颈上神经节活动对家兔脑功能的影响

目的：观察清醒家兔右侧颈上神经节(superior cervical ganglion，SCG)兴奋对脑功能的影响。方法：电刺激家兔右侧SCG1h，分别观察刺激期间及停刺激后2h内家兔双侧脑血流量(cerebral blood flow，CBF)、大脑皮质躯体感觉诱发电位(soreatosensory evoked potentials，SEP)变化，每隔20min记录1次。结果：刺激期间同侧各时间点的CBF均显著低于前对照(F=14．37922，P&;lt;O．001)；其中刺激停止后20，40，60，80min与前对照差异有显著性意义(F=14．37922，P&;lt;O．05)；刺激停止后100、120min与前对照差异有非常显著性意义(F=14．37922，P&;lt;O．001)；对侧各时间点的CBF与前对照相比差异均无显著性意义。同侧SEPP波振幅在刺激及停刺激期间各时间点均显著低于前对照(F=3．955，P&;lt;O．001)；对侧P波振幅与前对照相比除在停刺激后60，80min时显著低于对照(F=2．002，P&;lt;0．05)外，其余各时间点的P波振幅均非常显著低于对照(F=2．002，P&;lt;0．01)。双侧各时间点记录的P波潜伏期与前对照相比差异均无显著性意义。结论：一侧SCG兴奋可以影响脑功能的活动。     

"肾生髓"与中枢神经系统功能的关系

目的 从神经生理学角度,探讨中医"肾生髓"的本质 ,为"肾生髓"理论提供科学依据. 方法 2.5月龄 SD雄性大鼠,以单纯随机方法分成正常对照组、去势组和虚劳组.用听觉脑干诱发电位( ABR)、体感诱发电位( SEP)以及氨基酸类和单胺类中枢递质含量为指标,观察虚劳肾虚和去势肾虚模型大鼠的中枢神经系统( CNS)功能状况. 结果肾虚模型大鼠睾酮( T)水平下降时,虚劳组 [(271± 20) mg]胸腺质量明显低于正常对照组 [(565± 81) mg](P< 0.01).与对照组比较,肾虚模型大鼠神经系统功能下降,表现为造模后 ABR峰潜伏期延长( F=6.713,P< 0.001) , 阈值提高( F=9.555, P< 0.001); SEP的峰潜伏期延长( F=4.161, P=0.002),差异有非常显著性意义.中枢递质含量下降. 结论肾虚时血 T水平低下影响 CNS的兴奋性,这一作用可能是"肾"(性腺激素)通过调制某些中枢递质的合成与释放而产生效应的结果.     

FRIII矫治轻度骨性安氏III类错临床疗效的头影测量分析

目的探讨FRIII矫治轻度骨性三类错牙合所产生的硬组织变化特征.方法选择31例替牙期轻度骨性三类错牙合患者,使用FRIII治疗并对治疗前后的头颅侧位片通过头影测量技术进行比较分析.结果(1)SNA、ANB显著性增大(P<0.001);Cd-A显著性增大(P<0.01);SNB、Cd-Gn治疗前后差异无显著性.(2)U1-SN显著性增大(P<0.01)、IMPA显著性减小(P<0.01).(3)OP-SN显著性增大(P<0.001)、PP-FH治疗后变化无显著性.(4)FMA、Y轴角显著性增大(P<0.05).(5)N-Me、ANS-Me显著性增大(P<0.05),N-ANS治疗前后差异无显著性.结论使用FRIII治疗骨性三类错牙合能使上颌骨前向生长量明显增加,下颌骨产生一定的向下向后旋转;治疗后上前牙唇倾、下前牙舌倾,牙合平面产生一定的顺时针旋转而腭平面无明显变化;患者前面高在治疗后增大且主要表现为前下面高增加.     

单次电针与经皮穴位电刺激治疗前后体感诱发电位的比较

目的观察电针和经皮穴位电刺激(TEAS)前后体感诱发电位(SEP)的变化。方法 2015年10月至2016年4月本科实习生10例,采用自身前后对照研究,每例受试者均随机接受电针和TEAS治疗,间隔1周。治疗前后检测SEP的N20、N9潜伏期及波幅。结果电针治疗后,刺激侧N20潜伏期明显延长(Z=-2.620,P0.01);非刺激侧N9潜伏期延长(Z=-2.454,P0.05),N9波幅降低(Z=-2.330,P0.05)。TEAS治疗后,刺激侧和非刺激侧N9潜伏期均明显延长(Z2.695,P0.01)。两组治疗前后刺激侧及非刺激侧N20和N9潜伏期、波幅差值均无显著性差异(Z1.817,P0.05)。结论单次电针及TEAS治疗均可对SEP的N20、N9潜伏期及波幅产生影响,两种治疗对SEP的影响组间无明显差异。     

运动对老年高血压病患者血流动力学和心血管体液因子的影响

目的探讨运动对老年高血压病患者血流动力学和心血管体液因子的影响.方法高血压组为2～3级老年原发性高血压患者34例(药物控制),正常老年对照组31例,作自感劳累分级法(RPE)11～13级疲劳程度的症状限制性运动平板试验(改良的Bruce方案),试验前3 min、后3 min抽静脉血检测,观察运动过程的心率、血压、运动当量、运动时间及运动前、后的一氧化氮(NO)、内皮素(ET1)、血管紧张素Ⅱ (AngⅡ)、心房肽(ANF). 结果高血压组与对照组比较,平板运动前、运动峰时、恢复期3 min的心率、收缩压、舒张压及总的运动时间、峰时的运动当量,均P>0.05,差异无显著性意义;运动后高血压组NO上升48.7%,对照组上升52.0%,均P<0.05,差异有显著性意义;高血压组ANF运动前比对照组高 22.0%,P=0.006;2组运动前、后差值比较,NO、ET1、AngⅡ、ANF均P>0.05.运动前收缩压与运动峰时、运动后收缩压正相关(r=0.648, 0.630,P<0.001);运动前舒张压与运动峰时、运动后舒张压呈正相关 (r=0.359,0.520, P<0.001);年龄与平板运动当量呈负相关(r=0.655,P<0.001). 结论老年高血压患者在药物控制下参加轻度疲劳程度的运动(相当于8运动当量)过程中,其心率、血压的升高与正常对照组相似;血液中NO的变化有益于高血压病的治疗,短时间内未见ET1、AngⅡ和ANF水平的明显改变.     

脑卒中偏瘫患者双侧正中神经的F波变化研究

目的探讨脑卒中偏瘫患者双侧肢体的F波变化特点. 方法按Brunnstrom分级将80例脑卒中偏瘫患者分成3组,即第1组36例,第2组23例,第3组21例.19例正常人为对照组.运用肌电图学的方法,检测80例脑卒中偏瘫患者和对照组双侧肢体正中神经F波参数,并进行统计分析. 结果第1组(BrunnstromI～II级),无论在动态还是静态下,卒中患者的患侧肢体的F波参数均明显降低,低于健侧肢体和对照组(P<0.05),而健侧肢体与对照组差异无显著性;第2组(BrunnstromIII～IV级),静态情况下卒中患者的患侧肢体的F波参数明显增高,高于健侧肢体和对照组(P<0.05),而健侧肢体与对照组差异无显著性,动态情况下卒中患者的健侧肢体的F波参数明显高于对照组(P<0.05),而患侧与健侧差异无显著性;第3组(BrunnstromV～VI级),卒中患者的患侧肢体的F波参数明显高于健侧肢体和对照组,其中波幅增高明显(P<0.05),出现率也增高,但无统计学意义(P>0.05). 结论脑卒中后运动模式的动态变化过程是一个异常运动模式的过程,它包括患侧和健侧的变化.     

对社区老年人轻度认知障碍的调查与分析

目的 探讨深圳市社区老年人轻度认知障碍(MCI)流行病学情况并对其影响因素进行分析.方法 采用中文简易智力状态量表(MMSE)对深圳市罗湖区410例社区老年人进行测试.结果 本组社区老年人MCI的发生率为21.46%,不同年龄、学历、性别的社区老年人其MMSE得分有显著性差异(P&lt;0.001).其中初中以下文化程度与其他文化程度的老年人相比MMSE有显著性差异,高中以上文化程度相互之间MMSE无差异;高中以上文化程度者在70～79岁时,MCI发生率较60～69岁时有显著性增高(P&lt;0.05);女性老年痴呆(AD)的发生率较男性增高.多因素方差分析发现,影响本人群MMSE主要因素为学历(F=75.78,P&lt;0.001)与年龄(r年龄=-0.442,P&lt;0.001).结论 深圳市社区老年人MCI发生率与学历、年龄、性别有显著关系.应在社区中对诊断为MCI老年人实施预防AD的早期护理干预措施.     

联合多项神经电生理检查对早期诊断糖尿病周围神经病的价值分析

目的探讨神经传导检测(NCS)、F波、体感诱发电位（SEP）及皮肤交感反应(SSR)对糖尿病周围神经病变(DPN)的早期诊断价值。 方法共选取110例糖尿病患者纳入糖尿病组,同时选取健康志愿者50例纳入正常对照组。分别对上述对象进行正中神经、尺神经、胫后神经、腓总神经感觉及运动NCS检查、正中神经和胫后神经F波检查、上下肢SEP、SSR检查。 结果糖尿病组NCS检查总异常率为74.5％,感觉神经异常比例高于运动神经(均P<0.01)。糖尿病组F波总异常率为57.3％,远端运动神经传导正常者的F波异常率为50.7％。糖尿病组SEP近端周围神经电位总异常率为70.0％,上肢正中神经感觉传导正常者锁骨上电位无明显异常,下肢胫后神经感觉传导正常者臀点电位异常率为62.5％。糖尿病组SSR总异常率为80.0％,四肢NCS正常者中SSR异常率达72％。糖尿病组联合应用NCS、F波、SEP及SSR检查的总异常率高达90.9％,高于单独使用其中任何一项检查时的异常率(均P<0.05)。 结论NCS检查是诊断DPN患者的基本手段,将其与SSR、SEP及F波联用,能明显提高亚临床型DPN患者的早期检出率。     

急性CO中毒后迟发性脑病神经元特异性烯醇化酶测定的临床意义

目的探讨急性CO中毒后迟发性脑病(DEACMP)患者脑脊液(CSF)和血清神经元特异性烯酶化酶(NSE)的变化及临床意义.方法对49例DEACMP患者均在急性期入院3 d内抽取CSF和血标本进行NSE测定,其中34例于治疗30 d后再次采取标本复查,对比分析治疗前后NSE的变化.结果患者组急性期CSF和血清NSE含量较对照组明显增高(P<0.001);治疗后明显下降(P<0.001,P<0.005),与对照组比较差异无显著性(P>0.05);患者组CSF和血清NSE呈明显正相关(r=0.4614,P<0.001).结论 CSF和血清NSE测定可作为DEACMP诊断和病情判断的有效指标.     

短暂性脑缺血发作患者事件相关电位的变化

背景短暂性脑缺血发作( transient ischemia attack, TIA)是临床常见的脑血管病之一,采用客观评测方法对其高级神经活动认知功能损害进行评估. 目的研究 TIA患者的事件相关电位 (P300)的变化,探讨 TIA患者的认知损害及可能的机制. 设计以诊断为依据,病例对照研究. 地点和对象在兰州军区乌鲁木齐总医院神经内科门诊及住院诊治的 TIA患者 31例( TIA组),其中颈内动脉系统 9例,椎基底动脉系统 22例对照组均为来院体检的健康人 30例. 干预对 TIA患者及正常对照组进行简易精神状态检查法 (MMSE)、听觉 oddball刺激序列 P300检测及神经系统查体. 主要观察指标 MMSE评定分值, P3波潜伏期及 P3波幅测定. 结果 TIA组的 MMSE评分 [(27.13± 2.54)分 ],与对照组 [(29.02± 1.35)分 ]比较 ,差异有显著性意义 (t=2.213, P< 0.05). P3波潜伏期 TIA组 [(348.21± 20.33) ms]与对照组 [(330.32± 30.12) ms]比较 ,差异有显著性意义 (t=2.732, P < 0.01);椎基底动脉系统 TIA比颈内动脉系统 TIA的 P3波潜伏期延长 [(350.32± 31.21) ms,(339.32± 27.88) ms],差异有显著性意义 (t=2.479, P< 0.05); TIA患者的 P3波潜伏期延长与 TIA患者的发作次数呈正相关 (r=0.383,P< 0.01),与 MMSE评分呈负相关 (r=-0.259,P< 0.05). 结论 TIA患者的 P3波潜伏期显著延长,存在早期认知功能的损害. TIA患者的早期认知损害与 TIA发作次数有关.     

糖尿病性神经病的体感诱发电位分析

对２６例Ⅱ型糖尿病患者进行体感诱发电位（ＳＥＰ）检测,以了解其神经病变（ＤＮＰ）情况。结果：依临床表现诊断有工发症患者５４％,ＳＥＰ异常７６．９％,其中上肢异常５０％,下肢异常９０％。主要表现为上肢Ｎ９和下肢Ｐ４０潜伏期明显延长,Ｎ９平均峰潜伏期男１２．３ｍｓ,ｓ：０．８６,Ｐ〈０．００１,女分别为１１．６ｍｓ,０．８８,Ｐ〈０．００２;Ｐ４０平均峰值伏期男４５．７ｍｓ,ｓ：４．５５,Ｐ〈０．００     

Antioxidant LY231617 enhances electrophysiologic recovery after global cerebral ischemia in dogs

OBJECTIVE: The potent antioxidant LY231617 (2,6-bis(1,1-dimethylethyl)-4-[[(1-ethyl)amino]methyl]phenol hydrochloride) is cytoprotective in models of focal and global cerebral ischemia. We tested the hypothesis that administration of LY231617, before the insult, would improve recovery of cerebral electrical activity and metabolic function after transient global cerebral ischemia by improving cerebral blood flow (CBF) during the reperfusion period. DESIGN: Randomized, controlled, prospective study. SETTING: Research laboratory at a university teaching hospital. SUBJECTS: Twenty-four male beagle dogs. INTERVENTIONS: All experiments were performed under pentobarbital anesthesia and controlled conditions of normoxia, normocarbia, and normothermia. Twelve control dogs received 20 mL/kg saline (vehicle) bolus into the right atrium and 0.01 mL/kg/min i.v., beginning 20 mins before 13 mins of global cerebral ischemia (by aortic occlusion). The dogs in the drug-treated group received LY231617 as a 10-mg/kg bolus 20 mins before ischemia and 5 mg/kg/hr throughout reperfusion (n = 12). CBF was measured using radiolabeled microspheres. MEASUREMENTS AND MAIN RESULTS: Total CBF, cerebral oxygen consumption, and somatosensory evoked potentials (SEP) were measured during 240 mins of reperfusion. CBF was similar in both vehicle- and LY231617-treated animals at baseline and throughout the experimental period. In all animals, SEP became isoelectric between 60 and 100 secs after cross-clamping of the ascending aorta. SEP amplitude recovery was significantly higher in drug-treated animals compared with controls (73%+/-15% vs. 39%+/-14% [mean+/-SEM] from baseline at 120 mins [p<.05] and 86%+/-12% vs. 49%+/-14% from baseline at 240 mins [p< .05]). CONCLUSIONS: LY231617 improves recovery of cerebral electrical function after complete transient global ischemia via mechanisms unrelated to cerebral circulatory effects.     

糖尿病患者诱发电位的反应与临床参量的关系

目的了解2型糖尿病(DM)患者的视觉诱发电位(VEP),脑干听觉诱发电位(BAEP)、体感诱发电位(SEP)、事件相关电位(ERP)的表现与临床参量的关系。方法用NicoletVikingTV型肌电图/诱发电位仪对30例2型DM患者(DM组)及年龄和性别与之匹配的本院医务人员正常人30例(对照组)进行VEP,BAEP,SEP,ERP检测。应用SPSS统计软件分析DM组的EP表现及其与临床参量(病程、血糖、血脂、肾功能、血管病变)的关系。结果DM组(1)VEP异常20例,BAE异常18例,MNSEP异常为20例,PTNSEP异常22例,ERP异常1例。(2)VEP的P100潜伏期(PL)明显延长,BAEP的左侧Ⅰ波PL、双侧Ⅴ波PL,波幅(Amp)和各波间期(IPL)明显异常,SEP周围电位N9至皮层电位P25/P38的PL,Amp以及ERP中N2,P3a,P3b的PL,Am都有明显异常,与对照组比较(F=5.131～45.213,t=2.695～3.472P<0.05～0.01)。(3)EP改变与各临床参量有关。结论DM患者VEP,BAEP,SEP,ERP都有不同程度异常。异常程度和病程平行。     

F wave studies of neurogenic intermittent claudication in lumbar spinal stenosis

OBJECTIVE: Lumbar spinal stenosis (LSS) may result in neurogenic claudication (NC), which is thought to be a result of transient ischemia during exercise. In this study we evaluated the changes in F wave studies before and immediately after walking stress in patients with NC. DESIGN: Twenty-six patients with LSS who had signs and symptoms of NC and 20 healthy volunteers were included in this study. Routine motor and sensory nerve conduction studies and tibial F wave studies were performed in both groups. Immediately after walking stress test, tibial F wave studies were repeated. Exercise treadmill protocol was used for ambulation. Time to first symptoms and total ambulation time were recorded. RESULTS: After completion of the baseline electrophysiological examination, a walking stress test was performed using a treadmill, and 16 patients (61.5%) experienced neurogenic claudication during the trial. The mean time to first symptoms was 2.0 +/- 3.5 mins (minimum = 0, maximum = 14). In the control group 18 subjects (90%) completed the trial without any symptoms, and 2 (10%) subjects had to stop at an average of 10 mins because of generalized fatigue. Within 5 mins after the walking stress test, tibial F wave studies were repeated in both groups. There were significant increases in F latency values bilaterally in the patient group (P = 0.001 for both sides) but not in control subjects (P = 0.435 for right side and P = 0.122 for left side). CONCLUSION: Our data suggest that F wave studies after walking stress test provide more information for the diagnosis of NC.     

地尔硫䓬对离体大鼠心肌缺血再灌注损伤影响的研究

目的探讨地尔硫䓬对离体大鼠心肌缺血再灌注损伤的影响及其机制。 方法33只大鼠随机分为3组：正常对照组（N组）、缺血再灌注组（I-R组）、地尔硫䓬＋缺血再灌注组（D/I-R组）。N组持续灌流K-H液150 min;I-R组K-H液稳定灌流30 min后,结扎前降支30 min,继以K-H液再灌注90 min;D/I-R组给予地尔硫䓬（5 μmo/L）再灌注15 min,继以K-H液再灌流75 min。记录并分析各组大鼠左心室发展压、左心室内压力最大上升/下降速率（±dp/dtmax）、再灌注心律失常评分、心肌梗死面积以及各组左心室心尖组织的线粒体乙醛脱氢酶2（ALDH2）、Bcl-2以及Bax的mRNA基因与蛋白表达水平。 结果（1）左心室发展压D/I-R组再灌注30 min与45 min比I-R组压力明显升高［（92.68±5.09）mmHg vs（75.77±5.33）mmHg;（90.39±4.29）mmHg vs（72.34±7.49）mmHg;1 mmHg=0.133 kPa］,差异均具有统计学意义（F=72.81、51.92,P均=0.001）。（2）±dp/dtmax D/I-R组再灌注30 min与45 min时均比I-R组升高［＋dp/dtmax：（2885.45±286.47）mmHg vs （2063.64±105.57）mmHg;（2712.73±236.52）mmHg vs（2053.64±92.33）mmHg;-dp/dtmax：（2214.55±104.63）mmHg vs （1710.91±217.97）mmHg;（2119.09±84.43）mmHg vs（1544.55±207.72）mmHg］,差异均具有统计学意义（F=64.22、70.55、69.77、54.64,P均=0.001）。（3）N组仅有室性期前收缩的发生,未发生心室颤动、室性心动过速;D/I-R组出现室性期前收缩的个数较N组增加,差异具有统计学意义（P=0.001）;I-R组室性心动过速发生率高于D/I-R组,心室颤动时程与室性心动过速时程均较D/I-R组增加,差异具有统计学意义（P=0.013、0.049、0.001）;再灌注心律失常评分I-R组评分［5（3,6）,57.36］高于D/I-R组［3（1,4）,34.77］,差异具有统计学意义（P=0.001）。（4）心肌梗死面积I-R组高于D/I-R组［（55.51±1.43）% vs （17.01±1.13）%］,差异具有统计学意义（P<0.01）。（5）I-R组线粒体ALDH2表达明显减少。D/I-R组线粒体ALDH2表达与I-R组比较减少,但差异无统计学意义（P=0.11）,Bcl-2、Bax的表达均增加,D/I-R组Bcl-2/Bax的比值较I-R组增大（0.44 vs 0.22）,差异具有统计学意义（P=0.001）。 结论地尔硫䓬处理后能够减少缺血再灌注损伤。其保护作用机制之一可能是通过上调Bcl-2下调Bax的基因和蛋白表达,减少心肌细胞的凋亡,但其并不是通过上调线粒体ALDH2的基因与蛋白来实现。     

Time-related increase of oxygen utilization in continuously activated human visual cortex

Oxygen utilization increase is fractionally much less than that seen in glucose metabolism and blood flow soon after onset of neuronal activation, however its behavior during continued activation is less certain. We evaluated the effects of 25 min of visual stimulation on CBF, CMRO(2), and OEF using [(15)O] water and [(15)O] oxygen PET. Seven healthy volunteers underwent a PET session consisting of serial [(15)O] water and [(15)O] oxygen scans at the fixation-only baseline visual state and after 1, 13, and 25 min of the continuous visual stimulation using a black-white vertical grating. CBF, CMRO(2), and OEF values were calculated for the entire brain and for regions of interest in visual cortex centered over the area of activation. After 1 min of stimulation, CMRO(2) increased only 4.7% compared to baseline and CBF increased 40.7%. However, after 25 min of stimulation the increase in CMRO(2) compared to baseline was 15.0%, having tripled from that measured at 1 min (P < 0.05). CBF did not significantly change during this time. OEF was 48.3% at baseline. It decreased to 37.1% after 1 min of visual stimulation (P < 0.01) and then returned almost to baseline values after 25 min of activation OEF (45.7%). There were no significant variations in whole-brain values during the study. We suggest that in the activated brain, the increased energy demands initially are not fully met with oxidative metabolism and must predominantly be supported by increased glycolysis. With continued activation, oxygen utilization increases reducing the need for excess glycolysis.     

创伤后应激障碍样行为异常大鼠海马钙依赖性反应紊乱

目的探讨情感行为异常大鼠海马钙离子及其相关的钙依赖性反应,进一步认识创伤后应激障碍(PTSD)样行为异常的神经生物学基础。方法将240只雄性Wistar大鼠随机分组为海马阈下电刺激组(SE,n=96)、海马电极埋植对照组(CE,n=96)和正常对照组(NC,n=48),采用频率25Hz、波宽1ms、串长10s、串隔7min、强度100μA的恒流、单脉冲电流,反复刺激大鼠海马以建立PTSD样行为异常动物模型;采用神经生化、流式细胞仪、荧光标记术及Westernblotting等方法,定量观测了实验大鼠海马Na+-K+-ATP酶与Ca2+-ATP酶活性,细胞内游离钙离子含量与钙调素(CaM)相对活性平均通道荧光,以及海马组织总CaM表达的动态变化规律。结果电刺激停止后12h阈下刺激大鼠海马细胞线粒体Na+-K+-ATP酶活性即明显下降犤(0.56±0.17)mmol/(kg·s),F=4.438,P<0.05犦,48h仍显著低于NC组犤(0.61±0.17)mmol/(kg·s),P=0.026犦;24h线粒体Ca2+-ATP酶活性亦明显降低犤(0.53±0.14)mmol/(kg·s),F=4.999,P<0.05犦,72h仍显著低于NC组犤(0.61±0.17)mmol/(kg·s),P=0.027犦。海马细胞内游离钙离子含量于电刺激停止后12～48h明显高于两对照组(F=16.355,P<0.01),72h仍显著高于NC组犤(290±70)nmol/L,P=0.03犦,游离CaM平均通道荧光则同步降低(F=10.655,P<0.05),而海马组     

Hemodynamic Benefits of Right Ventricular Outflow Tract Pacing: Comparison with Right Ventricular Apex Pacing

To assess optimal hemodynamics in relation to stimulation site during right ventricular pacing, 17 consecutive patients who underwent cardiac catheterization were studied. In all patients, right ventricular apex and right ventricular outflow tract stimulation was performed at 85, 100, and 120 beats/min. Cardiac index at both pacing sites was compared using the left ventricular outflow tract continuous wave Doppler technique. Comparison of the two stimulation sites demonstrated that right ventricular outflow tract pacing resulted in a higher cardiac index at 85 beats/min (2.42 ± 1.2 vs 2.04 ±1.0 L/min per m², P < 0.002) at 100 beats/min (2.78 ± 1.4 vs 2.35 ± 1.1 L/min perm², P < 0.001) and 120 beats/min (3.00 ± 1.5 vs 2.61 ± 0.9 L/min perm², P < 0.001). From a total of 51 paired observations, 45 showed an increase in cardiac index during outflow tract pacing as compared to apex pacing. Right ventricular outflow tract pacing at 120 beats/min resulted in a lower cardiac index than right ventricular apex pacing in patients with significant coronary artery disease and/or impaired left ventricular function (ejection fraction ≤ 50%), whereas right ventricular outflow tract pacing produced higher cardiac indices in the absence of these abnormalities. Right ventricular outflow tract pacing resulted in higher cardiac indices as compared to apex pacing in all other subgroups at all other pacing sites tested. It is concluded that stimulation of the right ventricular outflow tract offers a significant hemodynamic benefit during single chamber pacing as compared to conventional apex pacing, particularly in the absence of significant coronary artery disease and/or left ventricular dysfunction.     

The comparative effects of epinephrine versus phenylephrine on regional cerebral blood flow during cardiopulmonary resuscitation

Epinephrine in larger doses than currently recommended during cardiopulmonary resuscitation (CPR) has been shown to improve cerebral blood flow (CBF) following a 10-min arrest in a swine model. The purpose of this pilot study was to measure CBF during CPR, comparing high-dose epinephrine to a pure alpha-1 agonist, phenylephrine. Ten swine each weighing greater than 15 kg, were instrumented for regional CBF measurements using tracer microspheres. CBF was measured during normal sinus rhythm (NSR). Following 10 min of ventricular fibrillation, CPR was begun and regional CBF was again measured. Following 3 min of CPR, the swine were randomized to receive either epinephrine (0.2 mg/kg), or phenylephrine (0.1 mg/kg), through a peripheral intravenous line. Regional CBF was again measured 1 min after drug administration. Regional CBF following drug administration was compared using an analysis of covariance. Adjusted CBFs are expressed in ml/min per 100 g for epinephrine and phenylephrine, respectively: left cerebral cortex (12.5 vs. 2.3, P = 0.002); right cerebral cortex (13.0 vs. 2.8, P = 0.003); cerebellum (32.9 vs. 4.1, P = 0.004); midbrain (35.7 vs. 2.6, P = 0.0004), pons (30.3 vs. 2.9, P = O.006); medulla (49.5 vs. 13.6, P = 0.02) and cervical spinal cord (49.6 vs. 14.1, P = 0.003).