Dopamine does not limit fetal cerebrovascular responses to hypoxia.
Dopamine does not limit fetal cerebrovascular responses to hypoxia.
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DOI：
10.1152/japplphysiol.00399.2006
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发表时间：
2007
影响因子：
3.3
通讯作者：
D. Mayock;Rachel Bennett;R. Robinson;C. Gleason
中科院分区：
文献类型：
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作者：
D. Mayock;Rachel Bennett;R. Robinson;C. Gleason
多巴胺在临床上用于稳定患病婴儿的平均动脉血压（MAP）。这种治疗干预的一个目标是维持足够的脑血流量（CBF）和灌注压。高剂量静脉注射多巴胺已被证实可增加近期胎羊的脑血管阻力（CVR）。我们假设这种血管反应可能会在急性等氧缺氧时限制脑血管舒张。我们研究了9只近期长期插管未麻醉的胎羊。使用放射性标记微球测量胎儿CBF，我们计算了基线、胎儿缺氧期间以及静脉注射2.5、7.5和25微克。kg（-1）多巴胺时的CVR。持续缺氧时Min（-1）。在急性等氧性胎儿缺氧期间，CBF比基线增加73.0 +/- 14.1%，CVR比基线下降38.9 +/- 4.9%。多巴胺输注2.5和7.5 mg .kg（-1）。在缺氧时开始的min（-1）没有改变CVR或MAP，但当多巴胺输注增加到25 mg .kg(-1).min（-1）时MAP增加。多巴胺在任何剂量下都没有改变脑血流或影响脑血流对缺氧的反应。然而，多巴胺输注率为25 μ g.kg(-1).min（-1）时，CVR增加。在最高多巴胺输注率下CVR的增加可能是对MAP增加的自我调节反应，与我们之前的发现相似。因此，在长期插管未麻醉的近期胎羊中，多巴胺不会改变预期的脑血管缺氧反应。
Dopamine is used clinically to stabilize mean arterial blood pressure (MAP) in sick infants. One goal of this therapeutic intervention is to maintain adequate cerebral blood flow (CBF) and perfusion pressure. High-dose intravenous dopamine has been previously demonstrated to increase cerebrovascular resistance (CVR) in near-term fetal sheep. We hypothesized that this vascular response might limit cerebral vasodilatation during acute isocapnic hypoxia. We studied nine near-term chronically catheterized unanesthetized fetal sheep. Using radiolabeled microspheres to measure fetal CBF, we calculated CVR at baseline, during fetal hypoxia, and then with the addition of an intravenous dopamine infusion at 2.5, 7.5, and 25 microg.kg(-1).min(-1) while hypoxia continued. During acute isocapnic fetal hypoxia, CBF increased 73.0 +/- 14.1% and CVR decreased 38.9 +/- 4.9% from baseline. Dopamine infusion at 2.5 and 7.5 microg.kg(-1).min(-1), begun during hypoxia, did not alter CVR or MAP, but MAP increased when dopamine infusion was increased to 25 microg.kg(-1).min(-1). Dopamine did not alter CBF or affect the CBF response to hypoxia at any dose. However, CVR increased at a dopamine infusion rate of 25 microg.kg(-1).min(-1). This increase in CVR at the highest dopamine infusion rate is likely an autoregulatory response to the increase in MAP, similar to our previous findings. Therefore, in chronically catheterized unanesthetized near-term fetal sheep, dopamine does not alter the expected cerebrovascular responses to hypoxia.