Spirometry of obstructive lung diseases, Egyptian COPD Initiative , Scribe medical events (www.scribeofegypt.com)

1. Spirometry of ObstructiveLung Diseases

2. Pulmonary Disorders Effects onPulmonary Function
Obstructive:
Any process that interferes with air flow either into or out of the lungs.
Large or small airways.
Restrictive:
Any process that interferes with the bellows action of the lungs or chest wall.
Reduced lung volumes.

3. Differential Diagnosis: COPD and Asthma
COPD
Onset In mid-life
Symptoms slowly progressive
Long smoking history
Dyspnea during exercise
Largely Irreversible airflow limitation
Asthma
Onset early in life (often childhood)
Symptoms vary from day to day
Symptoms at nigh/early morning
Allergy, rhinitis, and/or eczema also present
Family history of asthma
Largely reversible airflow limitation

4. Inflammatory Cascade inCOPD & Asthma

5. Measures of Assessment andMonitoring of Asthma
Asthma diagnosis criteria:
Positive episodic symptoms of airflow obstruction.
Airflow obstruction partially reversible.
R/ O alternative dx.

6. Objective lung functionmeasurements in Asthma
Spirometry:
▫Forced Expiratory Maneuvers.
Exhaled Nitric Oxide.
Peak Flows.

7. EPR-3 Statements for Asthma
The Expert Panel recommends that office-based physicians who care for asthma patients should have access to spirometry, which is useful in both diagnosis and periodic monitoring .
Spirometryshould be performed using equipment and techniques that meet standards developed by the ATS (EPR-2 1997).

8. GOLD 2013: Diagnosis of COPD
SPIROMETRY REQUIREDTO DIAGNOSE COPD
Presence of a post-bronchodilator FEV1/FVC < 0.70 confirms the presence of persistent airflow limitation and thus of COPD.
Key Indicators to Consider COPD Diagnosis:
1
•SYMPTOMS
•Dyspnea-progressive (worsens over time and with exercise)
•Chronic cough
•Sputum
2
•HISTORY OF EXPOSURE TO RISK FACTORS
•Tobacco smoke
•Smoke from home cooking/heating fuels
•Occupational dusts and chemical
3
•FAMILY HISTORY OF COPD
Adapted from GOLD 2013

9. Spirometry
Spirometryshould be performed after the administration of an adequate dose of a short acting inhaled bronchodilator (e.g. 400 ᶙg salbutamol) to minimize variability.
A post-bronchodilator FEV 1/FVC <0.70 confirms the presence of airflow limitation that is not fully reversible.
Where possible, values should be compared to age-related normal values to avoid over- diagnosis of COPD In the elderly.

10. Why Do We Need Spirometryin COPD?
Spirometryis useful for:
Screen individuals at risk for pulmonary disease.
Confirmation of COPD diagnosis.
Assessing severity of pulmonary dysfunction.
Guiding selection of treatment.
Assessing the effects of therapeutic interventions.

11. Who Should Be Screened forCOPD?
Consider COPD, and perform spirometry, if any of these indicators are present in an individual over age 40.
▫Dyspnea that is progressive, usually worse with exercise, and persistent.
▫Chronic cough (may be intermittent and unproductive).
▫Chronic sputum.
▫History of tobacco smoke exposure.
▫Exposure to occupational dusts and chemicals.
▫Risk factors.
▫Exposure to smoke from home cooking and heating fuels.

12. SpirometryOrigin
Most basic of Pulmonary Function Tests
Clinical Tools Origin -Mid 1800' s
▫John Hutchinson.
▫Water-sealed spirometryto measure vital capacity (VC).

13. Reasons for PerformingSpirometry
Diagnostic Purposes.
Monitoring Lung Disease.
Assessing Disability.

14. Spirometry
Spirometrywith flow volume loops assesses the mechanical properties of the respiratory system by measuring expiratory volumes and flow rates.
▫Maximal inspiratory and expiratory effort.
▫At least 3 tests of acceptable effort are performed to ensure reproducibility.

15. 21st Century Spirometry
Measurements of:
Forced Vital Capacity (FVC).
Forced Expiratory Volume in one second (FEV1).
Forced Expiratory Volume in six seconds (FEV6).
Forced Expiratory Flow over various Intervals (FEFx).
Peak Expiratory Flow (PEF).

16. Definitions and Terms
FEV1 -forced expiratory volume 1 -the volume of air that is forcefully exhaled in one second.
FEV6 -forced expiratory volume 6 -the volume of air that Is forcefully exhaled in six seconds.
FVC-forced vital capacity-the volume of air that can be maximally forcefully exhaled.
FEV/FVC-ratio of FEV1 to FVC, expressed as a percentage.

17. Definitions and Terms
FEV/FVC-ratio of FEV6 to FVC, expressed as a percentage.
FEF25 -75 -forced expiratory flow -the average forced expiratory flow during the mid (25 -75%) portion of the FVC.
PEF-peak expiratory flow rate -the peak flow rate during expiration.

18. Spirometry
Flow volume loops provide a graphic illustration of a patient's spirometricefforts.
Flow is plotted against volume to display a continuous loop from inspiration to expiration.
The volume versus time curve is a an alternative way of plotting spirometricresults.
The overall shape of the flow volume loop is important in Interpreting spirometricresults.

19. Acceptability & Repeatability

20. Acceptability
At least three (3) acceptable maneuvers
Good start to the test.
No hesitation or coughing for the 1stsecond.
FVC lasts at least 6 seconds with a plateau of at least 1 second.
No valsalvamaneuver or obstruction of the mouthpiece.
FIVC shows apparent maximal effort.

21. Repeatability
Repeatability criteria act as guideline to determine need for additional efforts.
▫Largest and 2nd largest FVC must be within 150 mL.
▫Largest and 2nd largest FEV 1 must be 150 mL.
▫PEF values may be variable (within 15%).
If three acceptable reproducible maneuvers are not recorded, up to B attempts may be recorded.

22. SpirometryValue
Spirometryis typically reported in both absolute values and as a predicted percentage of normal.
Normal values vary and are dependent on:
▫Gender,
▫Race,
▫Age, and
▫Height.

23. Reporting Standards
Largest FVC obtained from all acceptable efforts should be reported.
Largest FEV1 obtained from all acceptable trials should be reported.
May or may not come from largest FVC effort.
All other flows, should come from the effort with the largest sum of FEV 1 & FVC.
PEF should be the largest value obtained from at least 3 acceptable maneuvers.

24. Results ReportingExample

25. Report Format
Report should also include:
▫Age on testing day.
▫Height (standing without shoes).
▫Weight (without shoes).
▫Gender.
▫Race or ethnic origin.
▫Technologist comment section.

26. FEV1 Results for Asthma

27. FEV 1 Severity Results for Asthma

28. At Risk for COPD
Spirometricclassification of airflow limitation (in patients with FEV1/FVC<0.70).
▫GOLD 1(Mild; FEV1 ≥80% predicted).
▫GOLD 2 (Moderate; 50% ≤FEV1 <80% predicted).
▫GOLD 3 (Severe; 30% ≤FEV1 <50% predicted).
▫GOLD 4 (Very severe; FEV1 <30% predicted).
Adapted from GOLD 2013

29. Pre & Post BronchodilatorStudies
B-Adrenergic aerosols are most common form for testing.
Standardize.
▫Drug.
▫Dosage.
▫Delivery Device.
Minimum of 15 minutes between pre and post tests.

30. Pre & Post Bronchodilator Studies: Withholding Medications

31. Pre & Post BronchodilatorStudies: Interpretations
Determined based on improvement of FEV1.
Commonly expressed as Percent Change.
% Change = Post FEV 1 -Pre FEV1 x 100
Pre FEV1

32. Reversibility
Reversibility of airways obstruction can be assessed with the use of bronchodilators.
> 12% increase in the FEV1 and 200 ml
improvement in FEV1
OR
> 12% increase in the FVC and 200 ml
improvement in FVC.

33. Spirometry

34. Asthma Challenge Testing
Spirometrycan be used to detect the bronchial hyperreactivitythat characterizes asthma.
Increasing concentrations of histamine or methacholine.
Patients with asthma will demonstrate symptoms and produce spirometricresults consistent with airways obstruction at much lower threshold concentration than normals.

35. Bronchial Provocation for Asthma

36. Other Diagnostic Tests
Sputum Induction
6-Minute Walks
Impulse Oscillometry
Exhaled Nitric Oxide
Exhaled Breath Condensate

37. References