Dr Matonhodz Presentation - Walsall Healthcare NHS Trust

Report
Spirometry in Primary Care
Dr Max Matonhodze FRCP (London)
M A Med Ed (Keele)
Objectives
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Need for performing spirometry
Types of spirometers
Spirometric indices
Obstructive spirometry and severity scale
Practical tips
Quality control
Illustrative examples
COPD NICE guidance 2010
The presence of airflow obstruction should be
confirmed by performing post-bronchodilator
spirometry. All health professionals involved in
the care of people with COPD should have
access to spirometry and be competent in the
interpretation of the results.
WHY?
• 3 million people are estimated to have COPD
in UK
• 900 000 are diagnosed
• 2 million are living with undiagnosed COPD
• About 70% of COPD remain undiagnosed
Spirometry
• Spirometry is the gold standard for COPD diagnosis
• Widespread uptake has been limited by:
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Concerns over technical performance of operators
Difficulty with interpretation of results
Lack of approved local training courses
Lack of evidence showing clear benefit when spirometry
is incorporated into management
What is Spirometry?
Spirometry is a method of assessing
lung function by measuring the total
volume of air the patient can expel
from the lungs after a maximal
inhalation.
Why Perform Spirometry?
• Measure airflow obstruction to help make a definitive
diagnosis of COPD
• Confirm presence of airway obstruction
• Assess severity of airflow obstruction in COPD
• Detect airflow obstruction in smokers who may have few
or no symptoms
• Monitor disease progression in COPD
• Assess one aspect of response to therapy
• Assess prognosis (FEV1) in COPD
• Perform pre-operative assessment
Types of Spirometers
• Bellows spirometers:
Measure volume; mainly in lung function units
• Electronic desk top spirometers:
Measure flow and volume with real time display
• Small hand-held spirometers:
Inexpensive and quick to use but no print out
Volume Measuring Spirometer
Flow Measuring Spirometer
Desktop Electronic Spirometers
Small Hand-held Spirometers
Standard Spirometric Indicies
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FEV1 - Forced expiratory volume in one second:
The volume of air expired in the first second of the blow
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FVC - Forced vital capacity:
The total volume of air that can be forcibly exhaled in one
breath
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FEV1/FVC ratio:
The fraction of air exhaled in the first second relative to the total
volume exhaled
Additional Spirometric Indicies
• VC - Vital capacity:
A volume of a full breath exhaled in the patient’s own time
and not forced. Often slightly greater than the FVC,
particularly in COPD
• FEV6 – Forced expired volume in six seconds:
Often approximates the FVC. Easier to perform in older
and COPD patients but role in COPD diagnosis remains
under investigation
• MEFR – Mid-expiratory flow rates:
Derived from the mid portion of the flow volume curve
but is not useful for COPD diagnosis
Lung Volume Terminology
Inspiratory reserve
volume
Total
lung
capacity
Tidal volume
Expiratory reserve
volume
Residual volume
Inspiratory
capacity
Spirogram Patterns
• Normal
• Obstructive
• Restrictive
• Mixed Obstructive and Restrictive
Spirometry
Predicted Normal
Values
Predicted Normal Values
Affected by:
 Age
 Height
 Sex
 Ethnic Origin
Criteria for Normal
Post-bronchodilator Spirometry
• FEV1: % predicted > 80%
• FVC: % predicted > 80%
• FEV1/FVC: > 0.7 - 0.8, depending on age
Normal Trace Showing FEV1 and FVC
FVC
Volume, liters
5
4
FEV1 = 4L
3
FVC = 5L
2
FEV1/FVC = 0.8
1
1
2
3
Time, sec
4
5
6
SPIROMETRY
OBSTRUCTIVE
DISEASE
Spirometry: Obstructive Disease
Normal
5
Volume, liters
4
3
FEV1 = 1.8L
2
FVC = 3.2L
FEV1/FVC = 0.56
1
1
2
3
4
Time, seconds
5
6
Obstructive
Diseases Associated With
Airflow Obstruction
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COPD
Asthma
Bronchiectasis
Cystic Fibrosis
Post-tuberculosis
Lung cancer (greater risk in COPD)
Obliterative Bronchiolitis
Spirometric Diagnosis of COPD
• COPD is confirmed by post–bronchodilator
FEV1/FVC < 0.7 Plus
• FEV1 %pred >80%= Mild
• FEV1 %Pred 50-79% =moderate
• FEV1 % Pred 30-49% =Severe
• FEV1 %pred <30%= very severe
SPIROMETRY
RESTRICTIVE
DISEASE
Criteria: Restrictive Disease
• FEV1: normal or mildly reduced
• FVC: < 80% predicted
• FEV1/FVC: > 0.7
Spirometry: Restrictive Disease
Volume, liters
5
Normal
4
3
Restrictive
FEV1 = 1.9L
2
FVC = 2.0L
1
FEV1/FVC = 0.95
1
2
3
4
Time, seconds
5
6
Diseases Associated with a Restrictive Defect
Pulmonary
Extrapulmonary
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Fibrosing lung diseases
Pneumoconioses
Pulmonary edema
Parenchymal lung tumors
Lobectomy or
pneumonectomy
Thoracic cage deformity
Obesity
Pregnancy
Neuromuscular disorders
Fibrothorax
Mixed Obstructive/Restrictive
• FEV1: < 80% predicted
• FVC: < 80% predicted
• FEV1 /FVC: < 0.7
SPIROMETRY
Flow Volume
Flow Volume Curve
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Standard on most desk-top spirometers
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Adds more information than volume time
curve
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Less understood but not too difficult to
interpret
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Better at demonstrating mild airflow
obstruction
Flow Volume Curve
Maximum
expiratory flow
(PEF)
Expiratory
flow rate
L/sec
TLC
FVC
Inspiratory
flow rate
L/sec
Volume (L)
RV
Flow Volume Curve Patterns
Obstructive and Restrictive
Volume (L)
Reduced peak flow,
scooped out midcurve
Restrictive
Expiratory flow rate
Severe obstructive
Expiratory flow rate
Expiratory flow rate
Obstructive
Volume (L)
Steeple pattern,
reduced peak flow,
rapid fall off
Volume (L)
Normal shape,
normal peak flow,
reduced volume
Spirometry: Abnormal Patterns
Restrictive
Time
Slow rise, reduced
volume expired;
prolonged time to
full expiration
Mixed
Volume
Volume
Volume
Obstructive
Time
Fast rise to plateau
at reduced
maximum volume
Time
Slow rise to reduced
maximum volume;
measure static lung
volumes and full PFT’s
to confirm
PRACTICAL SESSION
Performing Spirometry
Spirometry Training
• Training is essential for operators to learn correct performance
and interpretation of results
• Training for competent performance of spirometry requires a
minimum of 3 hours
• Acquiring good spirometry performance and interpretation skills
requires practice, evaluation, and review
• Spirometry performance (who, when and where) should be
adapted to local needs and resources
• Training for spirometry should be evaluated
Obtaining Predicted Values
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Independent of the type of spirometer
Choose values that best represent the
tested population
Check for appropriateness if built into
the spirometer
Optimally, subjects should rest 10 minutes
before performing spirometry
Performing Spirometry - Preparation
1. Explain the purpose of the test and demonstrate
the procedure
2. Record the patient’s age, height and gender and
enter on the spirometer
3. Note when bronchodilator was last used
4. Have the patient sitting comfortably
5. Loosen any tight clothing
6. Empty the bladder beforehand if needed
Performing Spirometry
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Breath in until the lungs are full
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Hold the breath and seal the lips tightly
around a clean mouthpiece
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Blast the air out as forcibly and fast as
possible. Provide lots of encouragement!
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Continue blowing until the lungs feel
empty
Performing Spirometry
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Watch the patient during the blow to
assure the lips are sealed around the
mouthpiece
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Check to determine if an adequate trace
has been achieved
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Repeat the procedure at least twice
more until ideally 3 readings within
100ml or 5% of each other are
obtained
Volume, liters
Reproducibility - Quality of Results
Time, seconds
Three times FVC within 5% or 0.15 litre (150 ml)
Spirometry - Possible Side Effects
• Feeling light-headed
• Headache
• Getting red in the face
• Fainting: reduced venous return or vasovagal
attack (reflex)
• Transient urinary incontinence
Spirometry should be avoided after recent
heart attack or stroke
Spirometry - Quality Control
• Most common cause of inconsistent readings is
poor patient technique
 Sub-optimal inspiration
 Sub-maximal expiratory effort
 Delay in forced expiration
 Shortened expiratory time
 Air leak around the mouthpiece
• Subjects must be observed and encouraged
throughout the procedure
Spirometry – Common Problems
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Inadequate or incomplete blow
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Lack of blast effort during exhalation
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Slow start to maximal effort
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Lips not sealed around mouthpiece
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Coughing during the blow
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Extra breath during the blow
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Glottic closure or obstruction of mouthpiece
by tongue or teeth
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Poor posture – leaning forwards
Equipment Maintenance
• Most spirometers need regular calibration to check
accuracy
• Calibration is normally performed with a 3 litre
syringe
• Some electronic spirometers do not require
daily/weekly calibration
• Good equipment cleanliness and anti-infection control
are important; check instruction manual
• Spirometers should be regularly serviced; check
manufacturer’s recommendations
Troubleshooting
Examples - Unacceptable Traces
Unacceptable Trace - Poor Effort
Volume, liters
Normal
Variable expiratory effort
Inadequate sustaining of effort
May be accompanied by a slow start
Time, seconds
Unacceptable Trace – Stop Early
Volume, liters
Normal
Time, seconds
Volume, liters
Unacceptable Trace – Slow Start
Time, seconds
Unacceptable Trace - Coughing
Volume, liters
Normal
Time, seconds
Unacceptable Trace – Extra Breath
Volume, liters
Normal
Time, seconds
Spirometry
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Mrs PZ 47 yrs
FEV-1
FVC
FEV-1/FVC Ratio
= 0.8L (35% of pred)
= 2.4L (85% of pred)
= 30%
Spirometry
• Answer:
Spirometry
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Mr PY 83
FEV-1
FVC
FEV-1/FVC ratio
=0.6L (28%pred)
= 1.9 L (81% pred)
=31.5%
Spirometry
• Answer:
Spirometry
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Mr BY 63
FEV-1
= 1.6 L (63% pred
FVC
= 2.1 L (67% pred)
FEV-1/FVC ratio = 76%
Spirometry
• Answer-
Spirometry
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Mrs TZ 56
FEV-1
FVC
FEV-1/FVC ratio
=1.1L (41% pred)
= 2.3 L (63%pred)
=48%
Spirometry
• Answer?
Some Spirometry Resources
• Global Initiative for Chronic Obstructive Lung
Disease (GOLD) - www.goldcopd.org
• Spirometry in Practice - www.brit-thoracic.org.uk
• ATS-ERS Taskforce: Standardization of
Spirometry. ERJ 2005;29:319-338
www.thoracic.org/sections/publications/statements
• National Asthma Council: Spirometry Handbook
www.nationalasthma.org.au

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