上胸段硬膜外交感神经阻滞对兔蛛网膜下腔出血诱发脑血管痉挛的影响

目的 探讨上胸段硬膜外交感神经阻滞对兔蛛网膜下腔出血(SAH)诱发脑血管痉挛的影响.方法 日本大耳白兔24只,雌雄不拘,体重2.0～2.6 kg,随机分为3组(n=8).对照组(C组)枕大池注射生理盐水1 ml/kg,硬膜外腔注射生理盐水0.5 ml/2 h;S组枕大池注射自体动脉血1 ml/kg,硬膜外腔注射生理盐水0.5 ml/2 h;H组枕大池注射自体动脉血1 ml/kg,硬膜外腔注射0.5%利多卡因0.5 ml/2 h.记录家兔实验第4、5、6天进食量和神经功能状态,经颅多普勒超声测定实验前(T0)和实验第7天(T1)颈总动脉血流速度[平均血流速度(Vm)、收缩期峰血流速度(Vs)、舒张末血流速度(Vd)]搏动指数(PI)、阻力指数(RI),连续监测心率(HR)、平均动脉压(MAP)、心电图.结果 与C组相比,S组进食量下降和神经功能障碍发生率增加(P＜0.05);与S组相比,H组进食量下降和神经功能障碍发生率减少(P＜0.05);与T0时相比,T1时S组Vs、Vm及Vd升高,PI及RI降低,H组HR及上述指标降低(P＜0.05);与C组相比,T1时S组Vs、Vm及Vd升高,PI及RI降低,H组HR及上述指标降低(P＜0.05);与S组相比,T1时H组HR及上述指标降低(P＜0.05).结论 0.5%利多卡因上胸段硬膜外交感神经阻滞可抑制交感神经兴奋,从而改善兔SAH后脑血管痉挛.     

寰椎椎动脉沟环畸形及其X线分型对椎动脉血流动力学影响

目的 分析寰椎椎动脉沟环的X线分型，探讨寰椎动脉沟环对椎动脉血流动力学的影响。方法 回顾性分析临床有颈性眩晕症状，并同时做经颅多普勒和颈椎X线正侧位检查的患者，纳入64例有椎动脉沟环者作为实验组，42例没有椎动脉沟环者作为对照组，分析两者的基底动脉和椎动脉的收缩期峰流速(Vs)、舒张末期流速(Vd)、平均血流速度(Vm)、搏动指数(PI)检测结果。将椎动脉沟环分为半环组及全环组，对比两组的血流动力学情况。结果 实验组37例(57.8%)基底动脉或椎动脉血流异常；对照组9例(21.4%)基底动脉或椎动脉血流减慢。在平卧中立位，实验组与对照组对比，右椎动脉Vs、Vm,左椎动脉Vs、Vm,基底动脉Vs、Vm,组间差异均有统计学意义(P<0.05);右椎动脉Vd、PI,左椎动脉Vd、PI,基底动脉Vd、PI的两组间相比，差异均无统计学意义(P>0.05)。全环组与半环组的右椎动脉Vs、Vd、Vm、PI,左椎动脉Vs、Vd、Vm、PI,基底动脉Vs、Vd、Vm、PI相比，差异均无统计学意义(P>0.05)。结论 椎动脉沟环会使基底动脉、椎动脉血流速度减低，为临床诊断颈性眩晕提供...     

腹膜后腹腔镜手术中二氧化碳气腹对糖尿病患者脑血流的影响

目的采用经颅多普勒超声(TCD)对患者术中脑血流进行无创动态监测,观察腹膜后腹腔镜人工CO2气腹对糖尿病患者脑血流的影响。方法选择择期行腹膜后腹腔镜肾囊肿去顶术2型糖尿病患者20例,记录气腹前(T1)、气腹后10 min(T2)、30 min(T3)、60 min(T4)和停气腹后20min(T5)的平均脑血流速度(Vm)和搏动指数(PI)[PI=(Vs-Vd)/Vm]。结果T3与T4时颈内动脉颅内段(ICA)、大脑中动脉(MCA)和基底动脉(BA)的Vm比T1时明显增加(P<0.05),T2～T4时ICA、MCA、BA的PI值比T1时明显升高(P<0.05)。结论2型糖尿病患者在行腹膜后腹腔镜手术时,气腹持续时间超过30 min就会对脑血流产生影响。     

腹腔镜结直肠癌根治术气腹及Trendelenburg体位对≥60岁患者脑血流的影响

目的探讨气腹及Trendelenburg体位对腹腔镜结直肠癌根治术≥60岁患者脑动脉血流的影响。方法 2014年6月~2015年9月100例限期腹腔镜结直肠癌根治术≥60岁患者,ASAⅠ~Ⅱ级,手术时间2 h,按照年龄分为2组,每组50例:60~70岁为A组,70岁以上为B组。应用经颅多普勒技术监测右侧大脑中动脉血流信号,分别于麻醉诱导前(T0)、气管插管后5 min(T1)、气腹完成后(T2)、调节头低脚高30°体位即刻(T3),调节体位后1 h(T4),调节体位后2 h(T5)以及停气腹恢复平卧位10 min(T6)记录收缩期峰流速(Vs)、平均流速(Vm)和搏动指数(PI),并同时记录患者各时间点平均动脉压(MAP)。结果 A组患者Vs在T4~T6时点分别为(73.1±10.8)、(73.5±9.9)、(77.5±10.9)cm/s,较T1时点(66.4±9.3)cm/s显著升高(P0.05);Vm在T3~T6时点分别为(55.3±7.9)、(54.5±9.2)、(57.3±10.1)、(68.9±9.9)cm/s,较T1时点(48.3±8.1)cm/s显著升高(P0.05)。B组Vs在T3~T6分别为(74.4±9.5)、(78.2±9.5)、(79.0±10.3)、(82.0±9.3)cm/s,均较T1时点(65.8±8.9)cm/s显著增高(P0.05);Vm在T2~T6分别为(55.2±7.6)、(59.3±9.5)、(59.2±8.7)、(61.6±10.2)、(67.6±8.8)cm/s均较T1时点(46.5±8.9)cm/s显著增高(P0.05)。B组在T2~T5时点Vs和Vm均显著高于A组(P0.05),在T3~T6时点PI显著高于A组(P0.05)。2组间各时点MAP无明显差异(P0.05)。结论腹腔镜结直肠癌根治术中Trendelenburg 30°体位使老年患者脑动脉血流增加,≥70岁患者较60~70岁患者脑血流受气腹及体位的影响更加明显。     

经颅多普勒超声检查对重型颅脑损伤预后的判断价值

【摘要】〓目的〓探讨经颅多普勒超声检查(TCD)对重型颅脑损伤患者预后的判断价值。方法〓以2013 年2月至2014年10月在我院进行治疗的62例重型颅脑损伤患者作为病例组,并收集患者受伤后(术后)第1、3、7、14、21 d大脑中动脉的血流数据,以大脑中动脉收缩期血流速度(Vs)、舒张期血流速度(Vd)、博动指数(PI)作为观察指标;将同时期在我院接受TCD检查的健康44名对象作为对照组;将两组数据进行对比。结果〓患者受伤后(术后)第1 d脑血流速度即可发生改变;Vs和Vd值在第7 d降至最低,随后逐级恢复;PI指标则与脑血流速度变化趋势相反;第7 d的Vs是颅脑损伤的一个保护性因素。结论〓通过TCD检测的脑血流速度能反映重型颅脑损伤患者的颅内压力变化及预后情况,对颅脑损伤的治疗具有指导价值。     

超声引导下右侧星状神经节阻滞对腹腔镜胃癌根治术患者双侧脑血流的影响

目的观察超声引导下右侧星状神经节阻滞(stellate ganglion block, SGB)对腹腔镜下胃癌根治术患者双侧脑血流的影响。方法选择2017年8月至2019年2月择期行腹腔镜下胃癌根治术患者60例,男31例,女29例,年龄60~80岁,ASAⅡ或Ⅲ级,采用随机数字表法将患者随机分为两组,每组30例:SGB组(S组)和对照组(C组)。S组于麻醉诱导前在超声引导下行右侧SGB,注入0.375%罗哌卡因8 ml,C组注射等容量生理盐水。通过经颅多普勒超声(TCD)记录SGB前(T0)、SGB后5 min(T1)、30 min(T2)、60 min(T3)、手术结束(T4)时双侧大脑中动脉(MCA)平均血流速度(Vm),计算搏动指数(PI)和阻抗指数(RI),同时记录T0-T4时的MAP、HR和CVP。结果与T0时比较,T2-T4时C组双侧Vm、MAP明显降低,双侧PI和RI明显升高(P<0.05);T2-T4时S组双侧Vm明显明显降低(P<0.05),非阻滞侧PI和RI明显升高(P<0.05);T2时S组MAP明显降低(P<0.05)。T3、T4时C组MAP明显低于S组(P<0.05)。结论超声引导右侧星状神经节阻滞可以明显降低阻滞侧颅内动脉血管阻力,增加腹腔镜下胃癌根治术中颅内血流动力学的稳定性。     

去骨瓣减压术联合亚低温对颅脑外伤患者体液相关因子及脑血流的影响

目的观察去骨瓣减压术联合亚低温对颅脑外伤患者体液相关因子及脑血流的影响。方法随机将98例颅脑外伤患者分为2组,各49例。对照组行去骨瓣减压术,观察组行去骨瓣减压术联合亚低温治疗。比较2组不同时间的体液相关因子及脑血流变化。结果亚低温治疗即刻2组促肾上腺皮质激素(ACTH)、脑钠肽(BNP)、收缩期血流速度(Vs)、平均血流速度(Vm)水平差异无统计学意义(P0.05)。治疗后第7天观察组ACTH水平低于对照组,BNP、Vm、Vs水平高于对照组,差异有统计学意义(P0.05)。观察组GOS预后恢复良好率优于对照组,差异有统计学意义(P0.05)。结论去骨瓣减压术联合亚低温治疗颅脑外伤,可调节患者体液相关因子及脑血流水平,促进病情转归,改善预后。     

彩超引导显微手术治疗高血压脑出血的疗效及对脑血流动力学的影响

目的 探讨彩超引导显微手术治疗高血压脑出血的疗效及对脑血流动力学的影响。方法 回顾性分析2020年2月至2022年2月收治的高血压脑出血患者60例的临床资料。通过手术方式不同分为观察组32例、对照组28例，观察组采用彩超引导显微手术，对照组采用常规显微手术。比较两组围术期情况，手术前后舒张期末血流速度（Vd）、收缩期峰血流速度（Vs）、平均血流速度（Vm）、搏动指数（PI）、格拉斯哥昏迷指数（GCS）的变化及术后并发症发生率。结果 观察组的手术时间、术中出血量分别为（120.05±17.29） min、（38.96±4.30） mL，均短/少于对照组的（148.42±21.83） min、（47.28±3.65） mL，术后24 h血肿清除率为（86.37±5.19）%，明显高于对照组的（81.92±5.68）%，差异有统计学意义（P<0.05）；术后7 d时，观察组Vd、Vs、Vm分别为（39.11±3.64） cm/s、（94.04±11.69） cm/s、（58.06±5.28） cm/s，均明显高于对照组的（34.05±2.71） cm/s、（85.02±12.84） c...     

妇科腹腔镜手术中Trendelenburg体位时脑血流动力学的变化

目的应用经颅多普勒超声监测Trendelenburg体位(简称T位)时脑血流动力学的变化。方法择期腹腔镜下妇科手术患者40例,常规全身麻醉后行颈内静脉球部置管,监测麻醉诱导前(T1)、麻醉诱导后(T2)、气腹后(T3)、T位即刻(T4)、T位后30min(T5)、体位恢复后(T6)大脑中动脉平均血流速度(Vm)、搏动指数(PI)、阻力指数(RI),计算脑灌注压(CPP)。同时测量颈内静脉压,并于T2、T5采颈内静脉球部、桡动脉血进行血气分析。计算动-颈内静脉氧分压差(Da-jvO2)、二氧化碳分压差(Da-jvCO2)、血乳酸浓度差(Da-jvLac)和血糖浓度差(Da-jvGlu)。结果与T1时比较,T2时患者Vm、CPP明显降低(P0.05);与T2时比较,T4~T6时Vm明显升高(P0.05),T4、T5时PI、CVP和T5时RI、CPP明显升高(P0.05);T5时Da-jvO2明显降低(P0.05),Da-jvCO2、SjvO2明显升高(P0.05)。结论 Trendelenburg体位30min存在大脑过度灌注和脑氧摄取量减少,但未造成明显脑组织代谢障碍。     

头高位对糖尿病并发自主神经病变患者全麻下脑血流速度的影响

目的 评价头高位对糖尿病并发自主神经病变患者全麻下脑血流速度的影响.方法 择期行全麻手术患者60例,ASA分级Ⅰ或Ⅱ级,年龄40～60岁,体重52 ～70 kg,按照合并糖尿病情况,将患者分为3组:非糖尿病患者对照组(C组)、无自主神经病变的糖尿病组(D组)和糖尿病并发自主神经病变组(ANS-D组),每组20例.全麻诱导气管插管后,于平卧位(T0)、头高位45.后1.5 min(T1)、3.5 min(T2)、5.5 min(T3)时记录MAP和大脑中动脉血流速度(MBFV).结果 与T0时相比,C组和D组T1,2时MAP,T1时MBFV降低,ANS-D组T1-3时MAP和MBFV降低(P＜0.05),各组间比较MAP和MBFV差异无统计学意义(P＞0.05).结论 头高位时非糖尿病、无自主神经病变的糖尿病患者和糖尿病并发自主神经病变患者全麻下脑血流速度均降低且无差别.     

Pulsatile flow improves cerebral blood flow in pediatric cardiopulmonary bypass

The objective of this study was to evaluate the effect of pulsatile flow on cerebral blood flow (CBF) in infants with the use of a mild hypothermic cardiopulmonary bypass (CPB). Thirty infants scheduled for open heart surgery were randomized to the pulsatile group (Group P, n = 15) and nonpulsatile group (Group NP, n = 15). In Group P, pulsatile perfusion was applied during the aortic cross‐clamping period, whereas nonpulsatile perfusion was used in Group NP. The systolic peak velocity (Vs), the end of diastolic velocity (Vd), the mean velocity (Vm), and the pulsatility index (PI) and the resistance index (RI) of the middle cerebral artery were measured by a transcranial Doppler (TCD) ultrasound after anesthesia (T1; baseline), at the beginning of CPB (T2), 10 min after aortic cross‐clamping (T3), 3 min after declamping (T4), at the cessation of CPB (T5), and at the end of the operation (T6). During T3 and T4, the Vs in Group P was significantly higher than in Group NP. However, there were no statistically significant differences between Vd and Vm. The PI and RI in Group P were also higher than those in Group NP (both P < 0.05). During T5, Vd and Vm were higher in Group P (P < 0.05), whereas there was no difference in Vs. Additionally, PI and RI in Group P were significantly lower than those in Group NP (P < 0.05). However, there was no difference during T6. Pulsatile perfusion may increase CBF and decrease cerebral vascular resistance in the early period after mild hypothermic CPB.     

The effect of hematocrit on cerebral blood flow velocity in neonates and infants undergoing deep hypothermic cardiopulmonary bypass.

Varying degrees of hemodilution are used during deep hypothermic cardiopulmonary bypass. However, the optimal hematocrit (Hct) level to ensure adequate oxygen delivery without impairing microcirculatory flow is not known. In this prospective, randomized study, cerebral blood flow velocity in the middle cerebral artery was measured using transcranial Doppler sonography in 35 neonates and infants undergoing surgery with deep hypothermic cardiopulmonary bypass. Patients were randomized to low Hct (aiming for 20%) or high Hct (aiming for 30%) during cooling on cardiopulmonary bypass (CPB). Systolic (V(s)), mean (Vm), and diastolic (Vd) cerebral blood flow velocity, as well as pulsatility index (PI = [V(s) - Vd]/Vm) and resistance index (RI = [V(s) - Vd]/V(s)) were recorded at six time points: postinduction, at cannulation, after 10 min cooling on CPB, rewarmed to 35 degrees C on CPB, immediately off CPB, and at skin closure. Vm was significantly lower in the high Hct group compared with that in the low Hct group during cooling (P < 0.01). Postinduction, the high Hct group demonstrated significantly lower Vd immediately off CPB (P < 0.01) and significantly lower Vm and V(s) at skin closure (P < 0.001). We conclude that there is an inverse relation between hematocrit and cerebral blood flow velocity during deep hypothermic cardiopulmonary bypass in neonates and infants. Implications: There is an inverse relation between hematocrit and cerebral blood flow velocity during deep hypothermic cardiopulmonary bypass in neonates and infants. Further studies correlating Hct and cerebral blood flow velocity with cerebral metabolic rate and neurologic outcome are necessary to determine the optimal Hct during deep hypothermic cardiopulmonary bypass.     

Changes in cerebral blood volume with changes in position in awake and anesthetized subjects

Changes in posture affect cerebral blood volume (CBV), and moderate head-up tilt is used as a therapeutic maneuver to reduce CBV and intracranial pressure. However, CBV is rarely measured in the clinical setting. Near-infrared spectroscopy allows real-time bedside monitoring of cerebral hemodynamics, and we have used this technique to measure changes in CBV with changes in posture in 10 normal subjects and 10 propofol-anesthetized patients. In the awake subjects, changes in CBV were correlated with the degree of table tilt. CBV decreased with 18 degrees head-up tilt and increased with 18 degrees head-down tilt (P < 0.0001, r = -0.924). In anesthetized patients, there were differences between head-up and head-down tilt. In the head-down position, CBV was also correlated with the degree of table tilt (P < 0.001, r = -0.782), whereas there was a clinically insignificant reduction in CBV in the head-up position. Near-infrared spectroscopy allows continuous, real time measurement of changes in CBV at the bedside. IMPLICATIONS: Near-infrared spectroscopy, a bedside technique, has been used to measure changes in cerebral blood volume in normal subjects. We have used the same technique in anesthetized patients and have shown that, when a patient is placed in the head up position, the decrease in cerebral blood volume is attenuated, relative to normal subjects.     

Changes in intrathoracic blood volume associated with pneumoperitoneum and positioning

BACKGROUND: It is still controversial whether elevated cardiac filling pressures after the onset of pneumoperitoneum are the consequence of increased intrathoracic pressure or of increased venous return. The aim of this study was to assess the effects of pneumoperitoneum and body positioning on intrathoracic blood volume (ITBV). METHODS: Thirty anesthetized patients were randomly assigned to have CO2-pneumoperitoneum (13 mmHg) either in a supine, in a 15 degrees head-up tilt or in a 15 degrees head-down tilt position. Measurements of ITBV and hemodynamics by the double indicator method were recorded after induction of anesthesia and application of a fluid bolus (Lactated Ringer's solution 10 ml/kg), after positioning and after induction of pneumoperitoneum. RESULTS: Intrathoracic blood volume index (ITBVI) increased significantly after induction of pneumoperitoneum in all body positions (supine: from 18.5 +/- 3.3 -20.2 +/- 5.2 ml/kg (+6%) head-up from 16.7 +/- 3.8 - 17.4 +/- 3.7 ml/kg (+16%) and head-down: from 19.8 +/- 5.6 - 20.5 +/- 5.9 ml/kg (+14%)). Heart rate did not change significantly in any of the groups. Cardiac index showed a statistically significant change in the head-down position with pneumoperitoneum (-11%). A good correlation was found for stroke volume (SV) with ITBV (r = 0.79), but not with central venous pressure (r = 0.26). Systemic vascular resistance index increased significantly in all three groups (supine +6%, head-up +16%, head-down position +14%). CONCLUSION: The present study indicates that the onset of pneumoperitoneum, even with moderate intra-abdominal pressures, is associated with an increased intrathoracic blood volume in ASA I/II patients.     

Thermoregulatory response to intraoperative head-down tilt.

Thermoregulation interacts with cardiovascular regulation within the central nervous system. We therefore evaluated the effects of head-down tilt on intraoperative thermal and cardiovascular regulation. Thirty-two patients undergoing lower-abdominal surgery were randomly assigned to the 1) supine, 2) 15 degrees -20 degrees head-down tilt, 3) leg-up, or 4) combination of leg-up and head-down tilt position. Core temperature and forearm minus fingertip skin-temperature gradients (an index of peripheral vasoconstriction) were monitored for 3 h after the induction of combined general and lumbar epidural anesthesia. We also determined cardiac output and central-venous and esophageal pressures. Neither right atrial transmural pressure nor cardiac index was altered in the Head-Down Tilt group, but both increased significantly in the Leg-Up groups. The vasoconstriction threshold was reduced in both leg-up positions but was not significantly decreased by head-down tilt. Final core temperatures were 35.2 degrees C +/- 0.2 degrees C (mean +/- SEM) in the Supine group, 35.0 degrees C +/- 0.2 degrees C in the Head-Down Tilt group, 34.2 degrees C +/- 0.2 degrees C in the Leg-Up group (P < 0.05 compared with supine), and 34.3 degrees C +/- 0.2 degrees C when leg-up and head-down tilt were combined (P < 0.05 compared with supine). These results confirm that elevating the legs increases right atrial transmural pressure, reduces the vasoconstriction threshold, and aggravates intraoperative hypothermia. Surprisingly, maintaining a head-down tilt did not increase right atrial pressure. IMPLICATIONS: Intraoperative hypothermia is exaggerated when patients are maintained in the leg-up position because the vasoconstriction threshold is reduced. However, head-down tilt (Trendelenburg position) does not reduce the vasoconstriction threshold or aggravate hypothermia. The head-down tilt position thus does not require special perioperative thermal precautions or management unless the leg-up position is used simultaneously.     

Does patient position during liver surgery influence the risk of venous air embolism?

BACKGROUND: It is generally believed that positioning of the patient in a head-down tilt (Trendelenberg position) decreases the likelihood of a venous air embolism during liver resection. METHODS: The physiological effect of variation in horizontal attitude on central and hepatic venous pressure was measured in 10 patients during liver surgery. Hemodynamic indices were recorded with the operating table in the horizontal, 20 degrees head-up and 20 degrees head-down positions. RESULTS: There was no demonstrable pressure gradient between the hepatic and central venous levels in any of the positions. The absolute pressures did, however, vary in a predictable way, being highest in the head-down and lowest during head-up tilt. However, on no occasion was a negative intraluminal pressure recorded. CONCLUSION: The effect on venous pressures caused by the change in patient positioning alone during liver surgery does not affect the risk of venous air embolism.     

Cerebral blood flow velocity after mannitol infusion in children

Purpose

There is conflicting evidence as to whether the effect of mannitol on brain bulk arises from haemodynamic, rheologic, or osmotic mechanisms. If mannitol alters cerebral haemodynamics by inducing vasoconstriction, this change should be reflected in cerebral blood flow velocity (CBFV) in the middle cerebral artery (MCA). The purpose of this study was to evaluate the effect of mannitol on CBFV in children.

Methods

Children scheduled for intracranial surgery were enrolled. After a loading dose of 10 μg · kg^?1 of fentanyl, general anaesthesia was maintained with fentanyl (3 μg · kg^?1 · hr^?1), 66% nitrous oxide, and isoflurane (0.2–0.5% inspired). Mean and systolic CBFV (Vm and Vs) and pulsatility index (PI) were recorded with a transcranial Doppler (TCD) directed at the M1 segment of the MCA. Mannitol was administered, 1 gm · kg^?1 iv over 15 min. The osmolality (Osm), haematocrit (Hct), mean arterial pressure (MAP), heart rate (HR), and TCD variables were recorded before and 15, 30, 45, and 60 min after the mannitol infusion.

Results

Mannitol infusion resulted in an increase in Osm and decrease in Hct (P < 0.05). Heart rate, MAP and arterial carbon dioxide tensions did not change (P > 0.05) during the measuring period. The Vm did not vary from baseline. The Vs and P1 both increased briefly (P < 0.01 at 15 min and P < 0.05 at 30 min) after the mannitol, suggesting an increase in resistance distal to the MCA.

Conclusion

The time course of CBFV changes produced by mannitol corresponds with previous animal data concerning cerebrovascular tone. Our results suggest that mannitol briefly increases cerebrovascular resistance and thereby diminishes cerebral blood volume.