控制性降压对大脑影响的系统评价

Effects of Controlled Hypotension on Cerebra:A Systematic Review

目的通过评价控制性降压(CH)对脑血流、脑代谢及脑高级神经心理功能的影响,为临床安全应用提供依据。方法计算机检索MEDLINE(1966～2008)、EMbase(1974～2008)、Cochrane图书馆(2008年第2期)和中国生物医学文献数据库(CBM,1978～2008)、中国期刊全文数据库(CNKI,1994～2008),按纳入与排除标准收集所有相关临床随机对照试验,在评价其质量及提取数据后,采用RevMan4.2.7软件进行统计分析。结果共纳入9个RCT包括295例患者,多数研究方法学质量较低。由于结果指标为重复测量的多个均数间比较,无法进行Meta分析,仅作描述性分析。结果显示:CH组患者大脑中动脉血流、脑缺氧代谢产物、神经心理测量表评分与对照组相比差异均无统计学意义(P<0.05);但与对照组相比,CH组患者术后脑脊液和血中S100蛋白含量显著增高(P<0.02)。结论控制性降压不影响脑血流,不出现缺氧脑代谢,不影响神经生理功能,但在颅内动脉瘤夹闭术患者运用异氟醚行CH可能会加重脑损害。由于本系统评价纳入研究质量不高,病例数较少,上述结论尚需进一步设计严谨的大样本随机对照研究加以验证。

Objective To determine the effects of controlled hypotension （CH） on cerebral blood flow, cerebralmetabolism, and cognitive functions. Methods Randomized controlled trials （RCTs） were identified from MEDLINE （1966 to 2008）, EMbase （1974 to 2008）, The Cocbrane Library （Issue 2, 2008）, CBM （1978 to 2008）, and CNKI （1994 to 2008）. The quality of included trials was assessed by two reviewers independently. RevMan 4.2.7 software provided by The Cochrane Collaboration was used for statistical analysis. Results Nine RCTs involving a total of 295 patients were included. Most of the studies were of poor methodological quality. Meta-analysis was performed because the outcomes were the comparisons of the means of several repeated measures, and so a descriptive analysis was conducted. There were no significant differences in cerebral blood flow velocity, hypoxia-induced metabolites, and cognitive function between the CH group and the control group （P〈0.05）. But the S100B protein level in cerebrospinal fluid or blood was significantly higher in the CH group than that in the control group （P〈0.02）. Conclusion CH has no adverse effects on cerebral blood flow, cerebral metabolism, or cognitive functions. But isoflurane-induced hypotension may increase the release of S100B, indicating worse brain injury. The above conclusions were made from the limited evidence, and more rigorous RCTs are needed.