罗库溴铵预注和麻黄碱预处理对小儿罗库溴铵肌松起效的影响

目的 观察小儿在罗库溴铵预注、麻黄碱预处理和罗库溴铵预注复合麻黄碱预处理对罗库溴铵起效时间、插管条件和肌松时效的影响.方法 选择全麻下行择期手术的患儿80例,ASA Ⅰ或Ⅱ级,随机均分为四组.在麻醉诱导前预先静注:Ⅰ组生理盐水O.5 ml,Ⅱ组罗库溴铵0.06 mg/kg,Ⅲ组麻黄碱70 μg/kg,Ⅳ组罗库溴铵0.06 mg/kg和麻黄碱70 μg/kg.预注和预处理4min后,Ⅰ、Ⅲ组静注罗库溴铵0.6 mg/kg,Ⅱ、Ⅳ组静注罗库溴铵0.54 mg/kg.待四个成串刺激(TOF)第1个颤搐反应高度(Th)达最大阻滞程度后行气管插管.记录肌颤搐抑制75%、90%和达最大阻滞程度的时间,并评估气管插管条件,同时观察HR、BP变化.结果 Ⅰ、Ⅱ、Ⅲ、Ⅳ组的最大阻滞起效时间分别为(196±43)、(140±43)、(144±35)和(100±33)s,Ⅱ、Ⅲ、Ⅳ组的起效时间明显短于Ⅰ组(P＜0.05),Ⅳ组的起效时间较Ⅱ、Ⅲ组短(P＜0.05).各组气管插管条件均达到6～9分,优良率100%.各组麻醉诱导期间均无明显的心血管不良反应.各组的临床肌松作用时间和恢复指数差异均无统计学意义.结论 罗库溴铵预注和麻黄碱预处理分别使用均能缩短小儿罗库溴铵的肌松起效时间,而两种方法复合使用可进一步加快肌松起效,但该方法对罗库溴铵的肌松时效无明显的影响.     

不同剂量罗库溴铵对甲状腺手术喉返神经功能监测的影响

目的观察不同剂量罗库溴铵对甲状腺手术喉返神经(RLN)功能监测的影响。方法择期甲状腺手术患者90例,ASAⅠ或Ⅱ级,随机均分为三组,采用静-吸复合全身麻醉。麻醉诱导:丙泊酚1.5~2.0mg/kg、芬太尼4μg/kg和罗库溴铵0.3mg/kg(A组)、罗库溴铵0.6mg/kg(B组)和罗库溴铵0.9mg/kg(C组),吸入2%~3%七氟醚维持麻醉。采用TOF监测肌松。观察并记录给药前60s、给药后60s及插管后60s的BP、HR及体动变化、TOF出现第一个、第二个肌颤搐的时间及RLN振幅。结果与给药前60s比较,给药后60sB组和C组HR明显减慢,三组SBP和DBP明显降低(P0.05),气管插管后60sA组HR明显增快,SBP和DBP明显升高(P0.05)。与给药后60s比较,气管插管后60s三组HR明显增快,SBP和DBP明显升高(P0.05)。与A组比较,气管插管后60sB组和C组HR明显减慢、SBP、DBP明显降低(P0.05),C组术中未监测到RLN例数明显增加、等待时间明显延长(P0.05),B组和C组术中体动例数明显减少、TOF出现第一个肌颤搐时的RLN振幅明显降低(P0.05),三组监测时间、TOF出现第二个肌颤搐时的RLN振幅差异无统计学意义。结论 2倍ED95的罗库溴铵(0.6mg/kg)诱导复合七氟醚麻醉适用于甲状腺手术喉返神经功能的监测。     

罗库溴铵复合麻黄碱预先给药对全麻患者罗库溴铵肌松效应的影响

目的 探讨罗库溴铵复合麻黄碱预先给药对罗库溴铵肌松效应的影响.方法 择期全麻手术患者100例,ASAⅠ或Ⅱ级,年龄23～64岁,体重42～88 kg,身高150～181 cm,随机分为5组(n=20):罗库溴铵组(C组)、罗库溴铵预先给药组(R组)、麻黄碱预先给药组(E组)、罗库溴铵复合麻黄碱预先给药组(RE组)和琥珀酰胆碱组(S组).麻醉诱导前R组、E组和RE组分别静脉注射罗库溴铵0.06 mg/kg、麻黄碱70 μg/kg、罗库溴铵0.06 mg/kg复合麻黄碱70 μg/kg,C组和S组无预先给药.麻醉诱导后4 min时C组和E组静脉注射罗库溴铵0.6 mg/kg,R组和RE组静脉注射罗库溴铵0.54 mg/kg,S组静脉注射琥珀酰胆碱1 mg/kg.采用Cooper法评分标准评定气管插管条件.记录从麻醉诱导时静脉注射罗库溴铵完毕至肌颤搐(Th)降至25%、10%、0的时间(分别为T25、T10、T0)和Th恢复至25%、50%的时间(分别为RT25、RT50)、肌松维持时间(从T0至RT25的时间),麻醉诱导期间每分钟记录1次心率、收缩压、舒张压和平均动脉压.结果 各组气管插管条件差异无统计学意义(P＞0.05);与C组比较,其余4组T25、T10、T0均缩短,S组RT25、RT50缩短(P＜0.05);与RE组和S组比较,R组和E组T0延长(P＜0.05);与S组比较,C组、R组、E组和RE组肌松维持时间延长(P＜0.05).结论 罗库溴铵复合麻黄碱预先给药后罗库溴铵肌松起效时间短于单独预先给药,但对肌松程度和维持时间无明显影响.     

肝硬化病人乌司他丁预处理对罗库溴铵肌松作用的影响

目的观察肝硬化病人乌司他丁预处理对罗库溴铵肌松作用的影响。方法选择30例患有肝硬化的成年手术病人,随机均分为两组:乌司他丁组(Ⅰ组),静注乌司他丁5000U/kg后1min,静脉给予罗库溴铵0.6mg/kg;生理盐水组(Ⅱ组),静脉给予生理盐水0.1ml/kg后1min,静脉给予罗库溴铵0.6mg/kg。另选15例无肝脏疾患的、ASAⅠ～Ⅱ级择期成年手术病人为对照组(Ⅲ组),处理同Ⅱ组。肌松监测仪检测四个成串刺激(TOF)的变化,记录三组注药后罗库溴铵的起效时间(注药到TOFr=0)、TOF无反应时间(T1=0持续时间)、T1最大抑制程度、临床时效(TOFr恢复至25%时间)、T1恢复至75%时间、恢复指数。结果与Ⅱ、Ⅲ组比较,Ⅰ组插管剂量罗库溴铵的起效时间明显延长(P<0.05)。Ⅱ、Ⅲ组罗库溴铵肌松的起效时间相似。与Ⅱ组比较,Ⅰ、Ⅲ组T1恢复25%时间和恢复指数明显缩短(P<0.05)。Ⅰ、Ⅲ组罗库溴铵肌松的恢复时间相似。结论肝硬化病人乌司他丁预处理延长罗库溴铵的起效时间,但缩短罗库溴铵肌松作用时间。     

罗库溴铵对老年病人的药效动力学影响

目的 研究罗库溴铵对老年病人的肌松效应。方法 94例ASA Ⅰ～Ⅱ级的病人按年龄分为4组,Ⅰ组为对照组(28例,32～59岁),Ⅱ组(29例,60～69岁),Ⅲ组(27例,70～89岁)和Ⅳ组(10例,90～97岁)。四组病人均于全麻诱导时静注罗库溴铵0.6mg/kg,并进行四个成串刺激(TOF)肌松监测。术中持续静注罗库溴铵,用注射泵调控给药剂量,T_1维持10％～20％至手术结束。记录罗库溴铵起效时间、T_1为零时间、首次给药后T_110％恢复时间、停药后T_125％恢复时间以及每30min罗库溴铵用量。结果 (1)Ⅰ组病人罗库溴铵起效时间明显比其余三组长(P<0.01),Ⅳ组病人肌松起效时间快于Ⅱ组和Ⅲ组(P<0.01)。(2)Ⅰ组病人T_1为零时间明显比其余3组病人长(P<0.01),Ⅱ、Ⅲ组T_1为零时间相近(P>0.05),Ⅳ组病人则短于Ⅱ组和Ⅲ组(P<0.01)。(3)Ⅰ组和Ⅱ组首次给药后T_110％恢复时间和停药后T_125％恢复时间显著快于Ⅲ组和Ⅳ组(P<0.01)。(4)不同年龄组罗库溴铵用量不同,随年龄增加而减少(P<0.01)。结论 随着年龄的增长,尤其在高龄病人罗库溴铵起效时间,达最大效能时间增快、维持用量减少和肌松持续时间延长。     

罗库溴铵以限时法和预注法行快速气管插管的比较

目的 比较罗库溴铵以限时法和预注法行快速气管插管的条件、肌松效应及对循环系统的影响。方法 限时（Ⅰ、Ⅱ）组诱导前30秒静注0.6mg/kg罗库溴铵,诱导后45秒（I）、60秒（Ⅱ）行气管内插管,预注（Ⅲ）组诱导前2分钟预注0.06mg/kg罗库溴铵（诱导量0.54mg/kg）,诱导后60秒行气管内插管。记录拇内收肌诱发颤搐反应的抑制和恢复过程,评价各组插管效果。结果气管内插管条件各组间无明显差异;气管内插管时T1抑制百分比Ⅲ组明显小于其他各组;各且对循环系统的都很小。结论 罗库溴铵以限时法行快速气管插管较预注法为佳。     

罗库溴铵和维库溴铵在终末期肾衰竭病人临床药效的比较

目的　比较罗库溴铵和维库溴铵在终末期肾衰竭病人中的肌松效应。方法　 2 5例ASAⅢ级行肾移植术病人随机分为罗库溴铵组 (R组 ,15例 )和维库溴铵组 (V组 ,10例 )。麻醉诱导后分别给予 2×ED95剂量的罗库溴铵 (0 6mg/kg)或维库溴铵 (0 1mg/kg)。术中当T1恢复至 2 5 %时 ,追加 0 5×ED95剂量的罗库溴铵 (0 15mg/kg)或维库溴铵 (0 0 2 5mg/kg)。末次剂量后 ,使肌张力自然恢复或给予新斯的明拮抗。结果　初量罗库溴铵的起效时间为 (1 98± 0 4 7)min ,明显短于维库溴铵的 (3 2 5±0 82 )min。初量和追加量的罗库溴铵的肌松维持时间分别为 (4 6 87± 14 6 0 )min和 (34 86± 15 5 7)min,与维库溴铵相似。两组应用拮抗药后 ,恢复指数均显著缩短。结论　对于终末期肾衰竭病人 ,罗库溴铵的起效快于维库溴铵 ,肌松作用维持时间和恢复指数与维库溴铵相似。     

闭环靶控输注罗库溴铵在患儿麻醉中的应用

目的比较闭环靶控与传统持续两种不同药物输注方法,输注罗库溴铵在患儿麻醉中的效果。方法择期行下腹部手术的患儿86例,男53例,女33例,年龄1～3岁,BMI 14～21 kg/m~2,ASAⅠ或Ⅱ级。用随机数字表法分为闭环组(C组)和持续组(S组),每组43例。诱导时两组均给予罗库溴铵0.6 mg/kg,当四个成串刺激中第一次肌颤搐(T1)到达最大阻滞时气管插管。麻醉维持C组使用T1闭环肌松模式,设置T1=20%为增药条件,增药速度30μg·kg~(-1)·min~(-1),维持速度1.60μg·kg~(-1)·min~(-1),自动调整罗库溴铵用量。S组恒速泵注罗库溴铵5μg·kg~(-1)·min~(-1),肌松不满意时单次追加罗库溴铵0.2 mg/kg。记录术中丙泊酚总用量、瑞芬太尼总用量和罗库溴铵总用量,罗库溴铵追加次数。记录两组肌松恢复指数(RI)、罗库溴铵停药至术毕时间、手术时间、麻醉时间、拔管时间和PACU停留时间。记录术后呼吸抑制、低氧血症等麻醉并发症发生情况。结果 C组RI明显低于S组(P0.05)、罗库溴铵追加次数明显低于S组(P0.05),拔管时间明显短于S组(P0.05)。两组丙泊酚总用量、瑞芬太尼总用量、罗库溴铵总用量、罗库溴铵停药至术毕时间、手术时间、麻醉时间和PACU停留时间差异无统计学意义。两组均未见术后呼吸抑制,低氧血症等麻醉相关并发症。结论与持续输注法比较,闭环靶控输注罗库溴铵用于1～3岁患儿下腹部手术的恢复指数明显降低,肌松恢复更快速,术中患儿肌松效果更加确切,稳定。     

肥胖对女性患者罗库溴铵剂量-效应曲线的影响

目的观察肥胖对女性患者罗库溴铵剂量-效应曲线的影响,并计算肥胖女性患者罗库溴铵的95%有效剂量(ED95)。方法选择择期行全身麻醉女性患者80例,年龄18~45岁,ASAⅠ或Ⅱ级,手术时间1.5h。根据BMI 20~25kg/m2和30~35kg/m2分为N组与B组,每组40例。两组患者根据随机数字表法各分为0.075、0.1、0.15、0.3 mg/kg四个剂量组,分别为N1~N4组和B1~B4组。麻醉诱导同时开启注射泵,待患者意识消失后,校对肌松监护仪,启动TOF模式,N1~N4组和B1~B4组分别给予罗库溴铵单次剂量0.075、0.1、0.15、0.3mg/kg。记录各组患者给予罗库溴铵的首次剂量、第一个肌颤搐反应(T1)的最大抑制程度和肌松药起效时间。采用直线回归法建立罗库溴铵量效关系回归方程,计算N组和B组患者的ED50和ED95及其95%CI。结果 N组和B组的量效关系回归方程分别为Y1=3.464X1-2.230和Y2=3.843X2-2.750。B组ED50、ED75、ED90、和ED95分别为0.103、0.145、0.201和0.251 mg/kg明显小于N组0.122、0.176、0.254和0.324mg/kg(P0.05)。N组与B组T1最大抑制程度均随药量的增加而增大(P0.05)。结论肥胖影响年轻女性患者罗库溴铵的量效曲线,使其对罗库溴铵的敏感性增强,肥胖女性罗库溴铵ED95为0.251mg/kg。     

癫痫患者罗库溴铵95％有效量的测定

目的 通过测定癫痫患者罗库溴铵95％有效量(95％ effective dose,ED95),为癫痫患者合理应用罗库溴铵提供依据. 方法 选取择期行癫痫病灶切除术患者40例,ASA分级Ⅰ、Ⅱ级.根据罗库溴铵不同剂量按随机数字表法分为4组(每组10例):120 μg/kg组、180 μg/kg组、240 μg/kg组和300 μg/kg组.采用单次剂量注射法测定患者ED95,记录拇指内收肌“四个成串刺激(train of four stimulation,TOF)”第1个肌颤搐反应(T1)最大抑制的百分比及药物的起效时间,将最大抑制百分比进行概率单位转换,罗库溴铵的首次剂量做对数转换,用直线回归方法建立维库溴铵的剂量-反应曲线,计算出癫痫患者的罗库溴铵ED95值. 结果 各组间一般情况比较,差异无统计学意义(P＞0.05);不同剂量组起效时间比较,差异无统计学意义(P＞0.05),T1最大抑制程度随剂量增加而增加(P＜0.05),但240 μg/kg组和300 μg/kg组间差异无统计学意义(P＞0.05);癫痫患者罗库溴铵ED95值为445.3 μg/kg,高于目前正常人群广泛应用的ED95值300 μg/kg(P＜0.05). 结论 癫痫患者罗库溴铵的ED95值高于正常人群,在该类患者中应增加罗库溴铵的剂量约50％以取得与正常人群相同的肌松水平.     

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.     

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.     

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.     

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.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.