背景:中度至重度创伤性脑损伤(TBI)的全球死亡率约为30%,导致许多幸存者终身残疾。为了潜在地改善这种TBI人群的结果,二次伤害的管理,特别是脑血管反应性的失败(通过压力反应性指数评估;PRx,颅内压(ICP)和平均动脉血压(MAP)之间的相关性,在该领域获得了兴趣。然而,PRx的推导需要高分辨率数据和昂贵的技术解决方案,因为计算使用很短的时间窗口,这导致它仅在全球少数中心使用。作为一个解决方案,低分辨率(较长的时间窗口)PRx已被建议,称为Long-PRx或LPRx。尽管LPRx已被提出,但人们对得出这一度量的最佳方法知之甚少,提出了不同的阈值和时间窗口。此外,ICP监测对脑血管反应性措施的影响知之甚少.因此,这项观察性研究建立了与长期功能结果相关的LPRx的关键阈值,比较计算LPRx的不同时间窗口以及评估通过外部心室引流(EVD)和实质内压力装置(IPD)ICP监测确定的LPRx。
方法:该研究包括来自卡罗林斯卡大学医院的总共435名TBI患者。患者被分为活着的和活着的。死亡和有利的vs.基于1年格拉斯哥结果量表(GOS)的不利结果。计算Pearson卡方值,以逐步增加LPRx或ICP阈值。为每个LPRx或ICP参数产生最大卡方值的阈值具有最高的结果判别能力。该方法也完成了基于EVD的人群分割,IPD,和住院时间的数据记录。
结果:用10-120分钟窗口计算的LPRx表现类似,对于生存和有利的结局,最大卡方值在0.25-0.35的LPRx左右。在调查LPRx导出阈值的时间关系时,前4天似乎与结局最相关.基于颅内监测的数据分割发现EVD和IPD之间存在有限的差异,类似的LPRx值约为0.3。
结论:我们的工作表明,导致脑血管反应性受损的潜在预后因素可以,在某种程度上,使用较低分辨率的PRx度量(类似的发现阈值)检测到LPRx,临床上使用低至每分钟10分钟的MAP和ICP样本。此外,EVD衍生的LPRx,间歇性脑脊液引流,似乎呈现与IPD相似的结果能力。这种低分辨率低样本LPRx方法似乎足以替代PRx的临床预后价值,并且当PRx不可行时,可以独立于ICP监测方法实施。尽管需要进一步的研究。
BACKGROUND: Moderate-to-severe traumatic brain injury (TBI) has a global mortality rate of about 30%, resulting in acquired life-long disabilities in many survivors. To potentially improve outcomes in this TBI population, the management of secondary injuries, particularly the failure of cerebrovascular reactivity (assessed via the pressure reactivity index; PRx, a correlation between intracranial pressure (ICP) and mean arterial blood pressure (MAP)), has gained interest in the field. However, derivation of PRx requires high-resolution data and expensive technological solutions, as calculations use a short time-window, which has resulted in it being used in only a handful of centers worldwide. As a solution to this, low resolution (longer time-windows) PRx has been suggested, known as Long-PRx or LPRx. Though LPRx has been proposed little is known about the best methodology to derive this measure, with different thresholds and time-windows proposed. Furthermore, the impact of ICP monitoring on cerebrovascular reactivity measures is poorly understood. Hence, this observational study establishes critical thresholds of LPRx associated with long-term functional outcome, comparing different time-windows for calculating LPRx as well as evaluating LPRx determined through external ventricular drains (EVD) vs intraparenchymal pressure device (IPD) ICP monitoring.
METHODS: The study included a total of n = 435 TBI patients from the Karolinska University Hospital. Patients were dichotomized into alive vs. dead and favorable vs. unfavorable outcomes based on 1-year Glasgow Outcome Scale (GOS). Pearson\'s chi-square values were computed for incrementally increasing LPRx or ICP thresholds against outcome. The thresholds that generated the greatest chi-squared value for each LPRx or ICP parameter had the highest outcome discriminatory capacity. This methodology was also completed for the segmentation of the population based on EVD, IPD, and time of data recorded in hospital stay.
RESULTS: LPRx calculated with 10-120-min windows behaved similarly, with maximal chi-square values ranging at around a LPRx of 0.25-0.35, for both survival and favorable outcome. When investigating the temporal relations of LPRx derived thresholds, the first 4 days appeared to be the most associated with outcomes. The segmentation of the data based on intracranial monitoring found limited differences between EVD and IPD, with similar LPRx values around 0.3.
CONCLUSIONS: Our work suggests that the underlying prognostic factors causing impairment in cerebrovascular reactivity can, to some degree, be detected using lower resolution PRx metrics (similar found thresholding values) with LPRx found clinically using as low as 10 min-by-minute samples of MAP and ICP. Furthermore, EVD derived LPRx with intermittent cerebrospinal fluid draining, seems to present similar outcome capacity as IPD. This low-resolution low sample LPRx method appears to be an adequate substitute for the clinical prognostic value of PRx and may be implemented independent of ICP monitoring method when PRx is not feasible, though further research is warranted.