An assessment of dynamic autoregulation from spontaneous fluctuations of cerebral blood flow velocity: A comparison of two models, index of autoregulation and mean flow index
An assessment of dynamic autoregulation from spontaneous fluctuations of cerebral blood flow velocity: A comparison of two models, index of autoregulation and mean flow index
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DOI：
10.1213/01.ane.0000295802.89962.13
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发表时间：
2008-01-01
影响因子：
5.7
通讯作者：
Panerai, Ronney
中科院分区：
文献类型：
--
作者：
Czosnyka, Marek;Smielewski, Piotr;Panerai, Ronney
背景：利用血流速度（FV）、动脉血压和脑灌注压的自发缓慢波动来评估脑自动调节的各种方法已在临床实践中使用。我们研究了自动调节动态指数之间的关联。方法：对 50 名平均年龄 31 岁的头部受伤患者进行研究，这些患者接受镇静、麻痹和通气（轻度低碳酸血症），并持续监测动脉血压和颅内压。受伤后 3 天，在没有干预（例如抽吸）的期间，每天监测脑血 FV。对数字记录的数据进行回顾性分析。 ARI 计算为从 0（缺乏自动调节）到 9（最强自动调节）的系数，描述了自动调节的动态模型。 Mx 计算为 40 个连续 6 秒 FV 平均值与脑灌注压之间的相关系数，然后在整个记录期间取平均值。对每位患者在受伤后前 3 天内评估的 ARI 和 Mx 值进行平均。结果：ARI 和 Mx 显示出中等强度的相互线性关系，相关性 r = -0.62； P = 0.0001。这两个指数都与结果相关，表明达到不利结果的患者的自动调节能力较差。结论：ARI 和 Mx 在头部受伤患者中的一致性相对较好。自我调节会影响头部受伤后的结果。
BACKGROUND: Various methods of assessment of cerebral autoregulation, using spontaneous slow fluctuations of blood flow velocity (FV), arterial blood pressure, and cerebral perfusion pressure, have been used in clinical practice. We studied the association between the dynamic index of autoregulation. (ARI) and time correlation index (mean flow index, Mx) in a group of patients after head injury.METHODS: Fifty head-injured patients of an average age of 31 yr, sedated, paralyzed, and ventilated (mild hypocapnia) with continuous monitoring of arterial blood pressure and intracranial pressure were studied. Cerebral blood FV was monitored daily for 3 days after injury during periods that were free from interventions (e.g., suctioning).Digitally recorded data were analyzed retrospectively. ARI was calculated as a coefficient graded from 0 (absence of autoregulation) to 9 (strongest autoregulation), describing a dynamic model of autoregulation. Mx was calculated as the correlation coefficient between 40 consecutive 6-s averages of FV and cerebral perfusion pressure and then averaged over the whole recording period. ARI and Mx values, assessed during the first 3 days after injury, were averaged for each patient.RESULTS: ARI and Mx showed moderately strong mutual linear relationship with correlation r = -0.62; P = 0.0001. Both indices correlated with outcome, indicating worse autoregulation in patients achieving unfavorable outcome.CONCLUSION: ARI and Mx agree relatively well in head-injured patients. Autoregulation affects outcome after head injury.