1. Pulmonary Function Tests
Ghassan Jamaleddine, M.D.
American University of Beirut

2. Use of PFT’s Evaluating breathlessness
Initial evaluation of patient with known respiratory disease
Following the course of a respiratory disease
Pre-operative assessment
Disability evaluation
Screening of subclinical disease

3. Disadvantages of PFT’s
Patient’s cooperation and an informed technician are required
Measures the lung and chest as a unit
Evaluates disease at only one point in time
Errors in programs of computer driven automated equipment

4. Routine PFT’s Spirometry with or without Flow Volume loop
Static lung volumes
Single Breath Diffusing Capacity

9. Spirometry Forced vital capacity
Forced Expiratory Volume in one second (FEV1)
Percent Expired (FEV1/FVC or FEV1%)
Forced Mid-Expiratory Flow (FEF 25-75) or Maximal Mid-Expiratory Flow (MMEF or MMF)
Peak or Maximal Expiratory Flow Rate (PEF or MEFR)

11. Adapted from Fletcher C, Peto R
Adapted from Fletcher C, Peto R. The natural history of chronic airflow obstruction. Br Med J 1977; 1:

12. Pattern of defects seen on PFT’s
Obstructive Vent defect
FVC reduced or Normal
FEV1 reduced
FEV1/FVC is reduced
Example: Asthma, COPD
Restrictive Vent defect
FVC reduced
FEV1 normal or reduced
FEV1/FVC is increased
Example: pulmonary fibrosis, pleural effusion, neuromuscular

16. P1V1 = P2 (V1-Δ V)

18. Lung Volumes Functional Residual Capacity Expiratory Reserve Volume
Residual Volume
Inspiratory Capacity
Total Lung Capacity
Vital Capacity

19. FLOW VOLUME LOOP

22. Diffusion
Transfer of a gas across a tissue sheet, governed by Fick’s law
Rate of Transfer = A D x P/T

24. Diffusion Capacity (measurement)
A D x (P1- P2) T
AD/T = Diffusion constante
Rate of transfer (CO) = Vco = Dlco x (P1-P2)
Dlco = Vco/ PA –Pa = Vco/ PA
25 ml/min/mmHg

25. Diffusing Capacity Influenced by:
Changes in alveolar-capillary membrane
Pulmonary circulation
Ventilation perfusion matching
Hemoglobin concentration

26. Diffusion Capacity Very important in
Interstitial lung disease
Drug induced lung injury
Reduced in Emphysema because of destruction of alveolar units

27. PFT Patterns in Disease
PFT results are best interpreted with knowledge of the patients history, physical exam and occasionally chest X-ray.

28. PFT
Disease
Obstructive
Restrictive
FVC
N or  
FEV1
FEV1/FVC N
MMEF or V50
 N or 
MVV
FRC  RV
TLC
N or 

29. Case 1 14 year old boy came to ER with increasing shortness of breath
History of asthma since age of 2-3
Maintained on ICS and Beta2 agonists
Followed by Family physician, past year frequent attacks, several courses of antibiotics and systemic corticosteroids

30. Case 1 (cont’d)
In ER started on iv steroids and inhaled Beta 2 agonists, no improvement, admitted
No history of atopy, no nasal nor GI symptoms, no family history of asthma
Exam: decrease breath sounds
Admitted

31. Case 1 (cont’d) CXR, CBC, chemistry non revealing
After 2 days of treatment with steroids and inhaled bronchodilators there was no improvement in symptoms
Noticed faint voice and tachypnea on minimal exercise
PFT obtained

32. Case PFT’s FVC 93%, FEV1 45%, FEV1/FVC 41% TLC 90%, RV 90%, DLCO 100%
?????

34. Case 1(cont’d) FOB: subglottic stenosis (? Congenital)
Tracheostomy followed by reconstructive surgery
Total recovery, no more asthma treatment

35. Case 2
32 year old man presented with 2 months history of increasing shortness of breath
Married, non-smoker, bank employee, no history of asthma
No other symptoms
Shortness of breath increasing before presentation
Seen by multiple physicians, given a number of antibiotics, bronchodilators, aminophylline

36. Case 2 (Cont’d)
Exam: BP 120/80, RR 18, P100, BMI 29, afebrile, chest: clear… rest of exam was normal
ER: ABG’s normal, CXR: normal, CT angio: normal, neuro consult (fellow): no neuro problem
Patient reassured by the team

37. Case 2 (cont’d) Spirometry obtained: FVC 50% FEV1 55% FEV1/FVC 80%
MVV 20%
????

38. Case 2 (cont’d) Neurology attending reconsulted EMG: Myasthenia Gravis
Diagnosis suspected from FVC and MVV
Neuromuscular illness

39. Case 3
A 60 year old man with history of ex-smoking, history of seasonal colds, admitted for hernia operation
Pulmonary consulted for pre-op clearance because of obesity
The patient denied pulmonary complaints, but his wife disclosed that he has a chronic cough

40. Case 3
Predicted Values
Measured Values
% Predicted
FVC
6.00 liters
4.00 liters
67 %
FEV1
5.00 liters
2.00 liters
40 %
FEV1/FVC
83 %
50 %
60 %
Obstructed defect

41. Case 3

42. Pre-operative screening
Patients with known pulmonary illness or symptoms
Overweight patients
Patients undergoing surgery in the chest or near the diaphragm

43. Case 4
A 65 year old man non-smoker, lawyer, admitted for elective Lap Chole. Reports long history of mild cough, and dyspnea on exertion
Physical exam: bibasilar dry crackles (velcrow), clubbing of the fingers

44. Case 4 Predicted Values Measured Values % Predicted FVC 5.68 liters
65 %
FEV1
4.90 liters
3.52 liters
60 %
FEV1/FVC
84 %
79 %
94 %
Restricted defect

45. Case 4
TLC 60%
RV 40%
DLCO 40%
HRCT

46. Case 4

47. Case 5
68 year old man with progressive dyspnea of one year duration, ex-smoker, no cough, no wheezing, no orthopnea…
History of CAD, SVT post angioplasty on multiple medication
EF% 55
Meds: Plavix, beta one blocker, diuretics, cordarone, ARB,

48. Case 5
FVC 50%
FEV1 55%
FEV1/FVC 85%
TLC 70%
DLCO 50%

49. Case 5
PFT’s: Major drop in FVC and DLCO compared to the PFT done 2 years earlier
HRCT of chest: Increased markings over the bases, with areas of increased enhancement…. Consistent with Amiodarone toxicity

50. Follow up patients Connective Tissue diseases (e.g. scleroderma)
Patients on Therapy that might affect the pulmonary system
Neuromuscular diseases

51. Follow up Patients with Lung Diseases
Obstructive airway diseases
Interstitial lung diseases
Sarcoidosis
IPF
ILD (CTD)

52. Conclusion
PFT’s
Spirometry
Lung volumes
DLCO

53. Conclusion: Indications
Evaluating breathlessness
Initial evaluation of patient with known respiratory disease
Following the course of a respiratory disease
Pre-operative assessment
Disability evaluation
Screening of subclinical disease