右美托咪定不同途径给药对罗哌卡因腰丛-坐骨神经联合阻滞效果的影响

目的 评价右美托咪定(dexmedetomidine,Dex)不同途径给药方式对0.375％罗哌卡因腰丛挫骨神经联合阻滞(combined lumber plexus and sciatic nerve block,CLPSNB)效果的影响. 方法 90例CLPSNB患者按随机数字表法分为3组(每组30例):罗哌卡因组(R组),0.375％罗哌卡因50 ml行CLPSNB;罗哌卡因+Dex静脉注射组(D+R组),静脉输注Dex 1 μg/kg(输注时间10 min)同时0.375％罗哌卡因50 ml行CLPSNB;罗哌卡因局部麻醉药液混合Dex组(DR组),局部麻醉药Dex 1 μg/kg+0.375％罗哌卡因至50 ml行CLPSNB.R组和DR组同时静脉输注与D+R组相同容量的生理盐水.记录感觉阻滞和运动阻滞的起效时间和维持时间、术者的满意情况及副作用发生情况. 结果 3组感觉阻滞和运动阻滞的起效时间差异无统计学意义(P＞0.05);运动阻滞持续时间和首次使用镇痛药的时间DR组[(768±246) min和(1 080±300) min]、D+R组[(732±204) min和(1 050±288) min]显著长于R组[(420±126) min和(840±306) min] (P＜0.05);感觉阻滞持续时间DR组[(1008±258) min]显著长于R组[(624±216) min]、D+R组[(672±144) min](P＜0.05),而R组与D+R组比较,差异无统计学意义(P＞0.05).术者满意率DR组(100％)高于R组(85％)(P＜0.05).3组患者均未出现恶心、呕吐、低血压、呼吸抑制等副作用. 结论 Dex混合于0.375％罗哌卡因行CLPSNB麻醉效果及术者满意度佳.     

右美托咪定复合罗哌卡因骶管阻滞在小儿腹腔镜疝手术中的应用

目的 探讨右美托咪定(dexmedetomidine,Dex)复合罗哌卡因骶管阻滞在腹腔镜下小儿腹股沟疝手术中的作用. 方法采 用随机数字表法将52例斜疝患儿分为两组(每组26例):A组,Dex 1 μg/kg复合0.25％罗哌卡因1 ml/kg骶管阻滞;B组,0.25％罗哌卡因骶管阻滞组.记录两组患儿麻醉前(T0)、骶管阻滞后5 min(T1)、切皮时(T2)、手术结束时(T3)、拔气管导管时(T4)、苏醒后10 min时(T5)的MAP和HR,观察术后苏醒时间、苏醒时躁动发生率、躁动评分、术后镇痛评分、术后追加镇痛药的发生率及副作用. 结果 A组HR在T4时显著低于B组[(106±12)次/min比(117±12)次/min] (P＜0.05).与B组比较,A组苏醒期躁动发生率[3.8％比23.1％]、躁动评分[(1.9±0.6)分比(3.1±0.7)分]和术后4、8、12、16 h FLACC疼痛评分[(1.1±0.6)分比(2.2±0.7)分、(1.2±0.6)分比(3.8±0.9)分、(2.3±0.6)分比(4.2±0.7)分、(2.6±0.9)分比(3.8±0.8)分]均降低(P＜0.05);两组苏醒时及术后2、24 h的FLACC疼痛评分差异无统计学意义(P＞0.05).B组术后使用镇痛药曲马多为4例,A组无使用曲马多者(P＜0.05).两组均未发生明显的副作用. 结论 与单独使用罗哌卡因相比,Dex复合罗哌卡因骶管阻滞用于腹腔镜下小儿腹股沟疝手术能降低拔管时的应激反应,减少小儿苏醒期躁动,明显延长罗哌卡因骶管阻滞的术后镇痛时间.     

右美托咪定和可乐定硬膜外给药对硬膜外罗哌卡因麻醉效果的影响

目的 比较右美托咪定(dexmedetomidine,Dex)和可乐定硬膜外给药对罗哌卡因阻滞效果的影响. 方法 全组75例患者美国麻醉医师协会(ASA)分级Ⅰ或Ⅱ级,年龄55岁～65岁,拟行阴式子宫切除术.按随机数字表法分为硬膜外给予0.75％罗哌卡因15 ml含100 μg Dex组(RD组)、硬膜外给予0.75％罗哌卡因15ml含100 μg可乐定组(RC组)和硬膜外给予0.75％罗哌卡因15ml含生理盐水组(C组). 结果 RD组麻醉平面到达T10起效时间[(8.5±2.4)min]短于RC组和C组[(10.4±3.4) min和(12.7±4.3)min],RD组在较短的时间内[(13±4)min]达到最高阻滞平面,明显短于RC组和C组[(15±4) min和(18±4) min];RD组完全运动阻滞时间[(18±5)min]短于RC组和C组[(21±4) min和(24±4)min;(P＜0.05和P＜0.01)].RD组术后24 h曲马多用量[(87±17)mg]也显著少于RC组和C组[(101±21) mg和(146±19) mg;(P＜0.01)].RD组和RC组寒战发生率明显低于C组(P＜0.01),未发现1例呼吸抑制. 结论 硬膜外给予Dex可增强罗哌卡因硬膜外阻滞效果,与可乐定比较麻醉起效快、围术期呼吸循环稳定,减少术后镇痛药的应用.     

罗哌卡因与氟比洛芬酯用于淋巴静脉吻合术后镇痛效果的比较

目的探讨罗哌卡因和氟比洛芬酯用于继发性上肢淋巴水肿患者淋巴静脉吻合术后的镇痛效果。方法2014年10月~2016年3月,选择全麻淋巴静脉吻合术45例,随机分为罗哌卡因组(R组)、氟比洛芬酯预处理组(F_1组)和氟比洛芬酯后处理组(F_2组)各15例。R组在手术结束时应用0.2%罗哌卡因10 ml局部浸润麻醉切口,F_1组于麻醉诱导前5 min静注氟比洛芬酯100 mg,F_2组于手术结束前5 min静注氟比洛芬酯100 mg。记录术后1、2、6、12、24和48 h的疼痛视觉模拟评分(visual analogue scale,VAS)和追加镇痛药的例数。结果术后2 h时R组静息痛和运动痛VAS均低于F_1组、F_2组[静息痛(3.4±0.7)分vs.(4.2±0.9)分vs.(4.1±1.0)分,F=3.741,P=0.032;运动痛(3.7±0.6)分vs.(4.6±0.9)分vs.(4.4±1.0)分,F=4.305,P=0.020];术后6 h时R组静息痛VAS低于F_1组、F_2组[(2.7±0.5)分vs.(3.4±0.5)分vs.(3.1±0.6)分,F=5.783,P=0.006]。术后2 h时R组需要使用镇痛药的患者例数少于F_1和F_2组(1例vs.7例vs.5例,χ~2=6.058,P=0.048)。结论淋巴静脉吻合术后罗哌卡因局部浸润麻醉能取得较好的术后镇痛效果。     

K252a通过下调脊髓背角钾氯共转运体-2的表达缓解大鼠术后持续性痛

目的 观察鞘内注射酪氨酸激酶受体B(tyrosine kinase receptor B,TrkB)抑制剂K252a对皮肤/肌肉切口牵拉术(skin/muscle incision and retraction,SMIR)诱发的术后持续性痛大鼠脊髓背角钾氯共转运体-2(K+-Cl-cotransporter 2,KCC2)蛋白表达的影响. 方法 采用随机数字表法将52只成年雄性SD大鼠随机分成假手术组(对照组)、SMIR组、SMIR+二甲基亚砜(dimethyl sulfoxide,DMSO)组和SMIR+K252a组,每组13只.于术前1d及术后3、7、12、22、32 d测定大鼠机械缩足反射阈值(mechanical withdrawal threshold,MWT),Western blot测定术后7d大鼠脊髓背角KCC2蛋白的表达. 结果 与对照组比较,术后7、12、22 d时MWT在SMIR组[(22.5±2.3)、(24.9±1.4)、(29.5±2.4)g]和SMIR+DMSO组[(24.0±1.9)、(24.8±2.3)、(26.7±2.1)g]明显降低(P＜0.05);与SMIR组比较,术后7、12、22 d时MWT在SMIR+K252a组[(31.6±1.7)、(36.1±2.0)、(38.1±2.1)g]明显上调(P＜0.05).与对照组比较,术后7d时SMIR组和SMIR+DMSO组的脊髓背角KCC2表达明显下调(P＜0.05),SMIR+K252a组未检测到明显变化(P＞0.05).与SMIR组比较,SMIR+K252a组的脊髓背角KCC2表达明显上调(P＜0.05).结论 脊髓背角KCC2的表达变化可能参与了大鼠术后持续性痛的形成.     

罗哌卡因联合布托啡诺对妇科腹腔镜手术后疼痛影响的对照研究

目的观察静脉注射布托啡诺联合腹腔内注射罗哌卡因对妇科腹腔镜手术患者术后疼痛的影响。方法将2013年9月~2014年3月80例择期在全身麻醉下行妇科腹腔镜手术患者随机分为观察组(罗哌卡因联合布托啡诺组)和对照组,每组40例。观察组术前30分钟静脉注射布托啡诺20μg/kg,并在气腹结束前向手术创面喷洒0.4%罗哌卡因5 ml,缝合皮肤前向切口局部注射0.4%罗哌卡因5 ml。对照组给予同等量生理盐水。采用视觉模拟评分(visual analogue score,VAS)评价术后2、6、12、24 h的疼痛强度。结果术后2、6、12 h观察组的VAS均低于对照组(2 h:4.1±0.6 vs.6.8±0.8,t=-16.419,P=0.000;6 h:3.2±0.8 vs.7.1±1.5,t=-14.425,P=0.000;12 h:3.4±0.5 vs.6.2±1.9,t=-8.733,P=0.002),术后24 h 2组VAS差异无显著性(3.1±0.8 vs.3.2±0.7,t=-0.723,P=0.472)。结论布托啡诺联合罗哌卡因可显著缓解妇科腹腔镜术后疼痛,且无明显不良反应。     

舒芬太尼复合罗哌卡因用于下腹部手术后硬膜外自控镇痛

目的 观察舒芬太尼复合罗哌卡因用于下腹部手术后患者硬膜外自控镇痛(patient-controlled epidural analgesia,PCEA)的效果.方法 下腹部择期手术120例,年龄28 ～66岁,ASA分级Ⅰ、Ⅱ级,应用随机数字表法分为3组(每组40例):0.5 mg/L舒芬太尼复合0.2％罗哌卡因组(Ⅰ组)、5 mg/L芬太尼复合0.2％罗哌卡因组(Ⅱ组)和0.2％罗哌卡因组(Ⅲ组).所有患者术后镇痛均采用PCEA模式,观察镇痛后4、8、16、24、48 h的MAP、HR、VAS评分和Ramsay镇静评分(ramsay sedationscore,RSS)情况,并记录48 h内镇痛泵总按压次数以及恶心、呕吐、皮肤瘙痒及呼吸抑制的发生率.结果 各时点Ⅰ组VAS评分[(1.4±0.4)、(1.6±0.5)、(1.5±0.4)、(1.6±0.3)、(1.3±0.3)分]和Ⅱ组VAS评分[(1.5±0.6)、(1.6±0.4)、(1.7±0.6)、(1.5±0.4)、(1.4±0.6)分]明显低于Ⅲ组[(2.1±0.7)、(2.4±0.6)、(2.4±0.5)、(2.3±0.7)、(2.2±0.8)分](P＜0.05);在8、16、24 h,Ⅰ组RSS[(2.4±0.6)、(2.1±0.9)、(2.4±0.5)分]高于Ⅱ组[(1.4±0.7)、(1.6±0.6)、(1.6±0.4)分]和Ⅲ组RSS[(1.7±0.6)、(1.4±0.3)、(1.6±0.6)](P＜0.05);Ⅰ组和Ⅱ组镇痛泵总按压次数与Ⅲ组比较,差异有统计学意义(分别为3、4、18次,P＜0.05);Ⅰ组和Ⅱ组恶心呕吐的发生率高于Ⅲ组(分别为15％、12.5％、0,P＜0.05);3组皆未发生呼吸抑制.结论 0.5 mg/L舒芬太尼配伍0.2％罗哌卡因用于下腹部手术后PCEA效果确切,且副作用发生率低.     

地塞米松对0·5%罗哌卡因腰丛-坐骨神经联合阻滞作用的影响

目的评价地塞米松给药方式对0.5%罗哌卡因腰丛-坐骨神经联合阻滞(CLPSNB)作用时效的影响。方法60例神经刺激器定位CLPSNB患者随机分为三组,每组20例。A组,0.5%罗哌卡因45ml加地塞米松10mg行神经阻滞,同时静脉注射生理盐水(NS);B组,0.5%罗哌卡因45ml加NS2ml行神经阻滞,同时静脉注射地塞米松10mg;C组,0.5%罗哌卡因45ml加NS2ml神经阻滞,同时静脉注射NS2ml。结果感觉、运动阻滞持续时间A组[(15.2±3.3)h、(12.6±2.8)h]显著长于B组[(10.1±2.1)h、(7.9±1.6)h]和C组[(10.4±2.5)h、(7.6±2.3)h](P0.05)。结论地塞米松可以通过局部作用机制延长0.5%罗哌卡因CLPSNB持续时间。     

罗哌卡因复合舒芬太尼或地佐辛连续股神经阻滞在全膝关节置换术后镇痛中的应用

目的观察罗哌卡因与罗哌卡因复合舒芬太尼或地佐辛连续股神经阻滞(FNB)在全膝关节置换术(TKA)术后镇痛中的效果。方法择期行单侧TKA患者60例,采用统一麻醉和手术方案,术后FNB自控镇痛48h,持续剂量2ml/h,总量100ml。随机将患者均分为三组:罗哌卡因组(R组):0.225%罗哌卡因;罗哌卡因复合地佐辛组(D组):0.15%罗哌卡因含地佐辛10 mg;罗哌卡因复合舒芬太尼组(S组):0.15%罗哌卡因含舒芬太尼1μg/kg。记录三组患者术后1、3及7d静息状态下VAS(RVAS)评分、主动功能锻炼时VAS(AVAS)评分和被动功能锻炼时VAS(PVAS)评分;记录其他镇痛药物用量、不良事件发生情况。结果术后1、3、7d三组患者RVAS评分,术后1、7d的AVAS评分和术后1d的PVAS评分明显低于术前(P0.05);术后3d,S组与D组RVAS评分明显高于R组(P0.05)。三组术后恶心呕吐及谵妄发生率差异无统计学意义。结论罗哌卡因复合舒芬太尼或地佐辛用于FNB,可提供良好的TKA术后镇痛效果,且不增加不良反应;但0.15%罗哌卡因复合舒芬太尼或地佐辛不及0.225%罗哌卡因镇痛维持时间长,复合地佐辛这一现象更明显。     

不同剂量地塞米松对罗哌卡因神经阻滞作用的影响

目的比较不同剂量地塞米松复合罗哌卡因神经阻滞对罗哌卡因阻滞时效的影响。方法 60例内、外踝关节骨折拟行手术患者随机均分为三组。所有患者均在神经刺激器定位下行腰丛-坐骨神经阻滞麻醉。A组:0.4%罗哌卡因50ml;B组:0.4%罗哌卡因50ml加入地塞米松5mg;C组:0.4%罗哌卡因50ml加入地塞米松10mg。观察并记录腰丛、坐骨神经感觉阻滞起效时间、运动阻滞起效时间、感觉阻滞持续时间、运动阻滞持续时间。观察并记录三组患者术后24、48h镇痛泵的舒芬太尼用量、按压总次数和有效次数,记录三组患者术后12、24、36、48h的数字疼痛分级法(NRS)评分及恶心、呕吐、皮肤瘙痒、呼吸抑制等不良反应的发生率。结果 A组感觉阻滞持续时间和运动阻滞持续时间明显短于B、C组,且B组明显短于C组(P<0.01)。A组患者术后12、24h的NRS评分[(5.2±1.3)、(3.4±0.5)分]明显高于B组的[(1.1±0.3)、(1.6±0.6)]分和C组的[(0.4±0.1)、(1.0±0.2)]分(P<0.05)。A组患者按压总次数和有效次数、48h舒芬太尼用量明显多于B、C组(P<0.05)。结论 5和10mg地塞米松均能延长0.4%罗哌卡因腰丛-坐骨神经阻滞作用时间,且10mg作用更明显。     

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.