Pulmonary functions Tests: made easy

1. Pulmonary Functions Testing
Mahmoud Elhusseiny Abolmagd MSc, MD
Lecturer of Pulmonary & Critical Care Medicine
Mansoura University, Egypt

2. Pulmonary Function Testing
Made easy

3. Respiratory Functions of the Lung
• Ventilation
• Perfusion
• Diffusion

4. Non-Respiratory Functions of the Lung
1- Vascular reservoir
2- Filter for blood borne substances
3- Defense
4- Endocrine and metabolic functions
5- Pulmonary drug metabolism
6- Platelet formation in the lung

5. Why do I care about PFTs?
• Diagnosis of disease.
• Monitor progression of disease
• Monitor effectiveness of treatment.
• Pre-operative assessment.

6. Standard PFTs
• Spirometry
• Lung volumes
• DLCO
Types of PFTs
Special PFTs
• 6MWD test
• Peak flowmeter
• MIP and MEP
• CPET

7. Respiratory System Components

8. Major airways

9. Major airways
90% of the total airway resistance
2% of the cross sectional area

10. Small airways
Small diameter
Big concern
>98% of the cross sectional area
10% of the total airway resistance

12. Lung volumes &
Capacities

13. Lung Volumes & Capacities

15. What is a spirometry ?

16. Spirometry: equipment

17. Body plethysmography DLCO

18. Peak Flow Meter
Incentive Spirometry

19. Preparation of the patient
Precautions:-
1- Don’t smoke for one hour before test.
2- Don’t eat a large meal within 2 hours of test.
3- Please wear loose clothing.
4- Don’t perform exercise within 30 minutes of test.
Withhold bronchodilators:-
SABA: 6 hrs
LABA: 12 hrs
Oral BD (sustained release):24 hrs.

20. How to perform it ??

21. PFT report

22. Variables that have impact PFT values
• Age.
• Gender.
• Height & weight.
• Race.

23. Acceptability
1. Smooth continuous curve.
2. Lack of artifact induced by coughing.
3. Good start of test, good end of test.
4. Satisfactory exhalation with 6 seconds.
Assessment of the manoeuvers
Reproducibility
After 3 acceptable maneuver, the largest FEV1, FVC should be within 200 ml of each other

24. Unacceptable Efforts

25. Volume
(L)
Flow
(L/sec)
Normal
Obstruction
Asthma
Flow volume loop

26. Restriction
Flow volume loop
1. Relatively unaffected in
restrictive disease
2. Overall size of the curve will
appear smaller when
compared to normal on the
same scale.

27. Flow volume loop

28. Upper Airway Obstruction

29. education for health
DLCO
Increase in the following :
1- Exercise.
2- Supine position.
3- Bronchial asthma.
4- Pulmonary Hemorrhage.
5- Polycythemia.
Decrease in the following :
1- Emphysema.
2- ILD.
3- Anemia.
4- Pulmonary hypertension.

30. When you asked to interpret Spirometry

31. Value (95 % function test confidence interval)
FEV1 80-120%
FVC 80-120%
FEV1 /FVC > 80
FEF 25-75% 60
TLC 80-120%
FRC 80-120%
RV 80-120%
RV/TLC 20-35%
DLCO 80-120%
Normal Values of Pulmonary Function Tests

32. 1.
Assess validity
2.
Determine
ventilatory pattern
3.
Grade severity
4.
Grade response
to BD challenge
Spirometry interpretation

33. PFT interpretation

34. Obstructive Lung Disease
COPD vs BA

35. Obstructive Severity
• Interpretation of FEV1% predicted:
–>70 % Mild obstruction
–60-70 % Moderate obstruction
–50-60 % Moderately severe obstruction
–35-50 % Severe obstruction
–<35% Very severe obstruction

36. COPD Severity
• According to post bronchodilator FEV1%
predicted:
–>80 % GOLD stage I
–50-80 % GOLD stage II
–30-50 % GOLD stage III
–<30 % GOLD stage IV

37. Small airway obstruction severity
• Interpretation of FEF25-75 % predicted:
–>60 % Normal
–40-60 % Mild obstruction
–20-40 % Moderate obstruction
–<20 % Severe obstruction

38. • Improvement in FEV1 by 12% or
200 ml in repeating spirometry
after treatment with Salbutamol
2.5mg by nebulizer after 15-30
minutes
• Partial reversibility
Reversibility
• Normally (8%).
• Absence of reversibility ??!!

39. Bronchial challenge test
• Other names: bronchial provocation test and
methacholine challenge.
•  20% decrease in FEV1. {PC 20 – FEV1}.
• If PC20 – FEV1 < 1 mg/ml the test provides strong
confirmation of clinical diagnosis of BA.
• If PC20 –FEV1 > 8 mg/ml; BA is unlikely.
• Negative MCT excludes asthma with 95% certainty.

40. Methacholine test

41. Methacholine test

42. Restrictive Lung Disease
intrapulmonary vs extrapulmonary

43. Restrictive Severity
• Interpretation of FVC % predicted:
–>70 % Mild obstruction
–60-70 % Moderate obstruction
–50-60 % Moderately severe obstruction
–35-50 % Severe obstruction
–<35% Very severe obstruction

44. DLCO Severity
• Interpretation of DLCO % predicted:
–>60 % - < LLN Mild
–40-60 % Moderate
–<40 % Severe

45. 6MWD test

46. Case Scenarios

47. Case (1)

48. Case (2)

49. Case (3)

50. Case (4)

51. Case (5)

52. Case (6)

53. Case (7)

54. Case (8)

55. Common patterns
• 1- Asthma
• Obstructive pattern
• Significant reversibility
• Air trapping
• Normal or decreased diffusion
• 2- Emphysema:
• Obstructive pattern
• No reversibility
• Hyperinflation
• Air trapping
• Decreased diffusion

56. Common patterns
• 3- IPF:
• Decreased VC
• Decreased TLC
• Decreased FRC
• Decreased diffusion
• 5- Pulmonary hypertension:
• Normal spirometry
• Normal lung volumes
• Decreased diffusion

57. Spirometry interpretation