Am. J. Respir. Crit. Care Med., Vol 152, No. 2, 08 1995, 696-701.
Standard flow-time waveforms for testing of PEF meters
JL Hankinson and RO Crapo
National Institute for Occupational Safety and Health, Division of Respiratory Disease Studies, Morgantown, WV 26505, USA.
The American Thoracic Society (ATS) has recommended the use of 24
volume-time waveforms for the testing of spirometers. Although these
waveforms include values of peak expiratory flow (PEF), they were not
originally intended to test PEF meters, but, rather, volume parameters for
spirometers. In addition, the practice of using ATS volume-time Waveform 24
with varying multiplying factors does not provide the range of flow-time
waveform shapes (rise times) needed to evaluate PEF meters. Accordingly, we
have developed a set of 26 flow-time waveforms specifically selected to
evaluate PEF meters. PEF and other flow parameters (rise time and time to
PEF) can be directly measured from these flow-time waveforms. When PEF
determined directly from the flow- time curve was compared with PEF
determined indirectly from a volume- time curve (ATS-recommended algorithm
with an 80 ms time segment), as much as a 10.7% difference between the two
methods was observed using a waveform with a fast rise time. In contrast,
there was very little difference between the various methods of deriving
PEF for waveforms with slower rise times. These 26 flow-time waveforms
provide a means of defining PEF for the testing of software algorithms and
the testing of PEF meters with computer-driven mechanical pumps.
