Brady Ken M, Shaffner Donald H, Lee Jennifer K, Easley R Blaine, Smielewski Peter, Czosnyka Marek, Jallo George I, Guerguerian Anne-Marie
Division of Pediatric Anesthesiology and Critical Care Medicine, Johns Department of aAnesthesiology and Critical Care, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21287, USA.
Pediatrics. 2009 Dec;124(6):e1205-12. doi: 10.1542/peds.2009-0550.
We hypothesized that pressure reactivity index (PRx) values indicating preserved cerebrovascular pressure autoregulation would be associated with survival in children with traumatic brain injury (TBI). This hypothesis was tested in a prospective, blinded, observational, pilot study.
Twenty-one children admitted between May 2006 and September 2008 with severe TBI necessitating invasive intracranial pressure monitoring were enrolled in this study. The PRx was continuously monitored as a moving, linear correlation coefficient between low-frequency waves of intracranial and arterial blood pressures. Positive values of PRx approaching 1 indicate impaired cerebrovascular pressure reactivity, whereas negative PRx values or values close to 0 indicate preserved cerebrovascular pressure reactivity. Survival was the primary outcome and was compared with the average PRx value obtained during the intracranial pressure-monitoring period.
PRx was associated with survival in this cohort; survivors (N = 15) had a mean PRx +/- SD of 0.08 +/- 0.19, and nonsurvivors (N = 6) had a mean PRx of 0.69 +/- 0.21 (P = .0009). In this sample, continuous PRx monitoring suggested impaired cerebrovascular pressure reactivity at low levels of cerebral perfusion pressure (CPP) and intact cerebrovascular pressure reactivity at higher levels of CPP.
Intact cerebrovascular pressure reactivity quantified with the PRx is associated with survival after severe head trauma in children. The PRx is CPP dependent in children. The PRx may be useful for defining age-specific and possibly patient-specific optimal targets for CPP after TBI.
我们假设，表明脑血管压力自动调节功能得以保留的压力反应性指数（PRx）值与创伤性脑损伤（TBI）患儿的生存率相关。这一假设在一项前瞻性、盲法、观察性试点研究中得到了验证。
本研究纳入了2006年5月至2008年9月期间收治的21例因重度TBI而需要进行有创颅内压监测的患儿。PRx作为颅内压和动脉血压低频波之间的移动线性相关系数进行持续监测。PRx接近1的正值表明脑血管压力反应性受损，而PRx负值或接近0的值表明脑血管压力反应性得以保留。生存率是主要结局，并与颅内压监测期间获得的平均PRx值进行比较。
在该队列中，PRx与生存率相关；幸存者（N = 15）的平均PRx±标准差为0.08±0.19，非幸存者（N = 6）的平均PRx为0.69±0.21（P = 0.0009）。在本样本中，持续的PRx监测表明，在脑灌注压（CPP）较低水平时脑血管压力反应性受损，而在CPP较高水平时脑血管压力反应性正常。
用PRx量化的完整脑血管压力反应性与儿童重度颅脑外伤后的生存率相关。儿童的PRx依赖于CPP。PRx可能有助于确定TBI后针对特定年龄以及可能针对特定患者的CPP最佳目标。
