心肌保护的温度处理

心肌保护的温度处理李德闽综述汪曾炜审校作者单位：７１００３２第四军医大学西京医院研究生现在２１０００２南京军医总医院胸心外科低温有效降低了心肌的代谢，延缓能贮消耗，心脏外科一直将此作为心肌保护的有效措施〔１，２〕。冷血心肌停搏液（ＣＢＣ）心肌保护...     

曲马多对心肌梗死急性期损伤心肌超微结构的影响

目的　通过观察心肌梗死急性期损伤心肌超微结构的变化 ,探讨曲马多对心肌的保护作用。方法　 2 5～ 3 0kg家兔 1 6只 ,随机分为两组 :对照组 ,单纯结扎冠状动脉左对角支 ;曲马多组 ,于结扎前 1 0min静脉注射曲马多 4mg/kg ,并于结扎后 3h等量补充该药物。各组均行左股动脉穿刺监测MAP ,并分别于结扎前、结扎后 3h、结扎后 6h抽取颈外静脉血 ,测血中去甲肾上腺素的含量 ;于结扎 6h末取标本做电镜检查。结果　对照组在结扎后MAP明显降低 (P <0 0 1 ) ,曲马多组则无此变化 ;两组去甲肾上腺素差异表现不明显 ;电镜检查结果显示 ,曲马多组梗死区心肌细胞结构的破坏程度明显轻于对照组。结论　心肌梗死急性期曲马多可以减轻由于缺血所导致的心肌损伤程度。     

体外循环心肌氧供需平衡及其影响因素

以心肌氧供需平衡为基础的心肌保护技术是体外循环开心手术赖以成功的关键之一。维持体外循环中心肌氧供需平衡是一个极其复杂的课题，影响因素多，在体外循环各阶段各有特点。近年来，国内外研究的热点主要集中在：（１）停跳液介质对停搏心肌氧供需平衡的影响；（２）冠脉血流及血管活性药物对再灌注心肌氧供需平衡的影响。     

心肌组织工程——心肌再生

组织工程是当今医学发展的五大最主要前沿问题之一,主要研究组织和器官的形成和再生。它是应用生物学和工程学的原理和方法认识正常和病态生物组织的结构—功能关系,并设计、构造、改良生物的活组织,以修复或重建器官结构,维持或改善组织器官功能的一门新兴交叉边缘学科〔1〕。不言而喻,心肌组织工程的任务是,认识心肌的结构和功能关系,设计、构造、改良和培育活的心肌组织,维持或改善心肌的结构或功能。冠心病、风心病、心肌病等各种原因所致心肌损伤的共同特点,是具有完整舒缩功能的心肌细胞数量相对或绝对减少,受损心肌细胞由纤维组织瘢…     

心肌顿抑冬眠心肌和缺血心肌预适应

心肌顿抑冬眠心肌和缺血心肌预适应张维君，郭金成综述胡旭东审校传统观念认为，心肌缺血与其导致的心肌坏死是一种“全或无”的关系。近年来认为缺血对心肌的影响是多方面的：（１）缺血时间短（＜５分钟），心肌处于可逆性损伤，恢复再灌注后缺血心肌迅速恢复正常；（２...     

前列腺素E1对未成熟心肌缺血-再灌注损伤心肌超微结构变化的影响

目的观察前列腺素E1(PGE1)对未成熟心肌缺血-再灌注损伤后心肌超微结构变化的影响,探讨PGE1对未成熟心肌的保护作用.方法将24只3～4周龄中国大白兔按单纯随机抽样法分为3组,每组8只.Ⅰ组:正常对照组;Ⅱ组:缺血-再灌注损伤组;Ⅲ组:给药组,于缺血前静脉注射PGE1(10μg/kg).建立在体心脏缺血-再灌注损伤模型,用Maclab/8 s多功能生理仪监测左心室血流动力学变化及透射电子显微镜观察心肌超微结构的变化.结果再灌注60分钟后,Ⅲ组左心室发展压(LVDP)恢复率和左心室压力变化速率(±dp/dtmax)恢复率显著高于Ⅱ组 (P<0.05);Ⅲ组血浆肌酸激酶、乳酸脱氢酶活性低于Ⅱ组(P< 0.05);Ⅲ组心肌组织超氧化物歧化酶(SOD)活性高于Ⅱ组(P< 0.05),而MDA含量低于Ⅱ组(P<0.05).透射电子显微镜观察可见Ⅱ组线粒体水肿、破裂明显,而Ⅲ组线粒体损伤较轻.结论 PGE1能够提高SOD活性,减轻心肌缺血-再灌注生成的氧自由基对未成熟心肌及线粒体膜结构的损伤.     

体外循环心肌氧供需平衡及其影响因素

以心肌氧供需平衡为基础的心肌保护技术是体外循环开心手术赖以成功的关键之一。维持体外循环中心肌氧供需平衡是一个极其复杂的课题,影响因素多,在体外循环各阶段各有特点。近年来,国内外研究的热点主要集中在:(1)停跳液介质对停搏心肌氧供需平衡的影响:(2)冠脉血流及血管活性药物对再灌注心肌氧供需平衡的影响。     

金属硫蛋白对未成熟心肌和心肌间质的保护作用

目的探讨诱导金属硫蛋白(MT)在未成熟心肌中的表达对缺血-再灌注未成熟心肌和心肌间质的影响。方法将24只兔(14~21d)按随机数字表法分为4组,每组6只,对照组:腹腔注射蒸馏水0.3ml,24h后取离体心脏行Langendorff灌注;组1、组2和组3在腹腔注射3.6%ZnSO4(1.5ml/kg),分别于注射后12h、24h和48h取离体心脏行Langendorff灌注。测定心肌细胞中MT含量、血流动力学、生化指标,观察心肌超微结构改变。结果组2、组3与对照组、组1比较,MT含量、三磷酸腺苷(ATP)含量、超氧化物歧化酶活性、羟脯氨酸含量、心肌线粒体[Ca2+-ATPase]m、心肌线粒体合成ATP的能力明显增高(P<0.01),心肌含水量、丙二醛含量、心肌肌酸激酶、乳酸脱氢酶漏出率、心肌线粒体Ca2+含量、心肌线粒体[Ca2+]m和内皮素含量明显降低(P<0.01),心肌超微结构损伤明显减轻。结论腹腔注射ZnSO4可诱导心肌MT长时间表达,MT可减轻未成熟心肌和心肌间质的缺血-再灌注损伤。     

心脏不停跳手术患者心肌线粒体变化的观察

目的　观察心脏不停跳手术患者心肌线粒体形态及量化计分情况 ,探讨其对心肌的保护效果。　方法　16例二尖瓣置换术患者按不同的术式分为心脏不停跳组和心脏停搏组。分别于上、下腔静脉 (心脏不停跳组 )或主动脉 (心脏停搏组 )阻断前 ,阻断 6 0 min和开放后 2 0 min取心肌标本 ,在透射电子显微镜下观察线粒体形态并进行量化计分。　结果　上、下腔静脉或主动脉阻断前两组心肌线粒体计分差别无统计学意义 (P>0 .0 5 ) ;阻断 6 0 min和开放后 2 0 min心脏停搏组心肌线粒体计分均高于心脏不停跳组 (P<0 .0 1) ,心脏不停跳组心肌超微结构优于心脏停搏组。结论　浅低温心脏不停跳手术可减轻心肌缺血 -再灌注损伤 ,有较好的心肌保护作用。     

Reduction of Plasma Fibrinogen, Immunoglobulin G, and Immunoglobulin M Concentrations by Immunoadsorption Therapy with Tryptophan and Phenylalanine Adsorbents

Abstract Immunoadsorption (1A) therapy with tryptophan (TR-350) or phenylalanine (PH-350) adsorbents has been used to reduce the concentration of serum antibodies in human lymphocyte antigen (HLA)-immunized patients. Other forms of plasma purification have been reported to reduce the level of fibrinogen, which affects the blood properties. In this study we investigated the effects of IA therapy using both adsorbents on plasma fibrinogen and immunoglobulins G and M in 13 patients (8 patients were treated with TR-350, and 5 patients were treated with PH-350). During each session 1 plasma volume (2.8 ± 0.4 L of plasma) was processed through the immunocolumn and then returned to the patient together with the blood cells. Compared with the pretreatment values, the plasma fibrinogen, IgG, and IgM concentrations were significantly reduced after IA therapy (p < 0.01 for TR-350; p < 0.04 for PH-350). There was a positive correlation between the degree of reduction of plasma proteins and the number of IA treatments given. A nonpara-metric test (Wilcoxon's signed-rank test or the Mann-Whitney test) was used for statistical analysis. We conclude from our study that IA therapy effectively lowers the plasma levels of fibrinogen, IgG, and IgM and thus can be considered a valuable alternative to other blood purification methods.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

The multiply injured child

Blunt trauma is the principal cause of childhood death in many developed countries. This review outlines the differences between adults and children with respect to resuscitation and treatment of orthopaedic injuries in a child with polytrauma. Recent advances in techniques of fracture stabilization are reported.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.     

Intravenous endotoxin does not increase tissue extravasation of albumin in rats

Background : It is unclear whether activation of the inducible nitric oxide synthase (iNOS) increases or decreases the extravasation of plasma.
Methods : Chloralose anaesthetised male Wistar rats received E. coli lipopolysacharide (LPS), 3 mg kg^-1 i.v., or the corresponding volume of saline, 3 or 5 h before the end of the experiment. Mean arterial pressure (MAP) and heart rate (HR) were recorded. Tissue clearance of radio-labelled albumin, during the last 2 h of each experiment, was determined by a double-isotope method. In separate animals, the serum concentration of nitrite and nitrate was determined, 5 h after LPS or the solvent.
Main Results : LPS initially decreased MAP and lastingly increased HR. In the 3-h LPS animals (n=8), tissue plasma clearance was lower in the heart and calf muscle and increased only in diaphragm, compared to corresponding control animals (n=8). In the 5-h LPS rats, clearance was lowered (n=8) in the entire gastrointestinal tract and in testes, compared to controls (n=8). The serum nitrite/nitrate concentration was higher in animals given LPS (n=6) than in controls (n=6).
Conclusion : After LPS, tissue clearance of albumin was not increased in any major tissue, in spite of increased serum levels of NO end products. Apparently, after activation of iNOS, the augmented release of NO is not necessarily associated with increased albumin extravasation.     

Adrenaline markedly improves thoracic epidural analgesia produced by a low-dose infusion of bupivacaine, fentanyl and adrenaline after major surgery: A randomised, double-blind, cross-over study with and without adrenaline

Background: Basic pharmacological research indicates that there are synergistic antinociceptive effects at the spinal cord level between adrenaline, fentanyl and bupivacaine. Our clinical experience with such a mixture in a thoracic epidural infusion after major surgery confirms this. The objectives of the present study were to evaluate the effects on postoperative pain intensity, pain relief and side effects when removing adrenaline from this triple epidural mixture. Methods: A prospective, randomised, double-blind, cross-over study was carried out in 24 patients after major thoracic or abdominal surgery. Patients with only mild pain when coughing during a titrated thoracic epidural infusion of about 10 ml · h^?1 of bupivacaine 1 mg · ml^?1, fentanyl 2 μg · ml^?1, and adrenaline 2 μg · ml^?1 were included. On the 1^st and 2^nd postoperative days each patient was given a double-blind epidural infusion, at the same rate, with or without adrenaline. The effect was observed for 4 h or until pain when coughing became unacceptable in spite of a rescue analgesic procedure. Rescue analgesia consisted of up to two epidural bolus injections per hour and i.v. morphine if necessary. All patients received rectal paracetamol 1 g, every 8 h. Fentanyl serum concentrations were measured with a radioimmunoassay technique at the start and end of each study period. Main outcome measures were extent of sensory blockade and pain intensity at rest and when coughing, evaluated by a visual analogue scale, a verbal categorical rating scale, the Prince Henry Hospital pain score, and an overall quality of pain relief score. Results: The number of hypaesthetic dermatomal segments decreased (P <0.001) and pain intensity at rest and when coughing increased (P <0.001) when adrenaline was omitted from the triple epidural mixture. This change started within the first hour after removing adrenaline. After 3 h pain intensity when coughing had increased to unacceptable levels in spite of rescue analgesia (epidural bolus injections and i.v. morphine). Within 15–20 min after restarting the triple epidural mixture with adrenaline, pain intensity was again reduced to mild pain when coughing. Serum concentration of fentanyl doubled from 0.22 to 0.45 ng · ml^?1 (P <0.01), and there was more sedation during the period without adrenaline. Conclusions: Adrenaline increases sensory block and improves the pain-relieving effect of a mixture of bupivacaine and fentanyl infused epidurally at a thoracic level after major thoracic or abdominal surgery. Serum fentanyl concentrations doubled and sedation increased when adrenaline was removed from the epidural infusion, indicating more rapid vascular absorption and systemic effects of fentanyl.