Department of Anesthesia and Critical Care Medicine.
FROM Research Foundation, Papa Giovanni XXIII Hospital, Bergamo.
J Neurosurg Anesthesiol. 2023 Jul 1;35(3):313-321. doi: 10.1097/ANA.0000000000000847. Epub 2022 May 3.
The pressure reactivity index (PRx) has emerged as a surrogate method for the continuous bedside estimation of cerebral autoregulation and a predictor of unfavorable outcome after traumatic brain injury (TBI). However, calculation of PRx require continuous high-resolution monitoring currently limited to specialized intensive care units. The aim of this study was to evaluate a new index, the ultra-low-frequency PRx (UL-PRx) sampled at ∼0.0033 Hz at ∼5 minutes periods, and to investigate its association with outcome.
Demographic data, admission Glasgow coma scale, in-hospital mortality and Glasgow outcome scale extended at 12 months were extracted from electronic records. The filtering and preparation of time series of intracranial pressure (ICP), mean arterial pressure and cerebral perfusion pressure (CPP), and calculation of the indices (UL-PRx, Δ-optimal CPP), were performed in MATLAB using an in-house algorithm.
A total of 164 TBI patients were included in the study; in-hospital and 12-month mortality was 29.3% and 38.4%, respectively, and 64% of patients had poor neurological outcome at 12 months. On univariate analysis, ICP, CPP, UL-PRx, and ΔCPPopt were associated with 12-month mortality. After adjusting for age, Glasgow coma scale, ICP and CPP, mean UL-PRx and UL-PRx thresholds of 0 and +0.25 remained associated with 12-month mortality. Similar findings were obtained for in-hospital mortality. For mean UL-PRx, the area under the receiver operating characteristic curves for in-hospital and 12-month mortality were 0.78 (95% confidence interval [CI]: 0.69-0.87; P <0.001) and 0.70 (95% CI: 0.61-0.79; P <0.001), respectively, and 0.65 (95% CI: 0.57-0.74; P =0.001) for 12-month neurological outcome.
Our findings indicate that ultra-low-frequency sampling might provide sufficient resolution to derive information about the state of cerebrovascular autoregulation and prediction of 12-month outcome in TBI patients.
压力反应指数 (PRx) 已成为一种替代方法，可连续床边估计脑自动调节，并预测创伤性脑损伤 (TBI) 后的不良预后。然而，PRx 的计算需要目前仅限于专门重症监护病房的连续高分辨率监测。本研究的目的是评估一种新的指数，即超低频 PRx (UL-PRx)，以约 0.0033 Hz 的频率进行采样，时间约为 5 分钟，并研究其与预后的关系。
从电子记录中提取人口统计学数据、入院格拉斯哥昏迷量表、住院期间死亡率和 12 个月时的格拉斯哥结局量表扩展。使用 MATLAB 中的内部算法对颅内压 (ICP)、平均动脉压和脑灌注压 (CPP) 的时间序列进行滤波和准备，并计算指数 (UL-PRx、Δ-最优 CPP)。
共纳入 164 例 TBI 患者；住院期间和 12 个月死亡率分别为 29.3%和 38.4%，12 个月时 64%的患者神经预后不良。单因素分析显示，ICP、CPP、UL-PRx 和ΔCPPopt 与 12 个月死亡率相关。在校正年龄、格拉斯哥昏迷量表、ICP 和 CPP 后，平均 UL-PRx 和 UL-PRx 阈值为 0 和 +0.25 仍与 12 个月死亡率相关。住院期间死亡率也有类似发现。对于平均 UL-PRx，住院和 12 个月死亡率的受试者工作特征曲线下面积分别为 0.78(95%置信区间[CI]：0.69-0.87；P <0.001)和 0.70(95%CI：0.61-0.79；P <0.001)，而 12 个月时神经结局的面积为 0.65(95%CI：0.57-0.74；P =0.001)。
我们的发现表明，超低频采样可能提供足够的分辨率来获取关于脑血管自动调节状态的信息，并预测 TBI 患者 12 个月的预后。
