• Measure the patient’s standing height.
• Perform pre-bronchodilator spirometry as soon as you have determined that your patient requires the test.
• Administer a bronchodilator and then complete the rest of the consultation.
• By the time you have done this, sufficient time will have passed for the post-bronchodilator spirometry to be done (e.g. 10 minutes).
• With the results of spirometry now available you will be better equipped to discuss the diagnosis, outlook and agree on a management plan with your patient.

Selecting the Most Appropriate Reference Values

Spirometric indices such as FEV₁ and FVC vary with age, height, gender and ethnic origin. It is important to note that if the patient’s height, age or gender is entered incorrectly inaccurate reference values will result and the subsequent interpretation of the lung function test results will be affected.

The choice of predicted reference values against which the results are compared is important. The reference values chosen should closely match the subjects you are testing. More information on reference value selection is provided in Section 2. In general, Caucasian predicted values for FEV1 and FVC are usually reduced by 12-15% when testing people of other ethnic backgrounds

Spirometry Training

Inadequate operator training will result in poor quality spirometry. To obtain clinically useful results the operator must comprehend the basic principals of quality spirometry.

Anybody performing spirometry on patients must be:

• Adequately trained in the performance of the correct breathing manoeuvre.
• Trained to identify and overcome poor technique.
• Trained to use, maintain and validate the spirometer correctly.
• Trained to identify whether the tests have been done properly and are consistent with previous results.

It is strongly recommended that staff performing spirometry attend a comprehensive spirometry training course. Some of these training courses are modular and allow flexibility in time and content to suit the range of different settings in which spirometry is measured. It is possible for the practice nurse to attend training on spirometry test performance while the doctor attends training on spirometry test interpretation.  A list of certified spirometry training courses is available from the Australian and New Zealand Society of Respiratory Science (www.anzsrs.org.au) and Thoracic Society of Australia and New Zealand (www.thoracic.org.au).

Content Updated February 2005