1. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Chapter 19 Pulmonary Function Testing

2. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Learning Objectives List the three categories of pulmonary function tests. State the primary purposes of pulmonary function testing. Describe the pathophysiologic patterns associated with obstructive and restrictive lung disease. State what is meant by the term spirometer, and list the parameters that can be measured by it. 2

3. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Learning Objectives (cont.) List and describe the four general principles that should be considered for tests of pulmonary function. List and describe the measurements that indicate pulmonary mechanics. Describe the purpose and technique for the bronchial challenge test. List and describe the four volumes and four capacities that can be measured with pulmonary function testing. 3

4. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Learning Objections (cont.) Describe the purpose and techniques used to measure diffusion capacity. Interpret pulmonary function reports. 4

5. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. PFTs will measure: Dynamic flow rates of gases through airways, Lung volumes & capacities Ability of lungs to diffuse gases 5

6. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Purposes of PFT Identify & quantify changes in pulmonary function due to disease Evaluate effectiveness of therapy Perform epidemiological surveillance for pulmonary disease Assess patients for risk of postoperative complications Determine pulmonary disability 6

7. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.7 All of the following are contraindications to pulmonary function testing, except: A.Hypertension B.Pneumothorax C.Pulmonary Embolism D.Myocardial Infarction

8. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Pathophysiologic Patterns Two major categories of pulmonary disease exist:  Obstructive  Restrictive Primary abnormality in obstructive disease is increased airways resistance Primary problem in restrictive disease is decrease in either lung compliance or lung volumes or both Some pulmonary diseases cause both obstructive & restrictive disease 8

9. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Pathophysiologic Patterns 9

10. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. PFT Equipment Two general types of measuring devices exist, those that:  Measure volume  Measure flow Volume-measuring devices - spirometers Flow-measuring devices - pneumotachometers Every measuring device has capacity, accuracy, error, resolution, precision, linearity, & output 10

11. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Elements of Quality Assurance Accuracy & precision of measuring instruments Performance of Respiratory Therapist (RT) Test results when measuring a standard 11

12. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.12 All of the following are pathophysiological patterns of pulmonary diseases, except: A.Restrictive diseases will decrease lung compliance B.Obstructive diseases will increase airway resistance C.Restrictive disease will increase lung volumes D.Some pulmonary diseases can cause both obstructive and restrictive disease

13. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Principles of Measurement Most pulmonary function laboratories have 3 components. 1.Performing spirometry to measure airway mechanics 2.Measuring lung volumes & capacities 3.Measuring diffusion capacity of lung All 3 components are required when purpose of PFT is to identify presence & degree of pulmonary impairment 13

14. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Spirometry Tests of pulmonary mechanics  Forced vital capacity (FVC)  Forced expiratory volume in 1 second (FEV 1 )  Other forced expiratory flow measurements  Maximum voluntary ventilation These measurements assess ability of lungs to move large volumes of air quickly through airways 14

15. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Forced Vital Capacity Most common test of pulmonary mechanics Many measurements are made while patient is performing FVC maneuver FVC is an effort-dependent maneuver requiring careful patient instruction & cooperation To ensure validity, each patient must perform at least 3 acceptable FVC maneuvers 15

16. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Forced Vital Capacity (cont.) 16

17. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Other Measures of Pulmonary Mechanics FEV 1 - volume of gas exhaled in first 1-second of FVC maneuver FEV 1 /FVC - calculated by dividing largest FEV 1 by largest FVC FEF 200-1200 - average flow rate early in FVC maneuver FEF 25-75 - measure of flow during middle 50% of FVC PEFR - highest point on flow-volume graph 17

18. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Pulmonary Mechanics 18

19. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Pulmonary Mechanics 19

20. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Pulmonary Mechanics 20

21. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.21 What is the most commonly used test of pulmonary mechanics: A.Forced expiratory flow measurements (FEV1) B.Forced vital capacity (FVC) C.Maximum voluntary ventilation (MVV) D.Helium dilution technique

22. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Maximal Voluntary Ventilation (MVV) Effort-dependent test; patient asked to breathe deep & fast for 12 seconds Results reflect:  Patient effort  Function of respiratory muscles  Ability of chest wall to expand  Patency of airways 22

23. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. The MVV (cont.) 23

24. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Quality Assurance of Spirometry  3.0 L syringe used for accuracy & precision of volume or flow  Multiple strokes at various injection speeds  Average volume should meet the +/- 3% standard  95% expected performance range should be determined  Technologist performance should be observed & reviewed periodically 24

25. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Significance of Results Normal FEV 1 = 5.6 L for average 20-year-old man FEV 1 is reduced with both obstructive & restrictive lung disease. FEV 1 /FVC should be at least 70%  Reduced with obstructive disease  Normal with restrictive disease Other measures of expiratory flow are also reduced when obstructive disease is present 25

26. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Significance of Results (cont.) Normal MVV for males is 160 to 180 L/min & slightly lower in females MVV is reduced in patients with moderate to severe obstructive lung disease MVV may be normal or slightly reduced in patients with restrictive disease Undernourished patients may have reduced MVV 26

27. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Obstructive & Restrictive Disorders 27

28. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Obstructive & Restrictive Disorders 28

29. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Obstructive & Restrictive Disorders 29

30. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Reversibility If obstruction is present, reversibility must be evaluated Done by performing spirometry before & after therapy Bronchodilator is administered by small-volume nebulizer or MDI Reversibility indicates effective therapy Reversibility is defined as 15% or greater improvement in FEV 1 & at least 200-ml increase in FEV 1 30

31. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.31 If FEV1/FVC is less than 70%, this would indicate; A.Obstructive disease B.Obstructive and restrictive disease C.Restrictive disease D.Patient is in the normal range

32. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Lung Volumes & Capacities Lung Volumes Tidal volume Inspiratory reserve volume Expiratory reserve volume Residual volume Lung Capacities Total lung capacity Inspiratory capacity Functional residual capacity Vital capacity 32

33. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Lung Volumes & Capacities (cont.) 33

34. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.34 The functional residual capacity consist of which two lung volumes A.Tidal volume and inspiratory reserve volume B.Tidal volume and expiratory reserve volume C.Inspiratory reserve volume and residual volume D.Expiratory reserve volume and residual volume

35. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Techniques for Measuring RV Helium dilution  Based on fact that known amount of helium will be diluted by size of patient’s RV Nitrogen washout  Based on fact that 79% of RV is nitrogen  Volume of nitrogen exhaled ÷ 0.79 = RV Body box  Applies Boyle’s law to measure RV 35

36. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Quality Assurance for Measuring Lung Volume  Helium dilution & nitrogen washout  Accuracy & precision of volume & flow measuring device  Accuracy & linearity of gas analyzer  Leak test must be acceptable range  Plethysmography  Box & mouth pressure transducers must be calibrated & accurate 36

37. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Helium Dilution 37

38. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Nitrogen Washout 38

39. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Body Plethymography 39

40. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Significance of Results TLC, FRC, & RV increase with obstructive disease & decrease with restrictive impairment Normal tidal volume is 500 to 700 ml (5 to 8 ml/kg of predicted body weight); V T measurement alone not helpful Normal TLC is about 6 L Normal VC is about 4.8 L in adult; results vary with age, gender, height, & ethnicity 40

41. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Changes With Lung Disease 41

42. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Diffusing Capacity Most PF labs use carbon monoxide to measure the diffusion capacity of the lungs Results reported in ml/min/mm Hg Results may be low in both obstructive & restrictive lung disease Emphysema & pulmonary fibrosis are two common causes of reduced DLCO 42

43. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Single Breath Technique 43

44. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Interpreting the DLCO Factors that Decrease DLCO Anemia Carboxyhemoglobi n Pulmonary Embolism Diffused pulmonary fibrosis Pulmonary emphysema Factors that Increase DLCO Polycythemia Exercise Congestive heart failure 44

45. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Quality Assurance for Measuring Diffusing Capacity  Accuracy & precision of volume or flow measuring device  Accuracy & linearity of gas analyzer  Test acceptability & repeatability  Measuring diffusing capacity of 3.0 L to provide quality control standard 45

46. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.46 Which one of these factors can decrease the diffusing capacity of the lung: A.Polycythemia. B.Exercise. C.Congestive heart failure. D.Pulmonary emphysema.

47. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. PFT Report Interpretation FEV 1 /FVC ratio is good place to start; reduced (<70%) with obstructive lung disease If TLC less than 80% of predicted normal & FEV 1 /FVC is normal - restrictive disease is present If DLCO is <80% of normal - diffusion defect is present  Reduced surface area = emphysema  Thickened AC membrane = pulmonary fibrosis 47

48. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. PFT Report Interpretation 48

49. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Interpretation 49