性别对腹部手术病人罗库溴铵肌松作用的影响

目的研究性别对腹部手术病人罗库溴铵肌松作用的影响。方法拟在全麻下行腹部手术病人24例,年龄20-59岁,ASA Ⅰ或Ⅱ级,分为男性组(M组)与女性组(F组),每组12例。静脉注射异丙酚、芬太尼、罗库溴铵0．6 mg·kg-1行麻醉诱导。以4个成串刺激(TOF)监测神经肌肉阻滞深度,T1达最低时行气管插管。异丙酚靶控输注(效应室浓度3-4μg·ml-1)及静脉注射芬太尼维持麻醉。T1恢复至10％开始输注罗库溴铵,初始速率0．7 mg·kg-1·h-1,维持T1在5％-10％,术毕停用罗库溴铵,新斯的明0．05 mg·kg-1拮抗肌松效应,记录罗库溴铵的肌松作用指标。结果与F组比较,M 组身高与体重较高,T1最大抑制程度、罗库溴铵平均用药速率、新斯的明拮抗后T1自10％恢复到50％的时间、T1自25％恢复到75％的时间差异无统计学意义,起效时间延长,最大效应持续时间、T1恢复到10％的时间缩短;M组第1个10 min罗库溴铵用药平均速率大于其它时间段,且大于F组(P< 0．05)。结论单次静脉注射罗库溴铵的肌松作用存在性别差异,女性较男性病人敏感。     

全凭静脉麻醉中雷米芬太尼减少肌松药用量的机制探讨

目的：雷米芬太尼作为一种新型的麻醉性镇痛药在临床已经广泛应用于静脉全麻．目前发现在静脉全麻中雷米芬太尼可以明显减少肌肉松弛药的用量．这是否是雷米芬太尼与肌松药的协同作用还不清楚．本研究应用Organon-TOF—WATCH SX肌松监测仪观察垒凭静脉麻醉下腹腔镜手术中靶控输注不同剂量的雷米芬太尼对肌松药罗库溴铵的起效．作用和恢复时间的影响,以此来判断雷米芬太尼与肌松药之间是否有协同作用。方法：选择ASAI—II级．年龄25-55岁,妇科及普外科腹腔镜择期手术病人75例随机分为兰组,全麻诱导：咪唑安定0．04mg·kg^-1,丙泊酚TCI血药浓度3ug·ml^-1．罗库溴铵0．6mg·kg^-1．麻醉维持：A组单纯用TCl丙泊酚．B组用TCl丙泊酚加上TCI雷米芬太尼效应室浓度2ng．mr．．C组用TCI丙泊酚加上雷米芬太尼效应室浓度5ng．mI～,三组异丙酚TCI效应室浓度维持在3ug·ml^-1。左右,根据病人的反应调整．将麻醉深度控制在满足手术需要和术中BIS在40-60之间．用Organon—TOF—WATCH SX肌松监测仪记录罗库溴铵（0．6mg·kg^-1）的起效时间（从给药至TOF比值下降到25％的时间）、维持时间（从TOF值低于25％至恢复到25％）、恢复时间（从TOF比值恢复到25％至TOF比值恢复到75％）用美国Aspect公司的BIS-XP监测仪控制麻醉深度。结果：罗库溴铵的起效时间三组分别为0．96±0．35min．1．12±0．51min。1．11±0．34min,三组之间无统计学差异（P〉0．05）;罗库溴铵的作用时间三组分别为39．94±10．17min．42．45±11．07min。42．46±11．25min,备组间没有统计学差异（P〉0．05）．罗库溴铵的·I灰复时间三组分别为11．68±4．99min．13．44±5．93min．12．20±2．61min．各组间没有统计学差异（P〉0．05）。结论：不同TCI效应室浓度的雷米芬太尼没有明显延长单次注射罗库溴铵（0．6mg·kg^-1）的起效．作用和恢复时间．提示雷米芬太尼减少静脉全麻中肌松药用量的作用机制是中枢性的。     

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。     

术中磁共振成像对持续泵注罗库溴铵肌松效应的影响

目的 观察神经外科手术术中磁共振成像(iMRI)对罗库溴铵肌松效应的影响.方法 采用前瞻、随机、对照研究.择期行开颅手术的患者30例,ASA Ⅰ或Ⅱ级,随机均分为两组:iMRI组(M组)和非iMRI组(C组).采用加速度仪四个成串刺激(TOF)监测肌松.两组采用相同的保温措施.麻醉诱导后给予罗库溴铵0.6 mg/kg,T1为0时静脉泵注罗库溴铵0.3～0.7Mg·kg-1·h-1,维持T1在0～5%.关闭硬脑膜时停止泵注罗库溴铵.记录T1恢复25%、TOF恢复25%、75%、90%的时间,停止泵注罗库溴铵至手术结束时间,罗库溴铵用量等.结果 术中M组患者腋温逐渐升高,而C组逐渐降低.手术时M组和C组腋温分别为(37.00±0.36)℃和(35.53±0.74)℃.M组TOF 25%、TOF 75%、TOF 90%时间显著短于C组(P<0.05或P<0.01).结论 iMRI可使患者体温升高,加快罗库溴铵TOF 25%的恢复,缩短临床及体内作用时间,但对于恢复指数无显著影响.     

不同浓度异氟醚对罗库溴铵肌松作用的影响

目的 观察不同浓度异氟醚对罗库溴铵肌松作用的影响。方法 60例ASA Ⅰ-Ⅱ择期手术患者,随机分为3组,每组20例。组Ⅰ静脉注射罗库溴铵0.6 mg·kg-1;组Ⅱ吸入0.6％异氟醚后静脉注入罗库溴铵0.6mg·kg-1;组Ⅲ吸入1.2％异氟醚后从静脉注入罗库溴铵0.6mg·kg-1。分别记录各组注药后肌松作用的起效时间、作用时间及T1恢复时间。结果 与组Ⅰ相比,组Ⅱ、Ⅲ起效时间明显缩短(P<0.05),TOF无反应期明显延长(P<0.01),T1恢复25％、50％、90％时间明显延长(P<0.01),且组Ⅲ较组Ⅱ延长(P<0.05),恢复指数明显延长,且组Ⅲ较组Ⅱ延长(P<0.05)。结论 吸人异氟醚能明显缩短罗库溴铵起效时间,延长罗库溴铵作用时间,临床合并使用时应注意减少用量。     

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。     

腹部手术中慢性肝功能不全病人罗库溴铵的药效学

目的观察腹部手术中肝功能不全病人罗库溴铵的药效学.方法择期行开腹手术的病人26例,ASAⅠ～Ⅲ级,根据肝功能情况分为2组,Ⅰ组为门脉高压肝硬化病人(肝功能不全组),Ⅱ组为无肝脏疾病的病人(肝功能正常组),每组13例;监测神经肌肉传导功能,静脉注射诱导剂量罗库溴铵后T1恢复至5%时,持续静脉输注罗库溴铵,初始速率为600μg·kg-1·-1,每隔5 min以此间隔前速率的10%～20%为标准,调整输入速率,当维持T1=5%的输入速率不发生变化达到1h以上,则视为稳态需求量.记录起效时间(注肌松药毕至T1消失的时间)、高峰持续时间(T1由0恢复至5%的时间)、临床有效作用时间(肌松药停止持续输注后T1恢复由5%至25%的时间)和恢复指数(T1恢复由25%至75%的时间)、持续输注总量、手术时间、瑞芬太尼、异丙酚和咪达唑仑的用量.结果与Ⅱ组比较,Ⅰ组除术前肝功能指标差异有统计学意义外(P＜0.05),年龄、性别比、体重、手术时间、瑞芬太尼、异丙酚和咪达唑仑用量差异无统计学意义(P＞0.05),罗库溴铵起效时间、高峰持续时间、临床有效作用时间和恢复指数延长(P＜0.01).两组罗库溴铵持续静脉输注的时间相似(P＞0.05),罗库溴铵持续输注总量、平均用量和稳态需求量减少(P＜0.05或0.01).结论罗库溴铵0.6 mg/kg用于全麻诱导为肝功能不全和肝功能正常病人提供相似的气管插管条件,但在肝功能不全病人中其起效时间、临床作用时间和恢复时间延长,持续输注用量减少.     

持续泵注与间断静脉给予罗库溴铵的药效学比较

目的比较罗库溴铵持续泵注与间断给药的药效学特点,探讨其最佳的给药方式.方法50例ASAⅠ～Ⅱ级,无神经肌肉疾患,全麻下行择期手术的病人,随机分成罗库溴铵间断给药组(Ⅰ组)和持续泵注组(Ⅱ组),采用TOF刺激方式,监测拇内收肌的收缩反应.记录神经肌肉阻滞的最大阻滞时间及起效时间、恢复过程,并记录罗库溴铵的用药量.应用静脉麻醉药诱导及维持.全部病例均未予拮抗,使其在安静状态下自然恢复.当TOF恢复至T4/T1≥70%时,结束肌松监测,呼吸恢复满意后拔管.结果Ⅰ组维持肌松追加用药的间隔时间平均(29.24±6.26)min,各次追加的间隔时间之间无明显差异;Ⅱ组的平均泵注速率为(6.31±1.93)μg@kg-1@min-1,与Ⅰ组单位时间平均用量(5.43±1.46)μg·kg-1·     

肝移植术患者罗库溴铵不同给药方式肌松效果的比较

目的 比较肝移植术患者间断静脉注射(Ⅳ)、静脉输注(CI)和靶控输注(TCI)罗库溴铵的肌松效果.方法 拟行肝移植术的患者36例,性别不限,年龄21～63岁,体重48～80 kg,Child-Pugh评分7～9分,肝功能Child分级B或C级,随机分为3组(n=12):Ⅳ组、CI组和TCI组.采用TOF模式进行肌松监测,Ⅳ组:麻醉诱导时静脉注射罗库溴铵0.6 mg/kg,无肝前期T1恢复至25%时、无肝期和新肝期T4/T1(TOFR)恢复至25%时追加0.15 mg/kg.TCI组:麻醉诱导时靶控输注罗库溴铵,初始效应室靶浓度3μg/ml,调整靶浓度,维持T1 5%～10%;无肝期和新肝期开始时暂停TCI,随后以效应室靶浓度0.1μg/ml再次输注,调整靶浓度,维持T15%～10%.CI组:麻醉诱导时静脉注射罗库溴铵0.6 mg/kg,无肝前期以30μg·kg-1·min-1的速率开始静脉输注,调节输注速率,维持T1 5%～10%,无肝期和新肝期开始时暂停CI,随后以1μg·kg-1·min-1的速率静脉再次输注,调整输注速率,维持T15%～10%.各组于肌松达最大效应时行气管插管,于缝合腹膜后停止给药.记录麻醉诱导时罗库溴铵肌松起效时间、T1最大抑制程度和气管插管条件满意情况;记录各组无肝期T1 25%恢复时间及TOFR 25%恢复时间,新肝期停药后T125%恢复时间、TOFR 25%恢复时间、TOFR 75%恢复时间、TOFR90%恢复时间及恢复指数;记录罗库溴铵总用量.结果 与Ⅳ组比较,TCI组和CI组气管插管条件满意率、罗库溴铵总用量、麻醉诱导时罗库溴铵起效时间、T1最大抑制程度和各期肌松恢复情况差异均无统计学意义(P＞0.05).肌松效应监测图显示Ⅳ组各期罗库溴铵肌松效应波动较大,TCI组和CI组各期肌松效应较为平稳.结论 采用Ⅳ、CI和TCI给药时,肝移植术患者罗库溴铵肌松起效和恢复情况无差异,而采用TCI或CI给药时,肌松效应较Ⅳ更加平稳.     

年龄对罗库溴铵靶控输注时效的影响

目的 探讨靶控输注(TCI)罗库溴铵时年龄对其药效学的影响.方法 选择ASA Ⅰ或Ⅱ级、无神经肌肉疾患、接受丙泊酚-NzO/O2-芬太尼复合麻醉的患者30例,根据年龄分为老年组和青壮年组,每组15例.在静脉注入罗库溴铵0.6 mg/kg后用加速度仪采用四个成串刺激(TOF)方式监测拇内收肌的收缩反应.待T1恢复至10%时开始TCI罗库溴铵,靶控血浆浓度为2μg/ml.记录神经肌肉阻滞的最大阻滞时间及起效时间、恢复时间,并记录罗库溴铵的用药量.结果 老年组的平均输注速率为(7.6±0.9)μg·kg-1·min-1,青壮年组的平均输注速率为(8.2±0.8)/μg·kg-1·min-1.单次注入罗库溴铵0.6 mg/kg后的起效时间,两组间差异无统计学意义.青壮年组的肌松恢复过程明显快于老年组,表现为单次注药后老年组的无反应期明显长于青壮年组(P<0.01);停止TCI后T1恢复到25%、50%和75%的时间及恢复指数,老年组都明显长于青壮年组(P<0.01).但老年组罗库溴铵的平均用药量明显少于青壮年组(P<0.01).两组术中肌松均维持平稳.结论 罗库溴铵采用TCI在老年患者用药量虽然相应减少,但其恢复过程仍较青壮年组延长.     

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.     

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.     

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.