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Spirometry

Spirometry. “Spiro” – from the greek for breathing “Metry” – measurement “Spirometry” – The measurement of breathing. SPIROMETRY. SPIROMETRY.

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Spirometry

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  1. Spirometry “Spiro” – from the greek for breathing “Metry” – measurement “Spirometry” – The measurement of breathing

  2. SPIROMETRY

  3. SPIROMETRY • Spirometry plays a key role in the diagnosis and assessment of Chronic Obstructive Pulmonary Disease and yet research shows that it is under-utilised • Importance highlighted with the new GMS contract • Reliable method of differentiating between obstructive and restrictive disorders • Can be used to detect the severity of disease • Can detect COPD before symptoms become apparent

  4. When to perform spirometry Asthma • Interchangable with peak flow to demonstrate variability • May show changes suggestive of an alternative lung disease COPD • At the time of diagnosis to conform obstruction • To reconsider the diagnosis, if the patient shows an exceptionally good response to treatment • Annually to monitor progression of disease Screening? • All patients over 35, current or ex smokers, who have a chronic cough • Considered in patients with chronic bronchitis as a proportion of these will go on to develop airflow limitation NICE (2004) – all health professionals managing patients with COPD should have access to spirometry and be competent in the interpretation of the results.

  5. Who can perform spirometry Spirometry can be performed by any health care worker who is appropriately trained and who keeps his or her skills up to date Spirometry services should be supported by quality control processes

  6. ?Reversibility testing??? NICE 2004 R12 In most patients, routine spirometric reversibility testing is not necessary as a part of the diagnostic process or to plan initial therapy with bronchodilators or corticosteroids. It may be misleading or unhelpful because • Repeated FEV1 measurements can show spontaneous fluctuations • Results on different occasions may be inconsistant and not reproducible • Unless change in FEV1 is >400mls a single test may be misleading • Definition of magnitude of significant change is purely arbitrary • Response to long term therapy not predicted by acute reversibility testing History is Key in distinguishing asthma from COPD

  7. Patient preparation To withhold or not to withhold medication? If you are doing reversibility testing: • No short acting bronchodilators for 4 hours • No long acting bronchodilators for 12 hours • No sustained release oral bronchodilators for 24 hours For routine monitoring of COPD patients: • Take all medication as usual

  8. Terminology VC – Vital capacity, the total amount of air that acn be expelled from the lungs from full inspiration to full expiration FVC – Forced vital capacity, should be the same volume as VC but is sometimes reduced due to air trapping in COPD FEV1 – Forced expiratory volume in one second from full inspiration FEV1/FVC or FEV1% or FEV1/FVC ratio –The percentage of the FVC that is produced in the first second

  9. Patient preparation Before arrival • No large meal within 2 hours • No vigorous exercise within half an hour • Comfortable loose clothing • Empty bladder • ?false teeth

  10. Patient preparation Who should not perform spirometry? • Recent eye surgery • Recent MI • Recent CVA or other cerebral event • Any recent surgery • Any others?

  11. Patient preparation • Record patients date of birth, height, ethnic origin • Note if the patient is currently unwell or has had a recent exacerbation • Ensure the patient is comfortable • Sit the patient in a chair with arms • Explain the purpose of the test • You may need to demonstrate the correct technique • Allow the patient practice attempts

  12. Patient preparation • Record patients date of birth, height, ethnic origin • Note if the patient is currently unwell or has had a recent exacerbation • Ensure the patient is comfortable • Sit the patient in a chair with arms • Explain the purpose of the test • You may need to demonstrate the correct technique • Allow the patient practice attempts

  13. Measuring vital capacity (VC) The VC is a non forced measurement. It is often measured at the start of a session. • Patient breathes in as deeply as is comfortable • Seals lips around mouthpiece • Breathes out steadily at a comfortable pace • Continue until expiration complete • May need a nose clip • Repeat

  14. Measuring FEV1 and FVC • Ask the patient to take a deep breath in – full inspiration • Patient to blow out forcibly, as hard and fast as possible, until there is nothing left to dispell • Encourage patient to keep blowing • For some COPD patients this can take up to 15 seconds! • Spirometer may bleep to say manoeuvre complete • Repeat the procedure twice or until reproducible results

  15. Maintaining accuracy The most common reason for inacurate results is patient technique Common problems include: • Inadaquate or incomplete inhalation • Additional breath taken during manoeuvre • Lips not sealed around mouthpiece • A slow start to the forced exhalation • Some exhalation through the nose • Coughing

  16. Quality assurance Is the test valid? Reproducibility: • Minimum of 2 relaxed vital capacities • Minimum of 3 forced vital capacities • Maximum of 8 forced blows in one session • Best 2 blows within 5% or 100ml of each other

  17. Interpreation of results • Take the best of the 3 consistent readings of FEV1 and of FVC • Find the predicted normals for your patient – Your machine may do this for you!

  18. Depends on ; Age Sex Height Race Predicted Normals

  19. Based on large population surveyse.g.ERS93, ECCS83 Predicted values are the mean values obtained from the survey No surveys conducted in elderly populations Predicted Normal values

  20. Normal ventilatory function • FVC 80 – 120% of predicted • FEV1 80 – 120% of predicted • FEV1/FVC ratio >70%

  21. To calculate % predicted Actual Measurement x100 Predicted Value • e.g. Actual FEV1 = 4.0 litres Predicted FEV1 = 4.0 litres 4 x 100 = 100% 4

  22. To calculate the ratio of FEV1 to FVC (FEV1%, FEV1/FVC or FER) Actual FEV1 x100 Actual FVC e.g. FEV1 = 3.0 litres FVC = 4.0 litres 3 x100 =75% 4

  23. Results clasification • Normal • Obstructive • Restrictive • Combined

  24. Interpreting Spirometry

  25. Obstructive defects • COPD • Asthma • Bronchial carcinoma • Bronchiectasis

  26. Fibrosing lung disease (CFA, UIP, EAA, rheumatiod) Parenchymal tumours Pneumoconiosis (coal workers, asbestosis, silicosis, siderosis) Byssinosis Pulmonary oedema Restrictive defectsPulmonary causes

  27. Restrictive defectsExtra-pulmonary causes • Thoracic cage deformity • Obesity • Cardiac fialure • Neuromuscular problems • Pneunonectomy/lobectomy

  28. Combined defects • Severe COPD • Advanced bronchiectasis • Cystic fibrosis

  29. The history of Inhalers • 1956 :Riker laboratories (3M) developed the first meter dosed inhaler • 1969: Allen and Hanbury’s introduced inhaled salbutamol • 1972: introduction of first inhaled steroidClarke, 2003

  30. Aim of Inhaled therapy Deliver high concentration of drugs directly to lungs & bronchioles while reducing systemic side effects

  31. MDI’s • Correct technique depends on knowledge & skills • Holder & canister act as a pump • Pt’s ability to use MDI has shown to decline over time • Good technique delivers 10-15% to small airways • Increase by 12% with a spacer • Togger,2001

  32. Meter Dose Inhaler (MDI) • MDI is still the most common device used • Only 21% of people use inhalers correctly

  33. Meter dose Inhaler (MDI)

  34. Medication available in the metered dose inhaler • Terbutaline / Salbutamol • Ipratropium • Salmeterol • Budesonide / Beclometasone / Fluticasone / Ciclesonide • Seretide

  35. Spacers • Several types available • Holding chamber & one way valve • Reduces need for hand breath co-ordination • Spacer should be compatible with MDI • BTS, 2003

  36. Recommendations about spacers Cleaning: Clean no more than monthly as more frequent cleaning affects performance (due to a build up of static) Clean with water and washing up liquid and leave to air dry Wipe mouthpiece clean of detergent before use NOTE – Volumatic (large volume) spacer was discontinued in October 2005 and reintroduced in Feb 2006. (think patient choice/cost/ability to use)

  37. The Accuhaler Medication available • Salbutamol • Salmeterol • Fluticasone • Seretide • 100/50 • 250/50 • 500/50

  38. Turbohaler • Advantages less manual dexterity needed • No co-ordination required • Does not require spacer • Built in indicator to inform pt doses remaining

  39. Turbohaler

  40. Symbicort Turbohaler 3 strengths 100/6, 200/6, 400/12 Other drugs available in the turbohaler • Terbutaline • Budesonide • Formoterol

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