Effect of external high-frequency oscillation on severe cardiogenic pulmonary edema

Effective gas exchange can be maintained in animals without endotracheal intubation using external high-frequency oscillation (EHFO). The aim of this study was to evaluate the effect of EHFO in patients with respiratory failure due to severe cardiogenic pulmonary edema. Seven patients were ventilated with EHFO for 2h at 60 oscillations·min⁻¹, with a cuiras pressure of 36 cmH₂O (−26 to +10) and an inspiratory to expiratory ratio of 1:1, with EHFO. Blood gas values and hemodynamic parameters were measured. Significant increases were noted in cardiac index (2.3±0.5 to 2.5±0.5 l·m⁻²;P<0.05), stroke volume index (24±7 to 28±8 ml·m⁻²;P<0.05), and arterial O₂ pressure (Pao₂) (70±4 to 95±23 mmHg;P<0.01) without a change in pulmonary artery wedge pressure at 1 h after EHFO. The respiratory rate decreased from 28±3 to 22 ±3 breaths·min⁻¹ at 5 min after the termination of EHFO (P <0.01). Arterial CO₂ pressure (Paco₂) did not, however, decrease. Increased stroke volume without a change in pulmonary artery wedge pressure (preload) suggests either improved inotropic function of the left ventricle or reduced left ventricular afterload with EHFO. The use of EHFO may be effective not only for gas exchange but also for left ventricular function in patients with severe cardiogenic pulmonary edema.     

多巴酚丁胺负荷及运动试验~(99m)Tc-MIBI心肌断层显像与冠状动脉造影的对比研究

比较６９例冠心病患者多巴酚丁胺负荷９９ｍＴｃ甲氧基异丁基异腈（ＭＩＢＩ）心肌断层显像与８２例运动试验９９ｍＴｃＭＩＢＩ心肌断层显像的结果，以探讨它们对冠心病的诊断价值。结果表明：以冠状动脉造影结果为标准，多巴酚丁胺负荷诊断冠心病的敏感性和特异性分别为９１２％和８００％，运动试验分别为８９４％和８２９％。多巴酚丁胺负荷检出冠状动脉病变的敏感性和特异性：左前降支为７８１％和９１３％，回旋支为６６７％和９８２％，右冠状动脉为１００％和８３７％；运动试验分别为７８３％和９１１％，６００％和９６８％，９０９％和８５０％，差异均无显著性（Ｐ＞００５）。提示两者结果相近，对于不能进行运动试验的病人，多巴酚丁胺试验是一种有价值的诊断冠心病的方法。     

Effects of Ethanol on the Contractile Function of the Heart: A Review

Chronic ethanol consumption leads to a number of alterations in the contractile function of the heart and is a leading cause of cardiomyopathy. Ethanol also has an acute negative inotropic effect mediated by direct interaction with cardiac muscle cells, although this action is often masked by indirect actions resulting from enhanced release of catecholamines in vivo. This article reviews the effects of ethanol on the contractile function of the heart. The specific targets affected by ethanol in cardiac muscle cells are discussed in terms of potential mechanisms underlying the depressions of contractility resulting from both acute and chronic actions of ethanol.     

Ex vivo evaluation of ferromagnetism,heating, and artifacts produced by heart valve prostheses exposed to a 1.5-T MR system

Ex vivo testing techniques were used to determine the ferromagnetic qualities of, presence of heating in, and artifacts produced by 13 different heart valve prostheses exposed to a 1.5-T (64-MHz) magnetic resonance (MR) system. None of the heart valve prostheses showed a measurable deflection in the 1.5-T static magnetic field. Only minimal artifacts were produced during MR imaging with a fast spoiled GRASS (gradient-recalled acquisition in the steady state) pulse sequence. The largest temperature changes measured during a “worst case” MR imaging sequence (estimated average specific absorption rate, 2.5 W/kg; estimated spatial peak specific absorption rate, 7.6 W/kg) were +0.2°C with the implant imaged “in air” and +0.3°C with the implant imaged in normal saline. Therefore, MR procedures performed with a 1.5-T (64-MHz) MR system may be performed safely in patients with any of the 13 different heart valve prostheses evaluated in this study.     

羊心淋巴流阻断后血清生化指标的改变

为给临床心脏术后监测心淋巴管损伤程度及可能出现的并发症提供参考指标，以手术方法阻断羊心淋巴流并对其血清相关成份进行了测定。实验发现，实验组术后谷草转氨酶（ＳＧＯＴ）、谷丙转氨酶（ＳＧＰＴ）、碱性磷酸酶（ＡＫＰ）、乳酸脱氢酶（ＬＤＨ）均有不同程度的增高，以ＳＧＯＴ增高最为明显，术前均值为４７．５３Ｕ，术后２天增至１０４．２０Ｕ，高峰出现时间最早，多在术后２４小时。血清离子改变中低钾最为突出，血钾在术后２天明显降低（Ｐ＜０．０１），术后７天逐渐恢复，术后１４天恢复至术前水平。血清蛋白改变以球蛋白降低、白蛋白／球蛋白比值升高为主。提示心淋巴循环郁滞可导致心肌细胞损伤、毛细血管通透性和结构的改变。不同酶活性的变化对郁滞的敏感度存在着差异。     

Use of superparamagnetic contrast media to suppress signal from flowing spins: Preliminary experience

The authors describe their preliminary experience with the use of superparamagnetic magnetic resonance (MR) imaging contrast media for suppression of signal from flowing blood. The goal of this work was to determine if a superparamagnetic contrast agent could successfully eliminate blood signal during cardiac-gated MR imaging, thereby eliminating or reducing flow artifacts associated with the complex and variable hemodynamics within the heart chambers. Imaging and data analysis were performed in 17 dogs subjected to experimental myocardial infarction as part of a parallel project. Six doses (0.2, 1, 2, 3.5, 4, 5, and 10 mg/kg) of AMI-25, an experimental contrast agent, were used in the study. Spin-echo imaging was performed immediately before and every 5 minutes (for an average of 25 minutes) after bolus injection of the contrast agent. Variations in the image signal-to-noise ratio relative to a baseline (before injection of contrast agent) image were assessed as a function of dose and time. Preliminary results suggest that a considerable reduction in blood flow artifacts and, hence, increases in image signal-tonoise ratio can be achieved at doses greater than or equal to 3.5 mg/kg, for approximately 20 minutes after injection. Doses equal to or less than 2 mg/kg and images obtained more than 20 minutes after injection (regardless of dose) did not reliably show hemodynamic artifact suppression.     

比较异丙酚和依托咪酯对心脏瓣膜置换术患者过氧化脂质和超氧化物歧化酶的影响

目的:观察异丙酚对心脏瓣膜置换术患者过氧化脂质和超氧化物歧化酶的影响。方法:20例瓣膜置换术患者分为异丙酚组和依托咪酯组。分别在心肌缺血再灌注前后取血做过氧化脂质和超氧化物歧化酶测定,同时记录心电图和平均动脉压。结果:过氧化脂质在异丙酚组主动脉插管时下降,主动脉开放后升高,均有显著差异(P<0.05,P<0.01)。依托咪酯组主动脉开放后明显升高,亦高于异丙酚组同时值,差异均显著(P<0.01)。超氧化物歧化酶主动脉开放后两组均下降(P<0.05,P<0.01),两组间无差异。主动脉开放后心律失常、心肌缺血、电击复跳例数异丙酚组少于依托咪酯组。结论:异丙酚可明显降低心肌缺血再灌注后过氧化脂质含量,减少心律失常和心肌缺血现象。     

深低温对吸入麻醉药的MAC,心脏麻醉指数和心肌稳定性的影响

目的:研究深低温对吸入麻醉药MAC、心脏麻醉指数和心肌稳定性的影响。方法:新西兰白兔40只,随机分为氟烷、安氟醚、异氟醚和七氟醚组。采用夹尾试验法测定常温下(38℃±0.5℃)的最低肺泡有效浓度(MAC)。行体表降温后测定深低温下(23℃±0.5 ℃)的MAC。维持深低温增加吸入性麻醉药的浓度,同时用50Hz、25V电压胸外电击心脏。记录出现室颤或室性心律失常时的肺泡呼气末吸入麻醉药浓度。结果:从38℃到23℃兔体温每降低1℃,MAC下降值为:氟烷5.1％、安氟醚3.6％、异氟醚4.4％、七氟醚4.3％;氟烷、安氟醚、异氟醚和七氟醚心脏麻醉指数分别为4.4、3.18、6.25和4.6,异氟醚明显高于其它麻醉药;麻醉药浓度8MAC以内安氟醚和氟烷发生室颤的机率(100％)明显高于七氟醚和异氟醚(40％)。结论:异氟醚是深低温麻醉的最佳选择用药,而安氟醚则不宜用于低温麻醉。     

室间隔缺损的介入封堵治疗

对介入封堵治疗室间隔缺损的应用情况以及适应症、并发症等作一综述．     

白细胞介素-15在心脏移植排斥反应中的表达及意义

目的 探讨白细胞介素-15（IL-15）在心脏移植排斥反应中的表达及其与排斥反应的关系。方法 采用小鼠颈部心脏移植模型，随机分为2组：同基因移植组，供、受体均为C57BL／6小鼠；异基因移植组，供、受体分别为BALB／C、C57BL／6小鼠。以pactin作内参照，分别于术后第1、3、5、7天取移植心脏，用逆转录-聚合酶链式反应（RT—PCR）法观察IL-15的表达情况。结果 随着术后天数的增加，异基因移植组IL-15表达逐渐升高，第5天达高峰（与同基因移植组相比，P〈0．01）。结论 IL-15的表达与心脏移植急性排斥反应的发生发展密切相关，可作为心脏移植急性排斥反应的监测指标，对急性排斥反应的早期诊断和移植物的预后估计具有重要的临床意义。