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.

[email protected]


Aimed At:

New - to - practice Nurses.

Any Healthcare practitioner.


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.


What Is Spirometry?

Uses.


What Is Spirometry?

An objective measurement of lung function.

Measures lung size (FVC). Measures airway calibre (FEV1). Indicates airflow obstruction (FEV%).


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


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.


Airflow Obstruction

Any lung condition that causes narrowing of the airways: Inflammation. Mucus. Foreign body.


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.


Combined Obstructive / Restrictive

Airways are narrowed

Small lung volumes


Spirometry Definitions?

Uses, terms and definitions.


Common Terms

FEV1

FVC FEV1/FVC or FEV% or Ratio PEF VC


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.


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.


Basic SpirogramFVC

FEV1

1 second


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.


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).


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.


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.


Spirogram – Volume/time

FEV1 = 3.50L

FVC = 5.20L

FEV% = 67% (3.50/5.20) x 100

VC = 5.20L FEV1/VC% = 67%


Flow Volume Curve/Loop

Measurements are of flow.

Volume is calculated (integration).

Characteristic shapes with disease.

FEV1

FVC


Performance of Spirometry

Indications, before you test and how to make the measurement.


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


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.


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.


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


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.


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.


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 !


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).


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.


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.


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.


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.


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.


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.


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.


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.


Patient Errors

Sub maximal effort.Usually due to:

Poor understanding. Lack of motivation. Lack of co-ordination. Incomplete inspiration. Inadequate rest between attempts.


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.


Technical Errors

Poor start. Early termination. Cough. Sub-maximal effort. Unable to obtain 3 technically acceptable

efforts.


Poor Start


Early Termination


Cough


Sub-Maximal Effort

Good vs poor effort


Cough or Glottis closure


Insufficient inhalation



Errors

Most errors can be avoided by clear explanation and adequate coaching of the subject.


1

2

3

Volume

Time

Effort Induced Bronchospasm


Equipment

Rotating vane, pneumotachographs and ultrasonic devices.


Spirometers


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


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.


Pneumotachograph

FLOW = PRESSURE.

RESISTANCE.

The resistance is fixed, therefore the pressure difference is directly proportional to flow.


Pneumotachograph

Two types of resistive element: Fleisch Type.

A ‘bundle’ of capillary tubes.

Silverman or “Lilly” type.

One or more screens.


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.


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.


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.


Cleaning Equipment

Infection control, bacterial filters and cleaning spirometers.


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.


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.


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.


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.


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.


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.


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.


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.


Cleaning – Ultrasonic devices

Minimal cleaning required!

Wipe down outer casing after each use.

Dispose of spirette/breathing tubing after each patient.


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.


Checking your Equipment

Calibration


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.


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.


Results

All calibration data must be recorded and stored.

Calibration records should include:Date/time.Temperature.Barometric pressure.Syringe used.Operator name.


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.



Verification


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.


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.


Results

Volume measurements should be within 3% of the expected value.

Equipment will print out whether it is reading within acceptable limits.


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.


Results

All verification data must be recorded and stored.

Verification records should include:Date/time.Temperature.Barometric pressure.Syringe used.Operator name.


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.



Quality Control


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.


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.


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.


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.


Understanding the Results

Basic strategies


Possible Causes

ObstructionCOPDAsthmaEmphysemaBronchiectasisCystic FibrosisTumour

Etc!

RestrictionSarcoidFibrosisKyphosisHeart failureTumourObesity

Etc!


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

Mixed Lung Function

FEV1 Reduced FVC Reduced RVC Reduced Ratio < 70% PEF Reduced/Normal MEF 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 3

Conclusion Severe COPD with no significant

reversibility,

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


Portfolio

ARTP/BTS Foundation Certificate in Spirometry


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.


Portfolio

Contents Page. CV. Background information. Procedure for performing tests. How your spirometer works.


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.


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


Evidence from Working Practice

Cleaning.Procedure.Policy for infectious patients.Schedule.

audit trail.


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.


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.


Questions

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