copd resource pack section 3 spirometry -...
TRANSCRIPT
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
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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 Reversibility to Bronchodilator
No response Consider an alternative diagnosis (Refer to Asthma
Resource Pack)
Response (Refer to Asthma
Resource Pack)
Perform a Post Bronchodilator Spirometry
Test
Obstruction No Obstruction
Consider an alternative diagnosis
Refer to Section 2 of the COPD Resource pack
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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 (FEV1)
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 FEV1/ FVC ratio and should not be confused with it.
FEV1 % can predict future mortality and relates best to severity of breathlessness.
FEV1 can vary by up to 140ml within the same day and 170ml between days.
FEV1/ FVC Ratio
The ratio of FEV1 to FVC expressed as a percentage.
FEV1/ 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.
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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 (FEV1/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, FEV1, 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).
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4. SPIROMETRY INTERPRETATION
FEV1/ FVC Ratio
FEV1
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
E.g. Severe COPD Cystic fibrosis, Bronchiectasis,
Sarcoidosis
<70% ratio
DOWN
(from normal)
<80% predicted value
DOWN
(from normal)
<80% predicted value
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).
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5. CALCULATING SPIROMETRY VALUES AND RATIOS
Use the following method to calculate FEV 1/ FVC ratio:
Measured FEV 1 X 100 = FEV1/FVC ratio as a % Measured FVC Use the following method to calculate FEV1 % and FVC% predicted values:
Measured FEV 1 X 100 = % predicted FEV1 Predicted FEV 1 Measured FVC X 100 = % predicted FVC Predicted FVC
Use the following method to calculate % of FEV1 Improvement following reversibility testing Post test FEV1 – Baseline FEV1 X 100 = % of FEV1 improvement Baseline FEV1
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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)
www.fifeadtc.scot.nhs.uk.
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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). 2010 – 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
Beta2 agonist
Do baseline spirometry and record actual figures and % of predicted values.
Administer short acting beta2 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.
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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:
400-600mcg of Salbutamol (preferably via MDI and large volume spacer) Alternatively 2.5mg-5mg nebulised Salbutamol or 5mg-10mg nebulised Terbutaline1
3. Repeat spirometry 15 minutes post β2 agonist. Interpretation
FEV1 ≥400ml2 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.
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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 Bromide3 Repeat spirometry 30 minutes post anticholinergic
Dated ……………… Practice/Health Centre …………………………………………………………………
Authorised Personnel Authorising Signatory
1. 1.
2. 2.
3. 3.
4. 4.
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8. ERS 1993 PREDICTED NORMAL VALUES (MALE)
10.
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9. ERS 1993 PREDICTED NORMAL VALUES (FEMALE)
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Appendix 1: Patient Information Leaflet for Spirometry
In order to make an accurate diagnosis and achieve best treatment for your respiratory condition you have been asked to attend for lung function testing. 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.
Avoid taking your reliever medication for at least 2- 4 hours. E.g. Salbutamol (Ventolin), Terbutaline (Bricanyl), Ipratropium (Atrovent), Combivent.
Avoid taking your long acting reliever medication for at least 12 hours. E.g. Salmeterol (Serevent), Formoterol (Oxis).
Avoid taking your Tiotropium (Spiriva), Ventmax SR, Bambec, Neulin SA, Slo-Phyllin, Uniphyllin 'Phyllocontin Continus' for 24 hours.
Avoid taking Seretide or Symbicort or Fostair for at least 12 hours.
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. You can take your brown, red or orange steroid inhaler as normal prior to the test. If you have had recent abdominal or eye surgery or a heart attack, please phone to arrange another appointment. If you develop a chest infection and need antibiotics or steroid tablets before your appointment, please make another appointment for at least 4-6 weeks after the infection. If you would find it too distressing 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: https://intranet.fife.scot.nhs.uk/uploadfiles/publications/Spirometry%20Patient%20Information%20Leaflet-COPD%20RP%20S31.pdf
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Contraindications for performing COPD Screening: If the patient has a history of COPD or Asthma, do not perform COPD screening. Further contraindications are listed below
In the last 6 weeks has the patient had a: Yes No
Heart attack or stroke
Clot in the lung (pulmonary embolism)
Chest infection requiring treatment with antibiotics
Coughing up blood
In the last 3 months, has the patient had any:
Surgery on eye/ear/head/brain/chest/stomach
Has the patient ever had a:
Collapsed lung (Pneumothorax)
Cerebral or abdominal aneurysm
Does patient have Angina?
If yes, any chest pain today requiring GTN use?
Spirometry result:
MRC Dyspnoea Scale
Grade Assessment
1 Not troubled by breathlessness except on strenuous exercise.
2 Short of breath when hurrying on the level or walking up a slight hill.
3 Walks slower than people of the same age on the level because of breathlessness or has to stop for breath when walking at own pace.
4 Stops for breath after walking about 100m or after a few minutes on the level.
5 Too breathless to leave the house or breathless when dressing or undressing.
Downloadable version available at: https://intranet.fife.scot.nhs.uk/uploadfiles/publications/Spirometry%20Checklist-COPD%20RP%20S32.pdf
Name
Address Postcode
CHI
Date of Birth / / 19
Actual % Predicted
FEV1
Lung Age
Spirometry Checklist
Appendix 2: Spirometry Checklist
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
https://intranet.fife.scot.nhs.uk/uploadfiles/publications/Spirometry%20Infection%20Control-
COPD%20RP%20S3.pdf
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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: https://intranet.fife.scot.nhs.uk/uploadfiles/publications/Spirometry%20Micro%20Medical%203500%20MK5%20Spirometer%20Calibration%20Check-COPD%20RP%20S3.pdf
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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 11.
13. 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 2.
16. 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: https://intranet.fife.scot.nhs.uk/uploadfiles/publications/Spirometry%20Micro%20Medical%203500%20MK6%20Spirometer%20Calibration%20Check-COPD%20RP%20S3.pdf
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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: https://intranet.fife.scot.nhs.uk/uploadfiles/publications/Spirometry%20Calibration%20Log-COPD%20RP%20S3.pdf
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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: https://intranet.fife.scot.nhs.uk/uploadfiles/publications/Spirometry%20Quality%20Control%20Log-COPD%20RP%20S3.pdf