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Transcript of Competent performance of Spirometry1 Foundation Course In Spirometry 1-day Training Course Sandra...
Competent performance of Spirometry 1
Foundation Course In Spirometry
1-day Training CourseSandra Davies, Highly advanced Clinical Physiologist
Cardiopulmonary Unit, Prince Charles Hospital.
Competent performance of Spirometry 2
Aimed At:
New - to - practice Nurses.
Any Healthcare practitioner.
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Course Objectives
To understand what spirometry is. To learn how to maintain your spirometer.
Verification.Cleaning.
To perform spirometry accurately. To identify faults and errors.
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What Is Spirometry?
An objective measurement of lung function.
Measures lung size (FVC). Measures airway calibre (FEV1). Indicates airflow obstruction (FEV%).
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Spirometry As A Diagnostic Tool
British Thoracic Society (BTS) guidelines suggest that the use of spirometry should be increased in primary care for:Diagnosis Improvement of medical managementMonitoring of progression
Aims to provide a more efficient service
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What Does It Tell Us?
The difference between :
Normal lungs/airways. Airflow obstruction (e.g. Asthma, COPD). Restrictive disease (pulmonary fibrosis). Response to inhalers/treatment.
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Airflow Obstruction
Any lung condition that causes narrowing of the airways: Inflammation. Mucus. Foreign body.
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Restrictive Disease
Reduced volume in the lungs due to inability of lungs to expand.
Intrapulmonary diseases. Pulmonary fibrosis. Pulmonary oedema. Collapse/consolidation of the
lung. Extra-pulmonary conditions.
Large pleural effusion. Rib cage deformity (scoliosis). Respiratory muscle weakness.
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Combined Obstructive / Restrictive
Airways are narrowed
Small lung volumes
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Definitions - FEV1
FEV1 (litres) - Forced Expiratory Volume in one second.Volume of air blown out in the first second of a
forced blow out.Reduced in both obstructive and restrictive
disease.
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Definitions - FVC
Forced Vital Capacity (litres). Maximum volume blown out as hard as
possible, following a full inspiration. It is reduced in restrictive disease, and in
obstructive disease if air trapping occurs.
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Definitions: FEV%
Forced expiratory ratio(FEV%, FEV1%,FER)- L/min, L/sec. Percentage of FVC blown
out in the first second of a forced expiration.
FEV1/FVC x 100. Normal in restrictive
disease, reduced in obstructive disease.
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Peak Expiratory Flow (PEF).
The maximum flow achievable from a forced expiration starting at a full inspiration with an open glottis.
Achieved within first 100 milliseconds of blow.
Measured in L/min but sometimes expressed as L/sec (SI units).
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Peak Expiratory Flow
Not particularly informative on its own but serial monitoring can be useful.
Must be performed on a device capable of measuring flow (L/min or L/sec).
Measurement can either be integral to an FVC manoeuvre or separately on a Peak Flow Meter.
Differentiation of volume measurements to obtain PEF accentuates noise.
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Definitions: VC
Vital Capacity (litres). Slow Vital Capacity (SVC) or Relaxed Vital Capacity (RVC). Maximal amount of air breathed out steadily
from full inspiration to maximal expiration (not time dependent).
It should be >80% of predicted in ‘normals’, will be reduced in restrictive disease.
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Spirogram – Volume/time
FEV1 = 3.50L
FVC = 5.20L
FEV% = 67% (3.50/5.20) x 100
VC = 5.20L FEV1/VC% = 67%
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Flow Volume Curve/Loop
Measurements are of flow.
Volume is calculated (integration).
Characteristic shapes with disease.
FEV1
FVC
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Performance of Spirometry
Indications, before you test and how to make the measurement.
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Indications
Detect the presence or absence of lung disease
Quantify the extent of known disease Measure effects of occupational exposure Determine effects of therapy Assess risk for surgical procedures Evaluate disability or impairment
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When Not to Test.
Patient coughing up blood of unknown origin. Recent collapsed lung. Recent heart attack or blood clot on the lung. Aneurysms (aortic or abdominal). Recent surgery (chest, abdomen, eye). Acute nausea or vomiting.
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Plus …
Infectious patients e.g.Open T.B.MRSA (nose, throat etc).D & V.
Patients with current exacerbations. Semi conscious or confused patients. Very unwell patients.
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General Pre-test Procedures
On day of test patient asked to avoid: Smoking prior to testing. Alcohol consumption. Eating a substantial meal. Wearing clothing that
restricts full chest expansion.
Short-acting bronchodilators for 4 hours.
Performing vigorous exercise.
Bronchodilators
If possible please:
do not take reliever inhalers (blue, green, red, or purple inhalers) for 4-6hours prior to tests
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Before You Start…
Is the subject fit to do the test?Absolute contraindications.Relative contraindications.
Is the subject ABLE to do the test?Poor understanding comprehension.Poor motivation.Language barriers etc.
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Height and Weight
Essential for calculation of patients predicted ranges.
Requires accurate measuring device. Indoor clothing, without shoes, feet
together. Stand as tall as possible. Eyes looking straight ahead.
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Arm Span
For patients with a deformity of the thoracic cage, such as kyphoscoliosis, the arm span can be used to estimate height.
Two methods: Fingertip to fingertip (arms fully outstretched, back
against wall). Fingertip to mid-sternum. Correction factor should be applied:
Height = arm span/(1.06. or 1.03).
Specify on the report that arm span has been used !
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Recording Patient History
Check all pre test procedures have been adhered to, note any deviations.
Check for contraindications. Record full medication history. Bronchodilators.
device/ time of last use. Other drugs (may also affect the lungs).
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Smoking History
Record full smoking history. Increases airway resistance and therefore may affect
FEV1.
Ex-smoker / current/ never. Number of years smoked. Maximum packs per day.
1 pack is 20 cigarettes. Calculate pack years:
No. packs/day x years smoking.
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Preparation for Testing
Patient should be seated for 5-10minutes prior to testing.
For safety reasons, patient should NOT stand during spirometry.
Patient should sit upright in a chair with arms.
Dentures should be left in, other than if very loose.
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Equipment Preparation
Calibration or verification should be performed prior to every testing session:Calibration syringe (1L or 3L).Physiological check … blow in to the
spirometer! Have all consumables ready:
One-way valve mouthpiece.Tissues etc.
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Procedure
Full explanation of test given to patient. Implied consent.
Relaxed Vital Capacity should be performed first. Nose clips required.
Minimum of 3 manoeuvres performed for each test set.
Minimum of 30 seconds between attempts. May be longer if patient is breathless.
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Procedure: VC
Minimum of 3 patient efforts. Instruct patient to breathe in fully, place teeth
and lips securely around the mouthpiece and blow out at a steady speed until completely empty.
Encourage patient to keep breathing out for as long as possible.
Observe trace and patient throughout the blow.
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Procedure: FEV1 and FVC
Minimum of 3 efforts performed. Maximum 8 efforts.
Instruct patient to breathe in fully, place teeth and lips securely around the mouthpiece and blow out as fast and hard as possible until completely empty.
Encourage patient to keep going for as long as possible.
Observe trace and patient throughout the blow.
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Acceptability Criteria
2 VC’s within 100ml or 5%. 3 FEV1’s within 100ml or 5%. 3 FVC’s within 100ml or 5%. The results reported should be the biggest
values from technically acceptable manoeuvres, irrespective of the manoeuvre in which they occur.
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Patient Errors
Subject issues: Pain. Incontinence Understanding – demonstration needed. Volition – flow loop will be submaximal, essential need
for Practitioner encouragement
Requirements: Reproduce flow volume loop with effort.
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Patient Errors
Sub maximal effort.Usually due to:
Poor understanding. Lack of motivation. Lack of co-ordination. Incomplete inspiration. Inadequate rest between attempts.
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Patient Errors
Leaks.Usually due to:
‘Puffing’ cheeks out. Lips not tightly round the mouthpiece. Loose fitting dentures. Teeth not over the mouthpiece. Tongue obstructing the mouthpiece. Facial palsy.
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Technical Errors
Poor start. Early termination. Cough. Sub-maximal effort. Unable to obtain 3 technically acceptable
efforts.
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Errors
Most errors can be avoided by clear explanation and adequate coaching of the subject.
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Equipment
Rotating vane, pneumotachographs and ultrasonic devices.
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Rotating Vane Spirometer
Also called “turbine” spirometers
Swirl plate directs exhaled air onto the internal rotating vane
The rotations are detected by a digital transducer which sends impulses to CPU
Number of impulses per unit time is proportional to flow
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Rotating Vane Spirometer
ADVANTAGES.Cheap.Simple to use.Compact & portable.Unaffected by changes in atmospheric
conditions.
DISADVANTAGES.No graphical trace.Unable to calibrate, only verify.Cheaper models are not accurate particularly
over low expiratory flows.
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Pneumotachograph
FLOW = PRESSURE.
RESISTANCE.
The resistance is fixed, therefore the pressure difference is directly proportional to flow.
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Pneumotachograph
Two types of resistive element: Fleisch Type.
A ‘bundle’ of capillary tubes.
Silverman or “Lilly” type.
One or more screens.
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Pneumotachograph
ADVANTAGES.Portable.Accurate.Easily sterilised.Easy to use.Relatively cheap.
DISADVANTAGES.Require regular calibration.Measurements are easily affected by
condensation or particles on the element.Needs a printer or PC to obtain trace.
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Ultrasonic Spirometers
Transducers located on either side emit and receive sound in alternating directions.
When gas flow is present, a pulse that travels against the flow is slowed and a pulse travelling with the flow is sped up.
The transit time of the pulses is precisely measured and gas flow is then calculated.
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Ultrasonic Spirometer
ADVANTAGES.Portable.Accurate.Disposable transducer (infection control).Easy to use.Robust.
DISADVANTAGES.Needs a printer or PC to obtain trace.Cannot be calibrated.Consumables can be expensive.
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Cleaning Equipment
Infection control, bacterial filters and cleaning spirometers.
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Infection Control
Procedures to reduce cross-infection and contamination include: Hand washing (!). Use of disposable
mouthpieces/nose clips. Use of gloves when
handling contaminated items.
Disinfection of tubing. One way valves. Use of filters.
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Bacterial Filters
Provide a barrier between the patient and the equipment.
Appropriate filter will depend on efficiency, cost and performance.
Costs range from £0.45 to £2.50 each and are single patient use only.
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Infectious Patients
Patients with active infection or TB should not normally be tested.
Extra precautions should be taken for patients infected with Hepatitis B or HIV.
Patients with acute exacerbation's should ideally be tested when resolved.
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Cleaning
Cleaning of equipment involves the destruction of pathogens by either: Physical means (heat,
irradiation etc). Chemical means.
Decision depends on cost, effectiveness, ease of use and availability.
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Cleaning Procedures
All parts touched by patient should be wiped between patients.
Consumables must be disposed of between patients e.g mouthpieces.
All parts in contact with mucous membranes should be washed in warm soapy water and rinsed.
Tubing and other non disposables should be immersed in sterilising agents.
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Cleaning Spirometers
According to manufacturer’s instructions. Frequency will depend on how frequently
the device is used. Must consider:
How easy the spirometer is to dismantle.How long the cleaning process will take.What damage can be done by cleaning.
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Cleaning: Rotating Vane
Remove turbine transducer from housing.
Immerse in warm soapy water for routine cleaning.
Immerse in cold sterilising solution (Perasafe etc) for 10 minutes – NOT chlorine releasing!
Rinse in distilled water and air dry.
Reassemble.
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Cleaning: Pneumotach
Remove pneumotach. Immerse in cold sterilising
solution (Perasafe etc) for 10 minutes – NOT chlorine releasing!
Rinse well. Shake excess water out of
pneumotach. Air drying can take in
excess of 12hours.
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Cleaning – Ultrasonic devices
Minimal cleaning required!
Wipe down outer casing after each use.
Dispose of spirette/breathing tubing after each patient.
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Reassembly
Only reassemble equipment once it has dried completely.
Ensure all parts are fitted correctly e.g the correct rotating vane in the correct housing.
Calibrate/verify equipment before use.
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Calibration
The act of checking or adjusting (by comparison with a standard) the accuracy of a measuring instrument.
Ideally, a 3 litre syringe should be used.3 litres + 3% or + 90mls.
If adjustment is necessary, this is normally done by the software.
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When to Perform Calibration
After cleaning and reassembling the equipment.
At the start of each spirometry session. Whenever temperature fluctuates by >4oC. After every ten patients in a busy clinic. If there are any doubts about sequential
values in a stable subject.
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Results
All calibration data must be recorded and stored.
Calibration records should include:Date/time.Temperature.Barometric pressure.Syringe used.Operator name.
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Causes of Calibration Failure
Holes in the flow sensor or channels plugging with excess moisture (pneumotachographs).
Technical problems with computer interface. Leaks in the tubing or connector. Inaccurate timing on the recorder. Inappropriate calibration software.
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Verification
Provides information about the actual measurement obtained by the spirometer versus the expected measurement.
Many devices can not be internally adjusted and therefore have to be verified.
Verification checks whether the spirometer reads with in acceptable limits – cannot adjust it if it does not.
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When to Perform Verification
After cleaning and reassembling the equipment.
At the start of each spirometry session. Whenever temperature fluctuates by >4oC. After every ten patients in a busy clinic. If there are any doubts about sequential
values in a stable subject.
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Results
Volume measurements should be within 3% of the expected value.
Equipment will print out whether it is reading within acceptable limits.
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Syringes
Volume Syringe.1 or 3 litre calibration syringes can be used.
Flow Limited Syringe.Useful when calibrating flow measuring
devices.Allow assessment of flow sensing spirometers
using different speeds.
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Results
All verification data must be recorded and stored.
Verification records should include:Date/time.Temperature.Barometric pressure.Syringe used.Operator name.
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Verification Checks
If the calibration exceeds the +/- limit the spirometer should be thoroughly examined to locate the source of any discrepancy.
Any serious problems must be reported to the manufacturer.
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Quality Control
A thorough QC programme should be employed alongside the calibration protocol to ensure accuracy and precision of all equipment.
A QC programme should include:Biological measurements.Physical measurements.
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Biological QC
This should be performed on a weekly basis.
Biological QC involves healthy subjects performing spirometry on a regular basis to ensure that the equipment is reading accurately and precisely.
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Biological QC
Ensure the subject is not suffering with any illness and/or respiratory disorder.
The biological control should perform spirometry over a 2 week period.
From this the subjects mean results can be calculated.
These results should then be used for any subsequent QC measurements.
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Variability of QC
Biological QC is affected by natural variability. It can be said that the measurements of a
healthy subject will vary by 10% from day to day. Natural variability can be reduced to 5% by
following some simple procedures: Calibrate the equipment accurately before use. Test the subject at the same time of day. Use the same operator to test the subject.
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Possible Causes
ObstructionCOPDAsthmaEmphysemaBronchiectasisCystic FibrosisTumour
Etc!
RestrictionSarcoidFibrosisKyphosisHeart failureTumourObesity
Etc!
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Basic Understanding of Results
FEV ratio reduced <70% indicates airflow obstruction.
A reduced FEV1% predicted indicates how severe airway obstruction is.
A reduced FVC% predicted indicates restriction.
FEV1 /FVC Ratio
A normal subject should be able to blow out 70% of their lung volume in 1 second
NICE Guidelines for COPD work on < 70%
Obstructive Lung Function
FEV1reduced <80% predicted FVC normal/ or slightly reduced RVC normal Ratio < 70% PEF can be reduced or normal MEF reduced
Classification of COPD using FEV1 % Predicted FEV1 % Predicted
50- 80 %
30 – 49 %
< 30%
Classification
Mild
Moderate
SevereRef: NICE COPD Guidelines 2004
Restrictive Lung Function
FEV1Reduced FVC Reduced RVC Reduced Ratio >70% PEF Normal/ reduced MEF Normal/reduced
Combined Lung Disease
Both airways and lung size are affected Hence, both flow and volume are reduced
Case Studies
Patient 1
Rtd. painter and decorator, age 65y. Smoker since young adult. Recent cough and breathlessness, otherwise fit and well, No regular meds. Fhx asthma O/E lungs clear except for few fine crackles, no
wheezing P.F. 350l/min no diurnal variation on daily P.F. monitoring
Case studies 1
Spirometry Fev1= 1.67 ( 57% predicted) Reduced.
Fvc = 2.07 (55% predicted ) Reduced Fev1/Fvc ratio 81% normal
Case studies 1
Conclusion Fev1 and Fvc both well below
80%predicted , however the Fev1/Fvc ratio is above 70% suggesting ‘’Restrictive’’ rather than obstructive airway condition.
Diagnosis Pulmonary Fibrosis
Case studies 2
Patient 2
Cook, age 55y Smoker 30/day since mid 20’s Smokers cough , increasing SOBOE.
Case studies 2
O/E Spirometry Fev1= 1.39 ( 56% predicted ) Reduced Fvc = 2.53 ( 86% predicted ) Normal Fev1/Fvc ratio = 55% Reduced Post bronchodilator Fev1= 1.51 (+120ml and 9%) Post steroid trial Fev1=1.38
Case studies 2
Conclusion Spirometry shows moderate airway
obstruction not significantly reversed by bronchodilators or steroids.
Diagnosis
Moderate COPD
Case studies 3
Patient 3
Retired bricklayer 69y. Smoked 40/day since national service. Rtd
from work on health grounds 15y ago Productive cough, frequent bouts of
bronchitis, SOBOE O/E cyanosed
Case studies 3
Spirometry Fev1= 0.89 ( 28% predicted) Reduced Fvc = 2.74 (67% predicted ) Reduced Fev1/Fvc ratio = 32% Severe
obstruction Post bronchodilator Fev1 = 1.04 ( +150ml and 17% ) Post steroid Fev1=0.91 ( +20ml and 2% )
Case studies 4
Patient 4
Sales manager 42y old Smoker 10/day since early 20’s. Always
been ‘’ chesty’’ since childhood Bouts of cough and wheeze following
Urti’s from which he is always slow to recover
Case studies 4
O/E spirometry Fev1 = 3.24 ( 76% predicted ) slightly
reduced Fvc = 4.82 (91% predicted ) normal Fev1/Fvc ratio = 67% slightly
reduced Post bronchodilator Fev1= 4.17 ( +930ml and 29%)
Case studies 4
Conclusion Mild obstructive defect highly responsive
(significant reversibility criteria is FEV1 >400ml and 15% ) to bronchodilator.
Diagnosis Asthma
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Certificate Requirements
Attend an ARTP approved one day foundation course or two day Introduction to Spirometry course.
Complete a work based portfolio (takes approximately 6 months).
Undertake the practical assessment.
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Portfolio
Contents Page. CV. Background information. Procedure for performing tests. How your spirometer works.
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Evidence from Working Practice
Verification. 20 days verification results/ printouts showing within
range. Action to be taken if out of range.
Quality Control. Physiological. Test healthy subject for 10 days. Calculate normal physiological range.
Mean over 10 days -/+ 5%. Graph or tabulate results.
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QC
0
0.5
1
1.5
2
2.5
3
3.5
1 2 3 4 5 6 7 8 9 10
FEV1
FVC
Graphical QC Data
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Evidence from Working Practice
Cleaning.Procedure.Policy for infectious patients.Schedule.
audit trail.
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Patient Tests
10 patient tests required. All efforts must be shown if kit does not do
this, note every effort down.Show all efforts- even those not acceptable.Have to check testing to known acceptability
criteria. Looking for accurate results within
acceptability and reproducibility criteria.
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Problems Encountered
Easiest section !!! Problems with patient tests.
i.e slow blow. For each problem include the trace and state
how to overcame problem. 5 problems.
May be referenced from patient tests section if problem occurred.