不同剂量丙泊酚持续静注对心内直视手术病人肌钙蛋白Ⅰ的影响

目的　观察不同剂量丙泊酚对心内直视术病人肌钙蛋白 Ⅰ (CTn Ⅰ )的影响 ,寻求丙泊酚抑制心肌缺血再灌注损伤作用合适的剂量。方法　 2 7例心内直视手术患者随机分成A、B、C三组。咪唑安定、丙泊酚、维库溴铵、芬太尼诱导后 ,用微量泵持续输注丙泊酚 ,A组 2mg·kg-1·h-1、B组 5mg·kg-1·h-1、C组 8mg·kg-1·h-1。用化学发光法测定诱导后、停心肺转流 (CPB)即刻、CPB后30、6 0分钟和CPB后 3小时动脉血CTn Ⅰ浓度。结果　三组病人CPB后CTn Ⅰ均显著升高 (P <0 0 1)。组间比较 ,B组CPB后CTn Ⅰ值比A组低 (P <0 0 5和P <0 0 1)。C组和A组间CTn Ⅰ值无统计学差异。结论　心脏手术术中及术后CTn Ⅰ升高提示心肌存在不同程度损伤。术中 5mg·kg-1·h-1丙泊酚持续静注是较为理想的具有心肌保护作用的临床用药剂量     

异丙酚对成年大鼠血脑屏障通透性的影响

目的　观察静脉输注不同剂量异丙酚对大鼠血脑屏障 (BBB)通透性的影响。方法　 30只成年大鼠随机分为三组 :对照组 (C组 ,不用全麻药 ,n =6 ) ,异丙酚 70mg·kg-1·h-1组 (P1组 ,静脉注射异丙酚 2 0mg/kg继以静脉输注 5 0mg·kg-1·h-11小时 ,n =12 ) ,异丙酚 12 0mg·kg-1·h-1组 (P2组 ,静脉输注异丙酚 12 0mg·kg-1·h-11小时 ,n =12 )。取脑做EB染色观察、镧醛灌注后电镜观察及HE染色光镜观察。结果　P1、P2组EB染色、HE染色及电镜观察结果与C组相比均无明显差别。结论　本实验结果提示 ,静脉输注产生脑电图爆发抑制剂量的异丙酚 (70mg·kg-1·h-1)及更大剂量(12 0mg·kg-1·h-1) 1小时 ,虽然后者产生明显的循环抑制 ,但两者均未增加大鼠BBB对大分子 (EB 白蛋白 )和小分子 (镧离子 )的通透性 ,对中枢神经系统形态也无明显影响。     

丙泊酚对血液稀释时组织氧代谢的影响

目的　观察丙泊酚对急性等容血液稀释 (ANH)时组织氧代谢的影响。方法　择期手术病人 2 4例 ,随机分为三组 ,每组 8例 :A组为ANH组 ,P4组为ANH +丙泊酚 4mg组 ,P8组为ANH +丙泊酚 8mg组 ,三组病人ANH后Hct降至 2 7 1 %。漂浮导管放置完成后稳定 2 0min(T1 ) ,P4和P8组给予丙泊酚负荷剂量 2mg/kg后 ,分别给与丙泊酚维持剂量 (P4组 :4mg·kg-1 ·h-1 ;P8组 :8mg·kg-1 ·h-1 )。稳定 1 0min后 (T2 ) ,开始进行血液稀释。同时于T1 、T2 、T3 (血液稀释完成后1 5min)分别监测血液动力学指标和混合静脉血氧饱和度 (S vO2 ) ,血乳酸值 (T1 、T3 )。结果　三组病人ANH后均可见心排血量 (CO) ,每搏量 (SV)升高非常显著 ,外周血管阻力 (SVR)和动脉血氧含量(CaO2 )下降非常显著 ,氧供给 ( DO2 )、S vO2 及血乳酸改变不明显 ;P4和P8组SVR下降显著 ,MAP下降非常显著 ,组间比较无差异。结论　本实验剂量范围内 ,丙泊酚与ANH合用时 ,组织氧代谢水平未受明显影响     

丙泊酚对急性肾缺血再灌注过程脂质过氧化损伤的保护作用

目的　研究丙泊酚对家兔肾上腹主动脉阻断后肾脏脂质过氧化损伤的防治作用。方法　家兔 2 4只 ,随机等分为假手术组 (A组 )、缺血再灌注组 (B组 )和丙泊酚组 (C组 )。肾上腹主动脉阻断 30分钟再灌注 180分钟制成双侧急性肾缺血再灌注损伤 (ARIRI)动物模型。C组于阻断腹主动脉前静脉注射丙泊酚 5mg/kg ,继以微量泵持续输注 2 0mg·kg-1·h-1丙泊酚 15分钟 ,A、B组则以同样方法静注等容积生理盐水作对照。动态检测血中超氧化物歧化酶 (SOD)、丙二醛 (MDA)以及肾皮质中SOD、MDA的变化 ,并在电镜下观察肾组织形态学改变。结果　C组在再灌注期血和肾皮质中MDA浓度明显低于B组 (P <0 0 1) ,SOD活性显著高于B组 (P <0 0 1)。B组电镜见明显急性肾小管损伤及坏死 ,而C组肾小管损伤轻微。结论　丙泊酚对家兔ARIRI有良好保护作用     

丙泊酚在家兔肾下主动脉阻断术中对肾功能的保护作用

目的　探讨丙泊酚在肾下主动脉阻断术中对肾功能的保护作用及其机制。方法　 2 4只家兔随机分为假手术组 (A组 )、阻断组 (B组 )及丙泊酚 (C组 ) ,每组 8只。B、C组肾下主动脉阻断4 0分钟后再灌注 1小时 ,C组于阻断前 10分钟静注丙泊酚 5mg/kg ,继以持续输注丙泊酚 2 0mg·kg-1·h-1至松开前 5分钟 ;余两组以等容量生理盐水作对照。测定给药前 (C-10 )、松开前 (C40 )、松开后 1小时 (R60 )血中内皮素 1(ET 1)水平及尿素氮 (BUN)、肌酐 (Cr)、K+ 、Ca2 + 含量 ,记录阻断前、阻断后、松开后尿量并测定尿 β2 微球蛋白 (β2 MG)含量。结果　 (1)B组再灌注后血浆ET 1水平明显高于阻断前及A组 (P <0 0 5 ) ,C组阻断后及松开后血ET 1较阻断前无明显变化。 (2 )B组R60 时的血浆BUN、血K+ 含量明显高于基础水平 (P <0 0 5 ) ,C组无明显变化。 (3)B组及C组阻断后尿量均明显升高 ,再灌注后B组尿量明显低于阻断前 (P <0 0 5 ) ,B组尿 β2 MG明显高于阻断前及C组 (P <0 0 5 )。结论　肾下主动脉阻断可导致肾小球及肾小管功能障碍。丙泊酚对肾功能有保护作用 ,其机制与其抑制ET 1水平升高有关     

丙泊酚对风心瓣膜置换术后转流后左室功能的影响

目的　观察丙泊酚静脉复合麻醉对风心瓣膜置换手术患者心肺转流 (CPB)后左室功能的影响。方法　 2 0例风心瓣膜置换手术患者 ,随机分为咪唑安定组 (C组n =10 )和丙泊酚组 (P组n=10 ) ,分别以咪唑安定 0 1～ 0 2mg·kg-1·h-1或丙泊酚 2～ 6mg·kg-1·h-1维持麻醉 ,CPB期间和CPB后持续注药。两组芬太尼应用相同。观察缺血 /再灌注后 3 0分钟、60分钟和 2 4小时血清心肌酶谱变化 ,并采用Swan Ganz导管技术监测停CPB后MAP、HR、SI、CI、PCWP、SVRI和LVSWI变化。结果　缺血 /再灌注后三个时点LDH和CK MP均较麻醉前升高 ,C组升高更为明显。CK MB再灌注后 60分钟和 2 4小时 ;LDH再灌注 2 4小时与P组相比差异显著 (P <0 0 5 )。P组停CPB后各时点HR较基值显著减慢 (P <0 0 1) ,PCWP、SVRI显著降低 (P <0 0 1) ,SI、LVSWI显著增高 ,CI较C组相对为高。结论　丙泊酚维持麻醉 ,减轻了心肌缺血 /再灌注损伤 ,并降低心脏前、后负荷 ,维持满意的心脏指数 ,促进缺血后左心功能的恢复。     

大鼠肾上腺髓质增生模型的动态观察

目的　探讨利血平建立大鼠肾上腺髓质增生 (AMH)模型的最适剂量 ,观察其长期稳定性。方法　雄性Wistar大鼠 72只 ,随机分为A、B、C、D 4组各 18只 ,A组皮下注射利血平 0 .2mg·kg-1·d-1和 0 .9%生理盐水 0 .6mg·kg-1·d-1,B组皮下注射利血平 0 .4mg·kg-1·d-1和 0 .9%生理盐水 0 .4mg·kg-1·d-1,C组皮下注射利血平 0 .8mg·kg-1·d-1,D组皮下注射 0 .9%生理盐水0 .8mg·kg-1·d-1,每日 1次 ,持续 2个月后停药。分别于停药后 2周、2个月、6个月时测大鼠 2 4小时尿 3 甲氧基 4 羟基苦杏仁酸 (VMA )含量及血儿茶酚胺 (CA)水平 ,然后处死大鼠 ,取出肾上腺 ,作病理切片 ,测肾上腺髓质百分数 ,及AMH阳性率。结果　在各停药时段 ,B、C组与D组相比2 4h尿VMA含量、血浆CA水平和髓质百分数均有显著性升高 (P <0 .0 5 ) ,这三组各值与停药 2周相比差异均无显著性 (P >0 .0 5 ) ;在停药 6个月时 ,A组各值与停药 2周时相比有显著性下降( P <0 .0 5 ) ,与D组相比差异均无显著性 ( P >0 .0 5 )。结论　利血平所致大鼠AMH模型各生化指标稳定 ,但C组死亡率较高。     

BIS和AEPex比较性研究术前静注可乐定对麻醉深度的影响

目的　比较术前静注不同剂量的可乐定对麻醉深度和麻醉药用量的影响。方法　选 择ASAⅠ～Ⅱ级拟行腹腔镜胆囊切除术的患者48例,采用随机对照单盲的方法分四组,分别在术前 30min静脉缓慢注入可乐定0μg/kg(Ⅰ组,为对照组,生理盐水2～3ml)、2μg/kg(Ⅱ组)、3μg/kg (Ⅲ组)、4μg/kg(Ⅳ组)。使用丙泊酚、芬太尼、维库溴铵联合静脉麻醉,芬太尼首剂3μg/kg,2μg· kg-1·h-1维持,调节丙泊酚的输注速度(6～12mg·kg-1·h-1)以达到满意的麻醉深度,维持BP (收缩压或舒张压)在术前值±20%范围内波动。观测脑电双频指数(BIS)和听觉诱发电位指数 (AEPex)的变化,比较各组使用丙泊酚剂量的差异。结果　Ⅲ、Ⅳ组与Ⅰ组相比,BIS和AEPex值在 诱导后、插管后、气腹前、气腹后均低于Ⅰ组,差异有显著性(P<0.05)。Ⅱ组与Ⅰ组相比差异无显著 性。Ⅰ、Ⅱ、Ⅲ、Ⅳ组使用丙泊酚的剂量分别为8.0、7.8、6.8和6.7mg·kg-1·h-1。Ⅲ、Ⅳ组的丙泊 酚使用量低于Ⅰ组,差异有显著性(P<0.05)。结论　术前静脉使用大于2μg/kg的可乐定可以减 少麻醉药的用量,但以BP、HR稳定性来判断麻醉深度的方法,反而使麻醉的深度过深,BP、HR的波 动也大,应该适当减少麻醉药的用量。     

延长大鼠异种心脏移植后存活时间的实验研究

目的　研究如何延长大鼠异种心脏移植后的存活时间。方法　实验分为A、B、C、D四组。A组 :移植术前 12、8、4、0d及 10、6、2、0d分别将脾细胞 1× 10 8个 ,抗血清 0 .2ml静脉注入受体大鼠 ;B组 :在A组的基础上 ,加用中华眼镜蛇毒 (CCV) 0 .2mg·kg-1·d-1,术前 3d至术日腹腔注射。C组 :在B组的基础上 ,加用环孢素A(CsA) 10mg·kg-1·d-1、环磷酰胺 (Cy) 2 0mg·kg-1·d-1,术前 12d开始至术日腹腔注射。D组 :在C组的基础上 ,加用抗巨噬细胞和抗自然杀伤细胞单克隆抗体 2 5 0 μg·kg-1·d-1,术前 12d开始至术日腹腔注射。结果　A、B、C、D四组移植心脏分别存活 (0 .32± 0 .12 )h ,(2 5 .6± 9.6 )h、(48.6± 10 .4)h和 (72 .4± 2 1.7)h ;术日各组IgG均下降 ,尤以C、D组下降明显 ,与A、B组比较 ,差异有显著性 (P <0 .0 5 )。结论　术前静脉注射供体脾细胞及抗血清 ,尤其与CCV、CsA、Cy合用 ,能显著抑制IgG的产生 ,延长移植心脏的存活时间。     

丙泊酚对低温体外循环期间胃粘膜酸中毒的影响

目的　探讨丙泊酚对心内直视手术病人低温心肺转流 (CPB)期间胃粘膜酸中毒的影响。方法　 2 0例心内直视手术病人随机分为对照组 (A组 ,n =10 )和丙泊酚组 (B组 ,n =10 )。用芬太尼、咪唑安定、潘库溴铵维持麻醉 ,间断吸入异氟醚。B组于CPB开始至停机前持续静脉注入丙泊酚 5～ 8mg·kg-1·h-1。分别于CPB前 (T1)、停机前 (T2 )和停机后 4 0分钟 (T3)测定PaCO2 和胃粘膜PCO2 (PiCO2 ) ,计算PiCO2 与PaCO2 之差 [P(i a) CO2 ]和胃粘膜pH( pHi)。 结果　A、B两组T2 P(i a)CO2 较组内各时点均明显增高 ,pHi明显降低 (P <0 0 1) ;与A组比较 ,B组T2 、T3P(i a) CO2 显著降低 ,pHi显著增高 (P <0 0 5 ) ;与T1比较 :A组T3P(i a) CO2 仍显著增高 ,pHi显著降低 (P <0 0 5 ) ,B组T3P(i a) CO2 和 pHi基本恢复至T1水平。结论　低温CPB期间持续静脉注入一定剂量的丙泊酚可减轻胃粘膜低灌流和酸中毒。     

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 comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.     

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.     

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.