When you hear ‘respiratory care and diagnostics’, a number of devices used in this field, in respiratory laboratories and clinics may come to mind. There are many devices that may be used for respiratory disease diagnosis or as monitoring tools to track trends in a patient’s lung function. Spirometers and peak flow meters are perhaps some of the most widely used devices when it comes to the diagnosis and management of common respiratory diseases such as asthma, COPD and cystic fibrosis. These two devices share the same basic principle of operation. Both involve the patient blowing into the device via a mouthpiece, followed by the calculation and display of key parametric indicators of lung function based on this air flow. Spirometers and peak flow meters, however, may differ with respect to technology, functional capacity and intended use.
What is a peak flow meter?
A peak flow meter is a relatively straightforward tool that measures a patient’s ‘Peak Expiratory Flow’ or ‘PEF’. The PEF is a measure of how fast you are able to forcefully exhale after full inhalation. The regular collection of a patient’s PEF can help determine if the airways of the patient are narrowing. The device is commonly used by asthma patients to help keep their asthma under control. PEF testing can be performed as a means of early detection of potential asthma attacks, when they feel their symptoms are becoming worse or to help decide whether rescue medication is necessary. It is important that patients consult their doctor about what their personal best PEF is or should be, to provide a point of reference for PEF tracking in disease management.
What is a spirometer?
Spirometry, the evaluation of lung function with a spirometer, is one of the simplest and most commonly applied pulmonary function tests. A spirometer assesses a patient’s lung function, however, it offers a larger set of parametric values regarding lung health than a peak flow meter does. Spirometry requires a patient to perform specific breathing maneuvers using a spirometer. Each breathing maneuver has a specific pattern of inspiration and/or expiration pattern that the patient must follow in order to obtain a particular set of information related to their lung function. Through the assessment of inspiratory and/or expiratory flows, a spirometer can help detect not only the type of respiratory disease (if any) present, but also the degree to which the disease has progressed. Spirometers are particularly useful in the diagnosis of diseases such as COPD where the disease remains largely asymptomatic until lung capacity has been irreversibly compromised. Spirometers are therefore powerful tools which aim:
- To determine how well the lungs receive, hold, and utilize air
- To monitor a lung disease
- To observe the effectiveness of treatment
- To determine the level of a lung disease