Dynamic autoregulatory response after severe head injury
Dynamic autoregulatory response after severe head injury
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DOI：
10.3171/jns.2002.97.5.1054
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发表时间：
2002-11-01
影响因子：
4.1
通讯作者：
Robertson, CS
中科院分区：
文献类型：
--
作者：
Hlatky, R;Furuya, Y;Robertson, CS
Object.本研究的目的是评估重型颅脑损伤后脑压力自动调节功能受损的程度和时间。方法.在一项对122例严重头部创伤患者（中位格拉斯哥昏迷评分6分）的前瞻性研究中，在伤后前5天内每12小时进行一次压力自动调节动态试验，在接下来的5天内每天进行一次。计算每项试验的自动调节指数（[ARI]正常值5 +/- 1.1）。ARI随时间的变化进行了检查，并与其他生理变量进行比较。ARI在伤后12小时内平均为2.8 ± 1.9，并在伤后36至48小时继续下降至最低点1.7 ± 1.1。在此最低点，87%的患者的数值小于2.8。尽管脑血流量（CBF）和大脑中动脉血流速度（BFV）增加（p <0.001），但在伤后最初36 - 48小时内ARI持续恶化，并且不能用脑灌注压、潮气末CO2或脑O-2代谢率的变化来解释。在ARI恶化的同时，脑血管阻力显著降低（[CVR]，p < 0.001）。与BFV较低的患者相比，第1天BFV相对较高的患者CVR较低（p < 0.05），压力自动调节受损程度更高。结论.脑血管不能正常调节CBF可能在受损脑对继发性缺血性损伤的脆弱性中起作用。这些研究表明，这种脆弱性持续存在，甚至在受伤后的第一个24小时后增加。影响脑血管张力的局部因素可能是导致这些结果的原因。
Object. The purpose of this study was to evaluate the extent and timing of impairment of cerebral pressure autoregulation after severe head injury. Methods. In a prospective study of 122 patients with severe head trauma (median Glasgow Coma Scale Score 6), dynamic tests of pressure autoregulation were performed every 12 hours during the first 5 days postinjury and daily during the next 5 days. The autoregulatory index ([ARI] normal value 5 +/- 1.1) was calculated for each test. The changes in the ARI over time were examined and compared with other physiological variables. The ARI averaged 2.8 +/- 1.9 during the first 12 hours postinjury, and continued to decrease to a nadir of 1.7 +/- 1.1 at 36 to 48 hours postinjury. At this nadir, in 87% of the patients the value was less than 2.8. This continued deterioration in the ARI during the first 36 to 48 hours postinjury occurred despite an increase in cerebral blood flow ([CBF], p < 0.05) and in middle cerebral artery blood flow velocity ([BFV], p < 0.001), and could not be explained by changes in cerebral perfusion pressure, end-tidal CO2, or cerebral metabolic rate of O-2. A marked decrease in cerebrovascular resistance ([CVR], p < 0.001) accompanied this deterioration in the ARI. Patients with a relatively higher BFV on Day I had a lower CVR (p < 0.05) and more impaired pressure autoregulation than those with a lower BFV. Conclusions. The inability of cerebral vessels to regulate CBF normally may play a role in the vulnerability of the injured brain to secondary ischemic insults. These studies indicate that this vulnerability continues and even increases beyond the first 24 hours postinjury. Local factors affecting cerebrovascular tone may be responsible for these findings.