Pulmonary Function Test Part 1 (Dr. Mona Allangawi)


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  • Mild obstruction
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  • Pulmonary Function Test Part 1 (Dr. Mona Allangawi)

    1. 1. <ul><li>Pulmonary function test </li></ul><ul><li>Part I </li></ul><ul><li>Dr.Mona Allangawi </li></ul><ul><li>Consultant Pulmonary/Allergy </li></ul><ul><li>Hamad General Hospital - HMC </li></ul>
    2. 2. <ul><li>Pulmonary function test : </li></ul><ul><li>Group of procedures that measure the function of the </li></ul><ul><li>lungs </li></ul><ul><li>Spirometry </li></ul><ul><li>Lung volumes </li></ul><ul><li>Gas transfer </li></ul><ul><li>Bronchial chalenge </li></ul>
    3. 3. <ul><li>Indications </li></ul>
    4. 4. <ul><li>A.Diagnostic </li></ul>
    5. 5. <ul><ul><li>Symptoms: </li></ul></ul><ul><ul><li>dyspnea, wheezing, orthopnea, cough, phlegm production, chest pain </li></ul></ul><ul><ul><li>Signs: </li></ul></ul><ul><ul><li>decreased breath sounds, overinflation, expiratory slowing, cyanosis, chest deformitory, unexplained crackles </li></ul></ul><ul><ul><li>Abnormal laboratory tests: </li></ul></ul><ul><ul><li>hypoxemia, hypercapnia, polycythemia, abnormal chest radiographs </li></ul></ul><ul><li>To measure the effect of disease on pulmonary function </li></ul>
    6. 6. <ul><li>To screen individuals at risk of having pulmonary diseases </li></ul><ul><ul><li>Smokers </li></ul></ul><ul><ul><li>Individuals in occupations with exposures to injurious substances </li></ul></ul><ul><li>To assess preoperative risk </li></ul><ul><li>To assess prognosis (lung transplant, etc.) </li></ul><ul><li>To assess health status before enrollment in strenuous physical activity programs </li></ul>
    7. 7. <ul><li>B. Monitoring </li></ul>
    8. 8. <ul><li>To assess therapeutic interventions </li></ul><ul><ul><li>Bronchodilator therapy </li></ul></ul><ul><ul><li>Steroid treatment for asthma, interstitial lung disease, etc. </li></ul></ul><ul><ul><li>Other (antibiotics in cystic fibrosis, etc.) </li></ul></ul><ul><ul><li>To monitor for adverse reactions to drugs with known pulmonary toxicity </li></ul></ul>
    9. 9. <ul><li>C. Disability/Impairment Evaluations </li></ul>
    10. 10. <ul><li>To assess patients as part of a rehabilitation program </li></ul><ul><ul><li>Medical </li></ul></ul><ul><ul><li>Industrial </li></ul></ul><ul><ul><li>Vocational </li></ul></ul><ul><li>To assess risks as part of an insurance evaluation </li></ul>
    11. 11. <ul><li>Contraindications </li></ul>
    12. 12. <ul><li>Hemoptysis of unknown origin </li></ul><ul><li>Pneumothorax </li></ul><ul><li>Unstable angina pectoris </li></ul><ul><li>Recent myocardial infarction </li></ul><ul><li>Thoracic aneurysms </li></ul><ul><li>Abdominal aneurysms </li></ul><ul><li>Cerebral aneurysms </li></ul><ul><li>Recent eye surgery (increased intraocular pressure during forced expiration) </li></ul><ul><li>Recent abdominal or thoracic surgical procedures </li></ul><ul><li>History of syncope associated with forced exhalation </li></ul>
    13. 13. <ul><li>Pulmonary function test: </li></ul><ul><li>Spirometry </li></ul><ul><li>Lung volumes </li></ul><ul><li>Gas transfer </li></ul><ul><li>Bronchial chalenge </li></ul>
    14. 14. <ul><li>What is a spirometry ?? </li></ul><ul><li>Spirometry is a measure of airflow and </li></ul><ul><li>lung volumes during a forced expiratory </li></ul><ul><li>maneuver from full inspiration </li></ul>
    15. 15. <ul><li>How to do it ?? </li></ul>
    16. 16. <ul><li>Stand or sit up straight (The patient places a clip over the nose ) </li></ul><ul><li>Inhale maximally </li></ul><ul><li>Get a good seal around mouthpiece of the spirometer </li></ul><ul><li>Blow out as hard as fast as possible and count for at least 6 seconds. </li></ul><ul><li>Record the best of three trial </li></ul><ul><li>*pt should hold bronchodilator few hrs before the test </li></ul>
    17. 17. <ul><li>1. Volume Time Graph 2. Flow-volume loops </li></ul>
    18. 18. Volume Time Graph The volume is plotted against the time, it displays the expiration.
    19. 19. <ul><li>FVC </li></ul><ul><li>FEV1 </li></ul><ul><li>FEV1/FVC </li></ul><ul><li>FEF25% </li></ul><ul><li>FEF75% </li></ul>
    20. 20. <ul><li>Forced Vital Capacity (FVC) </li></ul><ul><li>The total amount of air expired as quickly as possible after taking the deepest possible breath. </li></ul>
    21. 21. <ul><li>FEV1 : </li></ul><ul><li>Volume of air which can be forcibly exhaled from the lungs in the first second of a forced expiratory maneuver. </li></ul>
    22. 22. <ul><li>FEV1/FVC </li></ul><ul><li>Ratio of FEV1 to FVC : </li></ul><ul><li>It indicates what percentage of the total FVC was expelled from the lungs during the first second of forced exhalation </li></ul><ul><li>This value is critically important in the diagnosis of obstructive and restrictive diseases </li></ul>
    23. 23. <ul><li>FEF25% </li></ul><ul><li>Amount of air that was forcibly expelled in the first 25% of the total forced vital capacity test. </li></ul><ul><li>FEF75% </li></ul><ul><li>The amount of air expelled from the lungs during the first (75%) of the forced vital capacity test. </li></ul><ul><li>FEF25%-75% </li></ul><ul><li>The amount of air expelled from the lungs during the middle half of the forced vital capacity test. </li></ul>
    24. 24. <ul><li>Flow-volume loops </li></ul>
    25. 25. <ul><li>Flow-volume loops </li></ul><ul><li>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. </li></ul>
    26. 26. <ul><li>The contour of the loop assists in the diagnosis and localization of airway obstruction as different lung disorders produce distinct ,easily recognized pattern. </li></ul>
    27. 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
    28. 29. <ul><li>Obstructive V/S restrictive lung disease ??? </li></ul>
    29. 30. <ul><li>Obstructive Lung Diseases </li></ul>
    30. 31. <ul><li>Common Obstructive Lung Diseases </li></ul><ul><li>Asthma </li></ul><ul><li>COPD (chronic bronchitis, emphysema and the overlap between them). </li></ul><ul><li>Cystic fibrosis. </li></ul>
    31. 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
    32. 33. <ul><li>FEV1 ≥ 80% of predicted Normal </li></ul><ul><li>FEV1 60-80% of predicted mild obst. </li></ul><ul><li>FEV1 40-60% of predicted moderate </li></ul><ul><li>FEV1 ≤ 40% of predicted severe </li></ul><ul><li>The cardinal feature is FEV1/FVC ratio If </li></ul><ul><li>the ratio less than 70 consider obstructed </li></ul><ul><li>disease . </li></ul><ul><li>*Predictors: Sex, Age, Ht </li></ul>
    33. 34. <ul><li>Predictors: Sex, Age, Ht ?? </li></ul><ul><li>The measurements are related to the following factors: </li></ul><ul><li>Age : </li></ul><ul><li>FVC and flow rates decline with age. The value of FVC increases up to 24 years of age and remain stable to age 35. </li></ul><ul><li>Height : </li></ul><ul><li>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. </li></ul><ul><li>Sex : </li></ul><ul><li>Most pulmonary function values are lower in female than male . </li></ul><ul><li>Weight : </li></ul><ul><li>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. </li></ul>
    34. 35. <ul><li>Flow volume loop in </li></ul><ul><li>Obstructive lung disease </li></ul>
    35. 36. Asthma <ul><li>Peak expiratory flow reduced so maximum height of the loop is reduced </li></ul><ul><li>Airflow reduces rapidly with the reduction in the lung volumes because the airways narrow and the loop become concave </li></ul><ul><li>Concavity may be the indicator of airflow obstruction and may present before the change in FEV1 or FEV1/FVC </li></ul>
    36. 37. Emphysema <ul><li>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 </li></ul>
    37. 38. <ul><li>Reversibility </li></ul><ul><li>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 </li></ul><ul><li>Reversibility is a characterestic feature of B.Asthma </li></ul><ul><li>In chronic asthma there may be only partial reversibility of the airflow obstruction </li></ul><ul><li>While in COPD the airflow is irriversible although some cases showed significant improvement. </li></ul>
    38. 39. Interpretation of PFTs <ul><li>Step 1. Look at the Flow-Volume loop to determine acceptability of the test, and look for upper airway obstruction pattern. </li></ul><ul><li>Step 2. Look at the FEV1 to determine if it is normal (≥ 80% predicted). </li></ul><ul><li>Step 3. Look at FVC to determine if it is within normal limits (≥ 80%). </li></ul><ul><li>Step 4. Look at the FEV1/FVC ratio to determine if it is within normal limits (≥ 70%). </li></ul>
    39. 40. <ul><li>Step 5. Look at FEF25-75% (Normal (≥ 60%) </li></ul><ul><li>If FEV1 , FEV1/FVC ratio, and FEF25-75% all are normal, the patient has a normal PFT. </li></ul><ul><li>If both FEV1 and FEV1/FVC are normal, but FEF25-75% is ≤ 60% ,then think about early obstruction or small airways obstruction. </li></ul>
    40. 41. <ul><li>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. </li></ul><ul><li>If FEV1 ≤ 80% , FVC ≤ 80% and FEV1/FVC ≥ 70% , there is restrictive defect, get lung volumes to confirm. </li></ul>
    41. 42. <ul><li>Examples </li></ul>
    42. 44. <ul><li>Mild Obstructive Defect with good response to </li></ul><ul><li>bronchodilator </li></ul><ul><li>Diagnosis: </li></ul><ul><li>B.Asthma </li></ul>
    43. 45. A 66 year old female complains of cough after dust exposure 109 5.2 5.67 PEF 82 2.23 1.82 FEF 25-75 72 81 FEV1/FVC 97 1.85 1.79 FEV1 85 2.58 2.2 FVC %Pred Ref Meas
    44. 46. <ul><li>Normal Spirometry </li></ul>
    45. 48. <ul><li>Flow volume loop suggestive of obstructive disease </li></ul><ul><li>Spirometry showed Severe Obstructive defect with no response to bronchodilator </li></ul><ul><li>Increased FVC could be because of Airtrapping or could be combined obstructive and restrictive defect to confirm need to do Lung Volume </li></ul><ul><li>diagnosis : </li></ul><ul><li>COPD </li></ul>
    46. 49. A 75 year old female has a history of dyspnea and palpitations 82 5.48 4.50 PEF 20 2.20 0.43 FEF25-75 69 55 FEV1/FVC 72 1.98 1.45 FEV1 93 2.82 2.62 FVC %Pred Ref Meas
    47. 50. <ul><li>Mild Obstructive defect </li></ul>
    48. 51. <ul><li>Large Airway Obstruction </li></ul>
    49. 52. <ul><li>1. Fixed obstruction </li></ul><ul><li>2. Variable extrathoracic obstruction </li></ul><ul><li>3. Variable intrathoracic obstruction </li></ul>
    50. 53. <ul><li>Flow Volume Loop in </li></ul><ul><li>Large Airway Obstruction </li></ul>
    51. 54. <ul><li>Fixed obstruction </li></ul><ul><li>1. Post intubation stenosis </li></ul><ul><li>2. Goiter </li></ul><ul><li>3. Endotracheal neoplasms </li></ul><ul><li>4. Bronchial stenosis </li></ul><ul><li>Maximum airflow is limited to a similar extent in both insp iration and exp iration </li></ul>
    52. 55. <ul><li>Variable extr athoracic </li></ul><ul><li>Obstruction </li></ul><ul><li>1. Bilateral and unilateral vocal cord paralysis </li></ul><ul><li>2. Vocal cord constriction </li></ul><ul><li>3. Reduced pharyngeal cross-sectional area </li></ul><ul><li>4. Airway burns </li></ul><ul><li>The obstruction worsens in insp iration because the negative pressure narrows the trachea and inspiratory flow is reduced to a greater extent than expiratory flow </li></ul>
    53. 56. <ul><li>In variable intr athoracic obstruction </li></ul><ul><li>1. Tracheomalacia </li></ul><ul><li>2. Polychondritis </li></ul><ul><li>3. Tumors of the lower trachea or main bronchus. </li></ul><ul><li>The narrowing is maximal in exp iration because of increased intrathoracic pressure compressing the airway. </li></ul><ul><li>The flow volume loop shows a greater reduction in the expiratory phase </li></ul>
    54. 57. Small Airways obstruction <ul><li>Diseases affecting primarily the small (peripheral) airways can be extensive yet not affect the FEV1(e.g. early COPD, interstitial granulomatous disorders). </li></ul><ul><li>Small airways status is reflected by the FEF25-75% (mid-range flow), best determined from the flow-volume loop. </li></ul><ul><li>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. </li></ul>
    55. 58. <ul><li>Example </li></ul>
    56. 59. A 38 year old female complains of wheezing on exertion 38 6.25 2.39 PEF 51 4.20 2.15 FEF25-75 78 63 FEV1/FVC 83 2.77 2.30 FEV1 103 3.54 3.66 FVC %Pred Ref Meas
    57. 60. <ul><li>Flow volume loop suggests a fixed upper airway obstruction </li></ul>
    58. 61. <ul><li>Effect of Smoking: </li></ul><ul><li>Smoking in patients with COPD is associated with decline in FEV1 of 90-150 mL/year </li></ul><ul><li>Smoking cessation is (associated with increase in FEV1 for first year) followed with a decline of only 30 mL/year </li></ul>
    59. 64. <ul><li>Restrictive Lung Diseases </li></ul>
    60. 65. <ul><li>A. Intrinsic Restrictive Lung Disorders </li></ul><ul><li>Sarcoidosis </li></ul><ul><li>Idiopathic pulmonary fibrosis </li></ul><ul><li>3. Interstitial pneumonitis </li></ul><ul><li>4. Tuberculosis </li></ul><ul><li>5. Pnuemonectomy (loss of lung) </li></ul><ul><li>6. Pneumonia </li></ul>
    61. 66. <ul><li>B. Extrinsic Restrictive Lung Disorders </li></ul><ul><li>Scoliosis, Kyphosis </li></ul><ul><li>Ankylosing Spondylitis </li></ul><ul><li>Pleural Effusion </li></ul><ul><li>Pregnancy </li></ul><ul><li>Gross Obesity </li></ul><ul><li>Tumors </li></ul><ul><li>Ascites </li></ul><ul><li>Pain on inspiration - pleurisy, rib fractures </li></ul>
    62. 67. <ul><li>C. Neuromuscular Restrictive Lung Disorders </li></ul><ul><li>Generalized Weakness – malnutrition </li></ul><ul><li>Paralysis of the diaphragm </li></ul><ul><li>Myasthenia Gravis </li></ul><ul><li>Muscular Dystrophy </li></ul><ul><li>Poliomyelitis </li></ul><ul><li>Amyotrophic Lateral Sclerosis </li></ul>
    63. 68. <ul><li>Full expantion of the lung is limited and therefore the FVC is reduced </li></ul><ul><li>FEV1 may be reduced because the stiffness of fibrotic lungs increases the expiratory pressure </li></ul><ul><li>FEV1/FVC will be Normal or Increased </li></ul><ul><li>*if you suspect restrictive pattern you must check TLC </li></ul>
    64. 69. <ul><li>Flow volume loop in </li></ul><ul><li>Restrictive lung disease </li></ul>
    65. 70. <ul><li>Flow volume loop in Restrictive lung disease : </li></ul><ul><li>Full lung expantion is prevented by fibrotic tissue in the lung parenchyma and the FVC is reduced . </li></ul><ul><li>Elastic recoil may increased by fibrotic tissue lead to increase the airflow </li></ul><ul><li>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. </li></ul>
    66. 73. <ul><li>Example </li></ul>
    67. 75. <ul><li>Mild restrictive defect suggested by reduced in FVC with normal to high FEV1/FVC </li></ul><ul><li>Need lung volume and diffusion capacity to assess if it is intrinsic or extrinsic type </li></ul>
    68. 76. Obstructive & restrictive defects Normal Reduced FEV1/FVC Reduced Normal FVC Reduced Reduced FEV1 Restriction Obstruction Parameter
    69. 77. <ul><li>Acceptability and Reproducibility Criteria </li></ul>
    70. 78. <ul><li>Acceptability Criteria </li></ul><ul><li>free from artifacts: </li></ul><ul><li>  Cough or glottis closure during the first second of exhalation </li></ul><ul><li>Eary termination or cutoff </li></ul><ul><li>Variable effort </li></ul><ul><li>Leak </li></ul><ul><li>Obstructed mouthpiece </li></ul><ul><li>  Have good starts </li></ul><ul><li>Have a satisfactory exhalation 6 s of exhalation </li></ul>
    71. 79. <ul><li>Reproducibility Criteria </li></ul><ul><li>After 3 acceptable spirograms been obtained </li></ul><ul><li>Are the two largest FVC within 0.2 L of each other? </li></ul><ul><li>Are the two largest FEV1 within 0.2 L of each other? </li></ul><ul><li>If both of these criteria are met, the test session may be concluded. </li></ul><ul><li>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 </li></ul>
    72. 80. Acceptability of the test
    73. 81. Early Glottic Closure Normal Poor Effort Cough
    74. 82. <ul><li>Example </li></ul>
    75. 83. 1.What is the defect?
    76. 84. <ul><li>Mild obstructive defect with good response to bronchodilator </li></ul><ul><li>Diagnosis </li></ul><ul><li>B.Asthma </li></ul>