Asthma Management Handbook

Performing spirometry in asthma review in adults

Recommendations

Perform or arrange spirometry at baseline and after symptoms stabilise (3–6 months) to establish the person’s personal best as the basis for future comparison.

Note: If reliable equipment and appropriately trained staff are available, spirometry can be performed in primary care. If not, refer to an appropriate provider such as an accredited respiratory function laboratory.

How this recommendation was developed

Consensus

Based on clinical experience and expert opinion (informed by evidence, where available).

Perform spirometry before and after bronchodilator. Ask patients to use their own reliever inhaler and take the opportunity to check inhaler technique.

​Note: Spirometry is reimbursed by MBS only if pre- and post-bronchodilator readings are taken and a permanently recorded tracing is retained.

How this recommendation was developed

Consensus

Based on clinical experience and expert opinion (informed by evidence, where available).

Do not advise patients to skip their preventer before a spirometry visit, but document whether the person has taken a combination preventer that contains a long-acting beta2 agonist on the day of spirometry.

Note: Patients referred to a respiratory function laboratory may be asked to skip certain medicines before a spirometry visit.

How this recommendation was developed

Consensus

Based on clinical experience and expert opinion (informed by evidence, where available).

Measure lung function using spirometry when:

  • making or confirming the diagnosis
  • assessing future risk
  • person has been experiencing worsening asthma control or a flare-up
  • monitoring response after dose adjustment
  • periodically reviewing asthma (every 1–2 years for most patients).
How this recommendation was developed

Consensus

Based on clinical experience and expert opinion (informed by evidence, where available).

Record spirometry at every asthma visit for:

  • patients with severe asthma
  • patients who are known to have poor perception of airflow limitation (e.g. those who do not feel any different with a 15% decrease or increase in FEV1). 
How this recommendation was developed

Consensus

Based on clinical experience and expert opinion (informed by evidence, where available).

When spirometry findings are markedly discordant with symptoms (e.g. normal spirometry in a patient with frequent symptoms, or FEV1 <70% predicted in a patient with no symptoms), consider the possibility of an alternative diagnosis and consider referral for specialist assessment.

How this recommendation was developed

Consensus

Based on clinical experience and expert opinion (informed by evidence, where available).

More information

Assessing asthma control in adults: spirometry

Spirometry is necessary when making the diagnosis of asthma and when establishing the patient’s baseline and personal best status.

In ongoing asthma management, spirometry is useful in the following clinical situations:

  • During a flare-up, spirometry provides objective evidence about the severity of bronchoconstriction.
  • After a dose adjustment (either an increase or a decrease), change in lung function measured by spirometry provides additional information about the response to treatment.
  • Spirometry can help identify if the person’s symptoms may be due to non-asthma conditions (e.g. for a patient with frequent respiratory symptoms, FEV1 above 80–90% predicted should prompt consideration of an alternative cause).
  • Spirometry can help identify if the person is a poor perceiver of airflow limitation (e.g. person is unable to feel the difference when FEV1 increases or decreases by 15%).
  • Repeating spirometry over time may identify lung function decline that is more rapid than expected decline due to ageing alone, so the person can be referred for specialist review. (Spirometry should be repeated approximately every 1–2 years in most patients but more frequently as indicated by individual needs.)

There are limits to the amount of information that can be gained from spirometry alone:

  • For an individual, spirometry readings are not closely reproducible between visits, so only a change in FEV1 of greater than 0.2 L and 12% from baseline can be considered clinically meaningful in adults.1
  • Older people with long-standing asthma may develop fixed (irreversible or incompletely reversible) airflow limitation. Reliance solely on lung function expressed as percentage predicted value as a guide to adjusting preventer treatment would risk dose-escalation and over-treatment in these patients.
  • At the population level, spirometry correlates poorly with symptom-based measures of asthma control,2 so in individual patients it is not possible to predict lung function from symptoms or vice versa.

To obtain reliable, good-quality readings, the spirometer must be well maintained and correctly calibrated, and the operator must be adequately trained and experienced.

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Spirometry in diagnosis and monitoring

Spirometry is the best lung function test for diagnosing asthma and for measuring lung function when assessing asthma control. Spirometry can:

  • detect airflow limitation
  • measure the degree of airflow limitation compared with predicted normal airflow (or with personal best)
  • demonstrate whether airflow limitation is reversible.

It should be performed by well-trained operators with well-maintained and calibrated equipment.3, 4

Before performing spirometry, check if the person has any contraindications (e.g. myocardial infarction, angina, aneurysm, recent surgery, suspected pulmonary embolism, suspected pneumothorax, fractured ribs). Advise them to stop if they become dizzy.

Clearly explain and physically demonstrate correct spirometry technique: 5

  • Sit upright with legs uncrossed and feet flat on the floor and do not lean forward.
  • Breathe in rapidly until lungs feel absolutely full. (Coaching is essential to do this properly.)
  • Do not pause for more than 1 second.
  • Place mouthpiece in mouth and close lips to form a tight seal.
  • Blast air out as hard and fast as possible and for as long as possible, until the lungs are completely empty or you are unable to blow out any longer.
  • Remove mouthpiece.

Repeat the test until you obtain three acceptable tests and these meet repeatability criteria.

Acceptability of test

A test is acceptable if all the following apply:

  • forced expiration started immediately after full inspiration
  • expiration started rapidly
  • maximal expiratory effort was maintained throughout the test, with no stops
  • the patient did not cough during the test
  • the patient did not stop early (before 6 seconds for adults and children over 10 years, or before 3 seconds for children under 10 years).

Record the highest FEV1 and FVC result from the three acceptable tests, even if they come from separate blows.5

Repeatability criteria

Repeatability criteria for a set of acceptable tests are met if both of the following apply:3

  • the difference between the highest and second-highest values for FEV1 is less than 150 mL
  • the difference between the highest and second-highest values for FVC is less than 150 mL.

For most people, it is not practical to make more than eight attempts to meet acceptability and repeatability criteria.5

Testing bronchodilator response (reversibility of airflow limitation)

Repeat spirometry 10-15 minutes after giving 4 separate puffs of salbutamol (100 mcg/actuation) via a pressurised metered-dose inhaler and spacer.5 (For patients who have reported unacceptable side-effects with 400 mcg, 2 puffs can be used.)

For adults and adolescents, record a clinically important bronchodilator response if FEV1 increases by ≥ 200 mL and ≥ 12%.5

For children, record a clinically important bronchodilator response if FEV1 increases by
≥ 12%.5

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References

  1. Pellegrino R, Viegi G, Brusasco V, et al. Interpretative strategies for lung function tests. Eur Respir J. 2005; 26: 948-968. Available from: http://erj.ersjournals.com/content/26/5/948
  2. Schatz M, Sorkness CA, Li JT, et al. Asthma Control Test: Reliability, validity, and responsiveness in patients not previously followed by asthma specialists. J Allergy Clin Immunol. 2006; 117: 549-556. Available from: http://www.jacionline.org/article/S0091-6749(06)00174-6/fulltext
  3. Miller MR, Hankinson J, Brusasco V, et al. Standardisation of spirometry. Eur Respir J. 2005; 26: 319-338. Available from: http://erj.ersjournals.com/content/26/2/319
  4. Levy ML, Quanjer PH, Booker R, et al. Diagnostic Spirometry in Primary Care: Proposed standards for general practice compliant with American Thoracic Society and European Respiratory Society recommendations. Prim Care Respir J. 2009; 18: 130-147. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19684995
  5. Johns DP, Pierce R. Pocket guide to spirometry. 3rd edn. McGraw Hill, North Ryde, 2011.