Yumoto Yasuo, Satoh Shoji, Fujita Yasuyuki, Koga Tsuyoshi, Kinukawa Naoko, Nakano Hitoo
Department of Obstetrics and Gynecology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Early Hum Dev. 2005 Jul;81(7):635-42. doi: 10.1016/j.earlhumdev.2005.04.004.
The objectives of this study are firstly to clarify how the Doppler isovolumetric contraction time (ICT) is influenced by arterial oxygen pressure (PaO2) or pH, and secondly to confirm the relationship between the Doppler ICT and myocardial contractility during hypoxemia and/or acidemia in the fetal lamb.
In 12 pregnant ewes, fetal hypoxemia and acidemia were induced by giving ewes a variable mixture of gases for 120 min. The chronological change of fetal PaO2, pH, Doppler ICT and maximum first derivative of the left ventricular pressure waveform (Max dp/dt) was recorded every 30 min.
Doppler ICT and PaO2 had no significant regression. On the other hand, Doppler ICT and pH demonstrated a significant negative regression. Moreover, one critical given pH point was indicated with statistical significance at 7.20 and the prolongation of the Doppler ICT was found more markedly in the range below the pH of 7.20 compared with the range above 7.20. A significant negative linear regression was found between the Doppler ICT and the Max dp/dt.
The measurement of Doppler ICT enables us to predict severe acidosis and a decrease of myocardial contractility in the fetus.
本研究的目的一是阐明动脉血氧分压（PaO2）或pH值如何影响多普勒等容收缩时间（ICT），二是证实胎儿低氧血症和/或酸血症期间多普勒ICT与心肌收缩力之间的关系。
对12只怀孕母羊给予不同混合气体120分钟，诱导胎儿发生低氧血症和酸血症。每隔30分钟记录胎儿PaO2、pH值、多普勒ICT和左心室压力波形的最大一阶导数（Max dp/dt）的时间变化。
多普勒ICT与PaO2无显著回归关系。另一方面，多普勒ICT与pH值呈显著负相关。此外，在pH值为7.20时，一个关键的给定pH点具有统计学意义，与pH值高于7.20的范围相比，在pH值低于7.20的范围内，多普勒ICT的延长更为明显。在多普勒ICT与Max dp/dt之间发现显著的负线性回归关系。
测量多普勒ICT能够使我们预测胎儿严重酸中毒和心肌收缩力下降。
