Near-infrared spectroscopy regional cerebral oxygen saturation (rSO2) has gained interest as a raw parameter and as a basis for measuring cerebrovascular reactivity (CVR) due to its noninvasive nature and high spatial resolution. However, the prognostic utility of these parameters has not yet been determined. This study aimed to identify threshold values of rSO2 and rSO2-based CVR at which outcomes worsened following traumatic brain injury (TBI). A retrospective multi-institutional cohort study was performed. The cohort included TBI patients treated in four adult intensive care units (ICU). The cerebral oxygen indices, COx (using rSO2 and cerebral perfusion pressure) as well as COx_a (using rSO2 and arterial blood pressure) were calculated for each patient. Grand mean thresholds along with exposure-based thresholds were determined utilizing sequential chi-squared analysis and univariate logistic regression, respectively. In the cohort of 129 patients, there was no identifiable threshold for raw rSO2 at which outcomes were found to worsen. For both COx and COx_a, an optimal grand mean threshold value of 0.2 was identified for both survival and favorable outcomes, while percent time above − 0.05 was uniformly found to have the best discriminative value. In this multi-institutional cohort study, raw rSO2was found to contain no significant prognostic information. However, rSO2-based indices of CVR, COx and COx_a, were found to have a uniform grand mean threshold of 0.2 and exposure-based threshold of − 0.05, above which clinical outcomes markedly worsened. This study lays the groundwork to transition to less invasive means of continuously measuring CVR.

中文翻译：

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近红外光谱局部氧饱和度和脑血管反应性指数在急性创伤性神经损伤中的预后价值：加拿大高分辨率创伤性脑损伤 (CAHR-TBI) 队列研究

近红外光谱局部脑氧饱和度 (rSO2) 由于其无创性和高空间分辨率，作为原始参数和测量脑血管反应性 (CVR) 的基础而引起人们的兴趣。然而，这些参数的预后效用尚未确定。本研究旨在确定 rSO2 和基于 rSO2 的 CVR 阈值，在该阈值下，创伤性脑损伤 (TBI) 后结果会恶化。进行了一项回顾性多机构队列研究。该队列包括在四个成人重症监护病房 (ICU) 接受治疗的 TBI 患者。计算每位患者的脑氧指数、COx（使用rSO2和脑灌注压）以及COx_a（使用rSO2和动脉血压）。分别利用序贯卡方分析和单变量逻辑回归确定总平均阈值和基于暴露的阈值。在 129 名患者的队列中，原始 rSO2 没有可识别的阈值，达到该阈值后结果会恶化。对于 COx 和 COx_a，针对生存和有利结果确定了最佳总平均阈值 0.2，而高于 − 0.05 的时间百分比被一致认为具有最佳判别值。在这项多机构队列研究中，发现原始 rSO2 不包含显着的预后信息。然而，基于 rSO2 的 CVR、COx 和 COx_a 指数被发现具有统一的总平均阈值 0.2 和基于暴露的阈值 - 0.05，高于该阈值临床结果明显恶化。这项研究为过渡到连续测量 CVR 的侵入性较小的方法奠定了基础。