Am. J. Respir. Crit. Care Med., Vol 152, No. 2, Aug 1995, 702-706.
Frequency response of portable PEF meters
JL Hankinson and MK Das
Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA.
Peak expiratory flow (PEF) is a dynamic parameter and therefore requires a
measuring device with a high-frequency response. This study evaluated the
frequency-response characteristics of eight commercially available PEF
meters, using simulated forced-expiratory maneuvers with a
computer-controlled mechanical pump. Three different PEF levels were used
(200, 400, and 600 L/min) at six levels of harmonic-frequency content
similar to those observed in human subjects. For waveforms with higher
frequency content (at the high end or above the physiologic range), the
Assess, Vitalograph, Pocket Peak, and Spir-O-Flow PEF meters all overread
PEF (greater than 15% difference from target values) at all three PEF
levels. These results suggest that the frequency response of PEF meters is
an important consideration in the selection of such meters and should be
included in device requirements. The current practice of using various
levels of American Thoracic Society (ATS) waveform 24 with its
low-frequency content may not adequately evaluate the frequency
characteristics of PEF meters. An upper range (5% of the fundamental
frequency) of 12 Hz, within the range observed in normal subjects, appears
to be more practical than an upper limit of 20 Hz.
