Interpreting Spirometry:
Patient or Data?
David Robiony-Rogers CRFS
Service Leader Respiratory Medicine
Capital & Coast District Health Board
The colours of disease
The colours of respiratory disease
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Medication type colour coding...
Spirometry
Spirometry is the timed measurement of dynamic lung volumes during forced
expiration and inspiration, and is used to quantify how effectively and how quickly the
lungs can be emptied.
Spirometry: Graphic Displays
Volume time curve
Flow volume loop
Spirometry Test
Spirometry Interpretation
Acceptability
* minimum of 3 acceptable manoeuvres
* good start and satisfactory effort
* no artefacts induced by coughing or glottic closure in 1st
second, or equipment problems
* minimum of 6 seconds exhalation and/or plateau in the
volume time curve
* Maximal inspiration prior to blow
Artefacts
a)
b)
c)
d)
e)
No artefact
Cough within 1st second of forced exhalation
Incomplete exhalation/early termination (glottic closure)
Slow start/submaximal forced effort at start of blow
Hesitant start
Spirograms
Normal and problematic
Flow Volume Loops
Normal and problematic
Reproducibility
Reproducibility
* two largest FVC within 0.150 L (150ml)
of each other
* two largest FEV1 within 0.150 L (150ml)
of each other
* must meet criteria for acceptability
If the reproducibility criteria is not met
after a total of 8 tests, stop testing.
Disease Patterns
 Obstructive pattern
A disproportionate reduction of maximal airflow from the lung in
relation to the maximal volume
 Restrictive pattern
Characterised by a normal FEV1/VC ratio and reduction in FVC below
the 5th percentile of the predicted
 Mixed pattern
Characterised by the coexistence of obstruction and restriction, and is
defined physiologically when both FEV1/FVC and FVC are below 5th
percentiles of the predicted value
Spirometric overlap between Asthma
and COPD
* COPD has been described as a disease characterized by fixed airflow obstruction
because in many patients FEV1 values improve little after bronchodilator challenge.
* Current guidelines on diagnosis and management describe COPD as a condition that
is partially reversible because some patients exhibit substantial improvements in
FEV1 (despite an FEV1-FVC ratio that remains below 0.70) that compares in
magnitude to what is observed in some asthma patients.
* Tashkin et al (2008) have shown that about 54% of a large COPD cohort (N = 5756)
exhibited an improvement in FEV1 values > 12% and 200 mL, while about 65% of
patients had FEV1 increases > 15%.
* This substantial overlap in FEV1 reversibility between asthma and COPD underscores
an important limitation of using this measurement to distinguish between asthma
and COPD.
Can Fam Physician. Oct 2011; 57(10): 1148–1152.
The overlap of Asthma and COPD
Disease Patterns
The presence and site of disease have various effects on the volumetime and maximal expiratory flow volume curve
Vitalograph Ltd 1986 &2000
Normal Ventilatory Function
The pattern of the lung and spirogram show a pattern of normality
Vitalograph Ltd 1986 &2000
Age: 22, Gender: Female; Height: 166 cm, Weight: 69.3 kg; BMI: 25.15
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
3.63
3.95
3.2 – 4.7
FEV1, L
3.02
3.43
2.8 – 4.0
FEV1/FVC, %
83
76.3 – 95.9
Age: 23; Gender: Male; Height: 175 cm; Weight: 67.6 kg; BMI: 22.07
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
5.49
5.39
4.5 – 6.3
FEV1, L
4.29
4.48
3.7 – 5.2
FEV1/FVC, %
78
73.6 – 93.0
Reversible Obstruction
The lungs and spirogram show a pattern of airway obstruction (black),
with the spirogram showing a marked improvement after the
administration of a bronchodilator (red)
Vitalograph Ltd 1986 &2000
Age: 75; Gender: Male; Height: 175 cm; Weight: 97.2 kg; BMI: 31.74
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
3.28
4.09
3.2 – 5.0
FEV1, L
2.07
2.97
2.2 – 3.7
FEV1/FVC, %
63
63.1 – 82.5
Age: 29; Gender: Female; Height: 162 cm; Weight: 98.6 kg; BMI: 37.57
Pre bronchodilator best
Post bronchodilator
best
% improvement
Reference
Ref ± CI
FVC, L
2.22
3.51
58
3.75
3.1 – 4.4
FEV1, L
1.49
2.68
80
3.18
2.6 – 3.8
67
76
Spirometry measure
FEV1/FVC, %
74.9 – 94.4
Irreversible Obstruction
The lungs and spirogram show a pattern of airflow obstruction, with
the spirogram showing little or no improvement after the
administration of a bronchodilator
Vitalograph Ltd 1986 &2000
Age: 74; Gender: Female; Height: 161 cm; Weight: 70.9 kg; BMI: 27.35
Pre bronchodilator best
Post bronchodilator
best
% improvement
Reference
Ref ± CI
FVC, L
1.46
1.72
18
2.78
2.1 – 3.5
FEV1, L
0.57
0.53
-7
2.08
1.5 – 2.7
39
31
1.42
1.51
Spirometry measure
FEV1/FVC, %
FEV6, L
65.3 – 84.9
6
2.64
2.0 – 3.3
Restrictive Defect
The lung and spirogram show a pattern of volume restriction
Vitalograph Ltd 1986 &2000
Age: 74; Gender: Male; Height: 160 cm; Weight: 82.3 kg; BMI: 32.15
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
2.01
3.15
2.4 – 3.9
FEV1, L
1.53
2.26
1.6 – 2.9
FEV1/FVC, %
76
63.1 – 82.5
Combined Pattern
The lungs and spirogram show a pattern of combined airflow
obstruction and volume restriction
Vitalograph Ltd 1986 &2000
Age: 69; Gender: Male; Height: 171 cm; Weight: 50.9 kg; BMI: 17.41
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
2.83
4.02
3.2 – 4.9
FEV1, L
0.94
2.96
2.2 – 3.7
FEV1/FVC, %
33
64.1 – 83.5
Age: 35; Gender: Male; Height: 168 cm; Weight: 90.6 kg; BMI: 32.10
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
2.52
4.76
3.9 – 5.6
FEV1, L
1.69
3.87
3.2 – 4.6
FEV1/FVC, %
67
71.2 – 90.5
Response to ß2-agonist
ß2-agonist bronchodilator
* Dose: 4 puffs of ß2-agonist delivered through a spacer
device
* Wait 15-20 minutes before repeating spirometry
* Significant response defined as >12% and more than 200mL
increase in either the FEV1 or FVC.
Spirometry: Pre & Post ß2-agonist
Severity classification
Severity of any spirometric abnormality based on the forced expiratory
volume in one second (FEV1)
Degree of severity
Mild
FEV1 % predicted
>70
Moderate
60-69
Moderately severe
50-59
Severe
35-49
Very severe
<35
ATS/ERS Task Force: Standardisation of lung function testing. Interpretative strategies for lung function tests. Eur Respir J 2005; 26: 948
Interpretation algorithm
No
Yes
Yes
No
National Asthma Council Australia: www.nationalasthma.org.au
Spirometry interpretation algorithm:
Primary Care Respiratory Alliance of Canada
Pre ß2-agonist FEV1/FVC ratio
Reduced < LLN
Normal > LLN
ß2-agonist
ß2-agonist
Reduced < LLN
Normal (not COPD)
FVC ≥ 80% predicted
FEV1 and FVC
 FEV1, 12% and 200mL
 FEV1, 12% and 200mL
 FEV1, 12% and 200mL
Restrictive disorder
Asthma vs COPD (history)
Consistent with asthma
Consistent with asthma
Refer to specialist
Modified from Primary Health Care Alliance of Canada spirometry interpretation algorithm 2011
Visual Interpretation
Age: 58; Gender: Female; Height: 156 cm; Weight: 61.1 kg; BMI: 25.11
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
1.47
2.08
1.4 – 2.7
FEV1, L
0.99
1.52
1.0 – 2.1
FEV1/FVC, %
67
63.0 – 82.5
Age: 68; Gender: Female; Height: 170 cm; Weight: 70.0 kg; BMI: 24.22
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
2.90
3.43
2.7 – 4.2
FEV1, L
2.04
2.61
2.0 – 3.3
FEV1/FVC, %
70
66.6 – 86.2
Age: 35; Gender: Male; Height: 168 cm; Weight: 90.6 kg; BMI: 32.10
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
2.52
4.76
3.9 – 5.6
FEV1, L
1.69
3.87
3.2 – 4.6
FEV1/FVC, %
67
71.2 – 90.5
Age: 50; Gender: Female; Height: 164 cm; Weight: 109.2 kg; BMI: 40.60
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
3.16
3.61
2.9 – 4.3
FEV1, L
2.35
2.86
2.3 – 3.5
FEV1/FVC, %
74
70.4 – 90.0
Age: 64; Gender: Male; Height: 162 cm; Weight: 60.5 kg; BMI: 23.05
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
3.34
3.64
2.9 – 4.4
FEV1, L
2.58
2.72
2.1 – 3.4
FEV1/FVC, %
77
65.2 – 84.5
Age: 70; Gender: Female; Height: 153 cm; Weight: 127.9 kg; BMI: 54.64
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
1.91
2.55
1.9 – 3.2
FEV1, L
1.59
1.92
1.4 – 2.4
FEV1/FVC, %
83
66.1 – 85.7
Age: 70; Gender: Female; Height: 144 cm; Weight: 81.8 kg; BMI: 39.45
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
2.05
2.15
1.6 – 2.7
FEV1, L
1.75
1.61
1.2 – 2.1
FEV1/FVC, %
85
66.1 – 85.7
Age: 52; Gender: Female; Height: 161 cm; Weight: 50.8 kg; BMI: 19.60
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
3.84
3.42
2.7 – 4.1
FEV1, L
2.72
2.70
2.1 – 3.3
FEV1/FVC, %
71
70.0 – 89.6
Age: 39; Gender: Female; Height: 157 cm; Weight: 100.1 kg; BMI: 40.61
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
3.09
3.44
2.8 – 4.1
FEV1, L
1.75
2.83
2.3 – 3.4
FEV1/FVC, %
56
72.7 – 92.3
Age: 67; Gender: Female; Height: 157 cm; Weight: 67.7 kg; BMI: 27.47
Spirometry measure
Best
Reference
Ref ± CI
FVC, L
2.67
2.83
2.2 – 3.5
FEV1, L
1.80
2.15
1.6 – 2.7
FEV1/FVC, %
67
66.8 – 86.4
Spirometry Education
Pulmonary Function Tests (PFT): Lesson 2 - Spirometry
Published on Feb 3, 2014
A discussion of FEV1, FVC, FEV1/FVC ratio, and the flow volume loop,
including how these are used in the diagnosis of various lung diseases,
with a particular focus on the distinction between obstructive and
restrictive lung disease. A summary of flow volume loop patterns in
upper airway obstruction is covered as well.
https://www.youtube.com/watch?v=yNDKD_xI684