Spirometry
Sonia Munde
Senior Respiratory Care Physiologist
Adult Respiratory Care & Rehab Team
Barts Health
COPD Definition
‘….airflow obstruction is usually progressive, not
fully reversible and does not change markedly over
several months. The disease is predominantly
caused by smoking.’
NICE 2010
Asthma Definition
‘….in susceptible individuals, inflammatory
symptoms are usually associated with widespread
but variable airflow obstruction and an increase in
airway response to a variety of stimuli.
Obstruction is often reversible, either
spontaneously or with treatment.’
BTS and SIGN 2003
Spirometry
 Spirometry is a method of assessing lung function
by measuring the volume of air the patient is able
to expel out from the lungs after maximal
inspiration ( FEV1, FVC and FEV1/FVC)
 And also on a slow effort ( SVC and FEV1/SVC)
 Spirometry is a reliable method of identifying
 Obstructive illness i.e. chronic obstructive pulmonary
disease
 Reversible disease I.e. Asthma
 Restrictive disease i.e. Pulmonary fibrosis
 It can be used to grade the severity of COPD
Diagnosing COPD
 At the time of their initial diagnostic evaluation in
addition to spirometry all patients should have:
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CXR- Chest X ray
FBC- Full Blood Count
BMI- Body Mass Index
Additional Investigations
 CT Scan
 ECG
 Echo
 Pulse Oximetry
 Sputum Culture
 Transfer factor for carbon monoxide (TLCO)
 Serial Domiciliary Peak Flows
 Alpha-1-antitrypsin
Spirometry measurements
 FEV1 - The volume of air that the patient is able to breathe
out in the first second of forced expiration
 FVC - The total volume of air that the patient can exhale
forcibly in one breathe
 FEV1 / FVC - The ratio is expressed as a percentage
 Peak Flow - The flow rate
 SVC – The total amount of air the patient can exhale slowly
on one breath
Indices Measured
Before performing Spirometry
 The patient, ideally, should –
- Avoid alcohol for at least 4 hours
- Avoid eating a substantial meal
- Wear loose fitting clothing
 If Reversibility is to be performed -
- Avoid taking short acting bronchodilators for at
least 4 hours prior to testing
- Avoid smoking for 1 hour prior to testing
-Be Well!!
Spirometry Contraindications
 Haemoptysis of unknown origin
 Pneumothorax (Need confirmation of resolution)
 Unstable cardiovascular status
 Myocardial Infarction (Last 3 months)
 Thoracic, abdominal or cerebral aneurysms
Spirometry Contraindications
 Recent Eye surgery (3 months)
 Recent thoracic or abdominal surgery (3 months)
 Pregnancy (1st Trimester contraindicated but in 2nd
and 3rd Trimester results may be effected by uterus
size)
Relaxed Vital Capacity(SVC)
 Take as large a breath of air in
as possible
 Pinch your nose or attach a
nose clip to prevent air
leakage
 Put the filter into your mouth
ensuring that there are no
leaks at the sides of your
mouth
 Breathe out for as long as
possible. This breath should
be in your own time and
should not be forced
Relaxed Vital Capacity (SVC)
 Performed due to collapsing alveoli in some patients
during Forced Vital Capacity technique
 This technique would usually be performed before
the Forced Vital Capacity readings
 The reading is sometimes referred to as VC, EVC or
RVC
 Minimum of three readings taken
 3 best results should be within 150mls of each other
Forced Vital Capacity (FVC)
 Take as large a breath of air
in as possible
 Put the filter into your
mouth ensuring there are no
leaks at the side of your
mouth
 Pinch your nose or attach a
nose clip to prevent air
leakage
 ‘Blast’ as quickly as possible
and for as long as possible
Forced Vital Capacity (FVC)
 A minimum of three readings should be taken
 There should be less than 5% or 150mls variance
between the best results
 The technique should be repeated until this is achieved
or the patient is exhausted and can no longer perform
the technique
 Time should be given to the patient to recover between
readings
Spirometry
Interpretation
Correction Factors
MAKE SURE YOU HAVE ENTERED THE
CORRECT HEIGHT,GENDER,AGE AND
ETHNICITY
BTS Guidelines Only
Ethnic Origin
Caucasian
Afro-Caribbean
Asian
Correction Factor
100%
Reduce by 13% (87%)
Reduce by 10% (90%)
Accurate Interpretation
 Use Best Test (Less than 5% Variance from next
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best)
Best Test – FVC, FEV1 or FVC & FEV1
If spirometer selects best test, CHECK
Minimum number of tests 3
Curve shape – effort, cough, extra breath etc
Relaxed Expiratory Vital Capacity (EVC) recorded
and used when better than FVC
Accurate height
Correction Factors
Normal Spirometry results
 FEV1/FVC ratio greater
than 70%- means NO
airway obstruction
present
 FEV1 > 80% predicted
 FVC > 80% predicted
Case Study 1
 47 years old
 Smoked 30 cigarettes a day since he was 15
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years old
Painter and decorator
Repeated chest infections every year
Finding it difficult to climb ladders and walk
up steep hills
Chronic Productive Cough
Spirometry shows
Obstruction
 FEV1/FVC Ratio <70% less
than or equal to 70%
 = obstruction present
 Than check FEV1
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classification
Mild 80% equal to or greater
Moderate 50-79%
Severe 30-49%
Very Severe 30% or less
 FVC should be normal at >
80% predicted
Examples Obstructive Disorders
 COPD
 Asthma
 Bronchiectasis
 Tumour
 Foreign Body
 Important to match clinical history and symptom
profile before making a formal diagnosis
NICE 2010
Consider alternative diagnoses in:
 Older people without typical symptoms of COPD
where the FEV1/FVC is <0.7
 Younger people with symptoms of COPD where the
FEV1/FVC ration is ≥ 0.7
Severity of Obstruction
NICE Guideline
(2004)
PostBronchodilato
r FEV1/FVC
FEV1 %
Predicted
ATS/ERS
(2004)
GOLD (2008)
NICE Guideline
(2010)
Severity of Airflow Obstruction
Post Bronchodilator
Post Bronchodilator
Post Bronchodilator
Mild
Stage 1-Mild
Stage 1-Mild*
<0.7
≥ 80%
<0.7
50-79%
Mild
Moderate
Stage 2Moderate
Stage 2Moderate
<0.7
30-49%
Moderate
Severe
Stage 3-Severe
Stage 3-Severe
<0.7
< 30%
Severe
Very Severe
Stage 4-Very
Severe**
Stage 4-Very
Severe**
*Symptoms should be present to diagnose COPD with mild airflow obstruction
**or FEV1 <50% with respiratory failure
Case Study 2
 35 years old
 Teacher
 20 pack year history of smoking
 Breathless in the last 6 months
 Breathless on exertion and has to stop if
walking fast
 None productive cough
Spirometry shows Restriction
 FEV1 less than 80%
predicted (60%)
 FVC less than 80%
predicted (49%)
 FEV1/FVC Ratio >70%
(96.6%)
Examples of Restrictive Disorders
 Kyphoscoliosis
 Muscular Dystrophy Problems
 Arthritis
 Pleural Problems
 Interstitial Lung Disease
 Obesity
 Drugs
Spirometry that shows a
Mixed/combined results
 FEV1 usually less than
80% predicted
 FVC less than 80%
predicted
 FEV1/FVC ratio is also
less than 70%
 Unlike restrictive pattern
when ratio is greater than
70% predicted
Examples Combined Disorders
 Severe COPD
 Multiple Pathology e.g.
 Kyphscoliosis and COPD
 Tumour and COPD
Why Annual FEV1?
 Used to detect sudden deterioration in lung function
 Should precipitate action if deterioration marked.
Normal deterioration in FEV1 thought to be
50ml/annum in none smoking individual
Asthma Or COPD ?
COPD Definition
‘….airflow obstruction is usually progressive, not
fully reversible and does not change markedly over
several months. The disease is predominantly
caused by smoking.’
NICE 2010
Asthma Definition
‘….in susceptible individuals, inflammatory
symptoms are usually associated with widespread
but variable airflow obstruction and an increase in
airway response to a variety of stimuli.
Obstruction is often reversible, either
spontaneously or with treatment.’
BTS and SIGN 2003
Post Bronchodilator Spirometry
 QOF 12 states that a diagnosis of COPD should be
confirmed by recording post bronchodilator
spirometry
 Bronchodilator should be taken 20 minutes prior to
spirometry being performed i.e.
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4 puffs Salbutamol 100mcg MDI with an spacer device
or
Salbutamol 2.5mg/ 5.0mg nebulised
Post Bronchodilator Spirometry
Why?
 Post Bronchodilator recommended by GOLD and
used in new trials e.g. UPLIFT
 Removes conflict with many guidelines
 Decrease work load in primary care
 Failure to use post bronchodilator over estimates
COPD by 25%
DOH 2009
Post Bronchodilator Spirometry
Why Not Reversibility?
 Repeated FEV1 measurements can show small
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spontaneous fluctuations
The results of a reversibility test performed on
different occasions can be inconsistent and not
reproducible
Over-reliance on a single reversibility test may be
misleading unless the change in FEV1 is greater than
400 ml
The definition of the magnitude of a significant
change is purely arbitrary
Response to long-term therapy is not predicted by
acute reversibility testing.
NICE 2010
Diagnosing COPD
COPD
Asthma
Nearly all
Possibly
Rare
Often
Common
Uncommon
Breathlessness
Present and
progressive
Variable
Night time waking with
breathlessness and or
wheeze
Uncommon
Common
Significant diurnal or day to
day variability of symptoms
Uncommon
Common
Smoker or ex-smoker
Symptoms under the age 35
Chronic Productive Cough
Smoking History
Cigarettes per Day x Years Smoked = 1 pack Year
20
e.g.
1 Pack Year =
50g/2oz tobacco
Cigars – Café Crème
Hamlet
Corona
20 cigarettes/day for 1 year or;
10 cigarettes/day for 2 years
40 cigarettes a day for 6 months
= 100 cigarettes
= 3 cigarettes
= 5 cigarettes
= 8+ cigarettes
20 pack years is considered a significant factor for developing
COPD
Reversibility
 Useful if diagnosis is not clear
 One off spirometry does not EXCLUDE the diagnosis
of Asthma
Either;
 Measure peak flows for 14 days morning and
evening. Diurnal variation of greater than 20%
indicates asthma
 Record pre and post bronchodilator spirometry
Understanding Reversibility
 An FEV1 that increases by < 400mls is likely to
have COPD
 An FEV1 that increases by > 400mls is likely to
have asthma
 However if;
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FEV1 < 80%
Ratio < 70%
Post > 400mls
Obstruction is not fully reversible
Spirometry results show
 Obstruction
 FEV1/FVC ratio = 39%
 FEV1 % predicted = 56%
 FVC % predicted = 115 %
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 Classification of obstruction Moderate airway obstruction
Spirometry results show
 Obstruction
 FEV1 /FVC ratio = 44%
 FEV1 % predicted = 76%
 FVC % predicted= 146%
 Classification FEV1 predicted 76% = Moderate
airway obstruction, with a large FVC, ?
hyperinflation
Spirometry results show
 Obstruction
 FEV1/FVC ratio = 50%
 FEV1 % predicted = 81%
 FVC % predicted = 128%
 Classification FEV1 = 81% therefore Mild
airway obstruction
Spirometry Results show
 Obstruction
 FEV1/FVC ratio = 65%
 FEV1 % predicted = 68%
 FVC % predicted = 86%
 Classification FEV1 % predicted= 68%
therefore moderate airway obstruction
Spirometry results show
 Obstruction
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FEV1/FVC ratio = 72%
FEV1 % predicted = 101% (2.05L)
SVC % predicted = 122% ( 2.92L)
FVC % predicted = 117% (2.84L)
 Normal spirometry however the SVC larger than FVC
therefore the true FEV1/FVC ratio is 70%
 FEV1 (2.05L) divide by SVC (2.92L) = 70% ratio
 Therefore mild airway obstruction
Spirometry results show
 Pre inhaler spirometry shows
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FEV1/FVC ratio = 57%
FEV1 % predicted = 50%
FVC % predicted = 69%
FEV1= 1.54L or 1540ml
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Post inhaler spirometry results
FEV1/FVC ratio= 81%
FEV1 % predicted= 67%
FVC % predicted = 85%
FEV1 = 2.06L or 2060ml
 Pre to post inhaler greater than a 400ml change in FEV1
 Pre inhaler mixed/combined pattern spirometry
 Post inhaler moderate airway obstruction with significant response
to Salbutamol
Spirometry results show
 Pre inhaler spirometry shows
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FEV1/FVC ratio = 36%
FEV1 % predicted = 38%
FVC % predicted = 88%
FEV1= 0.80L or 800ml
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Post inhaler spirometry results
FEV1/FVC ratio= 49%
FEV1 % predicted= 51%
FVC % predicted = 114%
FEV1 = 1.07L or 1760ml
 Pre to post inhaler less than a 400ml change in FEV1
 Pre inhaler severe airway obstruction
 Post inhaler moderate airway obstruction with NO significant
response to Salbutamol
Questions
References

SPIROMETRY IN PRACTICE
A PRACTICAL GUIDE TO USING SPIROMETRY IN PRIMARY CARE 2ND Edition
BTS 2005
http://www.britthoracic.org.uk/Portals/0/Clinical%20Information/COPD/COPD%20Consortium/spirometry_in
_practice051.pdf

NICE Guidelines for chronic obstructive pulmonary disease (2010)

GENERAL CONSIDERATIONS FOR LUNG FUNCTION TESTING
ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING
European Respiratory Journal 2005
http://erj.ersjournals.com/cgi/reprint/26/1/153.pdf

STANDARDISATION OF SPIROMETRY
ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING
European Respiratory Journal 2005
http://www.thoracic.org/sections/publications/statements/pages/pfet/pft2.html
References

SPIROMETRY IN PRACTICE
A PRACTICAL GUIDE TO USING SPIROMETRY IN PRIMARY CARE 2ND Edition
BTS 2005
http://www.britthoracic.org.uk/Portals/0/Clinical%20Information/COPD/COPD%20Consortium/spirometry_in
_practice051.pdf

GENERAL CONSIDERATIONS FOR LUNG FUNCTION TESTING
ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING
European Respiratory Journal 2005
http://erj.ersjournals.com/cgi/reprint/26/1/153.pdf

STANDARDISATION OF SPIROMETRY
ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING
European Respiratory Journal 2005
http://www.thoracic.org/sections/publications/statements/pages/pfet/pft2.html