复苏犬心肌损伤的实验研究

目的：本实验通过研究复苏犬的心理损伤，探讨心肌肌钙蛋白Ｔ对复苏犬心肌损伤的诊断价值。方法：利用犬室颤心跳呼吸骤停模型，进行标准心肺复苏，观察室颤前及复苏后犬血心肌肌钙蛋白Ｔ水平和心肌闰理学变化。结果：在犬恢复自主循环１ｈ后，血心肌肌钙蛋白Ｔ就明显升高，且其升高水平与病理学改变程度相对应。结论：（１）复苏犬存在急性心肌损伤；（２）心肌肌钙蛋白Ｔ血浓度能客观地反映心肌损伤状态。     

心肺复苏患者心肌损伤的临床研究

目的 探讨血清心肌肌钙蛋白T对复苏患者心肌损伤的临床价值。方法 对69例心跳、呼吸骤停的患者进行标准心肺复苏，观察心室颤动前和复苏后患者心肌肌钙蛋白T水平的变化。结果 复苏患者在恢复自主循环1h后，血清心肌肌钙蛋白T就明显升高，且升高水平与患者的病死率相对应。结论 复苏患者存在急性心肌损伤；心肌肌钙蛋白T浓度能客观地反映心肌受损状态。     

严重烫伤后早期血浆心肌肌钙蛋白T含量的变化

目的：探讨血浆心肌肌钙蛋白T（TnT）在烧伤后早期心肌损伤时的变化特点及其诊断学意义。方法：采用双抗夹心酶联免疫吸附法（ELISA）动态观察30％体表面积Ⅲ度烫伤大鼠伤后1、3、6、12和24小时血浆TnT水平及心肌组织病理学变化。结果：大鼠伤后3小时血浆TnT水平［（0．58土0．14）μg／L］较正常对照［（0．14士0．04）μg／L〕显著升高（P＜0.05），12小时达峰值［（3.53士0.69）μg／L，P＜0．o1〕，约为正常参考值的20倍。伤后24小时TnT水平〔（1．55士0．37）μg／L〕虽有所下降，但仍显著高于伤前（P＜0．01）。血浆TnT水平与心肌损伤程度相关。结论：血浆TnT可作为诊断烧伤后心肌损伤敏感而特异的指标。     

心肺复苏犬心肌及血浆内皮素含量变化的实验研究

目的:研究复苏犬心肌组织及血浆内皮素(endothelin,E T)含量的变化规律及意义。方法:电击致犬室颤、心跳呼吸骤停,15m in后进行标准复苏,观察心脏停跳15m in、复苏后0.5h、2h、4h时心肌组织及血E T含量。结果:复苏后0.5h心肌组织及血浆E T含量较对照组明显升高(P<0.01),复苏后2h血浆E T含量达最高,心肌组织E T含量持续升高至复苏后4h(P<0.01)。结论:复苏后心肌组织及血中E T含量变化可能是机体在急剧缺血再灌注后出现的一种强烈的自身应激调节机制,与复苏后的心肌损伤及血流动力学不稳定有关。     

急性心肌梗死诊断中心肌肌钙蛋白Ⅰ测定的作用

目的：观察急性心肌梗塞（AMI）后血中心肌肌钙蛋白I（cTnI）的动态变化。方法：应用免疫干膜层析技术，连续测定了84例AMI早期（1—8h）入院患者和20例正常人血中cTnI，结果与心肌酶（CK、CK—MB）对比。结果：AMI时血中cTnI升高时间较早，持续时间更长，且对心肌细胞损伤诊断的准确性、灵敏性和特异性均优于心肌酶，尤其cTnI定性测定方法简单。出结果迅速。结论：心肌肌钙蛋白I定性测定对急性心肌梗塞的诊断具有重要的临床价值。     

心肌肌钙蛋白T与危重儿心肌损伤相关分析

目的：探讨心肌肌钙蛋白T（cTnT）对危重儿心肌损伤的临床价值。方法：采用双抗体夹心法测定观察组47例危重儿与对照组非危重儿30例患儿cTnT水平。结果：47例危重患儿cTnT明显升高,与对照组比较有统计学差异（P〈0.01）。结论：危重儿存在心肌损害,cTnT对及时发现和诊断危重患儿心肌损伤具有重要意义。     

心脏手术前后心肌肌钙蛋白T和心肌酶谱的变化

目的：探讨血清心肌肌钙蛋白T（cTnI）和心肌酶谱在心肌手术损伤前后的变化及其临床意义。方法：动态观察20例二尖瓣瓣膜置换术患手术前,术后2h及24h血清cTnI和心肌酶谱变化。另制备家兔心肌损伤模型,检测动物模型伤前和伤后4,8,24h血清cTnI的变化特点。结果：二尖瓣瓣膜置换术患血清cTnI含量,心肌酶谱尖性在术后2,24h较术前显升高（P＜0．01）,其中血清cTnI含量术后2h增加倍数高于其他指标。家兔心肌损伤模型伤后4,8,24h血清cTnI含量较伤前或高非常显（P＜0．01）,呈后期大峰值双基线。结论：血清cTnI含量及心肌酶谱活性均对心肌损伤的诊断有意义,但cTnI的心肌特异性及早期灵敏度更高,cTnI后期峰值对心肌损伤的预后判断有重要价值。     

兔胸部爆炸冲击伤后早期血浆心肌肌钙蛋白Ⅰ含量的变化及意义

目的 探讨家兔胸部冲击伤后早期心肌损伤时，血浆心肌肌钙蛋白I（cTnI)的变化特点及其诊断意义。方法 采用自动化双位点荧光酶免疫定量检测法，观察兔胸部爆炸冲击伤后5min、30min、3h、6h、12h血浆cTnI水平及心肌组织病理学变化。结果 家兔伤后30min血浆cTnI水平显著升高，与正常对照组相比有统计学意义（P＜0．05），6h达峰值（P＜0．01），伤后12h以后又有所下降，但仍高于正常对照组（P＜0．01）。血浆cTnI水平与心肌损害严重程度密切相关。结论 血浆cTnI水平在胸部爆炸冲击伤后心肌损伤程度的诊断中是一个敏感而特异的指标。     

心肌肌钙蛋白在心脏疾病中的临床应用及意义

近年来,急性心肌梗死（AMI）的发病率明显增高,治疗上也有较大进展,其中最方便和有效者是溶栓治疗,因此对实验室检查提出了新的要求。近年来关于心肌肌钙蛋白（cTn）的研究表明,cTn是心脏特异性抗原,当心肌细胞损伤时,在血中出现时间早,持续时间长,因而引起了人们的重视。现就cTn测定在心肌损伤方面的临床应用及意义综述如下。1心肌肌钙蛋白的结构性质肌钙蛋白（Troponin,Tn）是肌肉组织收缩的调节蛋白,参与肌肉收缩的钙激活调节过程,本身是多肽,有三个亚单位：Tn－I,Tn－T,Tn－C。当肌肉组织受损或坏死时,Tn释放入血…     

停跳与非停跳冠脉搭桥术后心肌肌钙蛋白水平的变化及其临床意义探讨

目的 研究停跳与非停跳冠脉搭桥术后心肌肌钙蛋白水平的变化。方法 30例择期行冠脉搭桥术的患者根据手术方式分为不停跳组(n=15)和停跳组(n=15)。不停跳组采用Octopus组织固定器局部固定心肌后进行冠脉搭桥，而停跳组在体外循环心脏停跳下进行冠脉搭桥。分别于入手术室(T0)、麻醉诱导平稳后(T1)、手术结束即刻(TST)、术后4h(T4)、8h(T8)、12h(T12)、24h(T24)、36h(T36)、48h(T48)抽静脉血4ml测定心肌肌钙蛋白T(cTnT)和心肌肌钙蛋白Ⅰ(cTnI)。结果 两组患者T0和Tl时cTnT、cTnI正常，术后则显著性升高。两组之间，组2比组l术后各时间点cTnT和cTnI升高均有显著性差异。两组cTnT于术后8小时达到峰值，并一直保持较高水平；cTnI于术后12小时达高峰，不停跳组cTnI在术后36小时即恢复正常水平。结论 不停跳搭桥比体外循环搭桥手术对心肌细胞损伤轻，持续时间短。心肌损伤时，cTnT比cTnI峰值出现早，持续时间长，似乎更加灵敏。     

家兔心肺复苏后心肌肌钙蛋白T脱失的免疫组化研究

目的:观察家兔心肺复苏(CA-CPR)后心肌组织内心肌肌钙蛋白T(cTnT)的脱失情况,探讨心肌损伤的机制。方法:采用家兔缺氧型CA-CPR模型,于心肺复苏前后分时间点抽取动脉血,测血清cTnT值;自主循环恢复后4小时取心肌组织,应用免疫组化LSAB法显色观察cTnT表达的脱失情况。结果:自主循环恢复后血清cTnT明显升高。自主循环恢复后4小时心肌组织内cTnT明显脱失,图像分析显示心肺复苏后cTnT的脱失面积与正常家兔心肌之间存在显著性差异。结论:家兔心肺复苏后血清cTnT明显升高,心肌组织内cTnT的明显脱失,两者呈负相关。     

Plasma catecholamines and resuscitation from prolonged cardiac arrest

Plasma catecholamine levels rise markedly with cardiac arrest and attempted resuscitation. We examined whether epinephrine (EPI) or norepinephrine (NE) plasma concentrations could predict resuscitation outcome. In nine mongrel dogs, EPI and NE levels were drawn before cardiac arrest and after 8 and 14 min of cardiac arrest and CPR. Intravenous EPI (1 mg) was given 1 min before the last plasma level was drawn. Catecholamines were quantitated by high-performance liquid chromatography with triple-electrode coulometric electrochemical detection. Plasma catecholamines increased significantly with cardiac arrest, EPI levels increased from a control level of 15.9 +/- 3.0 to 396.0 +/- 63.3 pmol/ml after 8 min of cardiac arrest (p less than .05), and NE levels similarly increased from 4.4 +/- 1.7 to 66.5 +/- 12.0 pmol/ml (p less than .01). Neither the absolute catecholamine plasma concentration nor the response to cardiac arrest of the endogenous catecholamine concentrations could predict outcome, but catecholamine responses to exogenous EPI did correlate with outcome. Animals which were subsequently resuscitated had a greater increase in the plasma EPI concentrations after exogenous EPI than animals that were not resuscitated, a 53-fold vs. a 23-fold increase (p less than .05). Successfully resuscitated animals also had increased NE levels after exogenous EPI, while unsuccessfully resuscitated animals had either no change or a decrease (p less than .02). Successfully resuscitated animals had an increase in coronary perfusion pressure (p less than .01) in response to exogenous EPI, in contrast to those that were not resuscitated. This suggests that the exogenous administration of EPI during prolonged CPR is beneficial despite markedly elevated endogenous catecholamine levels.     

Plasma epinephrine levels in resuscitation with cardiopulmonary bypass

Since the highest plasma epinephrine levels have been recorded during resuscitation, we evaluated the isolated effect of cardiac arrest upon adrenomedullary secretion. We determined plasma epinephrine in dogs resuscitated with cardiopulmonary bypass (CPB) after cardiac arrest periods of 12 (CPB-12; n = 4) or 16 min (CPB-16; n = 5). Through 2 h of CPB and the following 6 h of critical care, there was no difference between CPB-12 and CPB-16 regarding most cardiopulmonary functional variables. Plasma epinephrine was markedly elevated immediately after initiation of CPB (p less than .01 at 1 min CPB vs. basal) and returned rapidly to basal concentrations. Comparison of plasma epinephrine levels between CPB and standard CPR groups showed that responses to cardiac arrest were similar (p greater than .05 at 1 min CPB vs. 11.5 min CPR). We conclude that cardiac arrest is the main or sole determinant of the plasma epinephrine elevation of resuscitation.     

Open-chest CPR improves survival and neurologic outcome following cardiac arrest

STUDY OBJECTIVE: To determine if 15 min of open-chest cardiac massage (OC-CPR) versus closed-chest compressions (CC-CPR) improves 72-h survival and neurologic outcome (behavioral and histologic) after 5 min of untreated cardiac arrest. METHODS: Mongrel dogs were anesthetized and instrumented. Cardiac arrest was induced by KCl injection and after a 5-min period of non-intervention, dogs were randomized to receive either CC-CPR (N = 7) or OC-CPR (N = 5) performed for 15 min. The dogs were then resuscitated and physiologic data was recorded. Surviving dogs were scored at 72 h using canine neurodeficit score of Safar et al. (NDS; 0 = behaviorally normal, 500 = brain death). Dogs that could not be resuscitated or died before 72 h were assigned a score of 500. Brain histology was performed on all survivors. RESULTS: All OC-CPR dogs were successfully resuscitated and were behaviorally normal at 72 h (NDS = 0). Histology in OC-CPR dogs showed little to no injury. Only three out of the seven CC-CPR dogs survived to 72 h. Of the survivors, one dog exhibited minor ataxia (NDS = 15), and two had incapacitating deficits (both NDS = 180). Two dogs died within 24 h after extubation, and one could not be resuscitated and the other could not be weaned from the ventilator (each NDS = 500). Histology of the CC-CPR survivors revealed moderate to severe lesions. NDS between groups was statistically significant (p < 0.0079). CONCLUSION: In our canine model of cardiac arrest, OC-CPR significantly improved 72-h survival and neurologic outcome when compared to CC-CPR.     

Myoglobin stratifies short-term risk in acute major pulmonary embolism

BACKGROUND: Concentrations of cardiac troponins can be elevated in acute pulmonary embolism (APE) indicating myocardial injury. Although concentration of myoglobin (MYO) increases after myocardial damage, even before detectable rise of cardiac troponin levels occurs, MYO was not evaluated in APE. Therefore, we assessed prevalence and prognostic significance of myoglobin in major APE. METHODS: We studied 46 patients (30 women, aged 61.9+/-17.8 years) with major APE defined with right ventricular dilatation. On admission serum myoglobin, and cardiac troponin T (cTnT) were measured. Serum MYO concentrations >58 ng/ml for women, and >72 ng/ml for men were considered abnormal. CTnT>0.01 ng/ml was regarded to indicate myocardial injury. RESULTS: MYO levels exceeding sex specific norms were found in 21/46 (45.7%) of patients, while detectable cTnT was found in 24/46 (52.1%) of patients. Seven patients died during hospitalization. Elevated MYO significantly predicted in-hospital mortality (OR 25, 95% CI 1.3-474.2), while increased cTnT concentration did not affect the survival. Among clinical and echocardiographic variables only older age indicated worse prognosis (OR 1.6, 95% CI 1.06-2.41). CONCLUSIONS: Myoglobin levels are elevated in serum on admission in almost half of patients with major APE. Elevated myoglobin level, marker of myocardial injury, is a powerful predictor of increased risk of fatal outcome in major pulmonary embolism.     

Relative importance of alpha and beta adrenergic receptors during resuscitation.

Successful resuscitation from cardiac arrest in the asphyxiated dog model has been ascribed to the use of artificial ventilation, closed chest cardiac massage, and administration of a vasopressor. Controversy remains over whether the most commonly employed vasopressor, epinephrine, exerts its effects primarily by elevating diastolic pressure and reestablishing coronary flow, or by exciting cardiac pacemaker cells and enhancing myocardial contractility. To observe pure alpha and beta adrenergic receptor influences during resuscitation, three groups (alpha-blocked, beta-blocked, unblocked) of dogs were studied. beta-blocked dogs resuscitated with phenylephrine and unblocked dogs resuscitated with epinephrine experienced 100% successful resumption of spontaneous circulation after 5 min of asphyxia-induced arrest. Only 27% of alpha-blocked animals resuscitated with isoproterenol were successfully revived. The appearance of the ECG during cardiac arrest and resuscitation could in no way be used to predict the outcome of resuscitation attempts. Results suggest that, initially, alpha receptor stimulation with concomitant diastolic pressure elevation is more important to the success of resuscitation than beta receptor stimulation.     

Myocardial injury in infants ventilated on the paediatric intensive care unit: a case control study

Introduction  

Cardiac troponin T (cTnT) has been used to assess prevalence of myocardial injury in critically ill children. The majority of studies investigated patients undergoing cardiac surgery. Myocardial injury has been associated with increased mortality. Our objectives were to investigate whether cTnT levels are elevated in infants without congenital heart disease admitted to the paediatric intensive care unit (PICU) and whether levels are associated with increased disease severity.     

Correlation of antemortem serum creatine kinase, creatine kinase-MB, troponin I, and troponin T with cardiac pathology

BACKGROUND: Spurious increases in serum troponins, especially troponin T, have been reported in patients with and without acute myocardial syndromes. METHODS: We studied 78 autopsied patients without clinical myocardial infarction (MI) and correlated histologic cardiac findings with antemortem serum creatine kinase (CK), its MB isoenzyme (CK-MB), cardiac troponin I (cTnI), and cardiac troponin T (cTnT). RESULTS: There was no significant myocardial pathology in 15 patients. Cardiac pathologies were in five groups: scarring from previous MI or patchy ventricular fibrosis (n = 9), recent MI (n = 27), healing MI (n = 7), degenerative myocyte changes consistent with congestive heart failure (CHF; n = 12), and other cardiac pathologies (n = 8). The median concentrations in the five groups were not significantly different for either CK or CK-MB. Compared with the no-pathology group, only the MI group was significantly different for cTnI, and the MI and other pathology groups were significantly different for cTnT. For patients with MI, 22%, 19%, 48%, and 65% had increased CK, CK-MB, cTnI, and cTnT, respectively; for CHF and other cardiac pathologies combined, the percentages were 28%, 17%, 22%, and 50%. For patients with increased cTnI, 72% and 28% had MI and other myocardial pathologies, respectively; patients with increased cTnT had 64% and 36%, respectively. Patients without myocardial pathology had no increases in CK-MB, cTnI, or cTnT. CONCLUSIONS: All patients with increased serum CK-MB, cTnI, and cTnT had significant cardiac histologic changes. The second-generation cTnT assay appears to be a more sensitive indicator of MI and other myocardial pathologies than the cTnI assay used in this study.