The aim of spirometry in general practice is to assess variability of airflow obstruction, and to measure the degree of airflow obstruction compared to predicted normal. Accurate measurement of respiratory function is necessary to assess and manage asthma.
Most adults and children over 6 years of age can perform spirometry.
Also known as Respiratory Function Tests (RFTs) are a series of tests of lung capacity and function which help to classify the type of respiratory disease in an individual.
- Forced Vital Capacity (FVC)
- Forced Expiratory Volume in 1 second (FEV1)
- FEV1/FVC ratio
- pre- and post-bronchodilator measurements
Why do we perform spirometry?
To aid diagnosis:
- Checking for reversibility post-bronchodilator
- Differential diagnosis between asthma and COPD
To assess and/or monitor:
- Respiratory symptoms such as cough or shortness of breath
- Disease severity
- If a medicine is working
- Intervention outcomes e.g. pre- and post- pulmonary rehabilitation
- Occupational health impacts
- Suitability for scuba diving
Spirometry testing requires skill in order to administer the testing and to interpret the results. It is recommended that health professionals seek out proper training.
How is Spirometry performed? This test involves you taking a full breath in and blowing out as hard and fast as you can for as long as possible into a calibrated spirometer. Measurements are made of how well your lungs can be emptied and filled with air. The test is performed while sitting down, with legs uncrossed & corect posture. The spirometry test takes 20mins to half an hour. It is usually done before and after breathing a bronchodilator spray such as Ventolin or Bryanyl to measure whether or not these agents are able to improve your breathing. Prior to the test you will be asked to stop taking your reliever puffers for 6 hours or your controller puffers for 12 hours prior to your test.
How to prepare for Spirometry?
Although there are no strict preparations to adhere to prior to having a spirometry test - it is recommended you refrain from smoking for 24 hours prior to your test, that you avoid eating large meals for 2 hours prior to your test, that you avoid vigorous exercise 30 minutes before your test and that you avoid alcohol on the day before your spirometry test.
- Relevant Specialties
- Respiratory and Sleep Medicine
- Internal Medicine
- Occupational and Environmental Medicine
- General Practice
- Medical Conditions
- Chronic obstructive pulmonary disease
- Cystic fibrosis
- Medical Devices
- Lilly (screen) pneumotach
- Turbine(actually a rotating vane, this spins, the revolutions are counted as they break a light beam)
- Pitot tube
- Hot-wire anemometer
- Peak flow meter