Pulmonary function test Part I Dr.Mona Allangawi Consultant Pulmonary

1. PFT I 1 Pulmonary function test Part I Dr.Mona Allangawi Consultant Pulmonary/Allergy Hamad General Hospital - HMC

2. PFT I 2 Pulmonary function test : Group of procedures that measure the function of the lungs Spirometry Lung volumes Gas transfer Bronchial chalenge

3. PFT I 3 Indications

4. PFT I 4 A.Diagnostic

5. PFT I 5 Symptoms: dyspnea, wheezing, orthopnea, cough, phlegm production, chest pain Signs: decreased breath sounds, overinflation, expiratory slowing, cyanosis, chest deformitory, unexplained crackles Abnormal laboratory tests: hypoxemia, hypercapnia, polycythemia, abnormal chest radiographs To measure the effect of disease on pulmonary function

6. PFT I 6 To screen individuals at risk of having pulmonary diseases Smokers Individuals in occupations with exposures to injurious substances To assess preoperative risk To assess prognosis (lung transplant, etc.) To assess health status before enrollment in strenuous physical activity programs

7. PFT I 7 B. Monitoring

8. PFT I 8 To assess therapeutic interventions Bronchodilator therapy Steroid treatment for asthma, interstitial lung disease, etc. Other (antibiotics in cystic fibrosis, etc.) To monitor for adverse reactions to drugs with known pulmonary toxicity

9. PFT I 9 C. Disability/Impairment Evaluations

10. PFT I 10 To assess patients as part of a rehabilitation program Medical Industrial Vocational To assess risks as part of an insurance evaluation

11. PFT I 11 Contraindications

12. PFT I 12 Hemoptysis of unknown origin Pneumothorax Unstable angina pectoris Recent myocardial infarction Thoracic aneurysms Abdominal aneurysms Cerebral aneurysms Recent eye surgery (increased intraocular pressure during forced expiration) Recent abdominal or thoracic surgical procedures History of syncope associated with forced exhalation

13. PFT I 13 Pulmonary function test: Spirometry Lung volumes Gas transfer Bronchial chalenge

14. PFT I 14 What is a spirometry ?? Spirometry is a measure of airflow and lung volumes during a forced expiratory maneuver from full inspiration

15. PFT I 15 How to do it ??

16. PFT I 16 Stand or sit up straight (The patient places a clip over the nose ) Inhale maximally Get a good seal around mouthpiece of the spirometer Blow out as hard as fast as possible and count for at least 6 seconds. Record the best of three trial *pt should hold bronchodilator few hrs before the test

17. PFT I 17 1. Volume Time Graph 2. Flow-volume loops

18. PFT I 18 Volume Time Graph The volume is plotted against the time, it displays the expiration.

19. PFT I 19 FVC FEV1 FEV1/FVC FEF25% FEF75%

20. PFT I 20 Forced Vital Capacity (FVC) The total amount of air expired as quickly as possible after taking the deepest possible breath.

21. PFT I 21 FEV1 : Volume of air which can be forcibly exhaled from the lungs in the first second of a forced expiratory maneuver.

22. PFT I 22 FEV1/FVC Ratio of FEV1 to FVC : It indicates what percentage of the total FVC was expelled from the lungs during the first second of forced exhalation This value is critically important in the diagnosis of obstructive and restrictive diseases

23. PFT I 23 FEF25% Amount of air that was forcibly expelled in the first 25% of the total forced vital capacity test. FEF75% The amount of air expelled from the lungs during the first (75%) of the forced vital capacity test. FEF25%-75% The amount of air expelled from the lungs during the middle half of the forced vital capacity test.

24. PFT I 24 Flow-volume loops

25. PFT I 25 Flow-volume loops Is a plot of inspiratory and expiratory flow in the vertical axis against volume in the horizental axis, during the performance of maximally forced inspiratory and expiratory maneuvers.

26. PFT I 26 The contour of the loop assists in the diagnosis and localization of airway obstruction as different lung disorders produce distinct ,easily recognized pattern.

27. PFT I 27

28. PFT I 28 Useful also in assesing acceptability of the manoeuvers: 1. Lack of early peak suggest poor effort. 2. Sudden tailing off of expiration curve suggest that the patient stopped blowing too early  3. Cough 

29. PFT I 29 Obstructive V/S restrictive lung disease ???

30. PFT I 30 Obstructive Lung Diseases

31. PFT I 31 Common Obstructive Lung Diseases Asthma COPD (chronic bronchitis, emphysema and the overlap between them). Cystic fibrosis.

32. PFT I 32 -Airflow is reduced because the airways narrow and the FEV1 is reduced -Spirogram may continue to rise for more than 6 seconds because lung take longer to empty -FVC may also be reduced because gas is trapped behind obstructed bronchi due to increase in intrathoracic pressure during maneuver compresses airways causing early airway closure and gas trapping but this reduction to a lesser extent than FEV1

33. PFT I 33 FEV1 = 80% of predicted Normal FEV1 60-80% of predicted mild obst. FEV1 40-60% of predicted moderate FEV1 = 40% of predicted severe The cardinal feature is FEV1/FVC ratio If the ratio less than 70 consider obstructed disease . *Predictors: Sex, Age, Ht

34. PFT I 34 Predictors: Sex, Age, Ht ?? The measurements are related to the following factors: Age : FVC and flow rates decline with age. The value of FVC increases up to 24 years of age and remain stable to age 35. Height : All spirometric measurements increase with body weight. It is due to an increase in number and/or size of alveoli relative to airways, the larger lungs are likely to take longer than smaller one. Sex : Most pulmonary function values are lower in female than male. Weight : A spirometric results are positively correlated with weight to the extent that increased weight means growth or muscle mass. Beyond this (in obesity) spirometric values (and lung values specially ERV) decrease with greater weight.

35. PFT I 35 Flow volume loop in Obstructive lung disease

36. PFT I 36 Asthma Peak expiratory flow reduced so maximum height of the loop is reduced Airflow reduces rapidly with the reduction in the lung volumes because the airways narrow and the loop become concave Concavity may be the indicator of airflow obstruction and may present before the change in FEV1 or FEV1/FVC

37. PFT I 37 Emphysema Airways may collapse during forced expiration because of destruction of the supporting lung tissue causing very reduced flow at low lung volume and a characteristic (dog-leg) appearance to the flow volume curve

38. PFT I 38 Reversibility Improvement in FEV1 by 12-15% or 200 ml in repeating spirometry after treatment with Sulbutamol 2.5mg or ipratrobium promide by nebuliser after 15-30 minutes Reversibility is a characterestic feature of B.Asthma In chronic asthma there may be only partial reversibility of the airflow obstruction While in COPD the airflow is irriversible although some cases showed significant improvement.

39. PFT I 39 Interpretation of PFTs Step 1. Look at the Flow-Volume loop to determine acceptability of the test, and look for upper airway obstruction pattern. Step 2. Look at the FEV1 to determine if it is normal (= 80% predicted). Step 3. Look at FVC to determine if it is within normal limits (= 80%). Step 4. Look at the FEV1/FVC ratio to determine if it is within normal limits (= 70%).

40. PFT I 40 Step 5. Look at FEF25-75% (Normal (= 60%) If FEV1, FEV1/FVC ratio, and FEF25-75% all are normal, the patient has a normal PFT. If both FEV1 and FEV1/FVC are normal, but FEF25-75% is = 60% ,then think about early obstruction or small airways obstruction.

41. PFT I 41 If FEV1 = 80% and FEV1/FVC = 70%, there is obstructive defect, if FVC is normal, it is pure obstruction. If FVC = 80% , possibility of additional restriction is there. If FEV1 = 80% , FVC = 80% and FEV1/FVC = 70% , there is restrictive defect, get lung volumes to confirm.

42. PFT I 42 Examples

43. PFT I 43 Mild obstructionMild obstruction

44. PFT I 44 Mild Obstructive Defect with good response to bronchodilator Diagnosis: B.Asthma

45. PFT I 45 A 66 year old female complains of cough after dust exposure NormalNormal

46. PFT I 46 Normal Spirometry

47. PFT I 47

48. PFT I 48 Flow volume loop suggestive of obstructive disease Spirometry showed Severe Obstructive defect with no response to bronchodilator Increased FVC could be because of Airtrapping or could be combined obstructive and restrictive defect to confirm need to do Lung Volume diagnosis : COPD

49. PFT I 49 A 75 year old female has a history of dyspnea and palpitations

50. PFT I 50 Mild Obstructive defect

51. PFT I 51 Large Airway Obstruction

52. PFT I 52 1. Fixed obstruction 2. Variable extrathoracic obstruction 3. Variable intrathoracic obstruction

53. PFT I 53 Flow Volume Loop in Large Airway Obstruction

54. PFT I 54 Fixed obstruction 1. Post intubation stenosis 2. Goiter 3. Endotracheal neoplasms 4. Bronchial stenosis Maximum airflow is limited to a similar extent in both inspiration and expiration

55. PFT I 55 Variable extrathoracic Obstruction 1. Bilateral and unilateral vocal cord paralysis 2. Vocal cord constriction 3. Reduced pharyngeal cross-sectional area 4. Airway burns The obstruction worsens in inspiration because the negative pressure narrows the trachea and inspiratory flow is reduced to a greater extent than expiratory flow

56. PFT I 56 In variable intrathoracic obstruction 1. Tracheomalacia 2. Polychondritis 3. Tumors of the lower trachea or main bronchus. The narrowing is maximal in expiration because of increased intrathoracic pressure compressing the airway. The flow volume loop shows a greater reduction in the expiratory phase

57. PFT I 57 Small Airways obstruction Diseases affecting primarily the small (peripheral) airways can be extensive yet not affect the FEV1(e.g. early COPD, interstitial granulomatous disorders). Small airways status is reflected by the FEF25-75% (mid-range flow), best determined from the flow-volume loop. Some patients have normal spirometry with the exception of a reduced FEF25-75%, this is suggestive of possible small airways dysfunction and potentially early obstruction.

58. PFT I 58 Example

59. PFT I 59 A 38 year old female complains of wheezing on exertion

60. PFT I 60 Flow volume loop suggests a fixed upper airway obstruction

61. PFT I 61 Effect of Smoking: Smoking in patients with COPD is associated with decline in FEV1 of 90-150 mL/year Smoking cessation is (associated with increase in FEV1 for first year) followed with a decline of only 30 mL/year

62. PFT I 62

63. PFT I 63

64. PFT I 64 Restrictive Lung Diseases

65. PFT I 65 A. Intrinsic Restrictive Lung Disorders Sarcoidosis Idiopathic pulmonary fibrosis 3. Interstitial pneumonitis 4. Tuberculosis 5. Pnuemonectomy (loss of lung) 6. Pneumonia

66. PFT I 66 B. Extrinsic Restrictive Lung Disorders Scoliosis, Kyphosis Ankylosing Spondylitis Pleural Effusion Pregnancy Gross Obesity Tumors Ascites Pain on inspiration - pleurisy, rib fractures

67. PFT I 67 C. Neuromuscular Restrictive Lung Disorders Generalized Weakness – malnutrition Paralysis of the diaphragm Myasthenia Gravis Muscular Dystrophy Poliomyelitis Amyotrophic Lateral Sclerosis

68. PFT I 68 Full expantion of the lung is limited and therefore the FVC is reduced FEV1 may be reduced because the stiffness of fibrotic lungs increases the expiratory pressure FEV1/FVC will be Normal or Increased *if you suspect restrictive pattern you must check TLC

69. PFT I 69 Flow volume loop in Restrictive lung disease

70. PFT I 70 Flow volume loop in Restrictive lung disease : Full lung expantion is prevented by fibrotic tissue in the lung parenchyma and the FVC is reduced . Elastic recoil may increased by fibrotic tissue lead to increase the airflow Both FEV1 and FVC may be reduced because the lungs are small and stiff ,but the peak expiratory flow may be preserved or even higher than predicted leads to tall,narrow and steep flow volume loop in expiratory phase.

71. PFT I 71

72. PFT I 72

73. PFT I 73 Example

74. PFT I 74

75. PFT I 75 Mild restrictive defect suggested by reduced in FVC with normal to high FEV1/FVC Need lung volume and diffusion capacity to assess if it is intrinsic or extrinsic type

76. PFT I 76 Obstructive & restrictive defects

77. PFT I 77 Acceptability and Reproducibility Criteria

78. PFT I 78 Acceptability Criteria free from artifacts:  Cough or glottis closure during the first second of exhalation Eary termination or cutoff Variable effort Leak Obstructed mouthpiece  Have good starts Have a satisfactory exhalation 6 s of exhalation

79. PFT I 79 Reproducibility Criteria After 3 acceptable spirograms been obtained Are the two largest FVC within 0.2 L of each other? Are the two largest FEV1 within 0.2 L of each other? If both of these criteria are met, the test session may be concluded. If both of these criteria are not met, continue testing until Both of the criteria are met with analysis of additional acceptable spirograms; OR a total of eight tests have been performed

80. PFT I 80 Acceptability of the test

81. PFT I 81

82. PFT I 82 Example

83. PFT I 83 1.What is the defect?

84. PFT I 84 Mild obstructive defect with good response to bronchodilator Diagnosis B.Asthma