Jaeger Matthias, Schuhmann Martin U, Soehle Martin, Meixensberger Jürgen
Department of Neurosurgery, University of Leipzig, Leipzig, Germany.
Crit Care Med. 2006 Jun;34(6):1783-8. doi: 10.1097/01.CCM.0000218413.51546.9E.
To evaluate whether two newly developed indexes of brain tissue oxygen pressure reactivity (ORx and bPtio2) provide information on the status of cerebrovascular autoregulation after traumatic brain injury. This was accomplished by analyzing the relationship between these indexes and an index of cerebrovascular pressure reactivity (PRx). PRx is an established parameter for estimation of cerebrovascular autoregulation.
Retrospective analysis of prospectively collected data.
Neurosurgical intensive care unit of a university hospital.
Twenty-seven patients suffering from severe traumatic brain injury.
Continuous monitoring of mean arterial blood pressure, intracranial pressure, cerebral perfusion pressure, and partial pressure of brain tissue oxygen (Ptio2) was performed for an average of 6.5 days. ORx was calculated as a moving correlation coefficient between values of cerebral perfusion pressure and Ptio2. The bPtio2 was calculated as a moving value of the slope of the linear regression function between cerebral perfusion pressure and Ptio2. PRx was calculated as a moving correlation coefficient between values for intracranial pressure and mean arterial blood pressure. Outcome was assessed at 6 months after traumatic brain injury (Glasgow Outcome Scale).
Both ORx and bPtio2 correlated significantly with PRx (r=.55 for ORx, r=.52 for bPtio2, p<.01). PRx and ORx showed a significantly negative correlation to the monitored Ptio2 values (r=-.42 for PRx, r=-.41 for ORx, p<.05) and outcome (r=-.52 for PRx, r=-.62 for ORx, p<.01), whereas bPtio2 did not.
ORx and, to a lesser extent, bPtio2 correlated with the autoregulatory marker PRx and provide additional information about the status of cerebrovascular autoregulation after traumatic brain injury. The data also suggested that patients with impaired autoregulation are at increased risk for secondary cerebral hypoxia.
评估两个新开发的脑组织氧分压反应性指标（ORx和bPtio2）是否能提供创伤性脑损伤后脑血管自动调节状态的相关信息。这通过分析这些指标与脑血管压力反应性指标（PRx）之间的关系来实现。PRx是用于评估脑血管自动调节的既定参数。
对前瞻性收集的数据进行回顾性分析。
大学医院的神经外科重症监护病房。
27例重度创伤性脑损伤患者。
连续监测平均动脉血压、颅内压、脑灌注压和脑组织氧分压（Ptio2），平均监测6.5天。ORx计算为脑灌注压值与Ptio2值之间的移动相关系数。bPtio2计算为脑灌注压与Ptio2之间线性回归函数斜率的移动值。PRx计算为颅内压值与平均动脉血压值之间的移动相关系数。在创伤性脑损伤后6个月评估结果（格拉斯哥预后量表）。
ORx和bPtio2均与PRx显著相关（ORx的r = 0.55，bPtio2的r = 0.52，p < 0.01）。PRx和ORx与监测的Ptio2值（PRx的r = -0.42，ORx的r = -0.41，p < 0.05）和结果（PRx的r = -0.52，ORx的r = -0.62，p < 0.01）呈显著负相关，而bPtio2则不然。
ORx以及在较小程度上的bPtio2与自动调节标志物PRx相关，并提供了创伤性脑损伤后脑血管自动调节状态的额外信息。数据还表明，自动调节受损的患者发生继发性脑缺氧的风险增加。
