Bronchodilator reversibility testing: laboratory practices in Australia and New Zealand

Objectives: To determine the variation in the methods used to assess and interpret the reversibility of airflow limitation in lung-function laboratories throughout Australia and New Zealand. Design: A postal survey performed in 2000, requesting details of methods used to assess and interpret bronchodilator reversibility. Setting and participants: 60 lung-function laboratories identified from the Australian and New Zealand Society of Respiratory Science mailing list. Main outcome measures: Bronchodilator agent, dose, mode of administration, time to repeat spirometry and definition of a significant response. Results: 37 laboratories responded (response rate, 64%). Thirty-three laboratories used salbutamol as their routine bronchodilator agent. Twenty-four laboratories used a metered-dose inhaler (MDI) with (21) or without (3) a spacer device as the preferred mode of bronchodilator administration. There was wide variation in the bronchodilator dose administered (median, 400 μg; range, 200-800 μg salbutamol for MDIs) and the time to repeat spirometry following bronchodilator administration (median, 10 min; range, 4-20 min). Ten laboratories used criteria consistent with either the National Asthma Council or Thoracic Society of Australia and New Zealand COPDX guidelines to define a significant bronchodilator response, and two used American Thoracic Society criteria. The remaining 25 respondents listed a variety of other criteria. Conclusion: The methods used to assess and interpret acute bronchodilator reversibility in lung-function laboratories in Australia and New Zealand vary considerably. This may have a significant effect on the diagnosis and management of patients. Laboratories should report the method used to assess bronchodilator response.