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。     

雷米芬太尼复合丙泊酚静脉麻醉的临床应用

目的观察雷米芬太尼复合丙泊酚静脉麻醉的效果。方法全身麻醉下腰椎手术患者60例,随机均分为雷米芬太尼复合丙泊酚静脉麻醉组(Ⅰ组)和静吸复合麻醉组(Ⅱ组)。雷米芬太尼和丙泊酚的负荷量分别为1μg/kg和1mg/kg,雷米芬太尼以0.5μg·kg-1·min-1速率输注。麻醉中通过增减雷米芬太尼0.1μg·kg-1·min-1输注速率调整麻醉深度。丙泊酚按5∶4∶3方案输注,即5mg·kg-1·h-1输注10min,4mg·kg-1·h-1输注10min,20min后3mg·kg-1·h-1恒速输注。观察两组气管插管反应、麻醉效果、苏醒质量。结果两组麻醉效果相同,均可抑制气管插管反应(P<0.01),且Ⅰ组较Ⅱ组明显(P<0.05)。Ⅰ组苏醒质量较Ⅱ组好(P<0.01),不良反应较Ⅱ组高(P<0.01),术中无知晓。结论雷米芬太尼复合丙泊酚用两个注射泵静脉麻醉,采用负荷量加两种以上速率输注全凭静脉麻醉简便易行。     

异丙酚、氯胺酮对哮喘大鼠气道痉挛及气道渗出的作用

目的 观察异丙酚、氯胺酮对抗原诱发哮喘大鼠气道痉挛及气道渗出的影响。方法哮喘大鼠30只随机分为5组:I组,静注生理盐水;Ⅱ组,静注异丙酚50 mg·kg·-1·h-1;Ⅲ组,静注异丙酚100 mg·kg-1·h-1;Ⅳ组,静注氯胺酮50 mg·kg-1·h-1;V组,静注氯胺酮100 mg·kg-1·h-1。30 min后静注伊文氏蓝;5 min后静注卵蛋白激发哮喘发作,并维持30 min。观察气道压、肺系数、肺湿干重比、肺含水量、肺组织伊文氏蓝含量变化。结果异丙酚和氯胺酮能显著缓解卵蛋白激发引起的气道痉挛反应(P<0.05),相同剂量异丙酚和氯胺酮对气道压的影响无显著性差异。异丙酚和氯胺酮均可明显降低大鼠肺系数、肺湿干重比和肺含水量(P<0.05)。静注异丙酚或氯胺酮后,肺组织伊文氏蓝渗出明显减少,与I组比较差异有显著性(P<0.05)。结论 异丙酚和氯胺酮均能缓解抗原诱发哮喘大鼠的气道痉挛,且能明显抑制哮喘大鼠的气道渗出。     

小儿纠正斜视手术前口服可乐定可减少术后呕吐

可乐定(氯压定,clonidine)是α_2-受体激动药,常给小儿作术前用药。作者为了观察小儿纠正斜视手术术前口服可乐定对术后呕吐的影响,特选择140例(ASAⅠ级)3～12岁患儿,按随机双盲法分成用安慰剂的对照Ⅰ组、安定(0.4mg·kg~(-1))Ⅱ组、可乐定(2μg·kg~(-1))Ⅲ组和可乐定(4μg·kg~(-1))Ⅳ组,每组35例。麻醉前平均100min(93～112min)按分组给药并口服阿托品0.03mg·kg~(-1)。患儿于午夜后禁食,术前三小时可饮全流10ml·kg~(-1)。均吸氟烷-氧化亚氮-氧,静注维库溴铵0.1mg·kg~(-1)后插气管导管,吸氟烧-N_2O-O_2维持麻醉,必要时间歇注维库溴铵0.02mg·kg~(-1)。拔气管导管前用新斯的明(0.05mg·kg~(-1))和阿托品(0.02mg·     

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     

脑电双频指数-靶控输注注射泵闭环丙泊酚靶控输注应用于妇科腹腔镜手术的安全效益研究

目的 观察BIS-靶控输注(target controlled infusion,TCI)注射泵闭环丙泊酚TCI对妇科腔镜手术患者丙泊酚的节约效应及血流动力学的影响. 方法 纳入ASA分级Ⅰ、Ⅱ级择期行妇科腔镜手术的患者40例,采用计算机随机数字表分组分为闭环组和开环组,每组20例.闭环组采用BIS监测闭环丙泊酚TCI维持全身麻醉,开环组采用BIS监测下人工调整丙泊酚TCI血浆效应浓度2～5 mg/L维持全身麻醉,BIS目标值50±5;瑞芬太尼血浆效应浓度4μg/L TCI.记录两组在入室后5 min(T0)、诱导后气管插管前(T1)、插管后1 min(T2)、插管后5 min(T3)、手术切皮时(T4)、切皮后30 min(T5)、缝皮(T6)、手术结束(T7)、意识恢复(T8)、拔管即刻(T9)及拔管后5 min(T10)等时点MAP、HR、BIS值的变化,同时记录两组患者诱导及维持丙泊酚用药量、苏醒时间及进入PACU时的疼痛数字评分(numerical rating scale,NRS)及Ramsay镇静评分. 结果 术中维持丙泊酚剂量闭环组[(6.2±1.4) mg· kg-1·h-1]较开环组[(6.9±1.0)mg·kg-1·h-1]降低了10％,两组各时点MAP、HR、BIS差异无统计学意义(P＞0.05),闭环组切皮时MAP、HR、BIS波动明显小于开环组(P＜0.05).两组患者苏醒时间、NRS及Ramsay镇静评分差异无统计学意义(P＞0.05). 结论 BIS-TCI注射泵闭环丙泊酚TCI与常规BIS监测下开环丙泊酚TCI可同样安全地应用于临床,可对患者个体化合理给予全身麻醉药物,并可部分降低术中丙泊酚使用剂量,降低麻醉后手术前的循环波动.同时,避免麻醉医师手动调控TCI靶控血浆浓度,极大地降低了麻醉医师的工作量,并使围麻醉期更加平稳安全.     

胸段硬膜外腔注射可乐定对上腹部手术术后膈肌功能的影响

目的　观察胸段硬膜外腔注射可乐定对上腹部手术 (UAS)术后膈肌功能的作用。方法　在连续硬膜外神经阻滞麻醉下行剖腹胆囊切除术病人 2 0例 ,均分为可乐定 (A)组与生理盐水(B)组。术后 2小时A组经硬膜外导管注入可乐定 4μg/kg ,B组注入生理盐水。记录注药前、注药后30分钟、2小时有无反常呼吸运动以及RR、VT。结果　A组注射可乐定 30分钟后膈肌功能改善 :反常呼吸运动消失 ,RR减慢 (由 2 0 0± 1 8降到 15 2± 1 7,P <0 0 0 1)、VT 增加 (由 2 19 8± 2 6 8ml/m2 增到 2 91 0± 2 5 5ml/m2 ,P <0 0 0 1) ,连续观察 2小时 ,膈肌功能仍优于注药前。B组注射生理盐水后上述指标无明显变化。结论　胸段硬膜外腔注射可乐定可改善UAS术后膈肌功能     

持续肺量计测定监测气腹对通气的影响

腹腔内注CO_2形成气腹才能进行腹腔镜检查。作者持续使用肺量计监测腹内压增加对通气功能的影响。作者选择择期妇科腹腔镜检查病人7例(ASAⅠ级)34.9±5岁,体重65.7±12kg。操作时间平均52±23min(25～92min)。麻醉前45min肌注咪唑安定0.1mg·kg~(-1)。静注芬太尼5μg·kg~(-1)和双异丙酚1mg·kg~(-1)阿屈可林0.4mg·kg~(-1)气管内插管,再分次静注每次0.1mg·kg~(-1)保持肌松,持续点滴双异丙酚维持麻醉,以半紧闭法机械通气,分钟通气量为100ml·kg~(-1),呼吸频率10次·min~(-1),吸入40％O_2-N_2混合气。记录麻醉诱导后5min病人仰卧位(基础值);腹内注入CO_2后1min,病人仰卧头低15°;腹内压达1.6kPa;持续注CO_2维持腹     

氯胺酮对小儿术后镇痛中吗啡作用的影响

目的　研究氯胺酮在小儿术后硬膜外自控镇痛中对吗啡作用的影响。方法　全麻下择期腹部手术病儿 37例 ,病人随机分为三组。负荷量 :Ⅰ组 (n =13)吗啡 10 μg/kg +氯胺酮 0 1mg/kg ;Ⅱ组 (n =10 )吗啡 10 μg/kg ;Ⅲ组 (n =14)吗啡 2 0 μg/kg。维持量 :Ⅰ组吗啡 1μg·kg-1·h-1+氯胺酮 0 0 3mg·kg-1·h-1;Ⅱ组吗啡 1μg·kg-1·h-1;Ⅲ组吗啡 2 μg·kg-1·h-1。单次给药剂量 :同各组每小时持续量 ;锁定时间 10min。按预定 6个时点记录疼痛、镇静评分、维持期吗啡耗量及不良反应发生率。结果　疼痛评分 :Ⅰ、Ⅲ组均为 0 0 0± 0 0 0 ,明显优于Ⅱ组 0 12± 0 17(P <0 0 1)。吗啡维持量 :Ⅰ、Ⅱ、Ⅲ组分别为 :5 1 0± 3 3μg/kg、6 3 4± 18 0 μg/kg、117 6± 2 0 1μg/kg(P <0 0 1)。镇静评分及不良反应发生率均无显著性差异。结论　小儿术后硬膜外自控镇痛中 ,微量氯胺酮明显增强吗啡的镇痛作用 ,减少吗啡用量     

瑞芬太尼用于无痛人工流产手术麻醉的临床观察

目的　观察瑞芬太尼用于无痛人工流产手术的可行性和安全性 ,并与丙泊酚无痛人工流产术比较。方法　选择门诊ASAⅠ级早期妊娠需人工流产者 6 0例 ,随机分成三组 ,瑞芬太尼组 (A组 ) ,瑞芬太尼 +丙泊酚组 (B组 )和丙泊酚组 (C组 ) ,每组 2 0例。A组 :瑞芬太尼 1 5 μg/kg持续静注6 0s,随后以 0 15 μg·kg 1·min 1持续输注至负压吸引结束停药 ;B组 :瑞芬太尼 1 0 μg·kg 1持续静注6 0s,随后以 0 1μg·kg 1·min 1持续输注 ,瑞芬太尼诱导结束后静注丙泊酚 1 0mg/kg ;C组 :单纯静注丙泊酚 2 5mg/kg持续静注 6 0s,必要时追加丙泊酚 0 5～ 1 0mg/kg。结果　术后三组患者对镇痛效果均表示高度满意 ,A、B和C组VAS分别为 (95 6± 11 8)mm、(99 1± 5 5 )mm和 (98 2±12 7)mm ,其中C组 8例术中出现肢体扭动等体动反应。A组和B组患者术中、术后血压和心率与给药前比较无显著变化 (P >0 0 5 ) ;C组术中血压心率较给药前显著下降 (P <0 0 5 ) ,但术后恢复至给药前水平 (P >0 0 5 )。术中三组患者在供氧状态下SpO2 均为 10 0 %。但三组患者呼吸均明显抑制 ,其中B组所有患者给丙泊酚后均出现呼吸暂停 ,C组 8例患者出现呼吸暂停。手术结束时A组和B组患者VT和RR已恢复至术前水平 (P >0 0 5 ) ,C组手术的中     

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.