Endoscopic vein harvest in elective off-pump coronary artery bypass grafting

While traditional open vein harvest was related to postoperative wound complications, endoscopic vein harvest was developed to minimize the morbidity in the greater saphenous vein harvest procedure. In this study, these two procedures were compared for postoperative wound healing and long-term graft patency. We reviewed all consecutive patients undergoing elective off-pump coronary artery bypass grafting from January 2004 to December 2005 and collected data regarding wound complications and coronary events. Wound complications included dehiscence, excessive discharge, edema, altered sensation, cellulitis, hema-toma, pain scale, and superlicial and deep wound infection. Coronary events were defined as diagnosis of myocardial infarction during the first year's follow-up. A total of 392 patients were included in our series, among whom 44 were excluded from the study due to emergent operation, preoperative intra-aortic balloon pump support, or the greater saphenous vein varicose characteristic, 78 belonged to open vein harvest group, and 270 to endoscopic vein harvest group. Wound complications were significantly less in the endoscopic group (5.2%) compared to the open group (19.2%) (P=0.0002). There was no significant difference on preopera-tive risk factors, total operative time, or hospitalization days. During one-year follow-up, both the early and late graft patency rates were similar between the two groups. Endoscopic vein harvest is safe and effective, which carries less risk for wound complica-tions and is associated with better satisfaction and cosmetic result than the traditional greater saphenous vein harvest procedure. The endoscopic vein harvest also demonstrates a great long-term patency.     

650MW核电机组凝汽器单侧冷却下汽机旁排投运分析

本文主要通过对中核运行2厂1/2号650MW核电机组的GCT-C旁排阀及减温减压装置热力过程的介绍,分析在失去一列CRF水时,即凝汽器在失去一列冷却水,在单侧冷却的情况下汽机旁排投运,此时相关热工参数是否仍能满足凝汽器设计要求。     

体外循环心脏直视术后患者的监护体会

目的：总结体外循环心脏直视术后患者的监护经验。方法：对56例体外循环心脏直视术后的患者在ICU的监护进行回顾性分析,从监护室的准备、呼吸系统的护理、循环系统的护理、引流管的护理、心理护理、压疮预警干预几个方面进行总结。结果：56例患者中除一例因术后并发重度低心排死亡外,其余均康复出院。结论：ICU对患者的监护极为重要,这是体外循环心内直视术后患者的安全保障,直接关系到手术的成败。     

涡轮设计方法改进研究

首先从涡轮总体设计性能要求出发,运用流线曲率法设计涡轮子午流道,并获得设计所需的气流速度三角形;然后运用课题组开发的“十四”参数法【1】进行二维叶栅设计,由参数曲面完成三维叶片造型以及构建涡轮特征模块化体系进行网格划分;最后得到可直接用于计算的网格。设计过程表明,经过改进后的设计方法可方便、快捷的完成涡轮设计。     

机器人避障行走的最短路径

机器人避障行走的路径必须由相切的直线段和圆弧组成,故建立了从圆外点向圆作切线和作两圆公切线的计算切点坐标的显式公式。针对众多组合绕行方案,设计出寻求最佳方案的计算简便且筛选全面的折线过滤法;指出紧贴障碍线的路径是最短路径,并给出了完整的证明。机器人在指定点处转弯需走圆弧,为确定圆心坐标,构建基于角平分线的近似方法,同时建立优化模型,并通过搜索求解,验证了该近似方法具有极高的精度。     

300MW机组湿法脱硫系统取消旁路逻辑变更

文章叙述了对茂名臻能热电有限公司300MW湿法脱硫系统取消旁路逻辑变更的介绍和分析。     

Effects of pH management during deep hypothermic bypass on cerebral oxygenation: alpha-stat versus pH-stat

Objective: There is a remarkable lack of scientific evidence to support the option to use alpha-stat or pH-stat management, as to which is more beneficial to brain protection during deep hypothermic CPB. This study examined cortical blood flow (CBF), cerebral oxygenation, and brain oxygen consumption in relation to deep hypothermic CPB with alpha-stat or pH-stat management. Methods: Twenty-two pigs were cooled with alpha-stat or pH-stat during CPB to 15℃ esophageal temperature. CBF and cerebral oxygenation were measured continuously with a laser flowmeter and near-infrared spectroscopy, respectively. Brain oxygen consumption was measured with standard laboratory techniques. Results: During CPB cooling, CBF was significantly decreased, about 52.2%±6.3% (P＜0.01 vs 92.6%±6.5% of pH-stat) at 15℃ in alpha-stat,whereas there were no significant changes in CBF in pH-stat. While cooling down, brain oxygen extraction (OER) progressively decreased, about 9.5%±0.9% and 10.9%±1.5% at 15 ℃ in alpha-stat and pH-stat, respectively. At 31℃ the decreased value in pH-stat was lower than in alpha-stat (29.9%±2.7% vs 22.5%±1.9%; P＜0.05). The ratio of CBF/OER were 2.0±0.3 in alpha-stat and pH-stat, respectively; it was kept in constant level in alpha-stat, and significantly increased by 19℃ to 15℃ in pH-stat (4.9±0.9 vs 2.3±0.4; P＜0.01). In mild hypothermia, cerebral oxyhemoglobin and oxygen saturation in alpha-stat were greater than that in pH-stat (102.5%±1.4% vs 99.1%±0.7%; P＜0.05). In deep hypothermia, brain oxygen saturation in pH-stat was greater than that in alpha-stat (99.2%±1.0% vs 93.8%±1.0%; P＜0.01), and deoxyhemoglobin in pH-stat decreased more greatly than that in alpha-stat (28.7%±6.8% vs 54.1%±4.7%; P＜0.05). Conclusions: In mild hypothermic CPB, brain tissue oxygen saturation was greater in alpha-stat than in pH-stat. However, cerebral oxygenation and brain tissue oxygen saturation were better in pH-stat than in alpha-stat during profound hypothermia. PH-stat strategyprovided much more oxygen to brain tissue before deep hypothermic circulatory arrest.     

二维冠状动脉旁路桥的局部形状模型

对于一个二维冠状动脉旁路桥的形状,局部利用扰动技术,导出其局部形状模型及广义形式．     

混合式教学在“六方位绕车介绍法”中的应用

以汽车销售实务中的"六方位绕车介绍法"为例,将混合式教学模式引入到教学内容中,通过开展"线上"+"线下"的教学模式,把学生的学习由浅到深地引向深度学习,便于学生对所学知识的掌握及运用,进而为汽车营销与服务专业教学模式探索出新的教学思路。     

The significance of troponin T and CK-MB release in coronary artery bypass surgery

Measurement of cardiac markers is an index of care standard in the assessment and diagnosis of cardiovascualr disease. Two of the major cardiac markers are Creatine Kinase isoenzyme CK-MB and Troponin T, which are extensively used in the diagnosis of heart disease. The release of Troponin T and creatine kinase isoenzyme (CK-MB) was investigated in 50 coronary artery bypass surgery patients. Measurement of plasma samples was carried out at five different time points, namely before surgery, 1,6,12,24 hours after surgery. The results indicated that CK-MB level were increased by a factor more than four times compared with the upper limit of baseline (befor surgery). Troponin T concentration showed more than six fold over the upper limit of baseline (before surgert) at 1,6,12,24 hours after surgery. In order to assess the significance of the length of the surgical procedure on the release of Troponin T and CK-MB, the surgery patient were divided into two groups according to the length of the surgical procedure: group I was selected on the basis that the surgical procedure they underwent lasted above 90 minutes and group II with a surgical procedure below 90 minutes. Both Troponin T and CK-MB showed a significant increase in-group I compared to group II. To investigate the likelihood that this effect is party due to myocardial infarction during surgery, the patients were divided into two groups: Group A with some sings of myocardial infarction on Q wave of ECG and group B without any change. The results showed approximately a two-fold increase of these markers in-group A compared to group B. Since these markers reach into blood following damage to myocardial their increase in patients with time course surgery of more than 90 minutes and those with a probability of MI during operation, indicating that these patient fall into a high risk group of repeat (MI) after surgery.