58例双瓣替换术体外循环管理体会

目的：回顾５８例双瓣替换术体外循环管理状况,总结双瓣替换术中灌注技术。方法：对５８例风湿性心脏瓣膜病人施行二尖瓣、主动脉瓣替换术中体外循环手术的临床资料、心肺转汉方法和心肌保护中的难点及处理进行回顾总结分析。结果：５８例中早期死亡２例,死亡率３．４５％Ｒ。结论：只有良好的体外循环灌注技术和心肌保护,才能保证双瓣替换术病人顺利渡过围术期,降低手术死亡率。     

心脏瓣膜替换术体外循环搏动性血流灌注临床应用研究

本文报道心脏瓣膜病二尖瓣替换或二尖瓣加主动脉瓣双瓣膜替换术６５例,用双盲法选择病例,其中体外循环搏动性血流灌注３３例,平流灌注３２例,两组比较：搏动组心脏自动复跳率明显提高,术中尿量明显增加,术后用呼吸机时间明显缩短,差异有极显著性（Ｐ＜００１）,肢体末梢皮肤温度恢复时间提前,应用心肌正性肌力药例数,时间明显减少,两组差异明显（Ｐ＜００５）,血红蛋白尿例数有所增高,血小板计数（ＰＣ）及术后引流量差异无显著性（Ｐ＞００５）,随搏动时间的延长,血浆游离血红蛋白呈进行性增高,平均每３０ｍｉｎ增高６ｍｇ,差异有非常显著性（Ｐ＜００１）。研究证明搏动性血流灌注明显优于平流灌注。     

温血心停跳液与冷晶体心停跳液对狗心率变异性的影响

为探讨体外循环（ＣＰＢ）导致心脏植物神经系统（ＣＡＳ）损伤的机理,了解温血心停跳液能否防止ＣＰＢ后心率变异性（ＨＲＶ）的降低,采用对照方法观察了温血心停跳液与冷晶体心停跳液对狗ＨＲＶ的影响。结果显示：ＣＰＢ后温血心停跳液组（ＷＢ组）和冷晶体心停跳液组（ＣＣ组）的全频谱（ＴＰ）、低频（ＬＦ）和高频（ＨＦ）均较术前明显降低（Ｐ＜０．０５）,而且ＣＣ组比ＷＢ组降低更明显（Ｐ＜０．０５）,但ＬＦ／ＨＦ在组内及组间均无明显变化（Ｐ＞０．０５）。ＣＰＢ后２４小时平均心率（ＭＨＲ）明显增加（Ｐ＜０．０５）,且ＣＣ组高于ＷＢ组（Ｐ＜０．０５）。本研究表明：采用温血心停跳液或冷晶体心停跳液的ＣＰＢ不会干扰ＣＡＳ平衡,但均能使ＨＲＶ降低,温血心停跳液不能防止ＨＲＶ损害。     

Clinical application of the M-numbers of aortic cannulas during hypothermic cardiopulmonary bypass in pediatric patients

A standardized system to describe the pressure-flow characteristics of a given cannula has recently been proposed and has been termed the M-number system. Using 3 different sizes of aortic cannulas in 50 pediatric cardiac patients on hypothermic cardiopulmonary bypass, we analyzed the correlation between experimentally and clinically derived M-numbers and found it to be positive. Clinical M-numbers were typically 0.35 to 0.55 greater than experimental M-numbers and correlated inversely with a patient's temperature change; this was most probably due to increased blood viscosity arising from hypothermia. This inverse relationship was more marked in higher M-number cannulas. The clinical data obtained in this study suggest that the experimentally derived M-number correlates strongly with the clinical performance of the cannula and that the influence of temperature is significant.     

乌司他丁对体外循环心脏手术凝血功能的影响

目的 对比研究乌司他丁对体外循环(CPB)心脏手术患者凝血功能的影响。方法 36例CPB心脏手术患者随机分为3组:试验1组术中应用乌司他丁30万~(KIU);试验2组应用乌司他丁60万~(KIU);对照组除不应用乌司他丁外其它治疗与两试验组相同。动态监测所有患者的凝血因子XI促凝活性(FXI:C)、抗凝血酶Ⅲ活性(AT—Ⅲ:A)和D—二聚体的水平变化;记录3组患者术后住院期间输血量、术后引流量。结果 3组患者术前上述参数组间比较均差异无显著意义(P>0.05);CPB结束和术后6h,试验2组 FXI:C明显高于其它两组(P<0.05);3组AT—Ⅲ:A无显著性差异(P>0.05);从CPB结束至术后24h,试验1组D—二聚体明显高于试验2组(P<0.05),且从术后6h至术后72h两试验组均明显低于对照组(P<0.05或P<0.01);两试验组术后引流量及输血量均明显少于对照组(P<0.01),且两试验组之间比较P<0.05。结论 大剂量乌司他丁能较好地保护凝血因子活性,抑制继发性纤溶亢进,从而减少心脏手术后患者的出血量和住院期间的输血量。     

心肺危险指数与肺癌术后并发症的预测

目的研究心肺危险指数与肺癌术后并发症的关系.方法对1 144例接受肿瘤切除手术的肺癌患者进行分析,从临床资料中计算出心脏危险指数(CRI)和肺危险指数(PRI),两者相加之和为心肺危险指数(CPRI),分析CPRI与肺癌术后并发症的关系.结果术后30天内发生并发症的有167例(14.6%),死亡25例(2.2%).本组CPRI分为1～10级,其中CPRI＜4的有808例,≥4的有336例.以CPRI≥4为标准,其预测肺癌手术风险的敏感性、特异性分别为81.4%、79.5%.结论CPRI可以作为预测肺癌术后并发症的一项重要指标,但不能完全预计肺切除术后风险,仍需结合其它因素综合考虑.     

Effects of new polymer-coated extracorporeal circuits on biocompatibility during cardiopulmonary bypass

An inflammatory response due to bioincompatibility of extracorporeal circuits is a major clinical issue during cardiopulmonary bypass (CPB). By using a swine model, we determined whether new polymer-coated circuits, the blood-contacting surfaces of which are coated with poly(2-methoxyethylacrylate) (PMEA), would reduce the inflammatory response during CPB. Plasma bradykinin levels and the percentages of CD35-positive monocytes in PMEA-coated circuits were significantly lower than those in uncoated circuits during CPB. The amount of proteins adsorbed on the PMEA-coated circuits was significantly lower than that on the uncoated circuits (0.30 microg/cm2 versus 3.42 microg/ cm2). Almost no IgG, IgM, or C3c/d was detected in proteins adsorbed on the PMEA-coated circuits although these proteins were clearly detected in proteins adsorbed on the uncoated circuits. We concluded that PMEA coating could reduce complement activation during CPB by suppressing the adsorption of IgG and IgM, which activate C3 via the classical pathway, on the surface of the circuits.     

Experimental Evidence of Cerebral Injury from Profound Hypothermia During Cardiopulmonary Bypass

Choreoathetosis, seizures, and impaired mental development continue to occur in children undergoing cardiopulmonary bypass (CPB) and profound hypothermia with or without circulatory arrest. Although there is some evidence that the hypothermia itself may be causing these neurologic problems, skepticism remains because of lack of evidence from experimental studies simulating the clinical setting. In this experimental study, we examined the effect of profound and moderate hypothermia on the brain while maintaining normal flow rates during CPB. Ten adult mongrel dogs equally divided into two groups were anesthetized and subjected to CPB and varying levels of hypothermia (group 1, ≤15°C; group 2, ≤32°C). Both groups were kept at the desired temperature for 1 hour prior to rewarming and discontinuation of CPB. The dogs were euthanized 4–6 weeks later and neuropathologic studies were performed. The mean CPB flow rates during cooling and at the desired rectal temperature were comparable in both groups: group 1, 108 ± 10 ml/kg/min versus 106 ± 7 ml/kg/min in group 2 (p= NS) and 95 ± 12 ml/kg/min in group 1 versus 101 ± 5 ml/kg/min in group 2 (p= NS). Because of the difference in temperature between the two groups, the mean cooling time (onset of CPB to desired rectal temperature) was longer in group 1 (70 ± 14 minutes) than in group 2 (28 ± 11 minutes, p= 0.007). Hence, the total mean CPB time was also longer in group 1 (198 ± 25 minutes) than in group 2 (143 ± 13 minutes, p= 0.002). The lowest mean blood and rectal temperature achieved in group 1 were 11 ± .9°C and 12 ± 1°C versus 29 ± .4°C (p < 0.001) and 30 ± .6°C (p= 0.001), respectively, in group 2 (p= 0.001). Neuronal loss and degeneration was noted in all dogs in group 1 ranging from 2 to 8 cells per 1000 cells counted compared to none in group 2 (p= 0.05). These lesions occurred in both the basal ganglia and the cortex, although they were more marked in the caudate when compared to the cortex and cerebellum. Both in the cortex and in the caudate, neuronal loss was more marked around the capillaries. We conclude that the use of profound hypothermia of ≤15°C and maintenance of normal flow rates during cooling at this temperature for 1 hour produces neuronal loss and degeneration in the brain. These lesions being more marked around capillaries points to the vulnerability of the neurons, probably because of their high lipid content to injury from the cold perfusate.     

The pharmacokinetics of anesthetic drugs and adjuvants during cardiopulmonary bypass

The institution of cardiopulmonary bypass during cardiac surgery has profound effects on the plasma concentration of drugs and thus their therapeutic effectiveness. These changes occur through acute hemodilution, altered plasma protein binding, hypotension, as well as the use of hypothermia and heparin administration. Isolation of the lungs from the circulation and the possible sequestration of drugs in the bypass circuit also affect drug plasma concentrations on bypass. The individual characteristics of the drug in question are also important in determining the final plasma concentration: Lipid soluble drugs with a high volume of distribution may be more readily taken up by bypass equipment, but the initial fall in concentration at the start of cardiopulmonary bypass may be more readily counteracted by back diffusion into plasma, if large tissue stores have accumulated. The extent of the drug's plasma protein binding is of importance as the effective free fraction in plasma for highly bound drugs will be sensitive to changes in plasma protein binding brought on by factors such as hemodilution, heparin administration as well as alpha, acid-glycoprotein binding. Clearly the fate of drugs administered before or on bypass is complex and can only be accurately determined by specific studies evaluating drug plasma concentrations. This review updates the available data on anesthetics and drugs used during cardiac surgery in order that anesthetists may predict better the likely effect of drugs administered before or during cardiopulmonary bypass.     

体外循环期间低体重患儿血浆乳酸水平的变化

目的研究低体重患儿体外循环(CPB)各时段血浆乳酸的变化。方法将23例患儿分为2组,A组体重<10kg 12例,B组体重>10kg(10~27kg)11例。在CPB前,主动脉阻断后,停CPB前,分别采血样检测血浆乳酸浓度。结果AB两组在主动脉阻断后血浆乳酸浓度分别为(4.6±1.2)mmol/L、(3.8±1.1)mmol/L,较CPB前明显升高,P<0.05,AB两组停CPB前乳酸水平分别为(4.1±1.3)mmol/L、(2.9±1.3)mmol/L,A组较B组为高,二组差异有统计学意义,P<0.05。B组至停CPB前明显下降,P<0.05,但仍高于转前水平,而A组下降不明显,P>0.05。结论低体重儿在CPB中无氧代谢更旺盛,清除乳酸能力较弱,术中血浆乳酸检测有助于判断组织氧平衡情况。