Jordanoglou J, Hadjistavrou C, Tatsis G, Anevlavis E, Melissinos C
Thorax. 1982 Apr;37(4):304-8. doi: 10.1136/thx.37.4.304.
Effective time of the forced expirogram is a sensitive index for the detection of mild airways obstruction. However, there is evidence that this measurement is not superior to maximum flow rates in the lower half of the forced vital capacity or even FEV1 and FEV1% in some patients suffering from obstructive lung disease. Furthermore we noticed that in some patients with a decrease of the forced vital capacity caused by exacerbation of airways obstruction, the effective time was not appreciably changed. We concluded that this apparent disadvantage of the effective time is the result of the different forced vital capacities. To eliminate this error we transformed the forced expirogram to the equivalent curve that the patient would produce, if his forced vital capacity was equal to the predicted mean value for his age, sex, and height. The derived corrected total effective time seems to have increased sensitivity for detection of small changes in expirograms obtained from the same subject or from different subjects.
用力呼气图的有效时间是检测轻度气道阻塞的一个敏感指标。然而，有证据表明，在一些患有阻塞性肺病的患者中，该测量指标在用力肺活量下半部分的表现并不优于最大流速，甚至在第一秒用力呼气容积（FEV1）和FEV1%方面也不占优势。此外，我们注意到，在一些因气道阻塞加重导致用力肺活量降低的患者中，有效时间并没有明显变化。我们得出结论，有效时间的这一明显劣势是由于用力肺活量不同所致。为消除这一误差，我们将用力呼气图转换为等效曲线，即假设患者的用力肺活量等于其年龄、性别和身高的预测平均值时他所产生的曲线。由此得出的校正后总有效时间似乎对检测同一受试者或不同受试者的呼气图中的微小变化具有更高的敏感性。
