Background & Summary
Peak flow meters play an important role in the management of asthma for a large number of patients, by indicating the how narrow or open the airways are. Peak flow readings are higher when patients are well, and lower when the airways are constricted.
The measurement of peak expiratory flow (PEF) was pioneered by Dr. B.M. Wright, who produced the first meter specifically designed to measure this index of lung function. Since the original design of instrument was introduced in the late 1950's, and the subsequent development of a more portable, lower cost version (the 'Mini-Wright' peak flow meter), other designs and copies have become available across Europe and the World.
How accurate are peak flow meters?
Since 1993, a group of European scientists have researched the problems and possible solutions, and in 2003, a new European Standard (EN 23747 ) for such instruments was published. The new standard sets minimum acceptable levels for accuracy, repeatability and general performance, and defines a new 'scale' for P.E.F. readings - thereby addressing the two major faults with the meters previously available. The new standard also has the advantage that readings are similar to those obtained from conventional spirometers, due to the new scale being based on 'absolute' airflows.
Peak flow meters that use the new 'E.U.' P.E.F. scale will become available in 2004, and only designs that can confirm to the strict standards within the EN 23747 definition can claim to be compliant.
It is known already that certain brands of peak flow meter, previously thought to have acceptable accuracy, have not been able to meet the more stringent accuracy requirements of the new tests.
Patients and Healthcare Professionals using the 'Mini-Wright' brand of peak flow meter can be reassured that this meter has already been shown to comply with the accuracy requirements, and EU-scale Mini-Wrights that conform to the EN 23747 standard will be available from Clement Clarke International Ltd., and distributors of our products in countries across Europe.
When will the new peak flow meters be available?
Within the rest of Europe, each country will decide when to change from the old scale to the new EU-Scale; new meters will be available throughout Europe from 2004 onwards.
N.B. The introduction of a new P.E.F. scale in Europe does not affect the United States or other countries, unless they have been using Wright-scale instruments. The A.T.S. (American Thoracic Society) scale meter will remain unchanged. Click here to see which Mini-Wright you are using
Low range meters - an omission from the EN 23747 standard?
Clement Clarke have researched the value of Low Range peak flow meters, and as of 1st June 2004, will make a Low Range Mini-Wright meter available, that complies with all aspects of the new EN 23747 Standard - with the exception that the upper limit of its readings will be 400 l/min.
Patients and professionals who have previously used a low range meter can be reassured that even though a change to the new EU-scale will occur, they will still be able to request a meter designed more specifically for their individual needs.
Multiple patient use - how do we protect against cross-infection?
More recently, Clement Clarke have become the first company to validate multiple-patient cleaning instructions (available at), which provide recommendations for the use of the instrument by more than one patient.
The Mini-Wright is suitable for both single-patient use, and multiple-patient use, provided the respective cleaning instructions are followed. In addition, disposable cardboard one-way mouthpieces are available for other brands of peak flow meter (which do not have the inbuilt protection of the Mini-Wright design).