1 / 51

Pulmonary Function Testing

Danish Thameem M.D. Pulmonary and Critical Care Medicine . Pulmonary Function Testing. Indications for Pulmonary Functions. Evaluation of a pulmonary symptom Evaluation of smokers without symptoms Evaluation of workers exposed to hazards Quantification of impairment

taline
Download Presentation

Pulmonary Function Testing

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Danish Thameem M.D. Pulmonary and Critical Care Medicine Pulmonary Function Testing

  2. Indications for Pulmonary Functions • Evaluation of a pulmonary symptom • Evaluation of smokers without symptoms • Evaluation of workers exposed to hazards • Quantification of impairment • Evaluate response to therapy • Preoperative assessment • Disability evaluation

  3. Timeline of cigarette smokers that develop obstructive lung disease.

  4. Types of Pulmonary Function Tests • Spirometry • Lung Volumes • Diffusion Capacity • Maximal Respiratory Pressures • Maximum Voluntary Ventilation (MVV) • Arterial Blood Gases • Pulse Oximetry • Bronchoprovocation

  5. Lung Volumes Diagram

  6. Lung Volumes and Capacities • Four Volumes • VT • IRV • ERV • RV • Four Capacities • VC • IC • FRC • TLC

  7. General Approach to Interpretation • Is the test interpretable? • Are the results normal? Or abnormal? • What is the pattern? • What is the severity? • What does this mean for the patient?

  8. Acceptability Criteria for Spirograms • Free from artifacts • Cough or glottis closure during the first second of exhalation • Early termination or cutoff • Variable effort • Leak • Obstructed mouthpiece • Satisfactory exhalation • 6 sec of exhalation and/or a plateau in the volume-time curve or • Reasonable duration or a plateau in the volume-time curve or • The subject cannot or should not continue to exhale

  9. Repeatability Criteria After three acceptable spirograms have been obtained, apply the following tests • Are the two largest FVCs within 0.2 L of each other? • Are the two largest FEV1s 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 spirogramsor • A total of eight tests have been performed or • Save a minimum of three best maneuvers

  10. Spirometry • FVC (forced vital capacity): maximum volume of air that can be exhaled during a forced maneuver (after maximal forced inspiration, TLC) • FEV1 (forced expired volume in one second): volume expired in the first second of maximal expiration after a maximal inspiration • FEV1/FVC: FEV1 expressed as a % of FVC, a clinically useful index of airflow limitation

  11. Spirogram

  12. Predicting Normal Values • Depend on patient’s • Height • Age • Gender • Racial & ethnic background • Weight & BMI (to a lesser degree) • Reference Standards

  13. Percent Predicted as Normal Range • Results are expressed as % Predicted of a predicted normal value of a person the same age, sex, and height. (FVC and FEV1) • Normal Ranges • FVC 80-120% • FEV1 80-120% • FEV1/FVC >0.70 of predicted ratio

  14. Obstruction vs. Restriction • If the FVC and / or FEV1 is below normal • The distinction between obstruction & restriction is based on the FEV1/FVC ratio • NIH/WHO - GOLD guidelines recommends using ratio below 0.70 for the diagnosis of COPD

  15. Obstructive Lung Disease • Emphysema & Chronic Bronchitis • Cystic Fibrosis • Asthma • Bronchiectasis • Some Interstitial Lung Disease: (combined)

  16. Restrictive Pattern • Normal or elevated FEV1/FVC ratio • With a low FEV1 or FVC suggests restriction • Lung Volumes are needed to confirm • Some patients with Asthma or COPD may have this pattern (“pseudorestriction”)

  17. Restrictive Lung Disease

  18. Rating of Severity • May be based on statements such as from the American Thoracic Society (ATS) • Obstructive Pattern - FEV1 • Restrictive Pattern – TLC (lung volumes) • If lung volumes not obtained - FVC

  19. ATS/ERS Standardization of Lung Function Testing: Interpretative Strategies for lung function tests - 2005

  20. Classification of COPD by SeverityGOLD Guidelines - 2009 I: Mild FEV1/FVC < 70%; FEV1 > 80% predicted II: ModerateFEV1/FVC < 70%; 50% <FEV1 < 80% III: SevereFEV1/FVC < 70%; 30% < FEV1 <50% IV: Very FEV1/FVC < 70%; FEV1 < 30% predictedSevereor FEV1 < 50% predicted plus chronicrespiratoryfailure

  21. Bronchodilator Response • Must use bronchodilator with rapid onset • Albuterol • Levalbuterol • Increase FEV1 or FVC from baseline • By at least 12% • By at least 200 mL • Both values must be met

  22. Flow Volume Loops

  23. Normal

  24. Upper Airway Obstruction Patterns • Detect obstructive lesions in the major airways. • Characterizes the lesion: Locationof the lesion: • Intrathoracic • Extrathoracic Behaviorof the lesion in rapid inspiration and expiration: • Fixed • Variable

  25. Variable Extrathoracic Obstruction Vocal cord paralysis Goiter Tumor Levitzky MG Pulmonary Physiology, McGraw Hill 4th ed, 1995, p 50

  26. Variable Intrathoracic Obstruction Tracheomalacia Intratracheal tumor Levitzky MG Pulmonary Physiology, McGraw Hill 4th ed, 1995, p 50

  27. Fixed Obstruction Tracheal stenosis/stricture Bilateral vocal cord paralysis Extrinsic compression Levitzky MG Pulmonary Physiology, McGraw Hill 4th ed, 1995, p 50

  28. Lung Volumes

  29. Lung Volumes Diagram

  30. Lung Volumes in Lung Diseases

  31. Diffusion Capacity • Estimates the transfer of oxygen in the alveolar air to the red blood cell. • Factors that influence the diffusion: 1) Area of the alveolar-capillary membrane (A) 2) Thickness of the membrane (T) 3) Driving pressure 4) Hemoglobin 5) Carboxyhemoglobin

  32. Diffusing Capacity • Single-breath DLCO measures the capacity of the lung to transfer gas • Patient exhales to RV then rapidly inhales gas mixture with minute amount of CO. After, 10 second breath-hold at TLC, the patient rapidly exhales & the exhaled gas is analyzed to measure the amount of CO transferred into the capillary blood during the maneuver

  33. Abnormalities of Diffusing Capacity • Decreased in conditions that disrupt the alveolar-capillary surface for gas transfer • Loss of surface area (resection, fibrosis, emphysema, pneumonia) • Reduced lung capillary volume (vasculitis, thromboembolism, primary pulmhtn, ILD) • Increased diffusion distance (PAP, PCP)

  34. Abnormalities of Diffusing Capacity • Increased by conditions that lead to recruitment of pulmonary vascular bed and increase in capillary blood volume • (exercise, mild CHF, asthma) • Or by increased amount of hemoglobin which binds CO • (pulmonary hemorrhage, erythrocytosis)

  35. CASE 1 • 54 y/o male smoker • PFT • FEV1 : 1.3 L (23%) • FVC : 2.3 L (45%) • FEV1/FVC : 56 • TLC 98% • RV : 156% • DLCO : 30%

  36. Diagnosis • Very severe obstructive defect • Severe reduction in DLCO • High RV • Air trapping COPD

  37. CASE 2 • 35 y/o F with SLE • FEV1 : (56%) • FVC : (45%) • FEV1/FVC 90 • TLC : 48% • RV: 45% • DLCO : 23% • FEV1 increased by 4% (0.1 L) with bronchodilator testing

  38. Diagnosis • Severe restriction without significant response to bronchodilators • Severe reduction in DLCO ILD PULMONARY FIBROSIS

  39. CASE 3 • 45 y/o female with history of allergic rhinitis and dyspnea on exertion • FEV1 - 3.2 (70%) pre, 4.5 (100%) post BD • FVC - 4.9 (70%) pre, 6.0 (85%) post BD • RATIO - 65% pre and 75% post • TLC - 6 L (100%) • DLCO - 100%

  40. Diagnosis • Mild obstruction with significant response to bronchodilators (normal) • Normal lung volumes and DLCO ASTHMA

  41. CASE 4 • 76 y/o male with weight loss and dyspnea • FEV1 - 4 L ( 85%) • FVC - 5.1 L (80%) • RATIO - 78% • TLC - 6 L ( 82%) • DLCO - 88%

  42. Diagnosis • Normal spirometry • Truncated inspiratory limb of the flow volume loop EXTRATHORACIC OBSTRUCTION

More Related