Pedersen O F, Rasmussen T R, Kjaergaard S K, Miller M R, Quanjer P H
University of Aarhus, Dept of Environmental and Occupational Medicine, Denmark.
Eur Respir J. 1995 May;8(5):849-55.
Little is known about the response of variable orifice peak flow meters to high frequency flow input. The purpose of this study was to define and test dynamic requirements for such peak flow meters. In a population sample we measured peak expiratory flow (PEF), rise time (tr), from 10-90% PEF and the duration of the flow in excess of 97.5, 95 and 90% of PEF, by use of a carefully calibrated Fleisch pneumotachograph with known and adequate frequency response. Three peak flow meters (Mini Wright, Vitalograph and Ferraris) were tested with an explosive decompression calibrator adjusted to values for PEF and tr as close as possible to the 95th and 5th percentile values, respectively, both for males and females, and with peak durations between 5 and more than 100 ms. The 95th percentile values of PEF were 597 L.min-1 for females and 894 L.min-1 for males. The 5th percentile values of tr were, respectively 55 and 45 ms. The duration of flow in excess of 95% PEF was longer than 10 ms in 99% of the subjects. For all meters, the deviation of PEF corrected for alinearity were less than 5% at a peak duration of 10 ms. We conclude that PEF, rise time, and peak duration can be used for description of dynamic properties of variable orifice meters, and that the tested meters had a satisfactory frequency response for recording PEF in mostly normal subjects.
关于可变孔口峰值流量计对高频气流输入的反应，人们了解甚少。本研究的目的是确定并测试此类峰值流量计的动态要求。在一个人群样本中，我们使用经过精心校准、具有已知且足够频率响应的 Fleisch 呼吸流速仪，测量了呼气峰值流速（PEF）、从 10%PEF 到 90%PEF 的上升时间（tr）以及超过 PEF 的 97.5%、95%和 90%时的气流持续时间。使用爆炸减压校准仪对三种峰值流量计（Mini Wright、Vitalograph 和 Ferraris）进行测试，将校准仪调整到尽可能接近男性和女性 PEF 及 tr 的第 95 和第 5 百分位数的值，且峰值持续时间在 5 至 100 多毫秒之间。女性 PEF 的第 95 百分位数为 597 L.min-1，男性为 894 L.min-1。tr 的第 5 百分位数分别为 55 和 45 毫秒。在 99%的受试者中，超过 95%PEF 的气流持续时间超过 10 毫秒。对于所有流量计，在峰值持续时间为 10 毫秒时，经线性校正后的 PEF 偏差小于 5%。我们得出结论，PEF、上升时间和峰值持续时间可用于描述可变孔口流量计的动态特性，并且所测试的流量计对于记录大多数正常受试者的 PEF 具有令人满意的频率响应。
