非体外循环冠状动脉旁路移植术的麻醉管理

目的探讨非体外循环下冠状动脉旁路移植术病人的麻醉管理。方法择期非体外循环下冠状动脉旁路移植术病人20例,采用静吸复合全麻。硝酸甘油、艾司洛尔、去氧肾上腺素、多巴胺等用于调控血流动力学指标。观察术后患者血中心肌肌钙蛋白I(cTnI)和肌酸激酶同工酶(CK-MB)含量的变化。结果所有患者均顺利完成麻醉和手术,无麻醉并发症,预后良好。术后各时间点血中cTnI和CK-MB含量与术前比均有一定程度升高。结论非体外循环下冠状动脉旁路移植术心肌损伤轻,麻醉管理的关键是维持血流动力学平稳和心肌氧供与氧耗的平衡。     

淫羊藿总黄酮注射液对正常麻醉开胸犬血流动力学的影响

目的 观察淫羊藿总黄酮注射液对正常麻醉开胸犬血流动力学的影响。方法 用脉冲多普勒超声血流仪分别测定心输出量、血压和冠脉流量,心导管插管测定左室内压,BIOPAC多导生理仪记录心电图。结果 淫羊藿总黄酮注射液可减慢心率,升高收缩压,短暂降低舒张压,增加心输出量、冠脉流量、心脏指数、左室做功指数,降低总外周阻力、冠脉阻力和左室内压最大变化速率,降低心肌耗氧指数,对左室内压无明显影响。结论 淫羊藿总黄酮注射液可通过增加冠脉流量。增加氧的供应,降低心肌耗氧量,改善心脏血流动力学。     

下体负压-立位作用下ST-T改变与心肌氧耗的关系

目的探讨负压 -立位作用下心电图ST T改变与心肌氧耗的关系。方法 68只雄性新西兰大耳白兔 ,对照组 2 1只 ,负压 -立位组 47只 ,根据家兔在负压 -立位过程中的ST T变化 ,将负压 -立位组分为阳性组和阴性组。测量的指标有 :心率、血压、左室内压及室内压变化速率峰值、室内压差×心率等指标。结果同对照组比 ,负压 -立位作用下血压、左室峰压、室内压变化速率峰值、室内压差与心率乘积出现了明显下降 ,阳性组的左室峰压、室内压变化速率峰值、室内压差与心率乘积在 - 30mmHg 2min和4min时下降幅度明显小于阴性组 ,而阳性组和阴性组的动脉血压在负压初期无明显差别。结论负压-立位作用下ST T改变不仅与动脉血压明显下降有关 ,还与心肌氧耗水平较高有关。     

术中连续监测ST段变化121例临床分析

为增加冠心病病人麻醉与手术安全性，及时发现和处理心肌缺血甚为重要。心电图（ＥＣＧ）ＳＴ段的变化可反映冠状动脉对心肌供血的情况〔１〕。本研究对５０岁以上冠心病或可疑冠心病病人进行术中ＥＣＧＳＴ段的连续监测，以便探讨手术和麻醉中ＳＴ段的变化规律。１材料与...     

PET-CT在冠状动脉疾病的临床应用

PET-CT可无创性检测心肌血流灌注、定量测定冠状动脉血流储备,并提供冠状动脉解剖影像、冠状动脉钙化积分,观察粥样斑块性质,对心肌存活性、心脏功能测定都有重要临床价值。将以上各种信息综合应用于临床,则对冠心病的诊断、治疗方案的选择及预后判断等具有重要意义。     

高海拔地区隐性冠心病的临床探讨(附68例报告)

高海拔地区隐性冠心病的主要易患因素是低氧环境下出现的高血脂、高血压和大量吸烟。本组病例提示了高原缺氧与易患因素的协同性致病作用,加快了冠状动脉的病变,心肌缺氧缺血,心电图ST—T的变化多种多样。运动试验使心脏自主神经兴奋性增强,终致血压增高,特别是舒张压升高≥2kPa时,即应早期确定本病的存在。     

茜Ⅱ和丹参注射液对实验性心肌梗塞疗效的比较

本文以冠状动脉血流量、颈动脉平均血压、心率、心外膜心电图ST段总和(ΣST),以及结扎左冠状动脉前降支(LAD)20h后心肌用硝基四氮唑蓝(N-BT)染色测定心肌梗塞的范围等指标,在心肌梗塞模型狗上观察了静脉注射茜Ⅱ和丹参注射液对实验性心肌梗塞的作用.实验表明,在使血压降低、心率减慢和ΣST减小等方面,两药在各自常用有效量的情况下作用基本相似,但在使冠状动脉流量增加和使心肌梗塞范围缩小等方面,茜Ⅱ的作用却明显地超过丹参注射液(P<0.02).     

KDML-Ⅱ型激光对缺血心肌的灌注效应和组织学实验研究

目的 :研究缺血心肌的血液灌注后改善情况及打孔后 2月孔道周围心肌组织学变化。材料及方法 :心肌缺血模型通过结扎左冠状动脉前降支第一对角支开口下方及供应心尖部血管分支 ,造成左室前侧壁及心尖的心肌缺血或梗死。 12只健康杂种犬随机分为对照组和实验组。实验组采用国产ＫＤＭＬ Ⅱ型激光 (功率 2 0Ｗ ,连续脉冲 ,光纤直径 1ｍｍ)在缺血区打孔 10～ 15个 ,对照组不作处理。术日观察 2ｈ心电图及血流动力学变化 ;术后2月 ,开胸。实验组于心肌打孔处 ,对照组于缺血区穿刺抽取标本 ,经相应处理后 ,分别测定孔道周围微血管数量、心肌的胶原…     

CT心肌动态与单次灌注成像对照研究

正目的研究CT心肌动态灌注成像对于冠状动脉狭窄所致心肌血流动力学异常的诊断准确性,并与冠状动脉造影及冠状动脉血流储备分数(FFR)比较。方法本研究经伦     

冠状动脉CTA评估心肌桥形态特征、发生位置与冠状动脉粥样硬化的关系

目的 通过MDCT冠状动脉血管造影(coronary CT angiography,CTA)评估心肌桥-壁冠状动脉与冠状动脉粥样硬化的关系.方法 回顾性分析663例冠状动脉CTA患者的图像资料,记录心肌桥的发生率、发生位置、长度及心肌桥的厚度,结合临床症状以及心电图和心脏超声表现,分析心肌桥发生的位置及狭窄程度与临床症状、心电图STT改变及超声室壁运动异常之间的关系,以及评估心肌桥与动脉粥样硬化的关系.结果 MDCTA心肌桥-壁冠状动脉发生率为38.0%(252/663),以前降支最多见,占44.0%(111/252).孤立性心肌桥壁冠状动脉狭窄程度与临床症状、心电图STT改变及超声室壁运动障碍之间差异有统计学意义.前降支存在心肌桥的患者,同支血管粥样硬化斑块的发生率高于无心肌桥的患者(P=0.003),深在型心肌桥合并动脉粥样硬化的几率明显高于浅表型心肌桥 (P＜0.001).心肌桥近端冠状动脉狭窄的发生率显著高于壁冠状动脉及其远端冠状动脉.结论 心脏收缩期壁冠状动脉中、重度狭窄的心肌桥不能仅视为解剖变异,而应引起临床医生的重视,因其会引起心肌灌注减低,出现相关临床症状.心肌桥近端动脉更易出现粥样硬化斑块,表明心肌桥可以作为评估冠状动脉粥样硬化性心脏病的危险因素之一.     

立位-下体负压时心血管指标的变化

目的了解立位 -下体负压 (HUT +LBNP)期间心血管系统的变化 ,确定心律变异和脉图两种方法在评价心血管调节功能中的作用。方法观察 1 6名被试者在 75°头高位倾斜加 - 4kPa下体负压 2 0min期间血压、脉图、心律变异和脑血氧饱和度的变化。结果 ( 1 )HUT +LBNP可引起被试者出现明显的心率、血压、规 -化低频峰功率 (LFn)、LFn/HFn增加 ,脑血氧饱和度、心电T波和规 -化高频峰功率(HFn)下降 ;( 2 )晕厥前出现明显的血压、心率和脑血氧饱和度下降 ;( 3)低耐力组在HUT +LBNP初期的心率明显高于高耐力组 ;( 4 )HUT +LBNP时脉搏波波形发生很大变化 ,无法进行分析。结论HUT +LBNP是一种负荷量较高的立位耐力检查方法 ,可充分暴露被检者在立位中的心血管调节功能 ;脉图检测方法不能作为评价被试者HUT +LBNP耐力的方法。     

下体负压对男女飞行学员心血管调节功能的影响

观察男女飞行学员在下体负压条件下各项生理指标的变化差异，男女两组受试者分别下体负压裤，在－50mmHg负压下持续暴露8min。在下体负压（LBNP）作用时，同步记录心电图、心率、血压、脑血流量、负压暴露时间。结果显示，在LBNP作用下，随着负压暴露时间的增加，所有受试者均出现心率增快，收缩压降低、脑血流量下降。研究表明，下体负压所产生的生理学效应在男女飞行学员间相似。     

下体负压下的心率变异分析

为探讨下体负压下的心率变异变化及其与血液动力这指标的关系，４０名健康男性参加了下体负压实验，用Ｈｏｌｔｅｒ记录了受试者Ｖ５导联心电图，并进行了心率变异（ＨＲＶ）分析；用超声多谱勒技术测定ＳＶ，ＣＯ。结果表明：在ＬＢＮＰ过程中两组受试者均出现了ＨＲＶ的降低，尤以高频谱质量（ＨＦ）降低显著，ＬＦ／ＨＦ在ＬＢＮＰ过程中呈升高趋势，耐力低者的ＬＦ／ＨＦ升高比耐力良好者明显，提示：晕厥前症状的发生可能是由于     

Effects of repeated brain ischemia induced by rapid lower body negative pressure on brain water and Na+,K+-ATPase activity in rats

BACKGROUND: It has been demonstrated that during +Gz exposure cerebral blood flow is significantly reduced resulting in brain ischemia. Animal centrifuge models are commonly used to investigate the mechanisms of +Gz-induced loss of consciousness (G-LOC) and their pathophysiological effects on the brain. These dynamic models are limited because we currently are unable to obtain accurate measures of membrane ion flux or single cell electrophysiological responses from animals under centrifugation. HYPOTHESIS: The aim of the present study was to develop a non-centrifuge animal model of short-term, repeatable and complete brain ischemia using a rodent lower body negative pressure (LBNP), and to investigate the effects of repeated complete brain ischemia induced by LBNP on brain Na+,K+-ATPase activity, Na+, K+ and water contents in rats. METHODS: Eight anesthetized rats were exposed randomly to LBNP of -2.67 kPa, -4.00 kPa, and -5.33 kPa, respectively, at the rate of -0.67 kPa x s(-1). The pressure rapidly returned to control level when EEG became isoelectric (flat). The mean arterial BP (MAP), EEG and ECG were recorded. Twenty-one rats were divided randomly into control, single LBNP exposure, and three LBNP exposures groups (n = 7 in each group). Brain samples were analyzed for Na+,K+-ATPase activity, Na+, K+ and water contents 1 h after single and three 2-min LBNP exposures (-4.00 kPa at a rate of 0.67 kPa x s(-1)), respectively. RESULTS: MAP decreased rapidly during LBNP exposure. The mean time to isoelectric EEG was 41.33 +/- 11.48, 30.67 +/- 3.88 and 25.67 +/- 3.45 s during -2.67, -4.00 and -5.33 kPa LBNP, respectively. Heart rate (HR) significantly decreased when EEG became isoelectric. MAP, HR and EEG rapidly returned after releasing LBNP. The brain Na+,K-ATPase activity decreased significantly after single LBNP exposure and decreased further after three LBNP exposures. The brain K+, Na+ and water contents increased significantly after three LBNP exposures. CONCLUSIONS: A rat model of short-term, repeatable brain ischemia was developed using rapid LBNP. Three -4.00 kPa LBNP exposures (2 min each) cause a significant reduction in brain Na+,K+-ATPase activity and brain edema in rats.     

反复体位改变对人体心电图节律的影响

目的观察和分析反复体位改变对人体心电图节律的影响。方法 150名志愿者在电动立位转床上进行反复体位改变实验,部分志愿者进行头高位倾斜(head-up tilt,HUT)实验、头低位倾斜(head-downtilt,HDT)实验、下体负压实验、低压缺氧检查、运动心肺功能检查,连续监测和记录心电图,统计并比较不同负荷实验中心电图节律失常的百分数。结果在反复体位改变实验中,23.33%(35/150)的志愿者心电图出现了节律失常,其中7.33%(11/150)出现了房室传导阻滞或阵发性室上速的典型节律改变。反复体位改变实验中心电图节律失常的发生率明显高于HUT实验、HDT实验、下体负压实验、低压缺氧检查和运动心肺功能检查(P<0.01),出现典型节律失常的志愿者在其它5项实验或检查中均未出现。结论一定模式的反复体位改变可引起健康志愿者心电图较高频率的节律失常,并出现房室传导阻滞或阵发性室上速的典型节律改变。这提示反复体位改变实验有可能在航天员和飞行员医学选拔或医学鉴定中得到应用。     

Lower body negative pressure treadmill exercise is more comfortable and produces similar physiological responses as weighted vest exercise

Lower body negative pressure (LBNP) treadmill exercise can generate a hypergravity load on the lower body that may improve athlete performance by mechanical and cardiovascular adaptations. This study compared the cardiovascular responses, subjective exertion and discomfort levels produced by LBNP exercise with those generated by a weighted vest (WV). We hypothesized that LBNP exercise is more comfortable than WV exercise at comparable levels of exercise. Nine subjects exercised on a treadmill at nine conditions, at 5.5 mph for 15 minutes, in which they ran in random order to avoid confounding effects: 100 %, 110 %, 120 %, 130 %, and 140 % body weight (BW), the latter four conditions were achieved by either LBNP chamber or WV. Heart rate (HR) and oxygen consumption (.VO(2)) were monitored continuously using ECG and open circuit spirometry. At the end of each test, subjects were asked to give discomfort and exertion scores using a ten-point visual analog scale (10 = maximal discomfort and exertion). For both HR and .VO(2), no significant differences were observed between LBNP and WV. Subjects reported significantly higher discomfort levels when exercising with the WV than with the LBNP at 120 % BW (5.1 +/- 0.55 vs. 3.1 +/- 0.64; p < 0.05), 130 % BW (6.2 +/- 0.42 vs. 2.3 +/- 0.44; p < 0.01) and 140 % BW (6.9 +/- 0.27 vs. 4.7 +/- 0.60; p < 0.01), while maintaining similar exertions at all conditions. Based on these results, LBNP exercise is more comfortable than standard WV exercise, while maintaining similar exertion, HR and .VO(2) values.     

Diagnostic potential of the lower-body negative pressure test in medical monitoring during extended space flights]

To put into service the diagnostic and prognostic capabilities of the lower body negative pressure test (LBNP) during extended space flights, cardiovascular reactions associated with various levels of test tolerance were analyzed and compared. The article gives account of 60 tests performed by 44 cosmonauts 33 to 53 years of age during 59- to 415-d flights. In 36 tests tolerance was good and in 24 - satisfactory. Medical evaluation was fulfilled using GaMMa-1M, an onboard multifunctional medical monitoring system. Dynamics of ECG, blood pressure, stroke and minute volumes, pulse filling, and vertebral-basilar tone exhibited some specific traits that mirrored LBNP tolerance. Established were diagnostically implicative values in the course of pressure drop. Evidence was obtained that during the test and ensuing data analysis consideration should be given as to the span of changes of each parameter, so the time of their initiation, and dynamics.     

Combat stress or hemorrhage? Evidence for a decision-assist algorithm for remote triage

INTRODUCTION: In the setting of remote military triage, when physical access to the patient is not possible, traditional physiological measurements available to a combat medic may not differentiate between a wounded soldier and an active soldier. We tested the hypothesis that changes in high-frequency R-R interval spectral power (RRI HF) and pulse pressure (PP) would differ between progressive central hypovolemia (simulated hemorrhage) and exercise to evaluate their potential for remotely distinguishing active from bleeding soldiers. The RRI HF and PP were used because of their ability to track central hypovolemia. METHODS: There were 12 (8 female/4 male) healthy, normotensive, nonsmoking subjects (age 27 +/- 2 yr; height 169 +/- 3 cm; weight 68 +/- 5 kg) who were exposed to progressive lower body negative pressure (LBNP) and a supine cycle ergometer protocol. ECG and blood pressure were measured continuously. Exercise workloads were determined by matching the heart rate (HR) responses to each LBNP level. Data were analyzed in time and frequency domains. RESULTS: HR increased from 67 +/- 3 bpm at rest to 101 +/- 4 bpm by -60 mmHg LBNP and was matched within 5% during exercise. By the final stage, RRI HF decreased by a similar magnitude during both LBNP (-78 +/- 7%) and exercise (-85 +/- 6%). PP decreased by 30 +/- 4% with LBNP compared with an increase of 20 +/- 6% during exercise. CONCLUSION: Monitoring PP in combination with RRI HF would distinguish a bleeding from an active soldier. Technologies that incorporate telemetry to track these derived vital signs would provide a combat medic with remote decision support to assess soldier status on the battlefield.     

反复下体负压致意识丧失对大鼠血脑屏障通透性的影响

为阐明多次发生＋Ｇｚ致意识丧失对脑的影响及其机制，观察了反复下体负压（ＬＢＮＰ）致意识丧失对大鼠血脑屏障（ＢＢＢ）通透性的影响。雄性ＳＤ大鼠，麻醉后置于－４．０ｋＰａ的下体负压舱内，至脑电波消失２ｍｉｎ后恢复常压。分别于一次和三次ＬＢＮＰ作用后１ｈ利用硝酸镧示踪法观察ＢＢＢ通透性的变化。一次ＬＢＮＰ致意识丧失组大鼠脑皮层组织变化不明显；三次ＬＢＮＰ致意识丧失组大鼠脑皮层组织中大部分毛细血管内皮细胞     

Effects of gender on the autonomic modulation of the cardiovascular responses to lower body negative pressure

BACKGROUND: The cardiovascular responses to submaximal lower body negative pressure (LBNP) appear to differ between genders, but the underlying mechanisms are uncertain. HYPOTHESIS: These differences are due to differences in the autonomic modulation of the cardiovascular system. METHODS: There were 14 women and 13 men who underwent LBNP to -50 mmHg in 10 mmHg increments of 6 min each. Heart rate (HR), stroke volume (SV), BP, forearm blood flow and R-R interval data were acquired. Spectral analysis of the R-R interval data was used to assess autonomic modulation with the low frequency component (LF) set at 0.04 to 0.15 Hz and the high frequency component (HF) at 0.15 to 0.4 Hz. RESULTS: The responses to LBNP to -40 mmHg did not differ between groups. LBNP of -50 mmHg evoked greater HR increases in the women than the men (7.2 +/- 1.0 vs. 3.8 +/- 1.1 bpm; p < 0.05), while SV, cardiac output and total peripheral conductance decreased more (-15 +/- 2 vs. -8 +/- 2 ml x beat(-1); -0.668 +/- 0.131 vs. -0.1778 +/- 0.124 L x min(-1); -0.009 +/- 0.002 vs. -0.004 +/- 0.001 units; p < 0.05). Normalized HF, an indicator of the vagal influence on HR variability, declined below rest at -40 mmHg while the LF/HF ratio, an indicator of sympathetic neural modulation of HR variability, increased above rest at -40 mmHg. These responses did not differ significantly between groups. CONCLUSIONS: These results suggest that gender differences in the cardiovascular responses to LBNP are not due to gross differences in modulation of the autonomic nervous systems.