Steinmeier Ralf, Hofmann Robby P, Bauhuf Christian, Hübner Ulrich, Fahlbusch Rudolf
Department of Neurosurgery, University of Erlangen-Nuernberg, Germany.
J Neurotrauma. 2002 Oct;19(10):1127-38. doi: 10.1089/08977150260337949.
In order to validate cross-correlation analysis between spontaneous slow oscillations of arterial blood pressure (aBP) and intracranial pressure (ICP) or flow velocity as a means to assess the status of cerebral autoregulation continuously, we compared its results with different autoregulation bedside tests. The second aim was to check the method's stability over longer time periods. aBP, ICP, and flow velocity in the middle cerebral artery (FV(MCA)) was measured continuously in 13 critically ill comatose patients. Cross-correlation analysis was performed online and offline between aBP and ICP (CC [aBP --> ICP]) and aBP/FV(MCA) (CC [aBP --> FV(MCA)]). Three different autoregulation bedside tests (cuff deflation, transient hyperemic response, orthostatic hypotension) were performed immediately before a 29-min cross-correlation test period. In addition, continuous cross-correlation autoregulation monitoring was performed over multiple hours (in order to analyze for stability and to assess the influence of other factors). Cluster analysis revealed two main clusters. Cluster 1 (indicative for disturbed autoregulation) showed a centroid at t = -0.21 +/- 3.32 sec, r = 0.43 +/- 0.18 for CC [aBP --> ICP], and t = 0 +/- 3.14 sec, r = 0.44 +/- 0.18 for CC [aBP --> FV(MCA)]. Cluster 2 (indicative for normal autoregulation) revealed a centroid at t = 4.94 +/- 3.74 sec, r =- 0.4 +/- 0.16 for CC [aBP --> ICP], and t = 3.38 +/- 4.44 sec, r = -0.38 +/- 0.18 for CC [aBP --> FV(MCA)]. Comparison between the cross-correlation test results and the bedside tests showed a sensitivity of 44-73% for CC [aBP --> FV(MCA)], whereas CC [aBP --> ICP] was more specific (60-80%). Long-term monitoring revealed stable cross-correlation tests in about 45% of the measurement time. It is concluded that cross-correlation between aBP, ICP, and FV(MCA) is a valid means to monitor the autoregulation status continuously, although further improvement of sensitivity and specificity is needed to make it reliable for clinical decision making.
为了验证动脉血压（aBP）的自发缓慢振荡与颅内压（ICP）或血流速度之间的互相关分析作为一种持续评估脑自动调节状态的方法，我们将其结果与不同的自动调节床边测试进行了比较。第二个目的是检查该方法在较长时间段内的稳定性。对13例重症昏迷患者连续测量大脑中动脉的aBP、ICP和血流速度（FV[MCA]）。在aBP与ICP（CC[aBP→ICP]）以及aBP/FV[MCA]（CC[aBP→FV[MCA]]）之间进行在线和离线互相关分析。在29分钟的互相关测试期之前立即进行三种不同的自动调节床边测试（袖带放气、短暂充血反应、直立性低血压）。此外，进行了数小时的连续互相关自动调节监测（以便分析稳定性并评估其他因素的影响）。聚类分析揭示了两个主要聚类。聚类1（指示自动调节受损）在CC[aBP→ICP]时，质心为t = -0.21±3.32秒，r = 0.43±0.18；在CC[aBP→FV[MCA]]时，质心为t = 0±3.14秒，r = 0.44±0.18。聚类2（指示自动调节正常）在CC[aBP→ICP]时，质心为t = 4.94±3.74秒，r = -0.4±0.16；在CC[aBP→FV[MCA]]时，质心为t = 3.38±4.44秒，r = -0.38±0.18。互相关测试结果与床边测试之间的比较表明，CC[aBP→FV[MCA]]的敏感性为44 - 73%，而CC[aBP→ICP]更具特异性（60 - 80%）。长期监测显示，在约45%的测量时间内互相关测试稳定。结论是，aBP、ICP和FV[MCA]之间的互相关是连续监测自动调节状态的有效方法，尽管需要进一步提高敏感性和特异性才能使其可靠地用于临床决策。
