高胸段硬膜外阻滞对非停跳冠状动脉搭桥术患者围术期血浆内皮素及心钠素水平的影响

目的评价高胸段硬膜外阻滞对冠心病行非停跳冠状动脉搭桥术患者血浆内皮素（ET）及心钠素（ANP）水平的影响。方法20例拟行非停跳冠状动脉搭桥术患者随机分为2组（n=10）：A组为全麻组；B组为高胸段硬膜外阻滞复合全麻组。采用放免法测定术前、术后1h、24h及48h血浆ET及ANP浓度；记录血液动力学参数及所用血管活性药剂量。结果与A组比较，B组术后各时点血浆ET及ANP浓度降低，血管活性药物用量减少（P〈0．05）。两组血液动力学指标尽管均在正常范围，但A组波动明显。结论高胸段硬膜外阻滞可抑制ET、ANP的释放，有助于冠状动脉搭桥术患者围术期血液动力学的稳定。     

不同镇痛方法对高血压病人上腹部手术后血浆内皮素及心钠素的影响

目的：观察不同镇痛方法对上腹部手术合并高血压病患者血浆内皮素（ET）及心钠素（ANP）的影响。方法：30例拟行上腹部手术的高血压患者根据不同镇痛方式随机分为三组：A组为对照组，术后根据需要间断肌注哌替啶镇痛；B组术后行硬膜外自控镇痛（PCEA）；C组术后行静脉自控镇痛（PCIA）。采用放免法测定术前、术毕、术后24h、术后48h血浆ET及ANP浓度；监测HR、BP及进行VAS评分。结果：B组及C组术后24h ET及ANP值显著低于A组（P＜0．05），且B组降低幅度更大（P＜0．01），持续时间更长，至术后48h B组仍低于A组（P＜0．05），而C组与A组比较差异无显著性。B及C组术后HR、SBP、DBP及VAS评分显著低于同期A（P＜0．05），且B组数值更低（P＜0．01）。结论：术后镇痛能有效减轻上腹部手术病人疼痛、改善循环功能、降低高血压病患者上腹部手术后ET及ANP值，减少术后并发症，有利于病人恢复，且PCEA效果更优。     

冠状动脉旁路移植术病人神经体液因子的变化

目的 检测具有高危因素的行冠状动脉旁路移植术（CABG）病人的相关神经体液因子，结合临床改变，寻找针对性的处理措施及依据，减少并发症。方法 48例病人分A组23例行体外循环冠状动脉旁路移植术（CCABG）；B组25例行非体外循环冠状动脉旁路移植术（OPCAB）。围术期分6个时间点测定血浆中血管紧张素Ⅱ（AGⅡ）、醛固酮（ALD）、心钠素（ANP）、胰岛素（INS）、血糖（SUG）和肌钙蛋白Ⅰ（cTnⅠ）。结果 血浆AGⅡ水平，A组术后6h、B组术后3h达高峰。血浆ALl）水平，A组术后6h、B组在术后0h达高峰。血浆ANP水平，A组术后0h、B组术中已达高峰。血浆胰岛素水平，A组术后24h、B组术后6h达高峰，术后24hA组显著高于B组。血糖水平，A组术后3h、B组术后0h达高峰。血浆AGⅡ、ALD、ANP和血糖水平术中及以后各时点A组均显著高于B组。血浆cTnⅠ水平，术后3—24hA组显著高于B组。结论 CABG均可出现血糖升高的高渗性利尿和高醛固酮血症的利尿，CCABG组是二者同时升高出现强而持久的利尿，OPCAB组则以高渗性利尿为主，持续时间短。CABG，尤其CCABG应使用血管紧张素转换酶抑制剂（ACEI）、AGⅡ受体拈抗剂（ARB）和抗醛固酮制剂；术后6h内更应降血糖，补充钾、镁制剂。     

肩锁关节手术后应用臂丛神经自控镇痛的临床研究

目的研究臂丛神经自控镇痛（PCRA）对围术期肩锁关节骨折脱位手术患者镇痛治疗应激反应的影响。方法45例拟行肩锁关节骨折脱位手术患者，根据不同镇痛方式随机分为三组：A组为对照组，术后根据需要间断肌注哌替啶镇痛；B组术后行PCRA；C组术后行静脉自控镇痛（PCIA）。测定术前、术后24、48h血浆皮质醇、血管紧张素Ⅱ的浓度；监测HR、BP及进行视觉模拟评分（VAS）；测量肩锁关节被动活动度。结果B组及C组术后24h皮质醇、血管紧张素Ⅱ值显著低于A组（P〈0．05），而B组降低幅度更大，持续时间更长，至术后48hB组仍低于A组（P〈0．05），而术后48hC组与A组比较差异无统计学意义。B组及C组术后HR、SBP、DBP及VAS显著低于同期A组（P〈0．05），且B组数值更低（P〈0．01）。B组及C组术后肩锁关节被动活动度显著大于同期A组（P〈0．05），且B组术后肩锁关节被动活动度更大（P〈0．01）。结论PCRA更能有效地减轻肩锁关节骨折脱位手术患者疼痛，降低患者术后皮质醇、血管紧张素Ⅱ水平，利于患者进行肩锁关节早期功能锻炼，减少术后并发症，有利于患者恢复。     

高乌甲素对手术创伤病人应激反应的影响

目的观察高乌甲素（lappaconitine,LA）对手术创伤病人应激水平的影响,探讨其调控应激反应的可能机制。方法选择乳腺癌根治术、椎管狭窄减压术、股骨头坏死人工头置换术患者,共36例,按病种对等随机分3组,高乌甲素组（L）、曲马多组（T）、空白对照组（B）,每组12例。常规全凭静脉麻醉下实施手术,在L组、T组诱导前30min分别静脉滴注LA8mg、曲马多100mg,30min滴注完。诱导后即开始在L组、T组连接电子输注泵,以LA0．28mg／ml或曲马多8mg／ml进行持续背景输注,术后清醒后再实施PCA。B组术后按需肌肉注射哌替啶（50mg／次）和氟哌利多（2．5mg／次）镇痛。分别于麻醉用药前30min、术毕即刻、术后24h、术后48h采取外周静脉血,用放免法分别测定血浆内β-EP、ACTH、ALD水平,另份血样送检测血糖、白细胞分类计数及凝血四项（APTT、TT、PT、FIB）。结果T组在术毕即刻、术后24h,以及B组在术后各时点血浆β-EP升高与L组比较均有统计学差异（P〈0．05或P〈0．01）;T组、B组在术后各时点血浆ACTH水平升高与L组比较均有统计学差异（P〈0．05或P〈0．01）;T组在术毕即刻、B组在术后各时点血浆ALD水平升高与L组比较均有统计差异（P〈0．05）。B组在术毕即刻、术后24h血糖升高与L组比较差异有统计学意义（P〈0．05）。T组、B组在术后24h、术后48h体温较基础值升高（1．03±0．06）℃;B组中性粒细胞分类比率在术后48h升高与基础值及L组比较有统计学差异（P〈0．05）;T组在术后48h,B组在术后24h、术后48h单核细胞分类比率升高与基础值和L组比较有统计学差异（P〈0．05）：T组、B组在术后24h、术后48hAPTT缩短、B组在术后48hFIB增加与L组比较均有统计学差异（P〈0．05）。结论LA可以部分抑制手术创伤病人应激水平的增高,其机制可能与LA多种药理作用有关。     

静吸全麻下老年高血压病人五种神经肽变化的临床研究

目的：观察静吸全麻下高血压老年病人血浆5种神经肽;降钙素基因相关肽（CGRP）、神经降压素（NT）、心钠素（ANP）、神经肽Y（NPY）、内皮素（ET）的变化。方法选择上腹部手术、高血压老年病人14例,分别于术前、麻醉诱导后3min、手术60min、术毕及术后24h抽静脉血,应用放射免疫方法测定血冰5种神经肽的水平。同时上同麻醉下行上腹部手术、非高血压老年病人14例作为对照组。结果高血压组ANP手术中及术后显著降低（P＜0．05或0．01）,而非高血压组无明显变化,高血压组NPY手术中及手显著性升高（P＜0．05或0．01）,非高血压组变化不明显;而GRP、NT和ET两组均明显变化。结论高血压老年病人静吸全麻下,行上腹部手术时,CGRP、NT及ET无明显变化,而NP和NPY则波动显著。     

深低温停循环肾损伤及其早期检测

目的建立一种新的不开胸深低温停循环（DHCA）兔模型,研究DHCA对。肾脏的损伤及早期检测指标。方法以体重3．5～4．0kg新西兰大耳兔（雌雄不拘）42只分为两组,每组各21只：两组均于右颈动静脉插管建立体外循环,A组肛温维持在28℃持续体外循环,B组肛温降至16～18℃时停循环,停循环60min后开放循环复温,在30min内复温至肛温35℃,之后维持体外循环30min,两组体外循环时间相同。在术前、术后6h、24h及48h分别采集静脉血检测血清肌酐（Cr）、p．痕迹蛋白（p．TP）、采集尿样本行尿中性粒细胞明胶酶相关脂质运载蛋白（NGAL）值检测。两组分别在术前、术后6h、24h及48h处死动物各4只,留取肾脏组织分别检测丙二醛（MDA）含量、HE染色和凋亡指标（TUNEL）染色以及透射电子显微镜观察。肾小管上皮细胞形态改变。结果A组围术期死亡4只,B组围术期死亡5只。（1）血清cr值：A组组内各时间点之间差异无统计学意义（P〉0．05）,B组在术后24h与组内及A组间比较明显升高（P〈0．05）。（2）血D．TP及尿NGAL值：A组组内各时间点之间差异无统计学意义（P〉0．05）。B组内术后6h、24h、48h与术前比较明显升高（P〈0．05）,B组在术后24h与组内其它时间点比较明显升高（P〈0．05）。B组术后6h、24h、48h与A组比较明显升高（P〈0．05）。（3）。肾组织丙二醛（MDA）含量：B组在术后24h与组内及组间比较明显升高（P〈0．05）。（4）HE染色可见B组在术后24h肾小管上皮细胞病理损伤明显,A组在术后24h。肾小管上皮细胞病理无明显改变。（5）TUNEL染色阳性率：B组在术后24h与组内及组间比较明显升高（P〈0．05）。（6）电子显微镜观察可见B组在术后24h。肾小管上皮细胞内细胞器病理损伤明显,A组肾小管上皮内细胞器病理变化不明显。结论不开胸DHCA兔模型对于研究DHCA造成的器官损伤是一种简单、方便、经济且能够长期生存的动物模型。在DHCA手术后24h肾损伤最严重,血D—TP和尿NGAL是DHCA肾损伤的早期检测指标。     

常规与非体外循环冠状动脉旁路移植术炎症因子比较

目的：比较多支冠状动脉（冠脉）病变行常规体外循环冠状动脉旁路移植术（CABG）和非体外循环冠状动脉旁路移植术（OPCAB）围术期心肌损伤和炎症因子的变化情况。方法：CABG组（A组，13例），OPCAB组（B组，22例）。分别于麻醉诱导后、手术结束后即刻、术后24h和48h进行血样检测，分别测定TNF－α、IL-1β、IL-8和IL－10水平。另外记录围手术期各项临床指标如引流量、输血量、呼吸机使用时间和发热时间等。结果：两组在年龄、冠脉病变程度、心功能和血管旁路移植数目上相似。术后IL－8水平OPCAB组相对稍高，但两组无显著差异。围术期CABG组IL－1、TNF较OPCAB明显为高（P＜0．05）。但炎症因子IL－10 OPCAB组却较CABG组明显升高（P＜0．05），术后24h达高峰。最后，CABG较OPCAB病人呼吸机使用时间延长且发热时间延长。结论：与CABG组相比，OPCAB组围术期炎症反应和术后并发发症明显降低。     

室间隔缺损患者体外循环前后血浆内皮素、一氧化氮、心钠素水平的变化

目的：探讨室间隔缺损（VSD）伴肺动脉高压（PH）患者体外循环（CPB）前后血浆内皮素（ET－1）,一氧化氮（NO）,心钠素（ANP）水平变化及吸入NO对他们的影响。方法：60例VSD患者,按有无PH分为无PH组（A组）20例,PH组（B组）40例。B组再随机分为吸入NO组（B1组）与不吸入NO组（B2组）各20列。分别测定血浆ET－1,NO,ANP含量。结果：术前B组血浆ET－1,NO,ANP水平明显高于A组（P＜0．05）,CPB后即刻3组血浆ET－1水平明显高于术前,NO水平明显低于术前（分别P＜0．05,P＜0．01）。CPB与B1组血浆ET－1水平较B2组下降快,NO水平较B2组升高快。B组术前血浆ET－1浓度与血浆NO浓度呈负相关,与血浆ANP浓度呈正相关。结论：ET－1／NO动脉平衡的破坏,可能参与了PH的发生,发展过程;ANP在PH的发病机制中起着有益的生理调节作用。CPB使血浆ET－1升高,NO,ANO水平降低;吸入NO可降低ET－1水平,提高NO水平。     

冠心病患者围术期内皮素变化的临床研究

目的研究冠心病患者围术期内皮素（ET）及血流动力学的改变,总结冠心病围术期的一些变化规律,为临床治疗提供参考。方法将37例冠心病患者及10例心瓣膜疾病患者依据不同的手术方式分为5组,冠状动脉旁路移植术＋室壁瘤切除术（CABG＋LVAN组）,体外循环冠状动脉旁路移植术（CABG组）,非体外循环冠状动脉旁路移植术（OPCAB组）,激光心肌打孔术（TMLR组）,对照组为风湿性心脏病行二尖瓣置换术患者。使用放射免疫分析法分别测定术前,主动脉阻断前（血管移植前或打孔前）,主动脉开放时（血管移植结束时或打孔后）,心肌再灌注后3h、6h、24h血ET值;并于术前、心肌再灌注后3h、6h、24h测定心排血指数（CI）。结果ET值组内比较：CABG＋LVAN组主动脉开放时（69．93±7．20pg／ml）,心肌再灌注后3h（89．99±5．76pg／ml）、6h（60．94±8．69pg／ml）、24h（68．99±10．30pg／ml）时ET值显著高于术前（40．17±13．37pg／ml,P〈0．05）;CABG组主动脉开放时（66．59±4．86pg／ml）,心肌再灌注后3h（95．97±10．72pg／ml）、6h（61．51±7．65pg／ml）、24h（57．85±6．34pg／ml）均显著高于术前（43．22±9．13pg／ml,P〈0．05）;OPCAB组血管移植结束时（66．47±5．90pg／ml）显著高于术前（44．80±6．51pg／ml,P〈0．05）;TMLR组打孔术后无显著升高;对照组主动脉开放时（69．92±10．80pg／ml）,心肌再灌注后3h（77．99±7．49pg／ml）、6h（46．76±7．61pg／ml）、24h（52．07±6．94pg／ml）显著高于术前（35．14±8．10pg／ml,P〈0．05）。组间比较：CABG组心肌再灌注后3h显著高于OPCAB组（95．97±10．72pg／ml vs．59．72±4．81pg／ml,P〈0．05）。心肌再灌注后各组CI均较术前明显增加,CABG组心肌再灌注后3h CI明显低于OPCAB组（2．17±0．46L／min·m^2 vs．3．25±0．05L／min·m^2,P〈0．05）。?     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

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.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.