
*Early airway closure (low ERV & high RV)
*FRC is more reduced than TLC&VC
*Low FEF50% , FEF75%, FEF25-75%,

48. Pseudorestrictive Disorders
Neuromuscular Disease:
*FRC normal
*IC&ERV decreased
*Decreased TLC
*Increased RV
*A-aO2 gradient normal
*MIP&MEP decreased

49. Pseudorestrictive Disorders
Asthma:
*FRC &TLC increased
*Improvement of FEV1&FVC with bronchodilators
*Positive bronchoprovacation test
*Increased diffusing capacity and DLco/VA

50. Pseudopseudorestrictive
Patients with obstructive diseases who do not
complete expiratory effort of FVC. This may
lead to a below normal FEV1 and FVC with
pseudonormalization of ratio.

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

55. Bronchiolitis
obliterans

56. Early Sarcoidosis

57. Cystic Fibrosis

58. Chronic

59. Hypersensitivity pneumonitis
HRCT Morphology
chronic: fibrosis
Intra- / interlobular septal thickening
Irregular interfaces
Traction bronchiectasis
acute - subacute
acinar (centrilobular) unsharp densities
ground glass (patchy - diffuse)

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

63. DIP

64. Cellular
NSIP

65. Mosaic Perfusion
Chronic pulmonary embolism
LOOK FOR
Pulmonary hypertension
idiopathic, cardiac disease, pulmonary
disease

66. CTEPH =
Chronic thrombembolic
pulmonary hypertension

67. Mixed Disorder
*Sarcoidosis
*Rhematoid
*Advanced IPF
*Bronchiectasis
*BOOP in smokers

68. PreoperativeAssessment
1- If FVC and FEV1>80% or 2L and DLco75%,
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

72. PreoperativeAssessment
3- Exercise testing:Maximum o2
consumption>75% or 20 mL/kg/min-----
pneumonectomy.
Maximum o2 consumption <40% or 10 mL/kg/min-
----Inoperable