目的:动脉二氧化碳分压(PaCO2)是脑血流量(CBF)的主要调节因子。PaCO2的紊乱被认为通过改变CBF使多种形式的脑损伤后的临床结果恶化。我们的目的是系统分析生物医学文献,以确定PaCO2排列对脑损伤后临床结局的影响。
方法:我们搜索了Cochrane库,pubmed,CINHAL,会议记录,和其他来源使用全面的策略。研究纳入标准是(1)人类受试者;(2)脑损伤;(3)伤后机械通气;(4)PaCO2的测量;和(5)不同PaCO2暴露之间的临床结果测量(例如死亡率)的比较。我们根据Cochrane手册的推荐方法进行了定性分析,以整理和总结PaCO2紊乱的影响。
结果:涉及脑损伤不同病因的17项研究(6项创伤性脑损伤,心脏骤停后综合征,两次脑血管意外,3例新生儿缺血性脑病)符合所有纳入标准,无排除标准。根据评估偏倚风险的Cochrane标准,确定了三项随机对照试验,只有一项被认为是高质量的研究。在13/17(76%)检查低碳酸血症的研究中,和7/10(70%)检查高碳酸血症的研究,暴露组(高碳酸血症或低碳酸血症)与不良临床结局相关.
结论:本报告中的大多数研究发现,脑损伤后暴露于低碳酸血症和高碳酸血症与不良的临床结局有关。然而,与良好临床结局相关的最佳PaCO2范围仍不清楚.
OBJECTIVE: Partial pressure of arterial carbon dioxide (PaCO2) is a major regulator of cerebral blood flow (CBF). Derangements in PaCO2 have been thought to worsen clinical outcomes after many forms of cerebral injury by altering CBF. Our aim was to systematically analyze the biomedical literature to determine the effects of PaCO2 derangements on clinical outcomes after cerebral injury.
METHODS: We performed a search of Cochrane Library, PUBMED, CINHAL, conference proceedings, and other sources using a comprehensive strategy. Study inclusion criteria were (1) human subjects; (2) cerebral injury; (3) mechanical ventilation post-injury; (4) measurement of PaCO2; and (5) comparison of a clinical outcome measure (e.g. mortality) between different PaCO2 exposures. We performed a qualitative analysis to collate and summarize effects of PaCO2 derangements according to the recommended methodology from the Cochrane Handbook.
RESULTS: Seventeen studies involving different etiologies of cerebral injury (six traumatic brain injury, six post-cardiac arrest syndrome, two cerebral vascular accident, three neonatal ischemic encephalopathy) met all inclusion and no exclusion criteria. Three randomized control trials were identified and only one was considered a high quality study as per the Cochrane criteria for assessing risk of bias. In 13/17 (76%) studies examining
hypocapnia, and 7/10 (70%) studies examining hypercapnia, the exposed group (hypercapnia or
hypocapnia) was associated with poor clinical outcome.
CONCLUSIONS: The majority of studies in this report found exposure to
hypocapnia and hypercapnia after cerebral injury to be associated with poor clinical outcome. However, the optimal PaCO2 range associated with good clinical outcome remains unclear.