The document provides information on spirometry testing including: - Contraindications and patient preparation for the test - Procedures for slow vital capacity, forced vital capacity, and maximum voluntary ventilation tests - Interpretation of test results including distinguishing obstructive, restrictive, and mixed abnormalities and assessing severity - Potential errors in test performance and assuring technical acceptability of results

1. Dr. Maha Yousif Assist. Lecturer of Chest Diseases Minufiya University, Egypt E-mail: drmahayousif@gmail.com Oct. 2008 Basics of spirometry

3. Contraindications to spirometry No absolute contraindications. FVC manoeuvre raise intra-cranial, intra-thoracic and intra-abdominal pressures so, Relative contraindications may be: ◆ Recent eye, thoracic or abdominal surgery ◆ Recent myocardial infarction, uncontrolled hypertension or pulmonary embolism ◆ Recent cerebrovascular haemorrhage or known cerebral or abdominal aneurysm ◆ Pneumothorax ◆ Haemoptysis of unknown origin (FVC maneuver may aggravate underlying condition.) ◆ Acute disorders affecting test performance (e.g. vomiting, nausea, vertigo)

4. Patient preparation Before the test ◘ Avoid: Acohol 4h Large meal 2h Smoking 1h Vigorous exercise 30min ◘ Wear loose , comfortable clothing. ◘ relaxed, and have time to visit the toilet.

5. For bronchodilator reversibility testing withhold bronchodilators prior to the test: ◘ Short-acting inhaled β2 agonists for 2–4h. ◘ Short-acting inhaled anticholinergics for 4–6 h. ◘ Long-acting inhaled or oral β2 agonists for 12–24 h ◘ Long-acting inhaled anticholinergics for 24–36 h. ◘ Theophyllines for 12 h. ◘ Sustained release theophyllines for 24 h.

6. Calibration To ensure accurate recording of the tested lung volumes. Daily routine. A spirometer that is transported from one location to another and exposed to changes in temperature should be re-calibration before use.

7. Performing the test Explain the procedure. Check any contraindications,complied instructions as withholding bronchodilators, not smoking,…… Accurately measure height, standing (without shoes) If patients are unable to stand, or have a severe spinal deformity such as a scoliosis, height can be estimated by measuring arm span. Enter the patient data to the software. N.B: False teeth, unless they are very ill-fitting and loose, should be left in. Record any deviations from the ideal so that subsequent tests can be carried out under the same conditions

8. Correct position of head and body Seating Position: (The standing position is not advised), The test position should be noted on the report. Upright position: Position of the head : upright or slightly leaned back. (If the neck is flexed forward the upper airways are narrowing. No leaning forward during the test.

9. Slow expiratory vital capacity( SVC,EVC). Should be tested before any forced maneuvres SVC Maneuvre 1) Breath normally (Facultative) 2) Execute a maximal slow inspiration 3) Execute a maximal slow expiration 4) Breath at rest Wait a minute or so before attempting another recording

10. Slow Vital Capacity (SVC) Main parameters measured are: EVC: Slow expiratory vital capacity( SVC). IVC : Inspiratory Vital cpacity ERV: Expiratory reserve volume IRV: Inspiratory reserve volume Others are: VE: Expired Volume per minute Vt : Tidal Volume Rf: Respiratory Frequency Ttot: Duration of a complete respiratory cycle Ti/Ttot, Vt/Ti

11. Forced Vital Capacity FVC Manoeuvre 1) Breath normally (Facultative) 2) Execute a Forced Maximal inspiration 3) Execute a Forced maximal expiration 4) Execute a maximal inspiration (Facultative) 5) Breath at rest Wait at least 1 minute before attempting another recording N.B Normally, the SVC and FVC are nearly equal. But in airway obstruction SVC > FVC.

12. Forced Vital Capacity The Main Measured Parameters are: FVC Forced Expiratory Vital Capacity. FEV1 Forced Expired Volume after one second. FEV1/FVC% Percentage of FEV1 against the FVC. PEF Expiratory Peak flow. MEF 25-75% (FEF 25-75% )Mean Forced expiratory flow. The representative graphs are: The flow-volume curve (loop). The volume-time curve.

13. Flow / volume curve Volume / time curve

14. The volume/time curve A normal volume/time curve has a typical shape. There is a rapid rise to the trace as three-quarters of the air is expired in the first second The trace plateaus between 4 and 6 seconds

15. A normal flow/volume curve has a typical shape ◘ Rises almost vertically to PEF ◘ The trace merges smoothly with the horizontal axis of the graph at FVC The flow/volume curve

16. Mid-expiratory flow rates (MEF25, MEF50, MEF75) MEF25: ‘The maximum flow achievable when 75% of the FVC has been expired’ (when 25% of the FVC remains in the lungs). MEF75: refers to the maximum flow achievable when 75% of the FVC remains in the lungs and the MEF50 is the maximum flow rate achievable when the lungs are half-empty a sign of early airflow obstruction ( small airway disease ). Some spirometers use the equivalent of MEF: the forced expiratory flow (FEF25, FEF50 and FEF75).

17. Peak expiratory flow: the highest flow achieved from a maximal forced expiratory manoeuvre started without hesitation from a position of maximal lung inflation’ occurs very early in a forced expiration – within the first tenth of a second airflow from the larger airways

18. Common errors Coughing

19. Failure to expire to FVC: The volume/time trace will fail to plateau The flow/volume trace will not merge with the horizontal axis and will ‘drop off’

20. Slow start to the forced expiratory manoeuvre: Will give an ‘S’ shape to the start of the volume/time trace, The flow/volume trace will have a sloping, rather than vertical start

21. Air leak: The volume/time trace will ‘dip’ downwards, rather than rise steadily to a plateau

23. Technical acceptability Maximum effort for the forced manoeuvre Immediate exhalation from the position of maximal inspiration No coughing Complete exhalation. Traces are smooth and free of irregularity The volume/time trace should plateau for at least 1 second and there should not be an ‘S’ shape to the beginning of the trace

24. The flow/volume trace should rise almost vertically to a peak and the trace should merge smoothly with the horizontal axis at the end of the blow At least three technically acceptable manoeuvres should be obtained, ideally with less than 0.2 L (5%) variability for FEV1 (and FVC) between the highest and second highest result. Quote the largest value. If the difference is > 5% this means Sub-maximal effort. (repeat the test) Reductions in PEF and FEV1 have been shown when inspiration is slow and/or there is a 4–6 s pause at total lung capacity (TLC) before beginning exhalation

26. Spirometry interpretation Spirometry parameters are considered to be within the normal range if: The FEV1, FVC and VC are between 80% and 120% of the reference value for someone of that age, gender, height and ethnic group The FEV1/FVC is about 75% (0.75) or over 80% of the reference value for someone of that age, gender, height and ethnic group

27. Obstructive abnormality Spirometry parameters compatible with airflow obstruction are: ◘ A reduced FEV1/FVC, or FEV1/VC. Values of less than 70% and/or less than 80% of the reference value ◘ An FEV1 of less than 80% of the reference value N.B: When the slow vital capacity is higher than the FVC, the FEV1/VC should be calculated ◘ Once the diagnosis of obstructive abnormality is made, comment on: Severity of obstruction. Reversibility of obstruction

28. Severity of obstruction The severity of reductions in the FEV1% pred can be characterized by the following scheme:

29. Reversibility test Response to β agonist is assessed after 10-15 min after inhalation of (100 mcg each, 400 mcg total dose) albuterol administered through a valved spacer device. When concern about tremor or heart rate exists, lower doses may be used. Response to an anticholinergic drug may be assessed 30 minutes after 4 inhalations (40 mcg each, 160 mcg total dose) of ipratropium bromide.

30. Reversibility test FVC before and after bronchodilator

31. Restrictive abnormality Spirometry parameters compatible with a restrictive abnormality are: ◘ An FEV1, FVC and VC reduced to less than 80% of their reference value ◘ A normal or high FEV1/FVC, or FEV1/VC (about 75%). The FEV1/FVC will be over 80% of the reference value ◘ The severity of restriction is based on the degree of reduction in FVC % Pred.the same classification as obstructive abnormality.

32. Mixed abnormality Reduced FVC & a low FEV1/FVC% ratio. Means: a combination of both obstruction and restriction, or airflow obstruction with gas trapping. It is necessary to measure the patient's total lung capacity to distinguish between these two possibilities.

36. Examples of lesions of the major airway detected with the flow-volume loop Variable extrathoracic lesions ◘ Vocal cord paralysis ◘ Subglottic stenosis ◘ Hypopharyngeal or tracheal tumour ◘ Goiter Variable intrathoracic lesions ◘ Tumor of lower trachea (below sternal notch) ◘ Tracheomalacia ◘ Strictures ◘ Wegener's granulomatosis or relapsing polychondritis Fixed lesions ◘ Fixed neoplasm in central airway (at any level) ◘ Vocal cord paralysis with fixed stenosis ◘ Fibrotic stricture

37. Maximum Voluntary Ventilation (MVV) Normally, the MVV is approximately = FEV1×40. If the FEV1 is 3.0 L, the MVV should be approximately 120 L/min. MVV/(40×FEV1)< 0.80 indicates that the MVV is low relative to the FEV1, means: ◘ a major airway obstruction ◘ neuromuscular diseases (amyotrophic lateral sclerosis, myasthenia gravis, polymyositis). ◘ Poor patient performance due to weakness, lack of coordination, ◘ the subject is massively obese? The MVV tends to decrease before the FEV1 does.

38. Maximum Voluntary Ventilation (MVV) MVV Manoeuvre Breath in and out deeply and rapidly for 12 second.

39. Obstructive abnormality: very severe, Restrictive abnormality: moderate (mixed).

40. Obstructive abnormality: very severe, Restrictive abnormality: severe (mixed).

41. Obstructive abnormality: severe, Restrictive abnormality: mild (mixed).

42. Moderate restrictive abnormality

43. Normal spirometry

44. Mild restrictive abnormality

45. Restrictive abnormality: moderatey severe

46. Obstructive abnormality: moderately severe.

47. The End