CEREBRAL AUTO-REGULATION DYNAMICS IN HUMANS
CEREBRAL AUTO-REGULATION DYNAMICS IN HUMANS
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DOI：
10.1161/01.str.20.1.45
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发表时间：
1989-01-01
期刊：
影响因子：
8.3
通讯作者：
NORNES, H
中科院分区：
文献类型：
--
作者：
AASLID, R;LINDEGAARD, KF;NORNES, H
我们研究了10名正常志愿者在正常碳酸血症、低碳酸血症和高碳酸血症时，脑血流对动脉血压急性阶跃性降低的反应。在收缩压以上充气2分钟后，通过快速放气大腿血压袖带诱导阶跃（约20 mm Hg）。采用一种新的伺服袖带法测量瞬时动脉血压，并通过经颅多普勒记录大脑中动脉血流速度来评估脑血流变化。在低碳酸血症中，早在血压逐步降低后4.1秒就可以看到血流量完全恢复到试验前水平，而在正常碳酸血症和高碳酸血症中反应较慢。根据血压和血流记录计算脑血管阻力的时程，并将调节速率确定为血压阶跃降低后2.5秒内每秒脑血管阻力的标准化变化。正常化的参考是计算出的脑血管阻力的变化，该变化将抵消动脉血压逐步降低对脑血流量的影响。在低碳酸血症、正常碳酸血症和高碳酸血症中，调节速率分别为0.38、0.20和0.11/sec。调节速率与PaCO 2之间存在高度显著的负相关性（p < 0.001），表明清醒正常人的脑自动调节的响应速率深刻地依赖于血管张力。
We studied the response of cerebral blood flow to acute step decreases in arterial blood pressure noninvasively and nonpharmacologically in 10 normal volunteers during normocapnia, hypocapnia, and hypercapnia. The step (approximately 20 mm Hg) was induced by rapidly deflating thigh blood pressure cuffs followng a 2-minute inflation above systolic blood pressure. Instantaneous arterial blood pressure was measured by a new servo-cuff method, and cerebral blood flow changes were assessed by transcranial Doppler recording of middle cerebral artery blood flow velocity. In hypocapnia, full restoration of blood flow to the pretest level was seen as early as 4.1 seconds after the step decrease in blood pressure, while the response was slower in normocapnia and hypercapnia. The time course of cerebrovascular resistance was calculated from blood pressure and blood flow recordings, and rate of regulation was determined as the normalized change in cerebrovascular resistance per second during 2.5 seconds just after the step decrease in blood pressure. The reference for normalization was the calculated change in cerebrovascular resistnce that would have nullified the effects of the step decrease in arterial blood pressure on cerebral blood flow. The rate of regulation was 0.38, 0.20, and 0.11/sec in hypocapnia, normocapnia, and hypercapnia, respectively. There was a highly significant inverse relation between rate of regulation and PaCO2 (p < 0.001), indicating that the response rate of cerebral autoregulation in awake normal humans is profoundly dependent on vascular tone.