COPD RESOURCE PACK SECTION 3 SPIROMETRY

Transcription

1 COPD RESOURCE PACK SECTION 3 SPIROMETRY In this section: 1. Protocol for Assessing Patients At Risk of COPD 2. Spirometry The Basics 3. Good Quality Spirometry 4. Spirometry Interpretation 5. Calculating Spirometry Values and Ratios 6. Classification of Airflow Obstruction Severity 7. Reversibility Testing 8. E.R.S 1993 Predicted Normal Values (Male) 9. E.R.S 1993 Predicted Normal Values (Female) Appendix 1: Patient Information Leaflet for Spirometry Appendix 2: Spirometry Checklist Appendix 3: Infection Control Appendix 4: Micro Medical 3500 MK5 Spirometer Calibration Check Appendix 5: Micro Medical 3500 MK6 Spirometer Calibration Check Appendix 6: Calibration Log Appendix 7: Spirometry Quality Control Log Page 1 of 20

2 1. PROTOCOL FOR ASSESSMENT PATIENTS AT RISK OF COPD INITIAL ASSESSMENT Patient Screening from High Risk Population (>35 years with a smoking history of >10 pack years) Baseline History Clinical picture suggests asthma Clinical picture suggests COPD Spirometry Normal Refer to Asthma Resource Pack Section 5b Spirometry Abnormal Perform a Post Bronchodilator Spirometry Test Perform Reversibility to Bronchodilator Obstruction No Obstruction No response Consider an alternative diagnosis (Refer to Asthma Resource Pack) Response (Refer to Asthma Resource Pack) Refer to Section 2 of the COPD Resource pack Consider an alternative diagnosis Page 2 of 20

3 2. SPIROMETRY THE BASICS Forced Vital capacity (FVC) The amount of air that can be exhaled from a position of maximum inhalation to maximum exhalation using maximum effort. Is expressed as an actual value in litres and also as a percentage of predicted based on patients age, height, gender and race. Forced Expiratory Volume in One Second (FEV 1 ) The volume of air exhaled in the first second of a forced exhalation from a position of maximum inhalation to maximum exhalation. Is expressed as an actual value in litres and also as a percentage of predicted based on patients age, height, gender and race. Once obstruction is established, FEV1 % of predicted is used to classify severity of disease. This % is different from the FEV 1 / FVC ratio and should not be confused with it. FEV 1 % can predict future mortality and relates best to severity of breathlessness. FEV 1 can vary by up to 140ml within the same day and 170ml between days. FEV 1 / FVC Ratio The ratio of FEV 1 to FVC expressed as a percentage. FEV 1 / FVC ratio is used to diagnose airways obstruction. A ratio of <70% is diagnostic of airways obstruction Relaxed Vital Capacity (VC or RVC) The amount of air that can be exhaled in a relaxed blow from a position of maximum inhalation to maximum exhalation. Is expressed as an actual value in litres and also as a percentage of predicted based on patient s age, height, gender and race. If actual value in litres is higher than the FVC it should be used to calculate ratios. Volume/Time Graph Plots volume (in litres) on vertical axis against time (in seconds) on horizontal axis. Flow Volume Graph Plots flow (in litres) on vertical axis against volume (in litres) on horizontal axis. Predicted Values The ERS predicted values only go up to age 70 years. If the patients is older than this values have to be calculated accordingly. However most spirometers do this for you. Page 3 of 20

4 3. GOOD QUALITY SPIROMETRY To ensure meaningful and accurate results spirometry should only be performed by professionals with adequate training. Spirometry carried out by an untrained person may lead to inaccurate diagnosis. Key points Clarify if patient has followed pre spirometry advice (Appendix 1). There are some circumstances when spirometry should be avoided (see Spirometry Checklist Appendix 2) Patient should be seated in chair with arms during the procedure. Demonstrate the procedure to the patient first. Ensure patient forms a tight seal with lips around the mouthpiece. Encourage patients to use maximum effort and continue blows for as long as possible. (May take up to 15 seconds). Patient to perform three relaxed blows first, using a nose clip (VC). Patient to perform a minimum of 3 forced blows (FEV 1 /FVC) and a maximum of 6 (use of nose clip not usually necessary). Before interpreting results ensure the following standards: Three technically acceptable readings have been achieved in both the relaxed and forced blows. The top two RVC, FEV 1, FVC readings are within 5% or 100mls of each other. Volume/time trace is a smooth, upward, convex curve free from any irregularities that suggest variable/ poor effort or coughing. Volume/time trace reaches a plateau. Maintenance and calibration of spirometers For cleaning instructions see manufacturers guidelines and MCN Infection Control advice (Appendix 3). In turbine flow head spirometers (Micro Medical Microlab) it is important to keep the transducer clean, as failure to do so may lead to inaccurate results. For calibration of spirometers refer to manufacturers guidelines (Appendices 4 & 5). If according to the manufacturer the spirometer does not need calibration it is still important the calibration of the spirometer is checked/validated regularly. This can be done by using a 3-litre calibration syringe. It is good practice to keep a log of results (Appendix 6). Page 4 of 20

5 4. SPIROMETRY INTERPRETATION FEV 1 / FVC Ratio FEV 1 FVC Normal Spirometry >70% ratio >80% predicted value >80% predicted value Obstructive Spirometry E.g. COPD, Asthma, Bronchial carcinoma <70% ratio DOWN (from normal) Usually <80% predicted value* DOWN ( from normal) >80% predicted value NORMAL (same as normal) Restrictive Spirometry E.g. Sarcoidosis, Pneumonectomy, Pulmonary fibrosis, Obesity, Kyphoscoliosis, Cardiac failure, Neuromuscular disease >70% ratio NORMAL or HIGH (from normal) <80% predicted value DOWN (from normal) <80% predicted value DOWN (from normal) Combination (Obstructive/Restrictive) Spirometry <70% ratio <80% predicted value <80% predicted value E.g. Severe COPD Cystic fibrosis, Bronchiectasis, Sarcoidosis DOWN (from normal) DOWN (from normal) DOWN (from normal) *FEV₁ % predicted can be normal in mild COPD (i.e. >80% predicted value) if patient has symptoms and FEV₁/FCV ratio <70% (see page 27). Page 5 of 20

6 5. CALCULATING SPIROMETRY VALUES AND RATIOS Use the following method to calculate FEV 1/ FVC ratio: Measured FEV 1 Measured FVC X 100 = FEV 1 /FVC ratio as a % Use the following method to calculate FEV1 % and FVC% predicted values: Measured FEV 1 Predicted FEV 1 X 100 = % predicted FEV 1 Measured FVC Predicted FVC X 100 = % predicted FVC Use the following method to calculate % of FEV1 Improvement following reversibility testing Post test FEV1 Baseline FEV1 Baseline FEV1 X 100 = % of FEV 1 improvement Page 6 of 20

7 6. CLASSIFICAITON OF AIRFLOW OBSTRUCTION SEVERITY SEVERITY FEV₁ Post-bronchodilator Mild airflow obstruction >80% predicted* Moderate airflow obstruction 50 79% predicted Severe airflow obstruction 30 49% predicted Very severe airflow obstruction <30% predicted** *Symptoms should be present to diagnose COPD in people with mild obstruction. **or FEV₁ <50% with respiratory failure. Ref: 1. National Institute for Clinical Excellence (NICE). Chronic Obstructive Pulmonary Disease. Management of COPD in Adults in Primary and Secondary Care. 2. Fife Formulary Respiratory Section (available on line) Page 7 of 20

8 7. REVERSIBILITY TESTING In most patients, routine spirometric reversibility testing is not necessary as part of the diagnostic process or to plan initial therapy with bronchodilators or corticosteroids. COPD and asthma are frequently distinguishable on the basis of history (and examination) in untreated patients presenting for the first time. Features from the history and examination should be used to differentiate COPD from asthma whenever possible. To help resolve cases where diagnostic doubt remains, or when both COPD and asthma are present, reversibility testing should be performed. Ref. National Institute for Clinical Excellence (NICE) Chronic Obstructive Pulmonary Disease. Management of COPD in Adults in Primary and Secondary Care. GMS quality indicators no longer require formal reversibility, but diagnosis must include a post-bronchodilator spirometry confirming airways obstruction. Bronchodilator Reversibility Beta 2 agonist Do baseline spirometry and record actual figures and % of predicted values. Administer short acting beta 2 agonist either: 4 6 puff Salbutamol 100mcgs via MDI and large volume spacer. 2.5mgs Salbutamol via a nebuliser. Repeat spirometry after 15 minutes. Steroid Reversibility Only perform if still diagnostic doubt after bronchodilator reversibility. Do baseline spirometry and record actual figures and % of predicted values. Administer steroids by either: Oral prednisilone 30mgs daily for 2 weeks. Inhaled steroids Beclomethasone 1000mcgs via MDI ± large volume spacer for 6 weeks. Repeat spirometry after 2 weeks for oral steroids trail and 6 weeks for inhaled steroids trail. Interpretation If response of >400ml to bronchodilators asthma may be present. If response of >400ml to inhaled steroids asthma may be present. NB. If you are going to perform reversibility tests you must have a patient group directive (PGD) that allows you to administer medication. Page 8 of 20

9 Reversibility Testing Protocol Reversibility testing should be carried out when clinically stable and free from infection i.e. at least 6 weeks post exacerbation. Bronchodilator Reversibility Objectives To detect those with asthma or substantial reversible component. To establish a post bronchodilator FEV1 (the measurement that best predicts COPD long term prognosis). Patient Preparation Patients should not have taken inhaled short acting brochodilators in the previous six hours, long acting β2 agonists in the previous 12 hours, or sustained release theophylline and long acting anticholinergic in the previous 24 hours. Method 1. Perform spirometry. 2. Administer short acting β2 agonist: mcg of Salbutamol (preferably via MDI and large volume spacer) Alternatively 2.5mg-5mg nebulised Salbutamol or 5mg-10mg nebulised Terbutaline 1 3. Repeat spirometry 15 minutes post β2 agonist. Interpretation FEV1 400ml 2 increase suggests asthma An increase in FEV1 by 15% and 200ml is greater than the natural variability of FEV1 if diagnosis is in doubt, consider completion of a peak flow diary. VC or FVC 300ml increase is greater than the natural variability of FVC. If pulmonary function returns to normal a diagnosis of COPD is ruled out. If no objective response patients may still benefit from brochodilators in terms of improved exercise capacity and perception of breathlessness. Page 9 of 20

10 Anticholinergic Reversibility to an anticholinergic is only necessary if short acting beta agonist cannot be tolerated. 1. Spirometry. VC, FEV1 and FVC 2. Administer anticholinergic: 4 puffs of Ipatroprium Bromide 20mcg (preferably via MDI and large volume spacer) Alternatively 500mcg nebulised Ipatroprium Bromide 3 Repeat spirometry 30 minutes post anticholinergic Dated Practice/Health Centre Authorised Personnel Authorising Signatory Page 10 of 20

11 8. ERS 1993 PREDICTED NORMAL VALUES (MALE) 10. Page 11 of 20

12 9. ERS 1993 PREDICTED NORMAL VALUES (FEMALE) Page 12 of 20

13 Appendix 1: Patient Information Leaflet for Spirometry You have been asked to attend the surgery for lung function tests (spirometry). These tests help your nurse/doctor to diagnose your respiratory condition(s). The tests may take up to 40 mins depending on the type of testing required. Your nurse/doctor will advise you how long an appointment you will need. WHAT TO EXPECT You will be asked to blow at least three times into a tube connected to a machine, which will record your lung function. You will be asked to breathe in to fill up your lungs with air then blow as hard and as long as you can to get the best results. To obtain the best possible results from your test please follow the instructions below prior to your appointment. If you have had any surgical procedure/operation in the last 6 weeks this test should be delayed. If you have had a chest infection in the last 6 weeks this test should be delayed. Ask your nurse/doctor if you have any concerns Before your test Avoid smoking for 24 hours Avoid alcohol for 4 hours Avoid vigorous exercise for 30 minutes Avoid a heavy meal for at least 2 hours Avoid wearing tight or restrictive clothing Empty your bladder before you attend for your tests Please take the following inhaler before your test:...(name and colour of inhaler).(number of puffs) (length of time before appointment) (Clinician to complete as appropriate) If you would find it too difficult to follow these instructions please do not worry. Do what you can and we can take things into account when interpreting the results. Downloadable version available at: ationleaflet-2016.pdf Page 13 of 20

14 Appendix 2: Spirometry Checklist Patient s details/ sticker Date ADVICE AND SAFETY DIAGNOSIS OR REVIEW (delete as required) Patient checks prior to spirometry test Wearing loose fitting clothing? Yes/No Bladder empty? Yes/No No large meal in past 2 hours Yes/No No smoking for 24 hours? Yes/No No vigorous exercise past 30 minutes Yes/No Prior to reversibility testing, withhold inhalers where possible a) Short-acting bronchodilators and anticholinergics for 4-6 hours b) Long-acting brocholdilators for at least 12 hours c) Long-acting anicholinergics for at least 24 hours d) Sustained release oral bronchodilators for 24 hours NB This is not necessary when undertaking post bronchodilator spirometry or for annual review when all normal inhalers should be taken as usual Yes/No/NA Yes/No/NA Yes/No/NA Yes/No/NA Within past 6 weeks has patient had any of the following. If yes, Spirometry not to be undertaken Myocardial Infarction Yes/No Stroke or TIA Yes/No Abdominal/thoracic/brain surgery Yes/No Pulmonary Embolism Yes/No Any eye or ear problems or surgery Yes/No Chest Infection Yes/No Worsening angina/unstable angina Yes/No Coughing up blood in sputum Yes/No Postpone Spirometry if any of the following present today or past week Blood Pressure > 160/100 today Yes/No Any nausea or vomiting Yes/No Any neck or spine problems Yes/No Has patient any of the following? If yes, do not perform Spirometry without expert advice Abdominal or cerebral aneurysms Yes/No Previous pneumothorax Yes/No COMPLETE SPIROMETRY Complete patient details on spirometer including a) Height measure accurately. If not possible (wheelchair, kyphoscoliosis etc) measure arms span from middle finger tip to middle finger tip b) Weight (if required) c) Sex d) Record correct ethnicity e) Record correct date of birth Preparation of patient - Sitting upright in chair with arms (standing if child) Full explanation of SVC/RVC procedure to patient including a) Full deep inspiration until lungs full b) Pinching nose/nose clip c) Sealing mouthpiece with lips d) Steady long breath out until unable to blow out any more e) Do not bend forward at waist whilst blowing Demonstration by practitioner of SVC/RVC blow Procedure completed by patient a) Give lots of encouragement b) Ensure good technique, no coughing etc c) At least 3 good blows completed ensuring the best 2 are within 100ml or 5% Page 14 of 20

15 Full explanation of FVC procedure to patient a) Full deep inspiration until lungs full b) Pinching nose etc not usually required c) Sealing mouthpiece with lips d) Forced fast breath out until unable to blow out any more e) Do not bend forward at waist whilst blowing Demonstration by practitioner of FVC blow Procedure completed by patient a) Encouragement given throughout b) Ensure good technique, no coughing etc c) At least 3 good blows completed (maximum 8) ensuring the best 2 are within 100ml or 5% Reversibility testing a) Perform SVC and FVC as above b) Give appropriate drug e.g. 4 individual puffs 100mcg Salbutamol via large volume spacer c) Ensure wait 15 minutes for bronchodilation effect d) Repeat FVC procedure. Ensure minimum 3 blows e) Best 2 blows to be within 100ml or 5% CHECK TRACING Check list for spirometry tracing a) Check name, age, date of birth, height, weight, sex and ethnicity correct b) SVC Minimum 3 good blows. Best 2 are within 100ml or 5% c) FVC Minimum 3 good blows (max 8). Best 2 are within 100ml or 5% d) If reversibility test done, ensure at least 15 minutes after baseline FVC e) Post bronchodilator FVC minimum 3 good blows. Best 2 are within 100ml or 5% Volume time curve ensure traces smooth, convex, rise steeply upwards, free from irregularities and have reached a plateaux Flow volume trace must reach a peak and then merge with baseline Yes/No Yes/No/NA Yes/No Yes/No/NA Yes/No/NA Yes/No/NA Yes/No/NA Predicted Actual % predicted Change mls Change % RESULTS SVC FVC FEV1 FEV1/FVC Post FVC Post FEV1 Post FEV1/FVC QUALITY CRITERIA This spirometry test complies with the BTS Quality Criteria a) SVC 3 good blows. Best 2 within 100ml or 5% b) FVC 3 good blows. Best 2 within 100ml or 5% c) Post FVC 3 good blows. Best 2 within 100ml or 5% This spirometry test does not comply with BTS Quality Criteria because Signed Signed DIAGNOSIS/COMMENTS COPD Mild (FEV1 >80%) Moderate (FEV %) Severe (FEV %) Very severe (FEV1 <30%) ASTHMA Signed OTHER Downloadable version available at: Page 15 of 20

16 Appendix 3: Infection Control PERFORMING SPIROMETRY GETTING IT RIGHT EVERY TIME INFECTION CONTROL Recorded cases of infection transmission form spirometry equipment between patients, and between patients and staff are rare. Cross contamination through mucosal contact with spirometry equipment and aerolisation of infective particles during forced expiratory manoeuvres are the main potential sources of infection. Cross infection is more likely when inspiratory manoeuvres are undertaken; these are not routinely undertaken in primary care settings and would require the use of disposable anti-bacterial and viral filters. INFECTION PREVENTION AND CONTROL MEASURES WASH HANDS BEFORE AND AFTER HANDLING EQUIPMENT AND BETWEEN PATIENTS. Wear disposable gloves when handling/disposing of mouthpieces. RISK REDUCTION DO NOT test patients with known infection, if possible. Test vulnerable patients (eg. Immunocompromised) at the start of a session on newly cleaned equipment. SINGLE USE EQUIPMENT It is essential that single use, disposable one-way valve mouthpieces are used. MANUAL CLEANING Removable Parts (if necessary) Remove flow transducer as per manufacturer s instructions and immerse in warm soapy solution for routine cleaning. E.g. hospec detergent After cleaning, the transducer should be rinsed briefly avoid putting water flow through the turbine as this can damage the delicate flow mechanism. Allow to air dry overnight. Spirometer Wipe the surface of the flow head of the spirometer between each patient with a neutral detergent wipe (eg cutan wipe) At the end of a clinic, wipe the whole spirometer with a neutral detergent wipe and thoroughly dry if and when necessary. Nose clips should be wiped with the same wipes and dried. This procedure should be carried out at the end of every spirometry session before storing the equipment away. Downloadable version available at COPD%20RP%20S3.pdf Page 16 of 20

17 Appendix 4: Micro Medical 3500 MK5 Spirometer Calibration Check The Micro Medical Spirometers are calibrated to read in litres at body temperature, barometric pressure saturated with water vapour (BTPS) for FEV1 and FVC. Please follow the instructions: 1. Place the spirometer and the 3L syringe on a flat, firm surface. 2. Empty and fill the syringe (by pulling and pushing the plunger) 3 times without connecting to the Spirometer. This helps bring the syringe up to room temperature. 3. Pull the plunger fully out to fill the syringe. 4. Connect the syringe directly to the transducer. Do not use a mouthpiece. 5. Set up the machine to record a FVC manoeuvre. 6. Empty the syringe volume into the transducer in a controlled, even manner. That is uninterrupted flow lasting between 1 and 5 seconds. 7. The syringe should be emptied evenly without pausing and avoiding banging on the end stop. If the syringe was not emptied smoothly and without banging, reject the manoeuvre and repeat. 8. The syringe calibration pass values must lie in the range of 2.97 to 3.15 litres. 9. Performing this manoeuvre three times ensures reproducibility. 10. If after checking, the spirometer appears to require recalibration then the machine should be sent either to the Medical Physics department at Ninewells or to the Supplier. 11. Records should be kept of all calibration checks and quality control. Downloadable version available at: %20MK5%20Spirometer%20Calibration%20Check-COPD%20RP%20S3.pdf Page 17 of 20

18 Appendix 5: Micro Medical 3500 MK6 Spirometer Calibration Check Micro Medical Spirometers are calibrated to read in litres at body temperature. Although the calibration should remain stable indefinitely the manufacturer recommends that the calibration be checked periodically. Please follow the instructions: 1. Place the spirometer and the 3L syringe on a flat, firm surface. 2. Hold down the return key as you turn the spirometer on using the on key. 3. Release the return key once the Customisation screen title is displayed. 4. Press the number 3 Calibrate flow transducer. The Calibration Check screen is displayed. 5. Press the number 1 Check Calibration. The Calibration Check screen is displayed. 6. The syringe volume is displayed as 3. If the supplied syringe is not 3L press Del and enter the volume of the syringe used i.e. 1 or 2. Note the syringe supplied by Dundee and Angus CHPs is 3L. 7. Press the return key. The Empty and fill syringe screen is displayed. 8. Connect the transducer (cylinder shape) to the spirometer. 9. Empty and fill the syringe (by pulling and pushing the plunger) 3 times without connecting to the spirometer. This helps bring the syringe up to room temperature. 10. Pull the plunger fully out to fill the syringe. 11. Connect the syringe directly to the transducer. Do not use a mouthpiece. 12. Empty the syringe swiftly, swiftly, without pausing and avoiding banging on the end stop. If the syringe was not emptied smoothly and without banging, press 2 to reject and repeat steps 10 and When a satisfactory manoeuvre has been performed press 3 to accept. The Calibration Check Report screen is displayed. If the expiratory calibration error is greater than 3% then a warning will be displayed. Check the syringe for leaks. If there are none found repeat steps 1-13 and if the warning is repeated the spirometer will need repair. Note the report will state an inspiratory calibration outwith acceptable parameters. 14. Press the F4 done button. Again the Calibration Check screen will be displayed. 15. To print a report press Press button 4 for exit. 17. Press 5 for exit. 18. Either continue with a patient test or switch off spirometer. 19. Keep the printed calibration report for practice records. Downloadable version available at: 0MK6%20Spirometer%20Calibration%20Check-COPD%20RP%20S3.pdf Page 18 of 20

19 Appendix 6: Calibration Log SPIROMETER CALIBRATION RESULTS (using 3 litre syringe) Date Expiratory FVC Signature Date Expiratory FVC Signature If the expiratory calibration is within 3%, it is within acceptable limit. Downloadable version available at: COPD%20RP%20S3.pdf Page 19 of 20

20 Appendix 7: Spirometry Quality Control Log SPIROMETRY QUALITY CONTROL LOG (BioQC) For logging your biological validation results. Spirometer Make: Model: Serial Number: Name BioQC: BioQC RANGE MIN MEAN MAX VC FEV1 FVC DATE VC FEV1 FVC Within range? Comments Signed If results are ouwith range check with manufacturer for further advice. Downloadable version available at: -COPD%20RP%20S3.pdf Page 20 of 20