How To Test For Spirometry

Transcription

1 Confirming Diagnosis Through Spirometry Shirley F. Jones, M.D., FCCP I have no conflicts of interest Instructional Objectives At the end of this session, learners will be able to: Select individual patients appropriate for screening (case-finding) with spirometry. Differentiate between normal, obstructive, and restrictive spirogram patterns.

2 Recommendations From the National Lung Health Education Program Primary care clinicians should perform an office spirometry test for the following patients: Patients 45 years old who report smoking (current smokers and those who recently quit) in order to detect COPD. Patients with respiratory symptoms, such as chronic cough, sputum production, wheezing, or dyspnea on exertion. Ferguson et al. Chest. 2000;117: Old Spirometer New Spirometers: Portable Office Spirometers

3 Predicted Normal Values Affected by: Age Height Sex Ethnic Origin What Is Normal? Criteria for Normal Postbronchodilator Spirometry : % predicted 80% FVC: % predicted 80% /FVC: 0.7

4 Spirometric Diagnosis of COPD COPD is confirmed by postbronchodilator /FVC < 0.7. Postbronchodilator /FVC measured minutes after 2 to 4 puffs of a short-acting bronchodilator. Normal Trace Showing and FVC Volume, liters FVC = 4L (90% predicted) FVC = 5L (95% predicted) /FVC = Time, seconds

5 Spirometry: : Obstructive Disease 5 Volume, liters Normal = 1.8L (65% predicted) FVC = 3.2L (80% predicted) /FVC = 0.56 Obstructive Time, seconds ARS: A positive bronchodilator response differentiates between patients with asthma and COPD 1)True 2) False 3) Not Sure 55% 39% 6% 1 2 3

6 Airflow Obstruction in COPD Is Partially Reversible 15 * Degree of Reversibility Patients, % 10 5 *65.6% showed a 15% increase in Change in % Postbronchodilator measured after administration of 80 µg ipratropium and 400 µg albuterol. Adapted with permission from Tashkin DP, et al. Eur Resp J. 2008; 31: Bronchodilator Reversibility Testing Provides the best achievable (and FVC) Must be interpreted with clinical history - neither asthma nor COPD are diagnosed on spirometry alone

7 Significant Bronchodilator Response increases by 200 ml and increases by 12% Flow Volume Loop Included with most commercial spirometers Generates and FVC measurements Depicts expiration and inspiration Clear and rapidly recognizable patterns Obstructive disease (eg, asthma, COPD) Restrictive disease Upper airway obstruction

8 Expiratory flow rate, L/sec Flow Volume Curve Maximum expiratory flow (PEF) TLC FVC RV Inspiratory flow rate, L/sec Volume, L Flow Volume Curve Patterns Obstructive and Restrictive Obstructive Severe Obstructive Restrictive Expiratory flow rate Volume, L Expiratory flow rate Volume, L Expiratory flow rate Volume, L Reduced peak flow, scooped out midcurve Steeple pattern, reduced peak flow, rapid fall off Normal shape, normal peak flow, reduced volume

9 Flow Volume Loop Spirometry Is a Useful Tool To Assess COPD Severity and Progression 1,2 Postbronchodilator is recommended for the diagnosis and assessment of COPD /FVC < % predicted /FVC < % < 80% predicted /FVC < % < 50% predicted /FVC < 0.70 <30% predicted I: Mild II: Moderate III: Severe IV: Very Severe 1. American Thoracic Society, European Respiratory Society. Standards for the diagnosis and management of patients with COPD. Accessed November 19, Global Initiative for Chronic Obstructive Lung Disease. Global strategy for diagnosis, management, and prevention of chronic obstructive pulmonary disease. Updated Global Initiative for Chronic Obstructive Lung Disease (GOLD). NHLBI/WHO Workshop report (updated 2006). (accessed March 14,2007)

10 Repeatability - Quality of Results Volume, liters Time, seconds Three times FVC within 5% or 0.15L (150 ml) ARS: How many trials are allowed by a single person per testing period to achieve repeatability? 1) 3 2) 6 47% 3) 8 30% 4) 12 5) as many as takes to get it right 10% 13% 0%

11 Nonrepeatablity Test Volume (L) Three Acceptable Maneuvers #3 #2 Curve FVC #1 1.0 # # # Time (s) American Thoracic Society. Am J Respir Crit Care Med. 1995;152: Official journal of the American Thoracic Society. American Lung Association. Reprinted with permission. ARS: Does this spirogram pass repeatability? 1) Yes 2) No 62% 3) Not sure 24% 14% 1 2 3

12 Summary Spirometry is the gold standard for diagnosing COPD and monitoring its progression. All patients 45 years old with a smoking history and all patients with respiratory symptoms, such as chronic productive cough, sputum production, and dyspnea, should be considered for spirometry. Spirometry requires accurate equipment, good test procedures, appropriate reference values, and proper interpretation. 1. Global Initiative for Chronic Obstructive Lung Disease. Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease Updated Available at: Accessed October 14, Audience Participation Please write down one thing you will do differently, apply, or search for additional information on as a result of what you learned in this presentation.