颅脑创伤中“最佳”脑灌注压的连续评估：一项可行性、可靠性及与预后相关性的队列研究。
Continuous Assessment of "Optimal" Cerebral Perfusion Pressure in Traumatic Brain Injury: A Cohort Study of Feasibility, Reliability, and Relation to Outcome.
机构信息
Department of Critical Care Medicine, University of Calgary, Calgary, Canada.
Department of Clinical Neurosciences, University of Calgary, Calgary, Canada.
出版信息
Neurocrit Care. 2019 Feb;30(1):51-61. doi: 10.1007/s12028-018-0570-4.
BACKGROUND
Guidelines recommend maintaining cerebral perfusion pressure (CPP) between 60 and 70 mmHg in patients with severe traumatic brain injury (TBI), but acknowledge that optimal CPP may vary depending on cerebral blood flow autoregulation. Previous retrospective studies suggest that targeting CPP where the pressure reactivity index (PRx) is optimized (CPP) may be associated with improved recovery.
METHODS
We performed a retrospective cohort study involving TBI patients who underwent PRx monitoring to assess issues of feasibility relevant to future interventional studies: (1) the proportion of time that CPP could be detected; (2) inter-observer variability in CPP determination; and (3) agreement between manual and automated CPP estimates. CPP was determined for consecutive 6-h epochs during the first week following TBI. Sixty PRx-CPP tracings were randomly selected and independently reviewed by six critical care professionals. We also assessed whether greater deviation between actual CPP and CPP (ΔCPP) was associated with poor outcomes using multivariable models.
RESULTS
In 71 patients, CPP could be manually determined in 985 of 1173 (84%) epochs. Inter-observer agreement for detectability was moderate (kappa 0.46, 0.23-0.68). In cases where there was consensus that it could be determined, agreement for the specific CPP value was excellent (weighted kappa 0.96, 0.91-1.00). Automated CPP was within 5 mmHg of manually determined CPP in 93% of epochs. Lower PRx was predictive of better recovery, but there was no association between ΔCPP and outcome. Percentage time spent below CPP increased over time among patients with poor outcomes (p = 0.03). This effect was magnified in patients with impaired autoregulation (defined as PRx > 0.2; p = 0.003).
CONCLUSION
Prospective interventional clinical trials with regular determination of CPP and corresponding adjustment of CPP goals are feasible, but measures to maximize consistency in CPP determination are necessary. Although we could not confirm a clear association between ΔCPP and outcome, time spent below CPP may be particularly harmful, especially when autoregulation is impaired.
背景
指南建议严重创伤性脑损伤（TBI）患者的脑灌注压（CPP）维持在 60-70mmHg 之间，但也承认最佳 CPP 可能因脑血流自动调节而异。先前的回顾性研究表明，针对压力反应指数（PRx）优化的 CPP 目标（CPP）可能与改善恢复相关。
方法
我们进行了一项回顾性队列研究，纳入了接受 PRx 监测的 TBI 患者，以评估与未来干预性研究相关的可行性问题：（1）可检测 CPP 的时间比例；（2）CPP 测定的观察者间变异性；（3）手动和自动 CPP 估计之间的一致性。在 TBI 后第一周的连续 6 小时时段内确定 CPP。随机选择 60 个 PRx-CPP 描记图，并由六名重症监护专业人员独立审查。我们还评估了实际 CPP 和 CPP 之间的差异（ΔCPP）是否与不良结局相关，使用多变量模型。
结果
在 71 名患者中，在 1173 个时段中的 985 个时段（84%）可以手动确定 CPP。可检测性的观察者间一致性为中度（kappa 0.46，0.23-0.68）。在可以确定的情况下，对特定 CPP 值的一致性为极好（加权 kappa 0.96，0.91-1.00）。在 93%的时段中，自动 CPP 与手动确定的 CPP 相差 5mmHg 以内。较低的 PRx 预测恢复较好，但 ΔCPP 与结局之间没有关联。在预后不良的患者中，CPP 以下的时间百分比随时间推移而增加（p=0.03）。在自动调节受损的患者中（定义为 PRx>0.2；p=0.003），这种影响更为明显。
结论
具有定期 CPP 测定和相应 CPP 目标调整的前瞻性干预性临床试验是可行的，但需要采取措施最大限度地提高 CPP 测定的一致性。尽管我们不能确认 ΔCPP 和结局之间的明确关联，但 CPP 以下的时间可能特别有害，特别是当自动调节受损时。
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