Brace R A
J Dev Physiol. 1987 Apr;9(2):97-103.
The purpose of this study was to determine whether the autonomic nervous system contributes to short-term fetal blood volume restitution following fetal haemorrhage. Unanaesthetized, chronically catheterized fetal sheep averaging 130 days gestation (term = 145-150 days) were studied 5 days after catheter implantation. Blockade of the autonomic nervous system was produced with a bolus intravenous injection of hexamethonium. In 7 blocked fetuses, an average of 17.6% of the initial blood volume was removed over 5 min and this was not different from the 16.5% blood volume removed in 7 control fetuses. However, blood volume restoration averaged 44.6% after 30 min in the blocked fetuses and this was significantly less than the 60.2% volume restoration in the control fetuses (P less than 0.05). Thus blood volume restoration averaged 74% of control in the blocked fetuses. Following blood reinfusion over 5 min, blood volume was transiently elevated in the control group, but averaged 3.4, 4.7, and 5.3% below normal (P less than 0.05) at 10, 20 and 30 min post reinfusion in the blocked group. In addition, arterial pressure was lower after haemorrhage in the blocked group and increased twice that in the control group during reinfusion. Thus, the present data suggest that the fetal autonomic nervous system plays a significant role in mediating the short-term changes in fetal blood volume and vascular pressures following fetal haemorrhage and reinfusion.
本研究的目的是确定自主神经系统是否有助于胎儿出血后短期内的血容量恢复。对平均妊娠130天（足月为145 - 150天）、未麻醉且长期留置导管的胎羊，在植入导管5天后进行研究。通过静脉推注六甲铵来阻断自主神经系统。在7只阻断自主神经系统的胎羊中，5分钟内平均抽取了初始血容量的17.6%，这与7只对照胎羊中抽取的16.5%血容量没有差异。然而，阻断组胎羊在30分钟后血容量恢复平均为44.6%，这显著低于对照组胎羊60.2%的血容量恢复率（P < 0.05）。因此，阻断组胎羊的血容量恢复平均为对照组的74%。在5分钟内回输血液后，对照组血容量短暂升高，但阻断组在回输后10、20和30分钟时血容量平均比正常水平低3.4%、4.7%和5.3%（P < 0.05）。此外，阻断组出血后动脉压较低，在回输期间升高幅度是对照组的两倍。因此，目前的数据表明，胎儿自主神经系统在介导胎儿出血和回输后胎儿血容量和血管压力的短期变化中起重要作用。
