Endresen J, Hill D W
Eur J Intensive Care Med. 1976;2(1):3-6. doi: 10.1007/BF00571889.
In six volunteers (5 male, 1 female) it has been shown that normal respiration made no statistical difference to the estimates of the mean stroke volume and the mean cardiac output as determined by the electrical impedance method of Kubicek et al, (1966). The coefficient of variation was usually increased by respiration. The use of those stroke volumes which occur only at end-expiration was not shown to yield a greater reproducibility with 3 other male volunteers. In the female subject it was found that the use of a digital averager triggered from the preceding R-wave of the ECG gave values for the mean stroke volume and cardiac output which were always lower than the conventional mean values obtained from a number of strokes. The expense of either of these approaches does not appear to be justified as a means of compensating for the effects of normal respiration on the impedance dZ/dt waveform.
在六名志愿者（5名男性，1名女性）中，研究表明，正常呼吸对通过Kubicek等人（1966年）的电阻抗法测定的平均每搏输出量和平均心输出量的估计值没有统计学差异。变异系数通常因呼吸而增加。对于另外三名男性志愿者，仅在呼气末出现的那些每搏输出量的使用并未显示出更高的可重复性。在女性受试者中，发现使用由心电图前一个R波触发的数字平均器得出的平均每搏输出量和心输出量值始终低于从多次搏动中获得的传统平均值。作为补偿正常呼吸对阻抗dZ/dt波形影响的一种手段，这些方法中的任何一种所花费的成本似乎都不合理。
