Ten-minute umbilical cord occlusion markedly reduces cerebral blood flow and heat production in fetal sheep
Ten-minute umbilical cord occlusion markedly reduces cerebral blood flow and heat production in fetal sheep
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DOI：
10.1067/mob.2003.440
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发表时间：
2003-07-01
影响因子：
9.8
通讯作者：
Longo, LD
中科院分区：
文献类型：
--
作者：
Lotgering, FK;Bishai, JM;Longo, LD
目的：这项研究是为了确定在何种程度上10分钟的总脐带闭塞影响自动调节脑血流和脑产热在feta.Study设计：在七个长期导管妊娠晚期胎羊（127-131天的妊娠），我们研究了胎儿血气，血流动力学和热反应10分钟完全脐带闭塞。10分钟的脐带闭塞导致明显的缺氧/缺血，氧含量从6.5 +/- 0.4降至0.6 +/- 0.1 vol%，乳酸浓度从1.8 +/- 0.2升至10.7 +/- 0.7 mmol/L。在此期间，胎仔心率从163.5 +/- 3.4次/分降至97.1 +/- 5.4次/分，平均动脉压从39.4 +/- 2.1 mmHg降至21.2 +/- 2.5 mmHg，脑血流量从101.3% +/- 8.9%降至49.7% +/-10.3%，脑产热从95.0% +/- 6.3%降至29.6% +/-4.8%。在脊髓闭塞期间，从第四分钟起脑血流为压力被动。脑产热的减少先于灌注压和脑血流量的减少。脑血流量和产热恢复到控制值超过60分钟后恢复脐flow.CONCLUSION：10分钟总脐带闭塞的结果在脑血流量和产热的主要减少，脑血流量的自动调节在4分钟内闭塞，可能是由于缺氧，结合低血压失去。脑产热的减少先于并超过血流量的减少，这一事实可能表明脑代谢的主动下调，其机制目前尚不清楚。
OBJECTIVE: The study was undertaken to determine to what extent a 10-minute total umbilical cord occlusion affects autoregulation of cerebral blood flow and cerebral heat production in the fetus.STUDY DESIGN: In seven chronically catheterized late-gestation fetal sheep (127-131 days' gestation), we studied fetal blood gas, hemodynamic, and thermal responses to 10-minute total umbilical cord occlusion.RESULTS: Ten-minute umbilical cord occlusion resulted in marked hypoxia/ischemia, with oxygen content decreasing from 6.5 +/- 0.4 to 0.6 +/- 0.1 vol% and lactate concentration increasing from 1.8 +/- 0.2 to 10.7 +/- 0.7 mmol/L. During this period, the fetuses showed reductions in heart rate from 163.5 +/- 3.4 to 97.1 +/- 5.4 beats/min, mean arterial pressure from 39.4 +/- 2.1 to 21.2 +/- 2.5 mm Hg, cerebral blood flow from 101.3% +/- 8.9% to 49.7% +/- 10.3%, and cerebral heat production from 95.0% +/- 6.3% to 29.6% +/- 4.8%. During cord occlusion, cerebral blood flow was pressure passive from the fourth minute onward. The reduction in cerebral heat production preceded the reduction in perfusion pressure and cerebral blood flow. Recovery of cerebral blood flow and heat production to control values was incomplete for more than 60 minutes after restoration of umbilical flow.CONCLUSION: Ten-minute total umbilical cord occlusion results in major reductions in cerebral blood flow and heat production, Autoregulation of cerebral blood flow was lost within 4 minutes of occlusion, probably as a result of hypoxia, combined with hypotension. The fact that the reduction in cerebral heat production preceded and exceeded the reduction in blood flow may suggest active down-regulation of cerebral metabolism, the mechanism of which is unclear at present.