Pedersen O F, Naeraa N, Lyager S, Hilberg C, Larsen L
Bull Eur Physiopathol Respir. 1983 Sep-Oct;19(5):515-20.
We have constructed a calibration device which simulates a maximum expiratory flow, and which can also be used to determine quantitatively the frequency response and linearity of flow recording equipment. It consists of a pressure chamber full of copper chips serving as a heat exchanger. When inflated to twice the atmospheric pressure, it delivers 8.2 l of air during deflation. Deflation is released by a falling weight. The time tS between 10% and 90% of the peak expiratory flow out of the chamber (PEFR) can be varied between 10 ms and 90 ms. PEFR up to 19 l X s-1 can be obtained by changing the size of an orifice in the outlet line. The calibrator was tested with a Fleisch no 4 pneumotachograph linear up to 15 l X s-1. The coefficient of variation of PEFR (12.2 l X s-1) and FVC (8.2 l) was 2% and 1% respectively for 10 consecutive deflations. The frequency response in terms of tS of the tested equipment can be evaluated from the flow-volume curve produced by the calibrator. Examination of tS in 50 medical students shows that tS of the equipment should be less than about 20 ms in order to correctly measure PEFR. By means of a single deflation, the linearity of the total recording system can be tested over a range of flows because the flow signal of the calibrator is declining almost linearly with time.
我们构建了一种校准装置，它能模拟最大呼气流量，还可用于定量测定流量记录设备的频率响应和线性度。它由一个充满铜屑作为热交换器的压力室组成。当充入两倍大气压时，放气过程中它可释放8.2升空气。放气由一个落体释放。压力室峰值呼气流量（PEFR）的10%至90%之间的时间tS可在10毫秒至90毫秒之间变化。通过改变出口管线中孔口的大小，可获得高达19升·秒⁻¹的PEFR。该校准器用一台线性度高达15升·秒⁻¹的Fleisch 4型呼吸流速计进行了测试。对于连续10次放气，PEFR（12.2升·秒⁻¹）和用力肺活量（FVC，8.2升）的变异系数分别为2%和1%。可根据校准器产生的流量-容积曲线评估被测设备在tS方面的频率响应。对50名医学生的tS检测表明，为正确测量PEFR，设备的tS应小于约20毫秒。通过单次放气，由于校准器的流量信号随时间几乎呈线性下降，可在一定流量范围内测试整个记录系统的线性度。
