Hernandez-Andrade Edgar, Hellström-Westas Lena, Thorngren-Jerneck Kristina, Jansson Tomas, Liuba Karina, Lingman Göran, Marsál Karel, Oskarsson Gylfi, Werner Olof, Ley David
Department of Obstetrics and Gynecology, University of Lund, Sweden.
J Matern Fetal Neonatal Med. 2005 Feb;17(2):101-9. doi: 10.1080/14767050500043509.
To investigate the perinatal adaptive response of the adrenal blood flow/adrenal fractional moving blood volume (AFMBV) and carotid blood flow (CBF), in sheep fetuses subjected to severe acute intrauterine hypoxia/asphyxia induced by total cord occlusion.
Adrenal blood flow velocity, AFMBV and CBF were measured in 13 exteriorized fetal sheep; eight of them underwent total umbilical cord occlusion to induce severe acute hypoxia/asphyxia. Five lambs were used as sham controls. Middle adrenal artery pulsatility index (MAAPI) and mean velocity (MAAMV) were recorded with pulsed Doppler ultrasound. AFMBV was estimated using power Doppler ultrasound. CBF was recorded with a transonic flowmeter. In the neonatal period, after resuscitation all lambs were followed for a 4-hour period and AFMBV and CBF were recorded. Mean arterial blood pressure (MABP) and fetal heart rate were recorded continuously. Arterial cortisol levels were measured at the beginning and at the end of the fetal and neonatal periods.
Following the total cord occlusion, there was a significant reduction in the CBF, MABP, and heart rate and adrenal flow/AFMBV after 2, 4 and 5 min, respectively. Cortisol levels in the asphyctic lambs at the end of the cord occlusion were significantly lower than those in controls. After resuscitation, the asphyctic lambs showed increased AFMBV and cortisol levels, and reduced MABP as compared to control lambs. No differences were found in CBF, MAAPI and MAAMV. Thereafter, no differences were observed between the two groups in any of the studied parameters. At the end of the cord occlusion period, there was a significant correlation between AFMBV and MABP (r=0.69), between AFMBV and CBF (r =0.65) and between CBF and MABP (r=0.89).
During severe acute intrauterine hypoxia, the fetal lamb is able to maintain the blood flow to the brain and the adrenal gland for 3-5 min. Changes in the AFMBV and the CBF were highly correlated to the changes in MABP. Adrenal FMBV and cortisol levels were higher in lamb neonates exposed to severe intrauterine asphyxia.
研究完全脐带阻断致严重急性宫内缺氧/窒息的绵羊胎儿肾上腺血流/肾上腺部分移动血容量（AFMBV）及颈动脉血流（CBF）的围产期适应性反应。
对13只体外胎儿绵羊测量肾上腺血流速度、AFMBV及CBF；其中8只进行完全脐带阻断以诱导严重急性缺氧/窒息。5只羔羊作为假手术对照。用脉冲多普勒超声记录肾上腺中动脉搏动指数（MAAPI）及平均速度（MAAMV）。用能量多普勒超声估算AFMBV。用跨音速流量计记录CBF。在新生儿期，复苏后所有羔羊随访4小时并记录AFMBV及CBF。连续记录平均动脉血压（MABP）及胎儿心率。在胎儿期和新生儿期开始及结束时测量动脉皮质醇水平。
完全脐带阻断后，分别在2、4和5分钟时，CBF、MABP及心率以及肾上腺血流/AFMBV显著降低。脐带阻断结束时，窒息羔羊的皮质醇水平显著低于对照组。复苏后，与对照羔羊相比，窒息羔羊的AFMBV及皮质醇水平升高，MABP降低。CBF、MAAPI及MAAMV无差异。此后，两组在任何研究参数上均未观察到差异。在脐带阻断期结束时，AFMBV与MABP之间（r = 0.69）、AFMBV与CBF之间（r = 0.65）以及CBF与MABP之间（r = 0.89）存在显著相关性。
在严重急性宫内缺氧期间，胎儿绵羊能够在3 - 5分钟内维持脑和肾上腺的血流。AFMBV和CBF的变化与MABP的变化高度相关。暴露于严重宫内窒息的羔羊新生儿的肾上腺FMBV和皮质醇水平较高。
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