Künzel W, Mann L I, Bhakthavathsalan A, Airomlooi J, Liu M
Am J Obstet Gynecol. 1977 May 15;128(2):201-8. doi: 10.1016/0002-9378(77)90688-3.
In 11 fetal sheep experiments, the blood pressure in the fetal aorta (FA) and in the umbilical vein (UV) was measured following umbilical vein occlusion (UVO), as was the fetal heart rate (FHR), pH, Pco2, and oxygen saturation (So2) in both fetal vessels, and umbilical blood flow (Qumb) of the common UV. The fetal electroencephalogram was recorded continuously throughout the experiment. The results (No. = 17) were grouped according to the response of FA So2 into moderate (So2greater than40 per cent, mean 49.8, S.D. 6.3, and severe So2less than40 per cent, mean 20.4, S.D. 9.2). After 8 to 10 seconds, the fetal blood pressure in FA increased. Umbilical vein blood pressure increased to 25 mm. Hg (S.D. 8) and 35 mm. Hg (S.D. 9) in the moderate and severe groups, respectively. As a result of the decreased perfusion pressure (FA-UV blood pressure) across the fetal side of the placenta, the Qumb fell from 147 ml. per kilogram per minute (S.D. 57) and 30 ml. per kilogram per minute (S.D. 55) to 84 ml. per kilogram per minute (S.D. 48) and 120 ml. per kilogram per minute (S.D.22), respectively. The fall in FA So2 was related to the decrease in Qumb: FA So2=37.6 x log Qumb - 22.8 (2alphaless than 0.001). There was a mild decrease in So2 from 70 to 55 per cent when Qumb fell from 250 to 120 ml. per kilogram per minute. Below 80 to 120ml. per kilogram per minute, the fall in FA So2 was almost linear. The So2 in the UV remained constant so that arteriovenous difference for oxygen (AV Do2) increased. Oxygen consumption decreased almost linearly when Qumb fell below 80 to 120 ml. per kilogram per minute. The fetal electroencephalogram showed no significant change in voltage and the faster activities. From these observations, it is concluded that a decrease in Qumb following UVO jeopardizes the fetus only if a critical Qumb of 80 to 120 ml. per kilogram per minute and fetal artery So2 of 50 to 60 per cent is achieved.
在11项胎羊实验中，在脐静脉闭塞（UVO）后测量了胎主动脉（FA）和脐静脉（UV）的血压，以及两条胎儿血管中的胎儿心率（FHR）、pH值、二氧化碳分压（Pco2）和氧饱和度（So2），还有脐静脉总血流量（Qumb）。在整个实验过程中持续记录胎儿脑电图。根据FA中So2的反应将结果（数量=17）分为中度（So2大于40%，平均49.8，标准差6.3）和重度（So2小于40%，平均20.4，标准差9.2）两组。8至10秒后，FA中的胎儿血压升高。中度和重度组中，脐静脉血压分别升至25毫米汞柱（标准差8）和35毫米汞柱（标准差9）。由于胎盘胎儿侧灌注压（FA - UV血压）降低，Qumb分别从每分钟每千克147毫升（标准差57）和30毫升（标准差55）降至每分钟每千克84毫升（标准差48）和120毫升（标准差22）。FA中So2的下降与Qumb的降低有关：FA So2 = 37.6×log Qumb - 22.8（2α小于0.001）。当Qumb从每分钟每千克250毫升降至120毫升时，So2从70%轻度降至55%。低于每分钟每千克80至120毫升时，FA中So2的下降几乎呈线性。UV中的So2保持恒定，因此动静脉氧差（AV Do2）增加。当Qumb低于每分钟每千克80至120毫升时，氧消耗几乎呈线性下降。胎儿脑电图显示电压和较快活动无显著变化。从这些观察结果得出结论，UVO后Qumb降低仅在达到每分钟每千克80至120毫升的临界Qumb和胎儿动脉So2为50%至60%时才会危及胎儿。
