Spirometry For the Diagnosis of COPD and Asthma

1. SpirometryFor the Diagnosis of COPD and Asthma Robert Cohen, M.D., F.C.C.P. Division of Pulmonary Medicine/Critical Care andOccupational Medicine John H. Stroger Jr. Hospital of Cook County

2. SpirometryFor the Diagnosis of COPD and Asthma Disclosure of Conflict of Interest Information I have no existing conflict of information to disclose Disclosure information stated above is current as of March 12, 2007

3. Asthma – Key Definitions • Chronic inflammatory disorder of the airways, leading to: • airway spasm that reverses with treatment or spontaneously • bronchial hyperresponsiveness. • Recurrent episodes of wheeze, chest tightness, breathlessness and cough

4. Initial Assessment and Diagnosis of Asthma Determine that: • Patient has history or presence of episodic symptoms of airflow obstruction • Airflow obstruction is at least partially reversible • Alternative diagnoses are excluded

5. Initial Assessment andDiagnosis of Asthma (continued) Methods for establishing diagnosis: • Detailed medical history • Physical exam • Spirometry to diagnose airways obstruction and demonstrate reversibility

10. COPD: Key Definitions1,2 • Simple chronic bronchitis • Chronic cough and sputum production • Chronic obstructive bronchitis • Airflow obstruction: reduced forced expiratory volume in 1 second (FEV1) and ratio of FEV1 to forced vital capacity (FVC) (FEV1/FVC) • Chronic cough and sputum production • Emphysema • Irreversible enlargement of air spaces distal to terminal bronchioles • Alveolar wall destruction • Airflow obstruction 1. American Thoracic Society. Am J Respir Crit Care Med. 1995;152:S77–S121. 2. NCAP. J Respir Dis. 2000;21(suppl):S5-S21.

11. Diagnosis of COPD EXPOSURE TO RISK FACTORS SYMPTOMS cough tobacco sputum occupation dyspnea indoor/outdoor pollution è SPIROMETRY

17. Spirometry – A Critical Tool to Assess and Monitor Disease: • Spirometry is the gold standard. • Health care workers involved in the diagnosis and management of Asthma and COPD patients should have access to spirometry.

18. The SpirometerNo Clinic Should Be Without One • Instrument which measures volume, flow, and time • Three maneuvers: FVC, SVC, and MVV • Volume Transducer • Dry Rolling Seal, Water Seal, Bellows • Measures volume/time to calculate flow • Flow Transducer • Pressure Differential, heated wire, Ultrasonic, rotating turbine • Integrates flow/time

22. Hand Held Flow Spirometers

23. Methods – Testing

25. Flow Spirometers

26. Forced Vital Capacity Maneuver • Most important maneuver • Maximal Inspiration to maximal expiration • Vigorous encouragement by tech • 6 seconds long • No coughs, hesitation, obstruction • At least 3 maneuvers, 2 reproducible

29. Forced Expiratory Volume – 1 SecondFEV1 Most important measurement • Best measure of impairment • Predicts survival • Predicts work capacity • Predicts ability to survive an operation

30. Interpretation of Spirometry What is Normal?

31. DETERMINATION OF ABNORMALITY • Comparison with Predicted/Reference Values • Calculation of Change over time

32. Disease Severity Measured by FEV1* Note – FVC, VC, or TLC must be normal

33. Response to Bronchodilators *Must have a minimum of 200 cc plus the appropriate % change!

34. Changes in airflow as a result of asthma

35. Initial Assessment andDiagnosis of Asthma (continued) Is airflow obstruction at least partially reversible? • Use spirometry to establish airflow obstruction: • FEV1 < 80% predicted; • FEV1/FVC <65% or below the lower limit of normal • Use spirometry to establish reversibility: • FEV1 increases >12% and at least 200 mL after using a short-acting inhaled beta2-agonist

36. Natural History of COPD • Normal decline in FEV1: 25 to 30 mL per year from peakat age 251 • FEV1 decline in smokers: 45 to 60 mL/y1 • Approximately 20% of smokers have accelerated decline:up to 150 to 200 mL/y • More cigarettes smoked = steeper rate of decline2 • Quitting at any age: better pulmonary function,slower rate of decline than those who continue to smoke2,3 • Return to normal rate of decline FEV1, forced expiratory volume in 1 second. 1. NCAP. J Respir Dis. 2000;21(suppl):S5-S21. 2. American Thoracic Society. Am J Respir Crit Care Med. 1995;152:S77-S121. 3. Higgins MW, et al. JAMA. 1993;269:2741-2748.

37. 100 75 50 25 0 25 50 75 Age-Related Decline in FEV1 IsAccelerated in Smokers FEV1, forced expiratory volume in 1 second. Never smoked or not susceptible to smoke Stopped at 45 y Stopped at 65 y Smoked regularly and susceptible to its effects FEV1 (% of value at age 25 y) Disability Death Age (y) Adapted with permission from Fletcher C, Peto R. BMJ. 1977;1:1645-1648.

38. Classification by Severity Stage Characteristics 0: At risk Normal spirometry Chronic symptoms (cough, sputum)  I: Mild FEV1/FVC < 70%; FEV1 ³ 80% predicted With or without chronic symptoms (cough, sputum) II: Moderate FEV1/FVC < 70%; 50% £ FEV1 < 80% predicted With or without chronic symptoms (cough, sputum, dyspnea) III: Severe FEV1/FVC < 70%; 30% £ FEV1 < 50% predicted With or without chronic symptoms (cough, sputum, dyspnea) IV: Very Severe FEV1/FVC < 70%; FEV1 < 30% predicted or FEV1 < 50% predicted plus chronic respiratory failure

40. Guidelines for Interpreting Change Over Time • Decreased FEV1 by 5% or 200ml over a work shift potentially important (Cotton Dust Standard). • If FEV1 or FVC decrease by >15%/year, then consider potentially important. • NIOSH – a decrease of 15% points of predicted over any period of time significant

41. Decrement in Lung Function With Age • Rule out accelerated decline in • Normal Decline in FEV1=20-30 • Decline in pts with COPD=50-80 • 15% of Smokers > 60 ml/yr • Longitudinal Evaluation of FEV1 • Evaluate if fall in FEV1 greater than > 15% points of predicted in serial testing. NIOSH

42. References • Series ‘‘ATS/ERS task force: Standardisation of lung function testing.’’ Eur Respir J 2005; Volume 26 – There are 5 Articles in this series. • ATS Statements are available at: http://www.thoracic.org/statements/ • NIOSH Spirometry Training Web Page: http://www.cdc.gov/niosh/topics/spirometry/default.html • NIOSH Spirometry Manual: http://www.cdc.gov/niosh/docs/2004-154c/