Interpreting Spirometry: Patient or Data? David Robiony-Rogers CRFS Service Leader Respiratory...

Interpreting Spirometry:Patient or Data?

David Robiony-Rogers CRFS

Service Leader Respiratory MedicineCapital & Coast District Health Board

The colours of disease

The colours of respiratory disease

For the movie conscious...

For the spacer conscious...

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) No artefactb) Cough within 1st second of forced exhalationc) Incomplete exhalation/early termination (glottic

closure)d) Slow start/submaximal forced effort at start of blowe) Hesitant start

SpirogramsNormal and problematic

Flow Volume LoopsNormal 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 patternA disproportionate reduction of maximal airflow from the lung in relation to the maximal volume

Restrictive patternCharacterised by a normal FEV1/VC ratio and reduction in FVC below the 5th percentile of the predicted

Mixed patternCharacterised 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 volume-time and maximal expiratory flow volume

curveVitalograph 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


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


Spirometry measure


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

Spirometry measure

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

FEV1/FVC, % 67 76 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 bronchodilatorVitalograph Ltd 1986 &2000


Spirometry measure

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

FEV1/FVC, % 39 31 65.3 – 84.9

FEV6, L 1.42 1.51 6 2.64 2.0 – 3.3

Restrictive Defect

The lung and spirogram show a pattern of volume restriction



Spirometry measure


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


Spirometry measure


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



Spirometry measure


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

Degree of severity FEV1 % predicted

Mild >70

Moderate 60-69

Moderately severe 50-59

Severe 35-49

Very severe <35

Severity of any spirometric abnormality based on the forced expiratory volume in one second (FEV1)

ATS/ERS Task Force: Standardisation of lung function testing. Interpretative strategies for lung function tests. Eur Respir J 2005; 26: 948

Interpretation algorithm

National Asthma Council Australia: www.nationalasthma.org.au

Yes

Yes No

No

Spirometry interpretation algorithm: Primary Care Respiratory Alliance of Canada

Asthma vs COPD (history)

Consistent with asthma

Consistent with asthma

Refer to specialist

FEV1, 12% and 200mL

FEV1, 12% and 200mL

FEV1, 12% and 200mL

Restrictive disorder

Reduced < LLN Normal (not COPD) FVC ≥ 80% predicted FEV1 and FVC

ß2-agonist ß2-agonist

Reduced < LLN Normal > LLN

Pre ß2-agonist FEV1/FVC ratio

Modified from Primary Health Care Alliance of Canada spirometry interpretation

algorithm 2011

Visual Interpretation


Spirometry measure


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


Spirometry measure


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


Spirometry measure


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


Spirometry measure


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


Spirometry measure


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


Spirometry measure


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


Spirometry measure


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


Spirometry measure


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


Spirometry measure


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


Spirometry measure


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

https://www.youtube.com/watch?v=yNDKD_xI684

Spirometry Education

Pulmonary Function Tests (PFT): Lesson 2 - SpirometryPublished on Feb 3, 2014A 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.



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