急进和渐进西藏对南极考察昆仑站预选队员心血管功能及其应激因子的影响*

目的: 分析急进和渐进西藏高原对拟进入中国南极考察昆仑站的第31、32和 33次预选队员的心血管功能及其相关应激因子水平的影响,为选拔合格的内陆考察队员提供科学依据。方法: 以 2014～2016 年第 31、32 和33次队共 85名中国南极考察昆仑站预选队员为研究对象,依据进入高原方式分为乘飞机急进高原组(急进组,n=55)和乘火车渐进高原组(渐进组,n=30),分别在上海出发(海拔 4 m)、到达拉萨(海拔 3 658 m)和进入更高海拔的羊八井(海拔 4 300 m)3个时间点,采用心功能仪和心电图仪动态检测预选队员的心血管功能,并同步采集队员的唾液样本,采用 ELISA法检测唾液中应激因子睾酮(T)、皮质醇(COR)和免疫球蛋白A(IgA)水平。结果: 与海拔 4 m 相比,两组队员在到达海拔 3 658 m、4 300 m 高原时,心率(HR)显著升高(P＜0.05),指端静脉血氧饱和度(SpO₂)显著下降(P＜0.05),但两组间在相同海拔高度上无显著差异;两组间心电传导异常率无显著差异;与海拔4 m相比,到达 3 658 m和 4 300 m处两组队员的血压均显著升高(P＜0.05),部分心肌收缩和泵血功能指标均显著降低(P＜0.05),但由于心率增加代偿,心输出量(CO)无显著变化。在海拔4 300 m时,急进组的肺水指数(TFC)显著高于渐进组(P＜0.01)。进入高原后与出发水平的差值比较,两组在海拔3 658 m 处 T变化量无显著性差异(P＞0.05),急进组 COR 和IgA变化量显著高于渐进组(P＜0.05);在海拔 4 300 m 处急进组 IgA变化量显著高于渐进组(P＜0.05)。结论: 对比渐进高原,急进高原对南极考察昆仑站预选队员的心血管功能及唾液中的应激激素和免疫球蛋白水平均有更明显影响。提示应在岗前严格选拔能适应南极昆仑站低氧环境的考察队员,保障南极考察队员身心健康,确保南极考察任务顺利实施。     

高原心搏量的自身调节

高原低氧坏境下,左心搏血功能及其调节尤为重要。我们应用超声心动图测定了不同海拔健康人左心泵功能指标,从而初步探讨了自身调节机制对高原心搏量的调节作用。 对象与方法 检查对象分别为平原南京(海拔20m),高原西宁(海拔2260m)与哈尔盖(海拔3232m)三     

不同途径行PCI治疗高龄冠心病患者的临床疗效和安全性比较

目的:比较不同动脉途径行经皮冠状动脉介入(PCI)治疗高龄冠心病患者的临床疗效和安全性。方法:选取214例高龄冠心病患者,按动脉途径不同分为对照组(107例)与研究组(107例),对照组行经股动脉PCI(TFI),研究组行经桡动脉PCI(TRI),比较两组的手术情况、手术前后心功能相关指标的变化及不良反应的发生情况。结果:两组手术成功率、支架置入数量、造影剂用量比较无显著差异(P0.05);研究组动脉穿刺时间、导管插入时间、X线曝光时间均显著长于对照组(P0.05),术后卧床时间、住院时间均显著少于对照组(P0.05)。手术后1 d,两组左室收缩末期内径(LVESD)、左室舒张末期内径(LVEDD)、左心射血分数(LVEF)较手术前均明显改善,但两组比较无显著性差异(P0.05)。研究组治疗期间外周血管并发症的发生率显著低于对照组(P0.05),但治疗期间及术后6个月心血管不良事件的发生率与对照组间无显著差异(P0.05)。结论:经桡动脉途径与股动脉PCI用于治疗高龄冠心病患者对患者心功能的改善作用相当,但经桡动脉行PCI术后卧床时间及住院时间较短,外周血管并发症的发生率较低,安全性更高。     

高原人体左心室舒张功能和顺应性的改变

应用同步描记心电图、心音图、颈动脉搏动图和心尖搏动图以测定高原人体的左心室舒张功能和顺应性。在4个不同海拔高度进行实验,即76m(海平对照)、2161m、3270m和4179m,每一高度40名健康男性青年,高原3组世居、移居各20名。结果显示:随着海拔增高,主动舒张时间指数(TRTI)有减小趋势,RF波相对振幅(F/H)逐渐降低,A波相对振幅(A/D)则渐趋增大,3270m以上增大明显(p<0.05),舒张振幅时间指数(DATI)逐渐降低,3270m以上差异极显著(p<0.001)。高原世居与移居者相比,在海拔4179m出现明显差别,移居组TRTI、DATI、F/H较低而A/D较高(D<0.05)。测定射血前期与左室射血时间比值(PEP/LVET)、射血分数(EF)及左室周径纤维平均缩短速度(mVcf)3项指标作对照,显示在此高度左室收缩功能仍能保持。高原慢性心肌缺氧可能是导致左室舒张功能和顺应性轻度降低的原因。     

超微血流成像术用于肾移植患者术后评估的临床价值分析

目的:探讨超微血流成像术用于肾移植患者术后评估的临床价值。方法:选取我院2019年2月-2019年8月收治的60例肾移植患者的临床资料,根据术后恢复情况分为A、B、C三组,A组(27例,术后肾功能恢复良好)、B组(20例,术后发生过敏肾功能异常病变但治疗后肾功恢复正常)、C组(13例,术后血肌酐水平持续增高肾功能异常者),三组均采用超微血管流成像术检测血管指数,比较不同组患者的血管指数并分析其与血肌酐水平的关系。结果:三组患者的肾移植长径、前后径、左右径、皮质厚度、叶间动脉阻力指数比较无显著差异(P0.05)。C组患者的肾皮质血管指数(23.34±6.03%)明显低于A组(33.23±3.45%)、B组(31.23±4.23%)(P0.05)。肾功能异常患者肾皮质的血管指数较低,且随着血肌酐水平的升高而下降,两者呈显著负相关(r=-0.23,P0.05)。结论:超声微血流成像术用于肾移植患者术后评估可较好地反映肾皮质血供及术后肾功能的变化。     

PEEP对骨肿瘤手术患者全身麻醉期呼吸功能和血流动力学的影响

目的:探讨呼气末正压通气(PEEP)对骨肿瘤手术患者全身麻醉期呼吸功能和血流动力学的影响。方法:选取2014年1月-2015年12月期间我院收治的60例骨肿瘤患者,所有患者给予常规麻醉诱导后连接呼吸机行机械通气,观察并记录不同PEEP通气(0cm H_2O,5cm H_2O和10cm H_2O)下呼吸功能及血流动力学指标。结果:PEEP 10cm H_2O通气水平的气道峰压(Peak)、气道平台压(Plat)显著高于PEEP 5cm H_2O和PEEP 0cm H_2O通气,PEEP 5cm H_2O通气水平的Ppeak和Pplat显著高于PEEP 0cm H_2O通气,差异均有统计学意义(P0.05);不同PEEP通气水平的心率(HR)、平均动脉压(MAP)和中心静脉压(CVP)比较差异无统计学意义(P0.05);不同PEEP通气水平的心脏指数(CI)、每搏指数(SVI)、全心射血分数(GEF)、心脏功能指数(CFI)、每搏变异度(SVV)、脉压变异率(PPV)、胸腔内血容量指数(ITBI)、血管外肺水指数(ELWI)和肺血管通透性指数(PVPI)比较差异无统计学意义(P0.05)。结论:增加PEEP通气值能够显著改善吸功能的Ppeak和Ppla指标,但不影响血流动力学指标,值得临床推广应用。     

心脏彩超评估高血压左心室肥厚伴左心衰竭患者心功能的临床价值及与NYHA分级的关系研究

目的:探讨心脏彩超评估高血压左心室肥厚(LVH)伴左心衰竭患者心功能的临床价值,分析其超声指标与美国纽约心脏病协会(NYHA)分级的相关性。方法:选择2017年5月至2018年5月我院收治的127例高血压LVH伴左心衰竭患者为观察组,根据NYHA分级将其分为NYHAⅡ级组(41例)、Ⅲ级组(47例)、Ⅳ级组(39例),另选择100例体检的健康志愿者为对照组。所有受试者均接受心脏彩超获得相关参数[左心房内径(LAD)、左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)、左心室短轴缩短率(LVFS)、左心室后壁厚度(LVPWT)、室间隔厚度(IVST)、左心室射血分数(LVEF)、左心室舒张早期充盈峰最大充盈速度/舒张晚期充盈峰最大峰值速度(E/A)比值、Tei指数],分析心脏彩超相关参数与NYHA分级之间相关性。结果:观察组患者LAD、LVEDD、LVESD、LVPWT、IVST、Tei指数高于对照组(P0.05),LVFS、LVEF、E/A比值低于对照组(P0.05)。Tei指数随着NYHA分级增高而增高(P0.05),LVFS、LVEF、E/A比值随着NYHA分级增高而降低(P0.05)。Spearman秩相关分析结果显示,Tei指数与NYHA分级呈正相关(rs=0.398,P0.05),LVFS、LVEF、E/A比值与NYHA分级呈负相关(rs=-0.285,-0.442,-0.305,P0.05)。结论:高血压LVH伴左心衰竭患者发生明显左室肥厚和左心功能降低,心脏彩超可准确评估高血压LVH伴左心衰竭患者的心功能和病情严重程度,且部分心脏彩超相关参数与NYHA分级相关。     

重组人脑利钠肽联合多巴胺对心肾综合征伴低血压的疗效及对血清NT-proBNP水平的影响

目的:研究重组人脑利钠肽联合多巴胺对心肾综合征伴低血压的疗效及对血清NT-proBNP水平的影响。方法:收集2015年4月至2016年4月我院的90例心肾综合征伴低血压患者,按抽签法分为实验组和对照组,每组45例。对照组用多巴胺治疗,实验组在对照组基础上加用重组人脑利钠肽。观察两组治疗疗效,治疗前后血压、心率、心动图指标每搏输出量(SV)、左心室射血分数(LVEF)、左心室舒张末内径(LVEDD),N末端前体脑钠肽(NT-proBNP)、血肌酐(SCr)、胱抑素C(Cys C)水平的变化。结果:治疗后,实验组总有效率为93.33%,显著高于对照组(68.88%,P0.05);SBP、DBP、MAP、SV、LVEF均显著高于对照组(P0.05),HR、血清NT-proBNP、SCr水平显著低于对照组(P0.05);两组LVEDD比较差异无统计学意义(P0.05)。结论:重组人脑利钠肽联合多巴胺对心肾综合征伴低血压的疗效显著,可缓解心脏负荷,改善心肾功能,降低NT-proBNP水平,提高治疗安全性。     

不同方式靶控输注丙泊酚对高龄患者诱导期血流动力学的影响

为了探究不同方式靶控输注丙泊酚对高龄患者诱导期血流动力学的影响,本研究选取我院2015年1月至2016年1月收治的80例行腹部手术患者作为研究对象,按照简单随机法将患者分为Ⅰ组(进行血浆靶控输注丙泊酚)、Ⅱ组(进行效应室靶控输注丙泊酚)、Ⅲ组(进行梯度血浆靶控输注丙泊酚)、Ⅳ组(进行梯度效应室靶控输注丙泊酚)。通过比较4组患者AAI值、心排血量、心排指数、外周血管阻力、平均动脉压及心率的变化,我们发现4组患者经丙泊酚诱导麻醉后,AAI值、心排指数、外周血管阻力、平均动脉压检测均低于麻醉前,心率明显高于麻醉诱导前(p0.05);而在T1时刻,Ⅱ组患者AAI值明显低于Ⅰ组、Ⅲ组、Ⅳ组患者(p0.05);在T2、T3、T4时刻各组心率、外周血管阻力、平均动脉压比较无明显差异(p0.05);T1时刻Ⅲ组、Ⅳ组患者心率明显低于Ⅰ组、Ⅱ组(p0.05);而Ⅳ组患者心排指数、外周血管阻力、平均动脉压下降幅度明显低于Ⅰ组、Ⅱ组、Ⅲ组患者(p0.05)。研究表明,对高龄患者进行麻醉时,采用梯度效应室靶控输注丙泊酚进行诱导麻醉,不仅不影响麻醉效果,同时可减轻对患者循环系统的影响,过程平稳,值得广泛应用于临床。     

胸阻抗法心排血量比较直接PCI和延迟PCI对急性ST段抬高型心肌梗死患者心功能的影响

目的:采用胸阻抗法心排血量检测和比较直接和延迟经皮冠状动脉介入术(PCI)对急性ST段抬高型心肌梗死(STEMI)患者心功能的影响。方法:收集2016年1月-2018年6月于解放军南部战区海军第一医院收治的114例STEMI患者完整资料,分为直接PCI组48例,延迟PCI组40例,对照组(未行任何再灌注治疗)26例。采用胸阻抗法心排血量检测各组患者治疗后3天、6个月的每搏输出量(SV)、心指数(CI)、左心收缩力指数(CTI)、射血分数(EF)等心功能参数,并随访患者6个月内因心力衰竭再住院的情况。结果:治疗后6个月,直接PCI组和延迟PCI组SV、CI、CTI、EF均显著高于对照组,且直接PCI组SV、CTI、EF明显高于延迟PCI组,各组间差异具有统计学意义(P<0.05)。直接PCI组和延迟PCI组6个月内因心力衰竭再住院分别为2.08%和5%,均显著低于对照组(19.23%),差异具有统计学意义(P<0.05)。结论:直接和延迟PCI均能改善STEMI患者中远期心功能,且直接PCI效果更为显著。     

Reversal of hyperdynamic response to continuous endotoxin administration by inhibition of NO synthesis.

Septic shock is characterized by an increase in cardiac output and a fall in systemic vascular resistance index and mean arterial pressure. Endotoxin alters the smooth muscle function of blood vessels, probably by means of an increased production of the potent vasodilator nitric oxide (NO). The present study was accomplished to determine how the inhibition of NO synthesis influences cardiovascular performance in an ovine model of hyperdynamic endotoxemia. Endotoxemia was induced in five range ewes (41 +/- 2 kg) by continuous infusion of Escherichia coli endotoxin (LPS, 10 ng.kg-1.min-1) over the entire study period. After 24 h of LPS infusion, cardiac output increased from 5.2 +/- 0.3 to 7.9 +/- 0.6 (SE) 1/min (P less than 0.05) and mean arterial pressure and systemic vascular resistance index fell from 92 +/- 5 to 79 +/- 6 mmHg (P = 0.08) and from 1,473 +/- 173 to 824 +/- 108 dyn.s.cm-5.m2 (P less than 0.05), respectively. The pulmonary shunt fraction increased from 0.23 +/- 0.03 to 0.32 +/- 0.03 (P less than 0.05). The intravenous administration of the NO synthase inhibitor N omega-nitro-L-arginine methyl ester (25 mg/kg) 24 h after the start of the LPS infusion changed these values to approximately baseline levels over the subsequent 4 h. Although N omega-nitro-L-arginine methyl ester increased pulmonary arterial pressure and pulmonary vascular resistance (P less than 0.05), right and left ventricular stroke volume index showed no significant changes. It is concluded that NO has a major function in cardiovascular performance in endotoxemia.(ABSTRACT TRUNCATED AT 250 WORDS)     

缬沙坦对维持性血液透析患者心脏功能和结构的影响

目的:探讨缬沙坦对维持性血液透析(maintenance hemodialysis,MHD)患者心脏功能和结构的影响。方法:100例MHD患者,随机分为治疗组(50例)与对照组(50例),对照组仅予基础治疗,治疗组加予口服缬沙坦治疗,总疗程为6个月。观察治疗前后超声心动图指标变化。结果:与治疗前及对照组同期比较,治疗组心脏结构指标左房收缩末期内径(LAD)、左室舒张末期内径(LVDD)、室间隔厚度(IVST)、左室后壁厚度(LVPWT)、左房内径指数(LAI)、左室重量指数(LVMI)及相对室壁厚度(RWT)有所降低,心脏功能指标:左室射血分数(LVEF),左室短轴缩短率(FS),二尖瓣口舒张早期和晚期最大血流速度比(E/A)值有所提高,差异均有统计学意义(P<0.05)。对照组超声心动图各项指标与治疗前相比变化不明显(P>0.05)。结论:缬沙坦能延缓或逆转左心室肥厚,明显改善左室舒张功能,有助于改善MHD患者心脏重构,改善心脏功能,从而延缓慢性肾功能衰竭尿毒症期患者的左心室重塑,降低心血管疾病的发生率和死亡率。缬沙坦对MHD患者心血管疾病并发症的预防和治疗及提高MHD患者生存率有一定临床指导意义。     

经胸超声心动图引导下行房间隔缺损封堵术治疗先天性房间隔缺损的临床研究

目的:探讨经胸超声心动图引导下行房间隔缺损封堵术治疗先天性房间隔缺损(Atrial septal defect,ASD)的临床疗效。方法:比较先天性ASD患者行超声心动图组(49例)或介入组(53例),患者的疗效及心脏功能的变化。结果:超声心动图组并发症发生率显著低于介入组(P0.05);术后4周,两组患者的心率、舒张期室间隔厚度(Interventricular septal thickness,IVST)、左室后壁厚度(Left ventricular posterior wall thickness,LVPWT)、左心室心肌重量(Left ventricular mass,LVM)和左心室心肌重量指数(Left ventricular mass index,LVMI)明显降低(P0.05),左心室射血分数(Left ventricular ejection fraction,LVEF)和左心室高峰充盈率(Left ventricular peak filling rate,LVPFR)均显著升高(P0.05),其余指标则无明显变化(P0.05);但术后1周超声心动图组的LVEF、IVST和LVMI即显著高于术前(P0.05)。结论:胸超声心动图引导下行ASD封堵术与X线介入封堵术疗效相当,但前者可能对ASD患者的心脏功能的改善更为显著。     

Cardiac performance in Turner's syndrome patients on growth hormone therapy.

OBJECTIVES: To investigate possible cardiac morphofunctional alterations observed in 26 Turner's syndrome (TS) patients on prolonged high-dose growth hormone (GH) therapy. STUDY DESIGN: We examined 26 TS subjects treated with rhGH (1 U/kg/week) for a mean period of 4.9 years (range 1-7.8) and 37 age-, weight- and height-matched healthy girls. Left ventricular volume, mass, systolic function, cardiac index, systemic vascular resistance and diastolic function were evaluated by two-dimensional and Doppler echocardiography. RESULTS: Heart rate and systolic blood pressure (BP) were higher in TS patients than in controls, while diastolic BP was lower. Left ventricular volumes, ejection fraction, mass index, M/V ratio and cardiac index did not differ significantly; systemic vascular resistance was slightly decreased. Left ventricular fractional shortening and mean velocity of circumferential shortening were slightly increased while end-systolic meridional stress was decreased in TS. Contractile state was normal in TS. Diastolic function assessment showed a shortening of isovolumetric relaxation and diastolic filling times with an increased atrial contribution and a normal pulmonary venous flow. CONCLUSION: Cardiac morphology in TS patients on GH therapy is similar to controls. The observed changes in left ventricular systolic and diastolic function should be interpreted as an adaptation to the higher heart rate and reduced peripheral vascular resistance induced by GH therapy.     

Effects of enhanced ventricular filling on cardiac pump performance in exercising dogs

The extent to which the normal increase in stroke volume during exercise can be augmented by increasing preload by dextran infusion was studied in seven dogs. Each dog ran 3 min on a level treadmill at mild (3-4 mph), moderate (6-8 mph), and severe (9-13 mph) loads during the control study and immediately after 10% dextran 14 ml/kg iv. During severe exercise dextran-augmented stroke volume (+5.4 ml or 19% vs. exercise without dextran, P less than 0.01) and left ventricular end-diastolic diameter and pressure did not change heart rate, aortic pressure, or maximum derivative of left ventricular pressure but decreased systemic vascular resistance by 16%. Similar increases in stroke volume and preload after dextran occurred during mild and moderate exercise when arterial pressure and heart rate were unchanged or increased and systemic vascular resistance was decreased. Thus altering preload above those levels normally encountered during exercise is a potential mechanism to increase stroke volume and cardiac output.     

Beta2-microglobulin knockout mice treated with anti-asialoGM1 exhibit improved hemodynamics and cardiac contractile function during acute intra-abdominal sepsis

We previously showed that beta2-microglobulin knockout mice treated with anti-asialoGM1 (beta2M/alphaAsGM1 mice) exhibit less hypothermia, reduced production of proinflammatory cytokines, less metabolic acidosis, and improved survival after cecal ligation and puncture (CLP) compared with wild-type mice. The present study was designed to assess hemodynamics and left ventricular contractility at 18 h after CLP. Arterial pressure was measured by carotid artery cannulation, and left ventricular pressure-volume loops were obtained by insertion of a 1.4-F conductance catheter into the left ventricle. Heart rate, stroke volume, and cardiac output were not significantly different between wild-type and beta2M/alphaAsGM1 mice after CLP. However, beta2M/alphaAsGM1 mice exhibited improved mean arterial pressure and systemic vascular resistance compared with wild-type mice. Myocardial function was also better preserved in beta2M/alphaAsGM1 mice as indicated by improved left ventricular pressure development over time, time-varying maximum elastance, endsystolic pressure-volume relationship, and preload recruitable stroke work. Overall, this study shows that cardiovascular collapse characterized by hypotension, myocardial depression, and low systemic vascular resistance occurs after CLP in wild-type mice. However, beta2M/alphaAsGM1 mice exhibit improved hemodynamics and cardiac contractile function after CLP that may account, in part, for our previously observed survival benefit.     

Comparison of haemodynamic responses to dopamine and salbutamol in severe cardiogenic shock complicating acute myocardial infarction.

Twelve patients with severe persistent cardiogenic shock complicating acute myocardial infarction underwent single crossover treatment with intravenous dopamine and salbutamol to determine the more beneficial therapy. Salbutamol (10 to 40 microgram/min) reduced systemic vascular resistance and progressively increased both cardiac index and stroke index. Heart rate increased from 95 to 104 beats/min. Changes in mean arterial pressure and pulmonary artery end-diastolic pressure were small and insignificant. Dopamine infusion at rates of 200 and 400 micrograms/min also increased cardiac index and stroke index. Systemic vascular resistance fell slightly but mean arterial pressure rose from 57 to 65 mm Hg. Heart rate increased from 95 to 105 beats/min. Changes in pulmonary artery end-diastolic pressure were again small and insignificant. Dopamine infusion at 800 micrograms/min caused an appreciable increase in systemic vascular resistance; a further increment in mean arterial pressure was observed, though cardiac index fell slightly. Heart rate and pulmonary artery end-diastolic pressure rose steeply. Salbutamol, a vasodilator, increased cardiac output in patients with cardiogenic shock complicating acute myocardial infarction but did not influence blood pressure. If correction of hypotension is essential dopamine in low doses may be the preferred agent. Doses of 800 microgram/min, which is within the therapeutic range, worsen other manifestations of left ventricular dysfunction.     

Effects of ibuprofen and pentoxifylline on the cardiovascular response of normal humans to endotoxin.

Endotoxin is a major mediator of the life-threatening cardiovascular dysfunction that characterizes Gram-negative sepsis. In animal models of endotoxemia, pretreatment with ibuprofen or pentoxifylline attenuates some of these cardiovascular changes. To evaluate the effects of these agents on the human cardiovascular response to endotoxemia, hemodynamic variables were measured serially in 24 normal subjects who were given intravenous endotoxin. The subjects were randomized to receive oral ibuprofen (n = 9), pentoxifylline (n = 10), or no medication before endotoxin administration (n = 5). The subjects were volume loaded 3-5 h after endotoxin administration, and hemodynamic measurements were reassessed. Core temperature after endotoxin alone or endotoxin-pentoxifylline approached a maximum at 3 h (greater than or equal to 38.6 degrees C), while the endotoxin-ibuprofen group remained afebrile. At 3 and 5 h, all three groups had significant increases in heart rate, cardiac index, oxygen delivery, and oxygen consumption, while systemic vascular resistance index decreased significantly from baseline. The oxygen extraction ratio remained unchanged. After volume loading, the left ventricular ejection fraction and left ventricular end-diastolic and end-systolic volume indexes did not differ among the groups. The hyperdynamic cardiovascular response to endotoxin in humans occurs in the absence of fever and is not significantly ameliorated by oral cyclooxygenase or phosphodiesterase inhibition.     

Impaired central hemodynamic response and exaggerated vasoconstriction during muscle metaboreflex activation in heart failure patients

The muscle metaboreflex is enhanced in chronic heart failure (CHF) patients, and this fact has been associated with the early fatigue shown by these patients in response to exercise. In animal studies of CHF, it was found that the limited capacity to enhance ventricular performance is responsible for a functional shift from a cardiac output to a systemic vascular resistance (SVR) increase in the mechanism by which the cardiovascular system raises blood pressure in response to the metaboreflex. However, the existence of this functional shift is still unknown in humans. The present study was undertaken to test the hypothesis that a similar hemodynamic response was also present in humans with CHF. The hemodynamic response to metaboreflex activation obtained through postexercise ischemia was assessed in nine patients with CHF and nine healthy controls (CTL) by means of impedance cardiography. The main results were that 1) the blood pressure rise due to the metaboreflex was similar in the two groups; 2) the CTL group achieved the blood pressure response via cardiac output increase, and the CHF group, via SVR increase; and 3) stroke volume was enhanced in the CTL group and decreased in the CHF group. This study demonstrates that in CHF patients, metaboreflex recruitment causes a functional shift from flow increase to peripheral vasoconstriction in the mechanism through which blood pressure is increased. The incapacity to enhance cardiac performance and stroke volume is probably the primary cause of this cardiovascular alteration.     

RIGHT AND LEFT VENTRICULAR HEMODYNAMIC INDICES AS PREDICTORS OF THE NEED FOR AND OUTCOME OF POST-CARDIOTOMY MECHANICAL INTRAAORTIC BALLOON PUMP SUPPORT

Preoperative cardiac catheterization data of 21 patients requiring intraaortic balloon pumping (IABP) for weaning from cardiopulmonary bypass were analyzed and compared with similar data in 28 patients who underwent nearly similar operative procedures, but did not require IABP for weaning. Cardiac index (CI) and systemic vascular resistance (SVR) were found to have predictive value for the need of IABP for weaning from cardiopulmonary bypass and differentiated survival from non-survival. Left ventricular end diastolic pressure (LVEDP) was not found to be predictive. Ejection fraction (EF) was significantly lower in those who required IABP than those who did not; EF did not predict the outcome. Pulmonary capillary wedge pressure ([unk]), pulmonary artery pressure ([unk]) and pulmonary vascular resistance (PVR) were predictive of the need for IABP, but not the outcome. Left ventricular minute work index (LVMWI) was significantly lower in those requiring IABP, right ventricular minute work index (RVMWI) was predictive of survival with IABP. Together, LVMWI and RVMWI were predictive of the need for and outcome of IABP following cardiopulmonary bypass. Twenty-seven of 28 control RVMWI's were normal. No patient requiring IABP had depressed RVMWI's preoperatively. Elevated preoperative RVMWI's were associated with 80% survival with postcardiotomy IABP; normal RVMWI's were associated with a 56% survival with post-cardiotomy IABP. Elevated preoperative RVMWI's reflected moderate to maximal right ventricular compensatory capacity in response to depressed left ventricular function. Normal preoperative RVMWI's in the presence of depressed LVMWI's were indicative of decreased right ventricular compensatory capacity in post-cardiotomy IABP-support settings. Right ventricular function is as important as left ventricular function as a prognosticator for the need and outcome of IABP support of the failing post-cardiotomy circulation.