50例麻痹性痴呆患者认知障碍特征

目的探讨麻痹性痴呆（GPI）患者认知障碍的特征。 方法选取首都医科大学附属北京地坛医院神经内科确诊的麻痹性痴呆患者50例及同期相匹配的无症状型神经梅毒（ANS）患者50例作为研究对象,采用简易精神状态量表（MMSE）评估各组患者认知障碍情况,比较不同痴呆程度GPI患者量表评分,采用多因素线性回归分析GPI患者MMSE评分的影响因素。 结果GPI组患者MMSE总分（22.50 ± 5.26）低于ANS组（28.60 ± 1.56）,差异有统计学意义（t = 7.852、P < 0.001）。两组患者MMSE各分项得分比较显示,GPI组患者定向力（6.78 ± 2.50）、注意力与计算力（3.16 ± 1.82）、回忆力（1.48 ± 1.05）和语言能力（7.28 ± 1.49）等均显著低于ANS组（9.68 ± 0.55、4.30 ± 1.07、2.70 ± 0.54、8.00 ± 0.00）,差异均有统计学意义（t = 8.006、P = 0.000,t = 3.811、P < 0.001,t = 7.271,P < 0.001,t = 3.428、P = 0.001)。中重度GPI患者的定向力、记忆力、回忆力及语言能力等各分项得分低于轻度组,但差异无统计学意义（t = 0.791、P = 0.433,t = 0.350、P = 0.728,t = 0.250,P = 0.804,t = 1.452、P = 0.153）。多因素线性回归分析显示,年龄影响MMSE评分,GPI患者年龄越大,MMSE评分越低（β =-0.365、P < 0.001）。 结论麻痹性痴呆患者存在全面性认知功能下降,年龄因素对认知障碍具有影响。     

脑源性神经营养因子与腹膜透析患者认知功能障碍的相关性分析

目的：探讨脑源性神经营养因子（BDNF）与持续性非卧床腹膜透析（CAPD）患者认知功能障碍的相关性。方法：以CAPD患者为研究对象,采用中文版蒙特利尔认知评估量表（MoCA）调查其认知功能,并检测血清BDNP水平,采用相关分析法探讨CAPD患者认知功能与BDNP的相关性。结果：（1）98例CAPD患者中伴有认知功能障碍者58例,占59．18％。（2）CAPD组MoCA总分、注意力、延迟回忆和抽象评分显著低于健康对照组,差异均有统计学意义（P＜0．05）。（3）CAPD伴认知功能障碍组和CAPD不伴认知功能障碍组的BDNF均显著低于健康对照组,差异有统计学意义（P＜0．01）;CAPD伴认知功能障碍组的BDNF显著低于CAPD不伴认知功能障碍组,差异有统计学意义（P＜0．01）。（4）血清BDNF与MoCA总分、注意力、延迟回忆和抽象均显著正相关（P＜0．05）。结论：CAPD患者认知功能障碍患病率较高,BDNF可能与CAPD患者认知功能障碍有美．     

麻痹性痴呆与无症状型神经梅毒患者的脑电信号复杂度分析

目的采用非线性动力学手段,分析麻痹性痴呆（GPI）和无症状型神经梅毒（AN）患者的脑电信号复杂度（LZC）特点。 方法选取2015年7月至2017年10月于首都医科大学附属北京地坛医院收治的42例麻痹性痴呆（GPI组）和43例无症状型神经梅毒患者（AN组）安静闭眼状态下的脑电信号（LZ）,于Matlab 7.0平台上进行LZC分析,比较两组患者LZC值的变化。 结果GPI组患者在各导联、左右半球及全脑LZC值均低于AN组,其中双额（F3、F4）、双颞（T5、T6）及右中央（C4）导联LZC值显著降低（F3：0.417 ± 0.116 vs. 0.468 ± 0.128,F4：0.413 ± 0.115 vs. 0.463 ± 0.130,T5：0.398 ± 0.117 vs. 0.457 ± 0.128,T6：0.395 ± 0.115 vs. 0.456 ± 0.128,C4：0.405 ± 0.120 vs. 0.462 ± 0.125）,差异均具有统计学意义（t = 2.792、P = 0.043,t = 2.753、P = 0.045,t = 2.711、P = 0.047,t = 2.766、P = 0.044,t = 3.017、P = 0.031）。 结论LZC值可作为认知功能变化较灵敏的观察指标。随着认知功能的降低,麻痹性痴呆患者额、颞区LZC值可同向下降,可能为麻痹性痴呆的早期诊断及预后评估提供有价值的预测依据。     

高血压合并脑小血管病患者情感淡漠危险因素及其与认知功能的相关性

目的 观察高血压合并脑小血管病（CSVD）患者情感淡漠危险因素及其与认知功能的相关性。方法 前瞻性纳入141例高血压合并CSVD患者,根据神经精神问卷-淡漠量表（NPI-Apathy）将其分为淡漠组（n=43）与非淡漠组（n=98）。比较组间一般资料、影像学标志物评分及影像学总负荷评分;以多因素logistic回归分析观察高血压合并CSVD患者情感淡漠的独立危险因素,以Spearman相关分析观察其情感淡漠与认知功能的相关性。结果 淡漠组患者年龄、高密度脂蛋白胆固醇（HDL-C）、侧脑室旁脑白质高信号（WMH）Fazekas评分、深部/幕下脑微出血及总负荷评分均高于非淡漠组（P均<0.05）;其简易精神状态检查（MMSE）及蒙特利尔认知评估（MoCA）评分均低于非淡漠组（P均<0.05）。HDL-C及侧脑室旁WMH Fazekas评分均为高血压合并CSVD患者情感淡漠的独立危险因素（P均<0.05）,且其NPI-Apathy评分与MMSE评分及MoCA评分均呈中度负相关（r=-0.543、-0.484,P均<0.001）。结论 HDL-C及侧脑室旁WMH Faz...     

戊型肝炎患者血清GP73变化特征及意义

目的观察戊型肝炎患者血清GP73变化特征。 方法分析80例健康体检者（对照组）和66例戊型肝炎患者（观察组）血清GP73水平的变化。 结果对照组研究对象血清GP73水平为（38.82 ± 15.67）ng/ml,观察组患者血清GP73为（80.06 ± 52.33）ng/ml,较对照组显著升高,差异具有统计学意义（t = 6.785、P < 0.00）;患者血清GP73水平与丙氨酸氨基转移酶（ALT）活性（r = 0.28、P = 0.015）、天门冬氨酸氨基转移酶（AST）活性（r = 0.36、P = 0.002）总胆红素（TBil）水平（r = 0.47、P < 0.001）均呈正相关,而与凝血酶原活动度（PTA）水平呈负相关（r =－0.329、P = 0.004）。 结论血清GP73显著升高的人群需考虑急性戊型肝炎病毒感染的可能。戊型肝炎患者的血清GP73水平可能与肝功能损伤程度具有一定的相关性。     

青少年肌阵挛性癫痫患者镜像同伦功能连接的初步研究

目的采用镜像同伦连接(VMHC)技术观察青少年肌阵挛性癫痫(JME)患者静息态功能连接的异常改变,以及连接强度与认知间的相关性。方法收集JME患者21例(JME组)及与之匹配的健康志愿者21名(对照组)进行静息态BOLD MR检查。图像数据采用DPABI中DPASFA软件进行预处理,之后采用REST软件进行VMHC分析,提取两组间有差异脑区,并将其与蒙特利尔认知评估量表(MoCa)评分进行相关性分析。结果与对照组比较,JME组的双侧尾状核、丘脑、额中回、额下回及枕中回VMHC值增加(Alphasim校正,P0.01);JME组的双侧尾状核VMHC值与MoCa评分呈正相关(r=0.43,P=0.015)。结论 JME患者静息态下基底核—丘脑—皮层环路中多个脑区间功能连接异常,且双侧尾状核异常可能与认知障碍有关。     

动脉自旋标记成像评估颈内动脉狭窄患者脑血流量

目的探讨以动脉自旋标记(ASL)成像评估颈内动脉狭窄患者脑血流量(CBF)的可行性。方法对30例一侧颈内动脉狭窄患者分别行MR平扫、DWI、三维时间飞跃(3D-TOF)及ASL序列扫描。根据3D-TOF序列图像将颈内动脉狭窄程度分为轻度、中度及重度,分别计算并对比健侧、患侧基底核区、半卵圆中心、前分水岭区、额叶皮质及颞叶皮质CBF。结果一侧颈内动脉轻度狭窄11例、中度狭窄9例、重度狭窄10例。轻度及中度狭窄患者健侧与患侧基底核区、半卵圆中心、前分水岭区、额叶皮质及颞叶皮质CBF差异均无统计学意义(P均0.05),而重度狭窄患者健侧脑区CBF均高于患侧(P均0.05)。上述脑区CBF值随狭窄程度增加而逐渐减小(P均0.05),颈内动脉狭窄程度与患侧大脑半球CBF呈高度负相关(r=-0.966,P0.001)。结论 ASL可定量、准确评估颈内动脉狭窄患者CBF,对指导临床治疗和评估疗效具有重要意义。     

21例神经梅毒患者异常图形翻转视觉诱发电位分析

目的探讨图形翻转视觉诱发电位（P-VEP）在神经梅毒所致视神经损伤患者的早期诊断及病情评估中的应用价值。 方法收集2016年1月至2019年12月于首都医科大学附属北京地坛医院完善P-VEP检查且P100波潜伏期异常的21例神经梅毒患者，分析其P-VEP结果、临床表现、脑脊液及血清指标的特点。 结果21例P-VEP异常的神经梅毒患者中以男性患者多见（76%、16/21），平均年龄为（45.0 ± 11.5）岁。17例患者眼部症状阳性，4例患者眼部症状阴性。17例眼部症状阳性的患者均被诊断为视神经炎。P-VEP异常主要表现为P100波潜伏期延长或P100波缺失。患眼P100波潜伏期（135.16 ± 22.21）ms较正常眼潜伏期（92.75 ± 8.26）ms显著延长，差异有统计学意义（t =－2.813、P = 0.007）。眼部症状阳性的神经梅毒患者较症状阴性患者的P100波潜伏期更长[（137.94 ± 23.12）ms vs.（120.33 ± 5.50）ms]，差异有统计学意义（t = 1.28、P = 0.217）。P100波潜伏期和脑脊液白细胞（r = 0.349、P = 0.155）及蛋白（r = 0.240、P = 0.323）间无显著相关性。追踪分析8例治疗后复查患者的临床资料，发现治疗前后P100波潜伏期变化与血清及脑脊液常规、生化指标间无显著相关性（P均> 0.05）。有5只患眼表现为P100波缺失，其在治疗后6个月内P100波仍缺失。 结论神经梅毒患者P-VEP检查P100波潜伏期延长或波形缺失提示视神经损害；P100波波形缺失可能提示视神经损伤较为严重或不可逆转；在神经梅毒患者未出现视神经受损症状前即可通过检查P-VEP发现视神经受损，为明确神经梅毒患者是否存在视神经损伤及损伤程度提供一定依据。     

基于弥散张量成像分析非病灶性颞叶癫痫患者脑白质网络结构变化与其执行功能障碍的关系

目的 基于弥散张量成像（DTI）评估非病灶性颞叶癫痫（nl-TLE）患者脑白质网络结构变化,分析其与患者执行功能障碍的关系。方法 比较40例nl-TLE患者（nl-TLE组）与43名健康志愿者（对照组）的神经心理学测试评分和执行功能特征;基于DTI分析组间脑白质体积存在显著差异脑区的分布,对比脑白质纤维束各向异性分数（FA）和平均扩散率（MD）;以Pearson相关分析观察nl-TLE患者脑白质体积及脑白质纤维束FA、MD值与其执行功能特征的相关性。结果 nl-TLE组蒙特利尔认知评估（MOCA）、波士顿命名测试（BNT）、雷伊听觉语言学习测试（RAVLT）即刻记忆及延迟回忆评分均低于对照组;其数字广度顺向、词语流畅性低于对照组,Stroop C、朝向一致目标RT、双朝向目标RT、执行网络效率值均高于对照组（P均<0.01）。nl-TLE组左（L）-海马、右（R）-颞上回、R-楔前叶、R-后扣带回脑白质体积均小于对照组（P均<0.001）;R-下纵束、L-扣带回、L-穹隆脑白质纤维束FA值较对照组降低,L-额枕下束、R-穹隆的脑白质纤维束MD值较对照组增加（P均<0.05）。nl-TLE患者上述脑区脑白质体积及脑白质纤维束FA值、MD值分别与数字广度顺向、词语流畅性、Stroop C、朝向一致目标RT、双朝向目标RT及执行网络效率值存在相关性（P均<0.05）。结论 DTI可用于评估nl-TLE患者脑白质网络结构;脑白质网络结构改变与患者执行功能障碍有关。     

乙型肝炎病毒感染者血清干扰素诱导基因20 kDa蛋白表达水平及其临床意义

目的观察乙型肝炎病毒感染者血清干扰素诱导基因20 kDa蛋白（ISG20）蛋白表达变化及其临床意义。 方法选取2017年3月至2018年6月汉中市中心医院收治的HBV感染所致慢性乙型肝炎患者（CHB组）67例、肝硬化患者（LC组）58例、肝癌患者（HCC组）54例和同期体检47例健康者（对照组）。采用酶联免疫吸附法检测各组研究对象血清ISG20蛋白水平。比较不同组患者血清ISG20水平差异。采用Spearman相关分析探讨血清ISG20水平与各组患者年龄、性别、红细胞计数、白细胞计数、血小板计数、天门冬氨酸氨基转移酶（AST）、丙氨酸氨基转移酶（ALT）、总胆红素（TBil）、直接胆红素（DBil）、白蛋白、凝血酶原、甲胎蛋白（AFP）、HBV DNA的相关性。 结果对照组患者血清ISG20水平为9.4（0.82～25.72）ng/ml，显著低于CHB组[18.6（1.87～56.32）ng/ml，Z =－1.567、P = 0.034]和HCC组[28.2（3.09～81.42）ng/ml，Z = －1.854、P = 0.021]。HCC组患者血清ISG20水平显著高于CHB组（Z =－1.431、P = 0.041）和LC组[12.9（2.81～77.54）ng/ml，Z =－1.987、P = 0.029）。HCC组不同Child-Pugh分级患者血清ISG20水平差异有统计学意义（H = 6.976、P = 0.031）。HCC组患者血清ISG20水平与AST（r = 0.323、P < 0.001）、ALT（r = 0.248、P = 0.036）、TBil（r = 0.221、P = 0.031）、DBil（r = 0.215、P = 0.043）、AFP（r = 0.176、P = 0.044）呈正相关，与白蛋白呈负相关（r =－0.239、P = 0.019）。 结论HBV感染者，尤其是HBV感染所致HCC患者，血清ISG20水平升高。血清ISG20水平与HBV感染疾病进展和临床参数有一定的相关性。     

Brain magnetic resonance and cognitive function changes in maintenance hemodialysis patients

Objective To investigate cerebrovascular lesions on maintenance hemodialysis (MHD) patients, including types of cerebrovascular disease, and cognitive function changes. Methods A cross-sectional study was applied. A total of 270 MHD patients at hemodialysis center of Peking Union Medical College Hospital were screened, and finally 117 cases were enrolled. Demographic information, aboratory data, MRI and MRA data were collected and assessed. Cognitive function was evaluated with C - MMSE (Chinese mini mental test examination) and C - MoCA (Chinese montreal cognitive assessment). The related factors were selected by Spearman correlation analysis, multiple linear regression and logistic regression analysis. Results The patients’average age was (56.0± 12.5) years, average hemodialysis age was (73.5±60.8) months. Only 5.1% patients had clinical history of cerebral infarction or hemorrhage. Pre - hemodialysis blood pressure was (142.7/80.3±18.2/12.9) mmHg, Post-hemodialysis blood pressure was (130.2/79.1±23.4/14.9) mmHg. A total of 18.8% patients had intra-hemodialysis hypotension, spKt/V was (1.45±0.25). MR results showed that 12.0% patients had cerebral artery stenosis, 5.1% patients had cortical infarcts, 39.3% patients had lacunar infarcts, 47.0% patients had microbleeds, 7.7% patients had chronic hematoma, 52.1% patients had abnormal brain whiter matter lesions (WMLs). In cognitive function evaluation, 20.9% patients had abnormal C-MMSE scores, but 65.2% patients had abnormal C-MoCA results. Multiple linear regression showed age (b=0.059, P＜0.01), dialysis age (b=0.005, P＜0.05) were associated with WMLs in MHD patients. Intra-hemodialysis hypotension was an independent risk factor of lacunar infarcts (b=2.123, P＜0.01) and microbleeds (b=3.531, P＜0.01). Low serum albumin level was an independent risk factor of cognitive decline (b=0.314, P＜0.05). Logistic regression analysis showed pre - hemodialysis systolic blood pressure was an independent risk factor of cortical infarcts [OR=1.088, 95%CI (1.018-1.152), P＜ 0.05]. Gender, dialysis age and pre - dialysis serum TCO2 level were related with chronic hematoma. Conclusions WMLs is related with dialysis voltage. Lacunar infarcts and mirobleeds are related with intra - hemodialysis hypotension. Lacunar infarcts, WMLs and nutritional status are contributed to decline of cognition in MHD patients.     

Cognitive recovery correlates with long-term increases of cerebral perfusion after head injury.

Prospective measurements of cerebral blood flow (CBF) and Cognitive Capacity Screening Examination (CCSE) were obtained following head injury among 42 patients for a mean total follow-up interval of 10 years. Clinical data obtained at the time of injury and detailed neurological examinations at each follow-up visit were correlated with serial CBF and CCSE scores. Comparisons of the group of patients who cognitively improved (n = 32) were made with the group that did not (n = 10). Of the total group, 76% showed cognitive improvements for as long as 10 years after injury, with CBF increases toward normal. Predictors for long-term cognitive improvements include: higher initial Glasgow Coma Scales, earlier recovery from coma, absence of signs of brain stem injury, and improvements of cerebral perfusion and autoregulation. Failure to improve correlated with low initial Glasgow Coma Scales, signs of brain stem injury, and persistent impairments of cerebral perfusion.     

Magnetic resonance imaging in patients with cerebral hyperperfusion and cognitive impairment after carotid endarterectomy

OBJECT: Cerebral hyperperfusion after carotid endarterectomy (CEA) impairs cognitive function and is often detected on cerebral blood flow (CBF) imaging. The purpose of the present study is to investigate structural brain damage seen on magnetic resonance (MR) images obtained in patients with cerebral hyperperfusion and cognitive impairment after CEA. METHODS: One hundred and fifty-eight patients with ipsilateral internal carotid artery stenosis (> or = 70%) underwent CEA. Neuropsychological testing was performed preoperatively and at the 1st postoperative month. Cerebral blood flow was measured using single-photon emission computed tomography before, immediately after, and 3 days after surgery. Magnetic resonance imaging was performed before and 1 day after surgery. In patients with post-CEA hyperperfusion (defined as a CBF increase > or = 100% compared with preoperative values) on CBF imaging, MR images were also obtained on the 3rd postoperative day, the day on which hyperperfusion syndrome developed, and 1 month after the operation. RESULTS: The incidence of postoperative cognitive impairment was significantly higher in patients with post-CEA hyperperfusion on CBF imaging (12 [75%] of 16 patients) than in those without (6 [4%] of 142 patients; p < 0.0001). Only 1 of 5 patients with cerebral hyperperfusion syndrome developed reversible brain edema in the cerebral hemisphere ipsilateral to the CEA on MR images obtained on the day hyperperfusion syndrome occurred. However, postoperative cognitive impairment developed in all 5 patients with cerebral hyperperfusion syndrome regardless of the presence or absence of new lesions on MR images. In addition, postoperative cognitive impairment developed in 5 (45%) of 11 patients with asymptomatic cerebral hyperperfusion on CBF imaging despite the absence of new lesions on any postoperative MR images. CONCLUSIONS: Although cerebral hyperperfusion syndrome after CEA sometimes results in reversible brain edema visible on MR imaging, postoperative cerebral hyperperfusion -- even when asymptomatic -- often results in impaired cognitive function without structural brain damage on MR imaging.     

支架植入术对认知功能障碍伴大脑中动脉狭窄患者认知功能的影响

目的探讨支架植入术对轻中度认知功能障碍伴单侧大脑中动脉(MCA)M1段重度狭窄患者认知功能的影响。方法将28例轻中度认知功能障碍伴单侧MCA M1段重度狭窄患者分为治疗组(n=13,接受支架植入术)及对照组(n=15)。对治疗组术前1周、术后6、12个月及对照组同期进行简易智力状态检查(MMSE)评分、蒙特利尔认知评估(MoCA)评分及事件相关电位P300检测。对治疗组中5例于术前1周及术后1个月行CT灌注成像(CTP),计算患侧与健侧脑血流量(CBF)和脑血容量(CBV)比值(rCBF和rCBV)、平均通过时间(MTT)和达峰时间(TTP)差值(dMTT和dTTP),并进行统计学分析。结果术前1周2组间MMSE、MoCA评分、事件相关电位P300的潜伏期及波幅差异均无统计学意义(P均0.05)。治疗组术后6、12个月相关评分及指标与对照组同期比较差异均有统计学意义(P均0.05)。治疗组中,术前1周、术后6、12个月MMSE、MoCA评分差异均有统计学意义(P均0.05),两两比较显示术后12个月MMSE、MoCA评分均高于术前1周(P均0.05),术后6个月MoCA评分高于术前1周(P=0.010)。2组间术前1周事件相关电位P300潜伏期及波幅差异均无统计学意义(P均0.05),治疗组术后6、12个月潜伏期均短于对照组同期指标(P均0.01),波幅均大于对照组同期指标(P均0.05)。治疗组术前1周、术后6、12个月潜伏期、波幅差异均有统计学意义(P均0.05);与术前1周比较,术后6、12个月潜伏期缩短(P均0.01),波幅增大(P均0.05);与术后6个月比较,术后12个月潜伏期缩短(P=0.010)。治疗组中,有无脑血管病危险因素患者间术前1周、术后6、12个月MMSE、MoCA评分差异均无统计学意义(P均0.05);5例接受CTP检查者术后1个月rCBF高于术前1周(P0.01),rCBV、dMTT及dTTP均低于术前1周(P均0.05)。结论支架植入术可改善轻中度认知功能障碍伴单侧MCA M1段重度狭窄患者脑组织血流灌注,从而改善其认知功能。事件相关电位P300检测指标潜伏期可早于MMSE评分发现认知功能改变。     

S-Ketamine Anesthesia Increases Cerebral Blood Flow in Excess of the Metabolic Needs in Humans

Background: Animal studies have demonstrated neuroprotective properties of S-ketamine, but its effects on cerebral blood flow (CBF), metabolic rate of oxygen (CMRO2), and glucose metabolic rate (GMR) have not been comprehensively studied in humans.

Methods: Positron emission tomography was used to quantify CBF and CMRO2 in eight healthy male volunteers awake and during S-ketamine infusion targeted to subanesthetic (150 ng/ml) and anesthetic (1,500-2,000 ng/ml) concentrations. In addition, subjects' GMRs were assessed awake and during anesthesia. Whole brain estimates for cerebral blood volume were obtained using kinetic modeling.

Results: The mean +/- SD serum S-ketamine concentration was 159 +/- 21 ng/ml at the subanesthetic and 1,959 +/- 442 ng/ml at the anesthetic levels. The total S-ketamine dose was 10.4 mg/kg. S-ketamine increased heart rate (maximally by 43.5%) and mean blood pressure (maximally by 27.0%) in a concentration-dependent manner (P = 0.001 for both). Subanesthetic S-ketamine increased whole brain CBF by 13.7% (P = 0.035). The greatest regional CBF increase was detected in the anterior cingulate (31.6%; P = 0.010). No changes were detected in CMRO2. Anesthetic S-ketamine increased whole brain CBF by 36.4% (P = 0.006) but had no effect on whole brain CMRO2 or GMR. Regionally, CBF was increased in nearly all brain structures studied (greatest increase in the insula 86.5%; P < 0.001), whereas CMRO2 increased only in the frontal cortex (by 15.7%; P = 0.007) and GMR increased only in the thalamus (by 11.7%; P = 0.010). Cerebral blood volume was increased by 51.9% (P = 0.011) during anesthesia.     

Effects of sevoflurane on intracranial pressure, cerebral blood flow and cerebral metabolism: A dose-response study in patients subjected to craniotomy for cerebral tumours

Background: Studies concerning the cerebrovascular effects of sevoflurane in patients with space-occupying lesions are few. This study was carried out as a dose-response study comparing the effects of increasing sevoflurane concentration (1.5% (0.7 MAC) to 2.5% (1.3 MAC)) on cerebral blood flow (CBF), intracranial pressure (ICP), cerebrovascular resistance (CVR), metabolic rate of oxygen (CMRO₂) and CO₂-reactivity in patients subjected to craniotomy for supratentorial brain tumours.
Methods: Anaesthesia was induced with propofol/fentanyl/atracurium and maintained with 1.5% sevoflurane in air/oxygen at normocapnia. Blood pressure was maintained constant by ephedrine. In group 1 (n=10), the patients received continuously 1.5% sevoflurane. Subdural ICP, CBF and CMRO₂ were measured twice at 30-min intervals. In group 2 (n=10), sevoflurane concentration was increased from 1.5% to 2.5% after CBF₁. CBF₂ was measured after 20 min during 2.5% sevoflurane. Finally, CO₂-reactivity was studied in both groups.
Results: In group 1, no time-dependent alterations in CBF, CVR, ICP and CMRO₂ were found. In group 2, an increase in sevoflurane from 1.5% to 2.5% resulted in an increase in CBF from 29 ± 10 to 34±12 ml 100g⁻¹ min⁻¹ and a decrease in CVR from 2.7±0.9 to 2.3±1.2 mmHg ml⁻¹ min 100g ( P <0.05), while ICP and CMRO₂ were unchanged. CO₂-reactivity was maintained at 1.5% and 2.5% sevoflurane.
Conclusion: Sevoflurane is a cerebral vasodilator in patients with cerebral tumours. Sevoflurane increases CBF and decreases CVR in a dose-dependent manner. CO₂-reactivity is preserved during 1.5% and 2.5% sevoflurane.     

Monitoring of cerebral blood flow and metabolism in traumatic brain injury

The aim of the present study was to investigate the course of cerebral blood flow (CBF) and metabolism in traumatic brain injury (TBI) patients and to specifically characterize the changes in lactate and glucose indices in the acute post-traumatic period with regard to neurological condition and functional outcome. For this purpose, 55 consecutive TBI patients (mean age 37 +/- 17 years, mean GCS 6.8 +/- 3.2) were prospectively and daily evaluated. Global CBF, cerebral metabolic rates of oxygen (CMRO2), glucose (CMRGlc), and lactate (CMRLct) were calculated using arterial jugular differences. In all patients, CBF was moderately decreased during the first 24 h in comparison with normal subjects although this relative oligemia was more pronounced in patients with poor outcome (p = 0.0007). Both CMRO2 and CMRGlc were significantly depressed and correlated to outcome (p < 0.0001, p = 0.0088). CMRLct analysis revealed positive values (lactate uptake) during the first 48 h, especially in patients with favorable outcome. Both CMRO2 and CMRLct correlated with GCS (p = 0.0001, p = 0.0205). CMRLct levels showed an opposite correlation with CBF in patients with favorable and poor outcome. In the former group, correlation analysis exhibited a negative slope with evidence for increasing lactate uptake associated with lower CBF values (r = -0.1940, p = 0.0242). On the contrary, in patients with adverse outcome, CMRLct values demonstrated a weak though opposite correlation with CBF (r = 0.0942, p = 0.2733). The present data emphasize the clinical significance of monitoring of cerebral blood flow and metabolism in TBI and provide evidence for metabolic coupling between astrocytes and neurons.     

S-ketamine anesthesia increases cerebral blood flow in excess of the metabolic needs in humans

BACKGROUND: Animal studies have demonstrated neuroprotective properties of S-ketamine, but its effects on cerebral blood flow (CBF), metabolic rate of oxygen (CMRO2), and glucose metabolic rate (GMR) have not been comprehensively studied in humans. METHODS: Positron emission tomography was used to quantify CBF and CMRO2 in eight healthy male volunteers awake and during S-ketamine infusion targeted to subanesthetic (150 ng/ml) and anesthetic (1,500-2,000 ng/ml) concentrations. In addition, subjects' GMRs were assessed awake and during anesthesia. Whole brain estimates for cerebral blood volume were obtained using kinetic modeling. RESULTS: The mean +/- SD serum S-ketamine concentration was 159 +/- 21 ng/ml at the subanesthetic and 1,959 +/- 442 ng/ml at the anesthetic levels. The total S-ketamine dose was 10.4 mg/kg. S-ketamine increased heart rate (maximally by 43.5%) and mean blood pressure (maximally by 27.0%) in a concentration-dependent manner (P = 0.001 for both). Subanesthetic S-ketamine increased whole brain CBF by 13.7% (P = 0.035). The greatest regional CBF increase was detected in the anterior cingulate (31.6%; P = 0.010). No changes were detected in CMRO2. Anesthetic S-ketamine increased whole brain CBF by 36.4% (P = 0.006) but had no effect on whole brain CMRO2 or GMR. Regionally, CBF was increased in nearly all brain structures studied (greatest increase in the insula 86.5%; P < 0.001), whereas CMRO2 increased only in the frontal cortex (by 15.7%; P = 0.007) and GMR increased only in the thalamus (by 11.7%; P = 0.010). Cerebral blood volume was increased by 51.9% (P = 0.011) during anesthesia. CONCLUSIONS: S-ketamine-induced CBF increases exceeded the minor changes in CMRO2 and GMR during anesthesia.