Richardson B S, Carmichael L, Homan J, Patrick J E
Department of Obstetrics and Gynaecology and Physiology, St. Joseph's Health Centre, Lawson Research Institute, University of Western Ontario, London, Canada.
Am J Obstet Gynecol. 1992 Aug;167(2):553-8. doi: 10.1016/s0002-9378(11)91452-5.
Our objective was to determine the effect of a prolonged and graded reduction in fetal arterial oxygen saturation on electrocortical activity and associated biophysical variables.
Fourteen unanesthetized fetal sheep were studied between 126 and 135 days' gestation with continuous monitoring of electrocortical and electroocular activity and breathing movements, during a 24-hour control period, and subsequently during 4 days of prolonged and graded hypoxemia induced by progressively lowering the maternal inspired oxygen concentration.
Graded reduction in fetal arterial oxygen saturation resulted in little change in arterial pH until close to 30% when metabolic acidemia was apparent. The incidence of low-voltage electrocortical activity, electroocular activity, and breathing movements were marginally decreased with hypoxemia alone; however, a significant decrease was not apparent until associated with the onset of fetal acidemia.
Hypoxemia of a chronic nature must approach the level at which acidemia becomes apparent before a marked change in fetal behavioral activity is noted.
我们的目的是确定胎儿动脉血氧饱和度的长期分级降低对脑电活动及相关生物物理变量的影响。
对14只未麻醉的孕126至135天的胎羊进行研究，在24小时的对照期内持续监测脑电和眼电活动以及呼吸运动，随后在通过逐步降低母体吸入氧浓度诱导的4天长期分级低氧血症期间进行监测。
胎儿动脉血氧饱和度的分级降低在接近30%时代谢性酸血症明显之前，动脉pH值几乎没有变化。仅低氧血症时，低电压脑电活动、眼电活动和呼吸运动的发生率略有下降；然而，直到与胎儿酸血症发作相关时，才出现明显下降。
在注意到胎儿行为活动有明显变化之前，慢性低氧血症必须达到酸血症明显的水平。
