De-mystifying Outpatient Pulmonary Function Tests (PFTs)

1. De-mystifying Outpatient Pulmonary Function Tests (PFTs) Mani S. Kavuru, MD Professor & Division Chief Pulmonary & Critical Care Medicine Thomas Jefferson University / Hospital (No Disclosures)

2. Key learning Objectives • Consider the concept of spirometry in the primary care setting; • Review the spirometric maneuver, common patterns, concept of normality; • Discuss spirometry in the approach to lung disease; • Briefly review utility of other pulmonary function measures

3. Office Spirometry:Outline • Why do you need it in PCP offices? Utility in screening, smoking cessation • What is spirometry? Basics of technique, interpretation, etc. Office vs. Diagnostic (in labs) • Who could / should perform it? Training, quality control issues • Challenges, controversies?

4. Morbidity and Mortality of COPD • COPD is the 4th leading cause of death • Half the patients die within 10 years of diagnosis • 100,000 deaths/year in the U.S. • $13 billion/year in direct medical costs

6. The Lung Health Study Preliminary Results: • 10 Participating Centers • Patient Demographics • 5,887 current smokers enrolled • Age 35-59 (mean 48.5 ± 6.8 years) • FEV1/FVC 63% ± 5.5 • 63% men, 37% women • 96% white Tashkin DP, et al. Am Rev Respir Dis. 1992; 145 (2 pt) 1):301-10.

8. John Hutchinson (1811 – 1861)

9. References • ATS/ERS position statements; • Books: Miller, Scacci, Gast: Lab Evaluation of Pulmonary Function; Clausen; others • Jefferson interpretation statements; CCF Disease Management document;

10. Pulmonary Function Tests • Spirogram, +/- BDs • Lung volumes • Diffusing capacity • ABGs, 6 minute walk • Bronchoprovocation testing (i.e. mecolyl) • Cardiopulmonary exercise testing

15. HOW: Standardized Testing • Spirometry using ATS & AARC standards • Patient sitting in chair with arms • Use nose-clips! (O2 disconnected) • Reproducible tests, 3 valid efforts min. • No cough in first second • Back extrapolation guidelines (good start) • Good peak flow effort • Exhalation 6 seconds or >1 second plateau

20. Test Reproducibility

21. Non-Reproducible

22. Poor Start of Test

23. Normal Spirometry : Variable Effort

24. Glottic Closure : Cough

25. Mild Obstruction : Severe Obstruction

26. Restriction : Variable Intrathoracic

27. Variable Extrathoracic : FixedUpper Airway Obstruction

28. Reference Standards

31. Spirometric Reference Values From a Sample of the U.S. Population (NHANES III) • Age 8-80 (N=7,429), asympt. non-smokers, ’88 – ’94 • ATS criteria met (’87, ’94), QA by NIOSH • Caucasians, African-Americans, Mex-Am • Age, standing Ht > weight , BMI • FVC, FEV1, FEV6, PEF, FEF25 – 75 Hankinson. AJRCCM 1999;159:179-187

37. Spirometry • Two main measurements: • total volume exhaled (FVC) • lung/thorax expansion • HPP, IPF - restrictive lung diseases • volume exhaled in 1st second of exhalation (FEV1) • airway diameter • obstructive lung diseases • asthma, emphysema, chronic bronchitis, etc.

40. Classification of Lung Diseases • Obstructive Disease: asthma; chronic bronchitis; emphysema; CF; • Restriction--Intra-parenchymal disease (lung tissue is abnormal, e.g. HP, pulmonary fibrosis) • Restriction--Extra-parenchymal disease (lung tissue is normal); chest wall deformities, kyphosis, scoliosis, obesity, pleural effusions, ascites • Neuromuscular disorders (“bellows”)

41. Criticism of FEF 25-75% and Other Tests of Small Airway Disease FEF 25-75% • Does not detect small airway disease. • Is volume dependent. • Is affected by elastic recoil, small airways dysfunction and large airways dysfunction. • Is more variable than FEV1, but not as sensitive as FEV1/FVC%.

46. Spirometry Spirometry provides an objective measurement of lung function Measures VOLUME; the amount of air a person can breath in (inhale); and breathe out (exhale) And the SPEED or FLOW RATE that is generated during that maneuver; Into a device called a Spirometer