不同剂量右美托咪啶对异丙酚抑制老年患者Supreme喉罩置入反应EC50的影响

目的 评价不同剂量右美托咪啶对异丙酚抑制老年患者Supreme喉罩置入反应半数有效血浆靶浓度(EC50)的影响.方法 择期全麻膝关节手术患者,性别不限,年龄≥65岁,体重指数20～28 kg/m2,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将患者随机分为3组:小剂量右美托咪啶组(D1组)和大剂量右美托咪啶组(D2组)分别静脉输注右美托咪啶0.4和0.8 μg/kg,输注时间10 min,对照组(C组)给予等容量生理盐水,靶控输注异丙酚,C组、D1组和D2组第1例患者血浆靶浓度分别为3.5、3.0和2.6 μg/ml,待血浆靶浓度和效应室靶浓度达到平衡,BIS值50 ～ 60时,开始置入喉罩.根据是否发生喉罩置入反应确定下1例患者的异丙酚靶浓度,相邻靶浓度的比值为1.1,置入喉罩时出现体动、口角动、牙咬喉罩、呛咳、吞咽等为阳性反应.计算异丙酚抑制喉罩置入反应的EC50及其95％可信区间 (95％CI).结果 C组、D1组和D2组异丙酚抑制喉罩置入反应的EC50及其95％CI分别为3.57(2.91 ～ 3.87)、3.09 (2.66～3.53)和2.62(2.30～3.15)μg/ml.D1组和D2组EC50低于C组,D2组EC50低于D1组(P＜0.05).结论 静脉输注右美托咪啶0.4和0.8μg/kg均可降低异丙酚抑制老年患者Supreme喉罩置入反应的EC50,0.8 μg/kg效应更明显.     

不同剂量右美托咪定对复合芬太尼时异丙酚抑制妇科手术患者喉罩置入反应效应的影响

目的 评价不同剂量右美托咪定对复合芬太尼时异丙酚抑制妇科手术患者喉罩置入反应效应的影响.方法 择期拟行妇科短小手术(乳腺区段切除术、宫腔镜手术)患者125例,年龄20～60岁,ASA分级Ⅰ或Ⅱ级,Mallampati分级Ⅰ或Ⅱ级.采用随机数字表法,将其分为5组(n=25):生理盐水组(NS组)、不同剂量右美托咪定组(D1-4组)分别静脉输注生理盐水40 ml、右美托咪定0.4、0.6、0.8、1.0 μg/kg(40ml),输注时间10 min,随后靶控输注1％异丙酚,采用序贯法进行试验,异丙酚初始血浆浓度设定为3.0 μg/ml,当效应室浓度达预设血浆浓度时静脉注射芬太尼1.5 μg/kg,4 min后置入喉罩,喉罩置入失败,则下一例患者采用高一级浓度,喉罩置入成功,则下一例患者采用低一级浓度,相邻浓度比值为1.1,喉罩置入失败的标准为:喉罩难置入或置入喉罩时出现体动、口角动、牙咬喉罩、吞咽和/或流泪等.计算各组复合芬太尼时异丙酚抑制喉罩置入反应的半数有效效应室浓度(ECe50)及其95％可信区间(95％CI).结果 NS组和D14组异丙酚抑制妇科手术患者喉罩置入反应的ECe50其95％CI分别为3.09(2.83 ～ 3.36)、2.48(2.26 ～ 2.73)、2.29(2.18～ 2.41)、2.04(1.95 ～ 2.12)和1.67 (1.55 ～ 1.81) μg/ml,组间比较差异有统计学意义(P＜0.05).结论 右美托咪定可呈剂量依赖性地增强复合芬太尼时异丙酚抑制妇科手术患者喉罩置入反应的效应.     

右美托咪啶对瑞芬太尼抑制切皮时患者体动反应半数有效效应室靶浓度的影响

目的 评价右美托咪啶对瑞芬太尼抑制切皮时患者体动反应半数有效效应室靶浓度(EC50)的影响.方法 择期拟行乳房肿瘤切除术患者40例,年龄20～50岁,体重45～58 kg,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将其随机分为瑞芬太尼组(R组)和右美托咪啶复合瑞芬太尼组(RD组),每组20例.R组和RD组切皮前分别静脉输注生理盐水和右美托咪啶1.0μg/kg,输注时间10min,同时靶控输注异丙酚,血浆靶浓度设为3.0 mg/L,13 min后开始靶控输注瑞芬太尼.采用序贯法进行试验,RD组和R组初始效应室靶浓度分别为2.5和3.0μg/L,待两药浓度均达靶浓度后切开皮肤3 cm,有体动反应,则下一例采用高一级浓度,无体动反应,则下一例患者采用低一级浓度,相邻浓度比值为1.2,发生体动反应的标准为患者出现躯干、四肢或头颈可见的运动.计算瑞芬太尼抑制患者体动反应的EC50及其95％可信区间.结果 RD组瑞芬太尼抑制切皮时体动反应的EC50为1.7 μg/L,95％可信区间为1.5～1.9 μg/L,R组瑞芬太尼抑制切皮时体动反应的EC50为2.5 μg/L,95％可信区间为2.2～2.7 μg/L,差异有统计学意义(P＜0.01).结论 靶控输注异丙酚(血浆靶浓度3.0 mg/L)下,静脉输注右美托咪啶1.0μg/kg可降低瑞芬太尼抑制切皮时患者体动反应的EC50.     

丙泊酚和右美托咪定全麻诱导对瑞芬太尼抑制喉罩插入反应效应室浓度的影响

目的探讨右美托咪定对抑制喉罩插入反应所需瑞芬太尼剂量的影响。方法拟行乳房肿瘤切除术患者60例,随机分为三组:麻醉诱导前分别输注生理盐水(D1组)和右美托咪定0.25μg/kg(D2组)和0.5μg/kg(D3组)。泵注结束后用效应室靶控输注丙泊酚,靶浓度设定为3.5μg/ml。采用改良Dixon’s序贯法进行研究,靶控丙泊酚3min后效应室靶控输注瑞芬太尼,D1、D2和D3组设定初始靶浓度分别为1.9、1.1和0.8ng/ml,3min后插入SLIPA喉罩。如插入喉罩出现体动等阳性反应,下1例患者上调1个浓度梯度,如未出现则下1例患者下调1个浓度梯度,相邻瑞芬太尼浓度差值为0.2ng/ml,直至出现6个阳性和阴性反应交替现象。阳性和阴性反应交替的中点对应的瑞芬太尼浓度的均值为瑞芬太尼抑制喉罩插入反应的半数有效效应室浓度(Ce50)。结果 D1、D2和D3组瑞芬太尼抑制插入喉罩反应的Ce50(95%CI)分别为1.90ng/ml(1.65～2.15ng/ml)、1.05ng/ml(0.91～1.20ng/ml)和0.55ng/ml(0.32～0.79ng/ml)。D2和D3组Ce50均明显低于D1组,且D3组Ce50明显低于D2组(P0.05)。结论丙泊酚全麻时应用右美托咪定能剂量依赖性地减少插入喉罩所需的瑞芬太尼用量。     

靶控输注右美托咪定对丙泊酚致意识消失效应室半数有效浓度的影响

目的观察静脉靶控输注(target-controlled infusion,TCI)右美托咪定对丙泊酚致患者意识消失效应室半数有效浓度(Ce_(50))的影响。方法选择择期行喉罩全麻下手术患者64例,男28例,女36例,年龄20~60岁,ASAⅠ或Ⅱ级,随机分为四组:空白组(P组)、低浓度右美托咪定组(D1组)、中浓度右美托咪定组(D2组)和高浓度右美托咪定组(D3组),每组16例。麻醉诱导时分别以0、0.4、0.6和0.8ng/ml的血浆靶浓度靶控输注右美托咪定15min,然后以初始效应室靶浓度(Ce)1.0μg/ml靶控输注丙泊酚。每次待丙泊酚的效应室浓度与靶浓度平衡时以0.2μg/ml逐步升高丙泊酚的靶浓度,直至患者意识消失。观察和计算患者意识消失时丙泊酚的Ce50及其95%CI,观察麻醉诱导过程中不良反应情况。结果 P、D1、D2和D3组丙泊酚致意识消失Ce50及其95%CI分别为2.30(2.24~2.36)、1.92(1.87~1.96)、1.60(1.55~1.65)和1.41(1.35~1.45)μg/ml。丙泊酚致意识消失的效应室浓度与右美托咪定的血浆靶浓度呈负相关关系(r=-0.84,P0.01)。与P、D1和D2组比较,D3组心动过缓的发生率明显增加(P0.05)。结论随着右美托咪定血浆靶浓度的升高,丙泊酚致意识消失Ce_(50)逐渐降低。靶控输注右美托咪定0.4或0.6ng/ml能明显降低丙泊酚致意识消失Ce50,心动过缓发生率较低,适合辅助丙泊酚进行麻醉诱导。     

性别因素对复合右美托咪定时舒芬太尼抑制患者气管插管反应的影响

目的评价性别因素对复合右美托咪定时舒芬太尼抑制患者气管插管反应的影响。方法气管插管全麻下择期手术患者,ASA分级Ⅰ或Ⅱ级,年龄18～64岁,BMI<30 kg/m2,根据性别分为男性组(M组)和女性组(F组)。静脉输注右美托咪定0.4 μg/kg 5 min。10 min后TCI丙泊酚3 μg/ml和舒芬太尼。2组初始舒芬太尼靶浓度为0.35 ng/ml,根据是否发生气管插管反应确定下一例舒芬太尼靶浓度,相邻靶浓度比值为1.2。采用序贯法计算舒芬太尼抑制气管插管反应的半数有效浓度(EC50)及95%可信区间。结果 M组26例,F组28例。M组EC50(95%可信区间)为0.264 0(0.240 9～0.289 3)ng/ml;F组EC50(95%可信区间)为0.158 9(0.138 2～0.182 6)ng/ml。F组EC50低于M组(P<0.05)。结论复合右美托咪定时,舒芬太尼抑制气管插管反应的效应存在性别差异。     

不同剂量右美托咪定对靶控输注异丙酚病人意识消失半数有效血浆靶浓度的影响

目的 评价不同剂量右美托咪定对靶控输注异丙酚病人意识消失半数有效血浆靶浓度(EC5o)的影响.方法 择期全麻病人80例,ASA分级Ⅰ或Ⅱ级,年龄18～64岁,体重指数≤25 kg/m2,采用随机数字表法,将病人随机分为4组(n=20):对照组(C组)和不同剂量右美托咪定组(D1～3组).D1～3组分别静脉输注右美托咪定0.4、0.5和0.6 μg/kg,输注时间10 min,C组输注等容量生理盐水.随后靶控输注异丙酚,采用序贯法进行试验,异丙酚初始血浆靶浓度2.0 μg/ml,相邻浓度比值为1.1.意识消失的标准为睫毛反射消失、两次呼之不应.计算异丙酚使病人意识消失的EC50及其95％可信区间(95％CI).观察心动过缓、低血压和呼吸抑制等不良反应的发生情况.结果 C组和D1～3组异丙酚使病人意识消失的EC50及其95％ CI分别为2.59(2.51 ～ 2.67)、2.09(2.02 ～ 2.16)、1.82(1.70 ～1.95)和1.60 (1.49～ 1.72) μg/ml.C组、D1～3组异丙酚使病人意识消失的EC50依次降低(P＜0.05).与C组比较,D1～3组心动过缓和低血压发生率降低(P＜0.05);与D1组比较,D2,3组心动过缓发生率和D3组低血压发生率升高(P＜0.05);D2组和D3组心动过缓和低血压发生率比较差异无统计学意义(P＞0.05).各组无一例病人发生呼吸抑制.结论 靶控输注异丙酚时复合静脉输注右美托咪定0.4 μg/kg为适宜剂量,既可降低靶控输注异丙酚病人意识消失的EC50,又不发生不良反应.     

小剂量芬太尼对异丙酚抑制患者食管引流型喉罩插管反应半数有效血浆靶浓度的影响

目的 评价小剂量芬太尼对异丙酚抑制患者食管引流型喉罩插管反应半数有效血浆靶浓度(EC50)的影响,以探讨小剂量芬太尼的有效性.方法 择期行妇科腹腔镜手术患者46例,ASAⅠ或Ⅱ级,年龄20～50岁,体重指数≤30 kg/m2,随机分为异丙酚组(P组)和异丙酚-芬太尼组(PF组),每组23例.靶控输注异丙酚行麻醉诱导,PF组和P组初始血浆靶浓度分别为2.5、4.0 μg/ml,当血浆靶浓度与效应室靶浓度达平衡时,静脉注射芬太尼1 μg/kg或等容量生理盐水,注毕3.5 min时置入食管引流型喉罩.采用序贯法进行试验,若上1例有反应,则下1例采用高一级异丙酚血浆靶浓度;若上1例无反应,则下1例采用低一级浓度,P组和PF组异丙酚各相邻血浆靶浓度比值分别为1.2和1.1.发生食管引流型喉罩插管反应的标准:置入食管引流型喉罩时患者出现作呕、呛咳和/或肢体反应.采用概率单位法计算异丙酚抑制食管引流型喉罩插管反应的EC50及其95%可信区间.结果 P组异丙酚抑制喉罩插管反应的EC50及其95%可信区间为4.68(4.20～5.21)μg/ml,PF组异丙酚抑制喉罩插管反应的EC50及其95%可信区间为2.63(2.45～2.83)μg/ml,差异有统计学意义(P<0.05).结论 静脉注射芬太尼1μg/kg可增强异丙酚抑制患者食管引流型喉罩插管反应的效应.     

瑞芬太尼不同静脉输注速率对异丙酚抑制小儿喉罩置入反应半数有效血浆靶浓度的影响

目的 比较瑞芬太尼不同静脉输注速率对异丙酚抑制小儿喉罩置入反应半数有效血浆靶浓度(EC50)的影响,探讨瑞芬太尼用于纤维支气管镜检术麻醉时适宜的静脉输注速率.方法 择期行纤维支气管镜检术小儿84例,年龄7月～3岁,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将小儿分为3组(n=28):生理盐水对照组(C组)和静脉输注瑞芬太尼3或5 ng·kg-1·min-1组(R1组或R2组).喉罩置入反应定义为喉罩置入可诱发肢体和或呛咳反应.采用序贯法确定异丙酚血浆靶浓度:C组、R1组或R2组异丙酚初始靶浓度分别为5.2、4.8或4.4 μg/ml,相邻浓度差值为0.2 μg/ml,喉罩置入反应阴性则下一例采用低一级浓度,反应阳性则下一例采用高一级浓度.用概率单位法确定异丙酚EC50及其95％可信区间(CI).结果 C组异丙酚EC50(95％ CI)为5.03(4.92～ 5.12) μg/ml,R1组为4.71(4.58 ～ 4.84) μg/ml,R2组为4.46(4.20 ～ 4.94) μg/ml.与C组相比,R1组异丙酚EC50差异无统计学意义(P＞0.05),而R2组EC50降低,且也低于R1组(P＜0.05).结论 瑞芬太尼复合异丙酚麻醉用于小儿纤维支气管镜检术时,其静脉输注速率应不低于5 ng·kg-1·min-1.     

麻醉诱导时靶控输注丙泊酚抑制插入喉罩反应的半数有效浓度

目的全身麻醉诱导时靶控输注(TCI)丙泊酚抑制插入喉罩反应的血浆半数有效浓度(EC50)。方法择期手术需插入喉罩患者25例,麻醉诱导时丙泊酚的初始靶浓度为4.0μg/ml,依次降低丙泊酚靶浓度,各相邻比率为1∶1。以出现插喉罩阳性反应的上一级为入选本研究的第1例,共20例患者纳入本研究统计分析。按Dixon′s序贯法调节丙泊酚的血浆靶控浓度:如果出现插喉罩阳性反应,则使用上一级浓度;如果阴性反应,则使用下一级浓度。结果插入喉罩时TCI丙泊酚的EC50为2.43μg/ml,95%可信区间为2.05～2.89μg/ml。结论设定合适的浓度,靶控输注丙泊酚插入喉罩的麻醉方法是安全有效的,可减少麻醉诱导引起的不良反应,降低麻醉的风险。     

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.