老年脑梗塞患者海水浴体疗运动康复疗养前后脑血流动力学观察

目的 :观察老年脑梗塞患者康复疗养期采用海水浴体疗运动前后的脑血流动力学变化。方法 :应用经颅多普勒超声仪检测两组 (海水浴体疗组和休养组 )共 30例老年脑梗塞康复期患者疗养前后以及 2 0例老年健康对照组的双侧大脑中动脉 (MCA)血流参数 ,包括收缩期血流速度 (Vs)、舒张期血流速度 (Vd)、平均流速(Vm)、阻力指数 (RI)、搏动指数 (PI)。结果 :①与对照组相比 ,老年脑梗组MCA流速Vs、Vd、Vm显著降低 (P <0 0 1 ) ,RI、PI显著增高 (P <0 0 1 ) ;②与疗养前相比 ,经海水浴体疗运动 1个月后MCA流速Vs、Vd、Vm明显增高 (P <0 0 1 ) ,RI、PI显著降低 (P <0 0 1 ) ,而休养组患者则改变不明显 (P <0 0 5)。结论 :老年脑梗塞患者恢复期脑循环及血管贮备功能尚差 ,海水浴体疗运动一定疗程后可改善患者心脑血氧供应 ,改善脑血流动力学状况     

脑血流改变对新生儿缺氧缺血性脑病脑损伤及预后的评价

目的 :探讨脑血流改变在新生儿缺氧缺血性脑病(hypoxic ischemic encephalopathy,HIE)脑损伤及预后评价中的应用。方法:选择80例缺氧缺血性脑病患儿,其中轻度32例(轻度组),中度组28例,重度20例(中重度组);另选取40例健康新生儿作为对照组。采用彩色多普勒超声诊断仪连续5 d检测2组大脑前中动脉舒张末期速度(Vd)、收缩期峰值流速(Vs)、RI、搏动指数(PI)及平均速度(Vm),并进行比较。结果:出生后24 h内,3组HIE患儿的Vs、Vd及Vm均显著低于对照组(均P0.05);轻度组脑血流速度在48 h及以后与对照组相近,中重度组Vs、Vd及Vm与对照组比较差异均有统计学意义(均P0.01);脑血流在第5天尚未恢复正常;出生各时龄,中重度组Vs、Vd均明显低于轻度组(均P0.01),而Vm差异无统计学意义(P0.05)。出生24 h内,轻度组与中重度组PI与RI均显著升高,与对照组比较,差异均有统计学意义(均P0.01);中重度组PI显著高于轻度组(P0.01),PI差异无统计学意义,至第3天恢复正常。结论 :随着HIE严重程度的增加,患儿脑部血流量明显减少,而血流恢复较慢者可能对预后产生影响。     

床旁颅脑超声对早产儿早期脑血流灌注特点的评价

目的：探讨早产儿早期大脑中动脉、豆纹动脉脑血流灌注特点,分析脑血流变化规律。方法：选择80例早产儿为研究对象,按出生体质量分为A组（≥1 500 g）和B组（<1 500 g）各40例,另选择40例足月新生儿为足月儿组,分别于出生72 h内测量大脑中动脉、豆纹动脉血流动力学参数。结果：早产儿组大脑中动脉的收缩期峰值流速（Vs）、舒张末期速度（Vd）、平均血流速度（Vm）明显低于足月新生儿组,且B组Vs、Vm均低于A组（均P<0.05）;收缩期峰值流速与舒张末期速度比值（S/D）、RI组间差异无统计学意义（P>0.05）。早产儿组豆纹动脉的Vs、Vd、Vm、S/D、RI均明显低于足月儿组,B组豆纹动脉的Vs、Vd、Vm均低于A组（均P<0.05）。结论：大脑中动脉、豆纹动脉的脑血流动力学变化可敏感反映脑血流的灌注状态,对评估脑损伤程度和判断预后有重要的临床价值。     

应用三维经颅多普勒超声检查新生儿脑血流临床意义探讨

对足月正常分娩的新生儿33例,疾病儿36例,采用德国EME公司彩色三维经颅多普勒诊断仪监测脑血流。其结果:足月新生儿MCA、ACA与PCA分别为56.0、44.0与36.16。<2天组与≥2天组MCA左右两侧Vs无差异性,Vd左侧为17.41,Vm右侧为30.18,P1右侧为0.49;ACA右侧为37.29;≥2天组,Vd两侧均值为高。疾病组MCA、ACA与PCA的Vs两侧均值均高于正常新生儿组。故本研究可发现脑血流异常,以便及时进行治疗。     

高压氧治疗对中重型颅脑损伤患者脑血流动力学和动态脑电图的影响及疗效分析

目的 观察高压氧(HBO)治疗对外伤性中重型颅脑损伤患者脑血流动力学和动态脑电图(AEEG)的影响及其治疗效果。方法 142例外伤性中重型颅脑损伤患者分为常规治疗组（71例）和HBO+常规治疗组（71例）,常规治疗组采用必要的神经外科处理及常规药物治疗;HBO组+常规治疗组在常规治疗的基础上,病情稳定后加用HBO治疗3个疗程。另选30名健康体检者作为正常对照组。治疗前及治疗后第10天、第30天行经颅多普勒(TCD)检查,治疗前、治疗后第30天行动态脑电图（ambulatory electroencephalogram,AEEG）检查及格拉斯哥昏迷评分(GCS),伤后6个月随访,行格拉斯哥预后评分(GOS)。结果 治疗前常规治疗组与HBO+常规治疗组收缩期峰血流速度（Vs）、舒张期末血流速度（Vd）、平均血流速度(Vm)、搏动指数(PI)、脑血管阻力指数（RI）均明显高于正常对照组(P＜0.05),AEEG异常率分别为94.4％、95.8％。治疗后第10天,常规治疗组Vs、Vm、PI、RI较治疗前下降(P＜0.05),较正常对照组仍升高(P＜0.05);HBO+常规治疗组Vs、Vm、PI、RI与常规治疗组比较下降更为明显(P＜0.05),Vs、Vm、PI仍高于正常对照组(P＜0.05)。治疗后第30天,常规治疗组Vs、Vm降至低于正常组(P＜0.05),PI、RI仍高于正常对照组(P＜0.05);HBO+常规治疗组Vs、Vm、Vd、PI、RI与正常对照组比较差异无统计学意义(P＞0.05)。治疗后第30天2组AEEG异常率较治疗前明显下降（P＜0.05）,GCS较治疗前明显升高(P＜0.05),且HBO+常规治疗组与常规治疗组比较两者改善更为明显(P＜0.05);伤后6个月GOS评分显示,HBO+常规治疗组预后良好患者较常规治疗组明显增多,死亡率明显下降(P＜0.05)。结论 HBO治疗能缓解中重型颅脑损伤患者的脑血管痉挛,调节脑血流,并改善神经元细胞的电生理活动和功能,从而提高临床疗效。     

高压氧对新生儿缺氧缺血性脑病血浆内皮素-1、一氧化氮及脑血流动力学变化的影响

目的 探讨高压氧（HBO）对新生儿缺氧缺血性脑病（HIE）时血浆内皮素－1（ET－1）和一氧化氮（NO）含量的影响及其与脑血流动力学的关系。方法 对52例HIE新生儿在首次HBO治疗前后应用经颅多普勒超声（TCD）检测双侧大脑前，中，后动脉收缩峰流速（Vs)，舒张末期流速（Vd)，搏动指数（PI）和阻力指数（RI），同时用放射免疫法和硝酸还原酶法分别测定血浆ET－1和NO水平；另设足月，正常的新生儿15例为对照组，亦进行上述检测。结果 （1）脑血流示轻度组Vd,Vs局部降低，中，重度组Vd广泛降低，Vs呈局部降低，而重度组尤为显著（P均＜0．05）。HBO暴露后重度组左中动脉Vd仍低于对照组，其余与对照组之间差异均无显著性意义。（2）PI和RI在轻度组与对照组之间差异无显著性意义，在中度组则局部增高，而重度组双侧大脑动脉PI和RI广泛增高（P均＜0．05）。HBO暴露后PI和RI均降低，但与对照组之间差异无显著性意义。3）HIE各组NO和ET－1水平均高于对照组，且与病变程度成正相关。但NO／ET－1比值低于对照组（P均＜0．05），且重度组＜中度组＜轻度组，HBO暴露后HIE各组NO水平增高，ET－1水平下降（P均＜0．05），NO／ET－1比值升高，但各组之间差异无显著性意义。结论 HBO可能通过影响NO和ET－1水平而舒张脑血管和改善脑供血，在而对缺氧缺血性脑损伤具有保护作用。     

急进高原对脑血流动力学的影响研究

目的:观察急进高原对脑血流动力学的影响。方法:对某部新兵110例在进高原前后1～2天,采用Companion彩色经颅多普勒超声诊断仪,检测并记录基底动脉(BA)、椎动脉(VA)、大脑中动脉(MCA)、大脑前动脉(ACA)、大脑后动脉(PCA)收缩期峰流速(Vs)、舒张期末峰流速(Vd)、平均峰流速(Vm)、脉动指数(PI)和阻力指数(RI)等血流动力学指标。结果:(1)脑前循环血流量指标中,双侧MCA的Vm值显著增加,RACA的Vs值显著降低(P<0.01),双侧ICA和双侧MCA的Vd值显著增加(P<0.05,P<0.01);(2)脑后循环血流量指标中,BA的Vm值显著增加,双侧VA及RPCA的Vs值显著降低,RVA和BA血管的Vd显著增加(P<0.05,P<0.01);(3)前后循环的脑血管顺应性及灌注均增加,外周阻力均降低(P<0.01)。结论:急进高原者通过前后循环脑血流、脑血管壁顺应性及外周阻力的变化,可增加脑血管的远端血流灌注,代偿高原低压性缺氧导致的低氧血症。     

乌拉地尔复合利多卡因对老年原发性高血压患者气管插管时血流动力学的影响

目的观察乌拉地尔复合利多卡因对老年原发性高血压患者气管插管时血流动力学的影响。方法选择择期全麻手术患者120例,年龄58～75岁。随机分为A、B、C三组,每组40例,分别于诱导前3 min静注3 ml生理盐水、0.4 mg/kg乌拉地尔、0.4 mg/kg乌拉地尔+1 mg/kg利多卡因。分别记录三组麻醉诱导前(T0)、诱导后(T1)、气管插管时(T2)、1 min(T3)、3 min(T4)、5 min(T5)的HR、SBP、DBP。结果与T0时比较,T1时三组SBP、DBP明显下降,HR明显减慢(P<0.01),T2、T3、T4时,A组SBP、DBP明显升高,HR明显增快(P<0.01);B组SBP、DBP稍有升高(P>0.05),HR明显增快(P<0.01);C组SBP、DBP稍有升高,HR稍加快(P>0.05)。结论乌拉地尔复合利多卡因应用于老年原发性高血压患者的气管插管诱导,能更好地抑制插管应激产生的心血管反应,用于老年原发性高血压患者是安全可靠的。     

振动锻炼和太空养心丸对60 d头低位卧床脑血流的影响

目的 通过观察和比较60 d头低位(HDT)卧床期间振动锻炼、中药太空养心丸对脑血流的影响,进一步明确不同对抗方式对失重不良影响的对抗效果. 方法 21名健康男性志愿者,随机分为对照组、振动组和中药组3组,每组7人.对照组仅-6°HDT卧床60 d,口服安慰剂;振动组和中药组在HDT卧床期间分别进行阻抗振动锻炼和口服太空养心丸.卧床前、卧床第30天、第60天测量右侧大脑中动脉的血流速度. 结果 对照组的收缩期血流速度(Vs)在卧床第30天较卧床前显著降低(t=3.44,P<0.05),并且在第60天进一步降低t=5.07,P<0.01);舒张期血流速度(Vd)、平均血流速度(Vm)在卧床第60天显著降低(t=2.61、7.20,P<0.05).振动组的Vs在卧床第30天显著降低(t=2.49,P<0.05),并且在卧床第60天进一步降低(t=3.49,P<0.01);中药组Vs、Vd和Vm有降低趋势,但未达显著水平. 结论 60d头低位卧床可引起大脑中动脉血流速度显著降低.卧床期间服用太空养心丸对改善脑血流有一定作用,而振动锻炼则对脑血流影响不大.     

儿童汉语阅读障碍的脑血流与阅读技能研究

目的　探讨儿童汉语阅读障碍 (RD)的脑血流改变与阅读技能诊断测试 (CRSDT)评分的关系。方法　用非采血法SPECT显像测定 2 5例RD患儿和 2 0例正常对照者全脑血流量 (CBF)、左右脑血流量及局部脑血流量 (rCBF)。CRSDT测得阅读技能总粗分 (TRS) ,并分析TRS与CBF间的关系。结果　患儿组CBF为 (38.87± 3.77)mL·10 0g- 1 ·min- 1 ,明显低于对照组 [(4 3.6 5± 2 6 4)mL·10 0g- 1 ·min- 1 ,P <0 .0 1],患儿rCBF显著降低区域分布频率为额叶、枕叶 >顶枕交界区 >颞叶 >顶叶 >丘脑>其他 (小脑、脑干、基底节 ) ,RD组TRS与CBF呈明显正相关 (r为 0 .6 5 1,P <0 0 5 )。结论　RD儿童存在脑血流代谢降低 ,SPECT脑血流显像及定量测定能够客观评价其病变的严重程度。     

倾斜床模拟推拉动作下心率和血压变化

目的建立倾斜床模拟推拉动作模型 ,并观察其引发的心血管反应性特点。方法以 1 0名健康歼击机飞行员为被试者 ,随机进行 3次 90°立位 (HUT)和 90°倒立位 (HDT)体位转换试验 ,HUT 1min→HDT 1 0s→HUT 1min ,第 2、3次体位转换时HDT的持续时间分别为 1 5s和 2 0s。床体旋转速度为45°/s。间隔 4s监测一次血压 ,连续记录心电图。结果在HDT期间 ,各时间心率和血压较基础HUT明显下降。随后HUT时 ,除 1 1～ 1 5s血压外 ,其余各时间心率和血压较基础HUT明显下降。结论采用倾斜床可以模拟推拉动作所引起的心血管的反应 ,故其可作为推拉动作的模型     

21d头低位卧床期间脑底动脉血流动力学的变化

目的观察21d头低位卧床期间脑底动脉血流动力学的变化。方法6名健康男性志愿者,年龄24.8±6.1岁,进行了21dHDT-6°卧床试验。HDT前、HDT第10天及卧床结束时进行了3次立位耐力检查。HDT前(坐位)、HDT即刻(D0)、第1、3、7、10、21天用经颅超声多普勒(TCD)测量了双侧大脑前(ACA)、中(MCA)、后动脉(PCA)的血流动力学指标。结果卧床第10天和卧床结束时,受试者立位耐力比卧床前显著降低(P<0.05）。卧床第3天和第21天的右侧MCA的V     

Acute cardiovascular adaptation to 10 consecutive episodes of head-up tilt

BACKGROUND: The cardiovascular system is highly adaptable to sustained +Gz acceleration. Little is known as to whether the cardiovascular system can adapt to acute, repetitive +Gz exposures. This study tested the hypothesis that the cardiovascular system would adapt to repeated orthostatic challenges in a single session. METHODS: Over a 70-min period, 14 subjects were exposed to 10 +75 degrees head-up tilts (HUT). Each tilt involved a 5-min supine period followed by a 2-min HUT. Heart rate (HR), systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), total peripheral resistance (TPR), stroke volume (SV), and cardiac output (CO) were determined non-invasively. Cardiovascular responses to HUT10 for the final 30 s of the supine period and the first 30 s of the tilt period were compared with those of HUT1. Integrated cardiac baroreflex sensitivity (BRS) was assessed using the Valsalva maneuver. RESULTS: MAP and DBP increased in both supine (MAP p = 0.009, DBP p = 0.002) and tilt periods (MAP p = 0.003, DBP p = 0.009) for HUT10 compared with HUT1. TPR increased during the tilt period only (p = 0.001) during HUT10 compared with HUT1. CO and SV were decreased during the supine period at HUT10 relative to HUT1; however, there were no differences in the tilt period at HUT10 for either CO or SV. There was no change in the response of BRS, HR, or SBP from HUT1 to HUT10. CONCLUSIONS: This study indicates that 10 repetitive HUTs can elicit changes in the cardiovascular responses to orthostasis, reflected by an increased vascular resistance.     

21天头低位(-6°)卧床前后下体负压和头高位倾斜暴露时的心血管反应

目的探讨２１天头低位（ＨＤＴ）卧床对人体立位应激下心血管反应的影响,以及比较下体负压（ＬＢＮＰ）和头高位倾斜（ＨＵＴ）两种立位应激下心血管反应的差异。方法６名受试者在２１天ＨＤＴ前、后分别进行ＬＢＮＰ（－４．００ｋＰａ／３ｍｉｎ、－６．６７ｋＰａ／３ｍｉｎ及－９．３３ｋＰａ／３ｍｉｎ）和ＨＵＴ试验（３０°／３ｍｉｎ、４５°／３ｍｉｎ、６０°／３ｍｉｎ及７５°／３ｍｉｎ）,以比较两种检测方法的血压（ＢＰ）和心率（ＨＲ）的变化情况。结果与ＬＢＮＰ（或ＨＵＴ）前相比：①ＬＢＮＰ（ＨＵＴ）时ＨＲ显著增加（Ｐ＜０．０１）,ＳＢＰ显著降低（Ｐ＜０．０５）;卧床后相应的变化量增加。②ＬＢＮＰ时ＤＢＰ降低（卧床后达显著,Ｐ＜０．０５）;而ＨＵＴ时ＤＢＰ增加（卧床后达显著,Ｐ＜０．０５）。③ＬＢＮＰ时ＭＡＰ均显著降低（Ｐ＜０．０５）;而ＨＵＴ时在卧床前无变化（Ｐ＞０．０５）,在卧床后显著增加（Ｐ＜０．０５）。结论ＬＢＮＰ和ＨＵＴ引起的ＣＶＳ反应并不相同。笔者认为,ＨＵＴ更能促进心血管系统对立位应激的调节作用。     

Impairment of cardiovascular and vasomotor responses during tilt table simulation of "push-pull' maneuvers

BACKGROUND: Numerous studies have shown that tolerance to positive acceleration (+Gz) is impaired subsequent to an exposure of less than +1 Gz. HYPOTHESIS: Vasodilation induced by antecedent negative Gz (-Gz) exposure delays sympathetic vasoconstriction during subsequent +Gz, further reducing G-tolerance. METHODS: There were 20 subjects tested on an electronic tilt table, and exposed to the following randomized head-up tilt (HUT) and head-down tilt (HDT) conditions: +75 degrees HUT for 60 s, followed by transition to either 0 degrees (supine) HDT, or -25 degrees HDT, or -45 degrees HDT for 7 or 15 s at tilt rate of 45 degrees x s(-1). This was followed by HUT, divided into three periods: HUT1 (approximately 3-10 s), HUT2 (approximately 15-22 s), and HUT3 (approximately 27-35 s). Systolic blood pressure (SBP) was normalized to heart and head-levels. Stroke volume (SV) was estimated using impedance cardiography; forearm blood flow (FBF) estimated by venous occlusion plethysmography and forearm vascular resistance (FVR) was calculated from FBF and SBP. Total peripheral resistance (TPR) was estimated by MAP/(SV*HR). RESULTS: Heart-level SBP decreased significantly during HDT for both HDT durations (p < 0.01). SBP increased significantly at head-level during HDT (p < 0.001). During HUT1 heart and head-level SBP decreased for all conditions (p < 0.001), recovering to baseline levels by HUT2. TPR decreased significantly for all HDT conditions (p < 0.001), with this decrease related to the degree of HDT angle (p < 0.05). During HUT1, TPR remained depressed below baseline. At HUT2, TPR remained decreased for the -45 degrees/7-s condition only (p < 0.01). FBF decreased significantly during HDT (p < 0.02), with the magnitude related to the HDT angle. FBF remained elevated during HUT1 (p < 0.01). FVR decreased as a function of HDT angle during HDT (p < 0.001), with the decrease persisting into the HUT1 phase (p < 0.01). By the HUT2 and HUT3 periods, FVR were above baseline levels for the -45 degrees HDT condition (p < 0.01). CONCLUSION: These results confirm in humans the delayed recovery of peripheral vascular resistance observed in animal studies when -Gz precedes +Gz. Since SV recovered to baseline levels during the "pull" phase (HUT1-3), with TPR and forearm vascular resistance remaining depressed, baroreflex-mediated peripheral vascular control is delayed. This delay at higher subsequent +Gz levels is dangerous for the military pilot, since symptoms of G-intolerance due to delay in head-level BP recovery will ensue at lower absolute +Gz levels during push-pull type maneuvers.     

Cerebral blood flow velocity by transcranial Doppler during a vertical-rotating table simulation of the push-pull effect

BACKGROUND: The push-pull effect (PPE) has been suspected of causing many aircraft accidents. The perfusion and then withdrawal of cerebral blood during the PPE may change the state of the cerebral blood vessel. HYPOTHESIS: During head-down tilt (HDT) cerebral vasoconstriction occurs in response to the elevated perfusion pressure to maintain cerebral blood flow, and during subsequent head-up tilt (HUT) the increased resistance of the cerebral blood vessel recovers slowly. METHODS: Ten healthy male non-pilots were exposed to the following protocol using a rotating-table to simulate the push-pull maneuver: HUT (+1 Gz) for 1 min followed by transition to HDT (-1 Gz) 10 s followed by transition to HUT (+1 Gz) 1 min. Cerebral blood flow velocity and pulsatility indices in the left middle cerebral artery were continually measured with a transcranial Doppler (TCD) instrument. RESULTS: Mean blood flow velocity (Vm) increased significantly by 10%, during the first 5 s of HDT, recovered to baseline during HDT 5 10 s, and remained unchanged during subsequent HUT. Systolic blood flow velocity (Vs) increased by 9% during HDT 5-10 s and 11% during HUT 0-5 s. Diastolic blood flow velocity (Vd) decreased by -9% during HDT 5-10 s, and -22% during HUT 0-5 s. Vs-Vd increased by 26% during HDT 5 10 s, and 41%, during HUT 0-5 s. Pulsatile indices (PI) and resistance index (RI) increased by 26%) and 15% during HDT 5-10 s, and by 40% and 27% during HUT 0-5 s, respectively. Vs, Vs-Vd, PI, and RI remained at the higher level, and Vd remained at the lower level to HDT 15-20 s. CONCLUSIONS: The results indicate that cerebral vasoconstriction occurred to prevent brain over-perfusion during HDT. During HUT, the elevated resistance of the cerebral vessel remained at the higher level for about 20 s, and may have worsened the cerebral perfusion from exposure to +Gz. This may be one of the mechanisms of PPE.     

由心率与血压变异性估计民航飞行人员的心血管年龄

目的研究由心率与血压变异性估计民航飞行人员心血管年龄的方法 ,并探讨其在心血管疾病防治中的意义。方法先对 89名健康民航飞行人员的心率变异性 (HRV)与血压变异性 (BPV)的谱分析及压力反射敏感性 (BRS)数据进行主成分分析 ,再利用多重回归分析得出心血管年龄的估计方程。结果1 7个HRV、BPV与BRS原指标所蕴含的有关心血管自主神经调节功能状态的信息可由 7个主成分来反映 ,且原始指标变量的第 2与第 4主成分 (PC2 orig,PC4orig)及导出指标变量的第 2主成分 (PC2 deri)分别与实际年龄呈负相关关系 (P <0 .0 5) ,而原始指标变量的第 3主成分 (PC3orig)则与实际年龄呈正相关关系 (P <0 .0 1 ) ;根据估计方程得到的心血管年龄与实际年龄有较好的相关性 (r =0 .73,P <0 .0 1 )。结论由HRV与BPV分析估计得出的心血管年龄可综合反映健康飞行人员心血管自主神经调节功能随年龄的生理性变化 ,其实际应用价值有待进一步探讨     

心率/血压变异性与压力反射敏感度的年龄依赖性

目的 比较中年与青年男子心率变异性（ＨＲＶ）、收缩压变异性（ＳＢＰＶ）和压力反射敏感度（ＢＲＳ）的差别,探讨不同年龄组心血管自主神经调节的特点。方法 用自回归模型方法计算仰卧位与站立位ＨＲＶ和ＳＢＰＶ的谱指标,用序费法计算ＢＲＳ,并分析其间的相关性。结果 中年组两种体位下的ＨＲＶ谱指标及仰卧位时的ＢＲＳ均显著低于青年组（Ｐ〈０．０５,或Ｐ〈０．０１）。由仰卧位转为站立位后,中年组ＨＲＶ的总功率（Ｔ     

经颅多普勒在结核性脑膜炎的应用研究

目的　探讨结核性脑膜炎的脑血流动力学的变化特点 ,以及TCD检测在判断病情严重程度和临床预后的应用价值。方法　结核性脑膜炎组 2 0例和对照组正常人 30例 ,对病情及预后进行比较。结果　ACA ,MCA ,VA ,BA血流速度均增快 ;所测动脉PI值均升高。相关分析结果ACA Vs, Vd , Vm和MCA Vs与GCS ,GOS均成负相关 ;MCA PI值与GOS成负相关。结论　结核性脑膜炎异常改变波及颈内动脉系统和椎 基底动脉系统。大脑前、中动脉Vs流速越快 ,提示病情越严重 ,预后越差 ;大脑中动脉PI值越高 ,提示预后越差。     

The effect of low-level normobaric hypoxia on orthostatic responses

BACKGROUND: Altitude-induced hypoxia is believed to decrease tolerance to orthostasis. This preliminary investigation assesses the interaction between low-level normobaric hypoxia and the cardiovascular responses to orthostasis. HYPOTHESIS: We hypothesize that low-level hypoxia at simulated altitudes up to 3350 m adversely affects cardiovascular responses to orthostasis. METHODS: Six women and eight men underwent + 75 degrees head-up tilt (HUT) at 3 simulated altitudes (115 m (377 ft), 1680 m (5500 ft) and 3350 m (11,000 ft)). Minute ventilation (VE), tidal volume (VT), breathing frequency (f), heart rate (HR), and arterial blood pressure (BP) were measured non-invasively. Ventilatory parameters (VE, VT, and f) were measured during the control period to assess the respiratory response to hypoxia. Cardiovascular variables (HR and BP) during HUT were compared and analyzed by calculating the deviation from control (pre-tilt) values. RESULTS: Respiratory data showed no significant hypoxic ventilatory response. The average HR deviation significantly decreased (p < 0.05) with HUT from 13 +/- 2 bpm (115 m) to 9 +/- 2 bpm (3350 m). The pattern of mean arterial BP deviation with HUT was similar across the three altitudes (-6.6 +/- 2.9 mm Hg at 115 m to -6.8 +/- 2.4 mm Hg at 3350 m), with no significant differences. CONCLUSIONS: Changes in HR and arterial BP are fundamental aspects of the cardiovascular response to orthostatic stress. Although there were no significant changes in the BP response to orthostasis with hypoxia, the HR changes seen in this study suggest that the ability to modulate HR under orthostatic stress is reduced with exposure to low-level normobaric hypoxia.