Pedersen O F, Rasmussen T R, Omland O, Sigsgaard T, Quanjer P H, Miller M R
University of Aarhus, Dept of Environmental and Occupational Medicine, Denmark.
Eur Respir J. 1996 Apr;9(4):828-33. doi: 10.1183/09031936.96.09040828.
The purpose of this study was to examine whether the resistance of the peak flow meter influences its recordings. One hundred and twelve subjects, (healthy nonsmokers and smokers and subjects with lung diseases) performed three or more peak expiratory flow (PEF) manoeuvres through a Fleisch pneumotachograph with and without a mini-Wright peak flow meter added in random order as a resistance in series. The results were as follows. In comparison with a pneumotachograph alone, peak flow measured with an added mini-Wright meter had a smaller within-test variation, defined as the difference between the highest and second highest values of PEF in a series of blows. The mean (SE) variation was 14 (1.3) L.min-1 and 19 (1.5) L.min-1 with and without meter added, respectively. In comparison with the pneumotachograph alone, the addition of the mini-Wright meter caused PEF to be underread, especially at high flows. The difference (PEF with meter minus PEF without meter) = -0.064 (average PEF) -8 L.min-1; R2 = 0.13. The mean difference was -7.8 (1.1) %, and increased numerically for a given PEF, when maximal expiratory flow when 75% forced vital capacity remains to be exhaled (MEF75%FVC) decreased. The reproducibility criteria for repeated measurements of peak flow are more appropriately set at 30 L.min-1 than the commonly used 20 L.min-1, because a within-test variation of less than 30 L.min-1 was achieved in 76% of the subjects without PEF meter inserted and in 88% with meter inserted, with no difference between healthy untrained subjects and patients. The resistance of the peak expiratory flow meter causes less variation in recordings but reduces peak expiratory flow, especially at high values and when the peak is large as compared with the rest of the maximal expiratory flow-volume curve.
本研究的目的是检验峰值流量计的阻力是否会影响其记录结果。112名受试者（健康非吸烟者、吸烟者以及患有肺部疾病的受试者）通过Fleisch呼吸流速计进行三次或更多次呼气峰值流速（PEF）操作，操作过程中随机顺序添加或不添加微型赖特峰值流量计作为串联阻力。结果如下。与单独使用呼吸流速计相比，添加微型赖特流量计测得的峰值流速在测试内的变化较小，测试内变化定义为一系列吹气中PEF最高值与第二高值之间的差值。添加和未添加流量计情况下，平均（标准误）变化分别为14（1.3）L·min⁻¹和19（1.5）L·min⁻¹。与单独使用呼吸流速计相比，添加微型赖特流量计会导致PEF读数偏低，尤其是在高流速时。差值（有流量计的PEF减去无流量计的PEF）=-0.064（平均PEF）-8 L·min⁻¹；R² = 0.13。平均差值为-7.8（1.1）%，对于给定的PEF，当呼出75%用力肺活量时的最大呼气流量（MEF75%FVC）降低时，该差值在数值上会增加。重复测量峰值流速的可重复性标准设定为30 L·min⁻¹比常用的20 L·min⁻¹更合适，因为在未插入PEF流量计的76%受试者和插入流量计的88%受试者中，测试内变化小于30 L·min⁻¹，健康未受过训练的受试者与患者之间无差异。呼气峰值流量计的阻力会使记录结果的变化较小，但会降低呼气峰值流速，尤其是在高值时以及当峰值与最大呼气流量-容积曲线的其余部分相比很大时。
