Fan Bin Bin, Sun Xiao Chuan, Huang Zhi Jian, Yang Xiao Min, Guo Zong Duo, He Zhao Hui
Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Chin Neurosurg J. 2021 Mar 2;7(1):16. doi: 10.1186/s41016-021-00231-7.
Dysfunction of cerebral autoregulation is one of the pathophysiological mechanisms that causes delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH). Pressure reactivity index (PRx) have been confirmed to reflect the level of cerebral autoregulation and used to derive optimal cerebral perfusion pressure (CPPopt). The goal of this study is to explore the associations between autoregulation, CPPopt, PRx, and DCI.
Continuous intracranial pressure (ICP), arterial blood pressure (ABP), and cerebral perfusion pressure (CPP) signals acquired from 61 aSAH patients were retrospectively analyzed. PRx was calculated and collected by Pneumatic computer system. The CPP at the lowest PRx was determined as the CPPopt. The duration of a hypoperfusion event (dHP) was defined as the cumulative time that the PRx was > 0.3 and the CPP was <CPPopt. The duration of CPP more than 10 mmHg below CPPopt (ΔCPPopt < - 10 mmHg) was also used to assess hypoperfusion. The percent of the time of hypoperfusion by dHP and ΔCPPopt < - 10 mmHg (%dHP and %ΔCPPopt) were compared between DCI group and control group, utilizing univariate and multivariable logistic regression. It was the clinical prognosis at 3 months after hemorrhage that was assessed with the modified Rankin Scale, and logistic regression and ROC analysis were used for predictive power for unfavorable outcomes (mRs 3-5).
Data from 52 patients were included in the final analysis of 61 patients. The mean %dHP in DCI was 29.23% and 10.66% in control. The mean %ΔCPPopt < - 10 mmHg was 22.28%, and 5.90% in control. The %dHP (p < 0.001) and the %ΔCPPopt < - 10mmHg (p < 0.001) was significantly longer in the DCI group. In multivariate logistic regression model, %ΔCPPopt <- 10 mmHg (p < 0.001) and %dHP (p < 0.001) were independent risk factor for predicting DCI, and %ΔCPPopt <- 10 mmHg (p = 0.010) and %dHP (p = 0.026) were independent risk factor for predicting unfavorable outcomes.
The increase of duration of hypoperfusion events and duration of CPP below CPPopt over 10 mmHg, evaluated as time of lowered CPP, is highly indicative of DCI and unfavorable outcomes.
脑自动调节功能障碍是蛛网膜下腔出血（SAH）后导致迟发性脑缺血（DCI）的病理生理机制之一。压力反应性指数（PRx）已被证实可反映脑自动调节水平，并用于推导最佳脑灌注压（CPPopt）。本研究的目的是探讨自动调节、CPPopt、PRx与DCI之间的关联。
回顾性分析61例急性SAH患者获得的连续颅内压（ICP）、动脉血压（ABP）和脑灌注压（CPP）信号。PRx由气动计算机系统计算并收集。将最低PRx时的CPP确定为CPPopt。低灌注事件持续时间（dHP）定义为PRx>0.3且CPP<CPPopt的累计时间。CPP低于CPPopt超过10 mmHg（ΔCPPopt<-10 mmHg）的持续时间也用于评估低灌注。采用单因素和多因素逻辑回归比较DCI组和对照组dHP和ΔCPPopt<-10 mmHg导致的低灌注时间百分比（%dHP和%ΔCPPopt）。用改良Rankin量表评估出血后3个月的临床预后，并采用逻辑回归和ROC分析评估不良结局（mRs 3-5）的预测能力。
61例患者中，52例患者的数据纳入最终分析。DCI组的平均%dHP为29.23%，对照组为10.66%。平均%ΔCPPopt<-10 mmHg在DCI组为22.28%，对照组为5.90%。DCI组的%dHP（p<0.001）和%ΔCPPopt<-10 mmHg（p<0.001）明显更长。在多因素逻辑回归模型中，%ΔCPPopt<-10 mmHg（p<0.001）和%dHP（p<0.001）是预测DCI的独立危险因素，%ΔCPPopt<-10 mmHg（p=0.010）和%dHP（p=0.026）是预测不良结局的独立危险因素。
以CPP降低时间评估，低灌注事件持续时间和CPP低于CPPopt超过10 mmHg的持续时间增加高度提示DCI和不良结局。
