右美托咪定对全麻下脑功能区肿瘤切除术唤醒试验中应激反应的影响

目的评价右美托咪定对丙泊酚联合瑞芬太尼全麻下脑功能区肿瘤切除术患者唤醒试验中应激反应的影响。方法拟行术中唤醒试验的脑功能区肿瘤切除术患者48例,随机均分为右美托咪定组和对照组,右美托咪定组麻醉诱导前10min将负荷量0.8μg/kg右美托咪定进行静脉输注,继以0.4μg·kg-1·h-1进行维持;对照组采用等量生理盐水进行静脉输注。丙泊酚和瑞芬太尼靶控输注进行麻醉诱导与维持,于唤醒试验前30min停用丙泊酚和肌松药,调整瑞芬太尼血浆浓度为1ng/ml,右美托咪定组输注速率0.1μg·kg-1·h-1。记录两组患者唤醒前麻醉时间、麻醉药用量和唤醒时间,分别于唤醒前30min(T1)、唤醒时(T2)、唤醒后5min(T3)和研究结束后加深麻醉10min(T4)时,记录两组患者MAP、HR和BIS值,及血浆中去甲肾上腺素(NE)和肾上腺素(E)浓度,记录两组患者唤醒期间不良反应发生情况。结果两组患者唤醒时间、唤醒前麻醉时间和顺阿曲库铵用量差异无统计学意义。与对照组比较,右美托咪定组患者唤醒前丙泊酚和瑞芬太尼用量明显减少(P0.05)。与T1时比较,T2和T3时两组患者MAP和BIS均明显升高、HR明显增快(P0.05)。与对照组比较,T2和T3时右美托咪定组MAP明显降低(P0.05),T1~T4时HR明显减慢(P0.05),T1~T4时右美托咪定组患者NE和E浓度明显降低(P0.05),右美托咪定组患者躁动、心动过速、呛咳和高血压发生率均明显降低(P0.05)。各时点两组BIS值差异无统计学意义。结论右美托咪定对丙泊酚联合瑞芬太尼全麻下脑功能区肿瘤切除术唤醒试验中应激反应有较好的抑制作用,能够降低血浆NE和E浓度,对血流动力学影响较小,不良反应发生率降低。     

不同剂量右美托咪定对丙泊酚复合瑞芬太尼用于整形外科手术患者麻醉效果的影响

目的 评价不同剂量右美托咪定对丙泊酚复合瑞芬太尼用于整形外科手术患者麻醉效果的影响.方法 择期行大面积皮肤瘢痕切除和进行皮瓣转移的手术患者60例,性别不限,年龄18～64岁,体重45 ～ 75 kg,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将患者分为3组(n=20):对照组(C组)、低剂量负荷量右美托咪定组(D1组)和高剂量负荷量右美托咪定组(D2组),D1组和D2组分别于麻醉诱导前10 min静脉输注右美托咪定0.6、1.0μg/kg负荷量,随后以0.4 μg· kg-1·h-1速率静脉输注至手术结束前30 min.麻醉诱导:靶控输注丙泊酚(血浆靶浓度4.0μg/ml)和瑞芬太尼(效应室靶浓度2.0 ng/ml),患者意识消失后静脉注射罗库溴铵0.6 mg/kg,气管插管后,机械通气,麻醉维持:靶控输注丙泊酚(血浆靶浓度2.0 ～ 3.5 μg/ml)和瑞芬太尼(效应室靶浓度1.5 ～ 2.5 ng/ml),维持Narcotrend指数为D级.分别于麻醉前、右美托咪定输注10 min、气管插管前即刻、气管插管后1 min、气管插管后5 min、停止输注右美托咪定、拔除气管导管前即刻、拔除气管导管后1 min、拔除气管导管后5min时记录Narcotrend指数、收缩压(SP)、舒张压(DP)和HR.记录麻醉诱导时间、丙泊酚和瑞芬太尼的用量,记录自主呼吸、定向力恢复和拔除气管导管的时间.拔除气管导管后10 min时行镇静-躁动评分,记录术中窦性心动过缓和麻醉恢复期不良事件的发生情况.结果 与C组比较,D1组和D2组丙泊酚、瑞芬太尼的总用量和拔除气管导管后10 min时镇静-躁动评分、麻醉恢复期恶心、呛咳和躁动的发生率降低,右美托咪定输注10 min时Narcotrend指数和HR降低,D2组麻醉诱导时间缩短(P＜0.05或0.01),D2组术中窦性心动过缓发生率高于C组和D1组(P＜0.05),3组间自主呼吸恢复时间、定向力恢复时间和拔除气管导管时间差异无统计学意义(P＞0.05).D1组和D2组气管插管前后和拔除气管导管前后SP、DP和HR差异无统计学意义(P＞0.05).结论 对于整形外科手术患者,麻醉诱导前静脉输注右美托咪定负荷量0.6 μg/kg,随后以0.4 μg·kg-1 ·h-1速率输注可缩短麻醉诱导时间,减少丙泊酚和瑞芬太尼用量,有效地抑制气管插管和拔除气管导管时的应激反应,降低了不良反应的发生.     

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。     

不同剂量右美托咪啶复合异丙酚和瑞芬太尼用于腹部手术病人麻醉的效果

目的 评价不同剂量右美托咪啶复合异丙酚和瑞芬太尼用于腹部手术病人麻醉的效果.方法 择期拟在全麻下行腹部手术病人90例,性别不限,年龄18-64岁,体重45～80 kg,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将其随机分为3组(n=30).对照组(C组)静脉输注生理盐水10ml/h;右美托咪啶0.25 μg·kg-1·h-1组(D1组)和右美托咪啶0.50μg·kg-1·h-1组(D2组)于15 min内静脉输注右美托咪啶负荷剂量0.5μg/kg,然后分别以0.25 μg·kg-1 ·h-1或的0.50 μg·kg -1·h-1速率静脉输注至拔除气管导管.麻醉诱导:TCI异丙酚,血浆靶浓度1.0μg/ml,静脉注射顺阿曲库铵0.2 mg/kg,TCI瑞芬太尼,血浆靶浓度3 ng/ml,气管插管后行机械通气.麻醉维持:TCI瑞芬太尼,血浆靶浓度5ng/ml,静脉输注顺阿曲库铵0.1 mg·kg-1·h-1,TCI异丙酚,调节其血浆靶浓度,维持Narcotrend指数37 ～ 46.记录术中瑞芬太尼、顺阿曲库铵和异丙酚的用量、气管导管拔除时间和苏醒时间、术中和麻醉恢复期不良反应的发生情况.结果 3间瑞芬太尼、顺阿曲库铵的用量和气管导管拔除时间差异无统计学意义(P＞0.05);与C组比较,D1组和D2组苏醒时间延长,术中高血压、心动过速和麻醉恢复期烦躁、呕吐、高血压、心动过速的发生率降低,D2组异丙酚用量减少(P＜0.05);与D1组比较,D2组苏醒时间延长,术中高血压和麻醉恢复期烦躁、心动过速和高血压的发生率降低(P＜0.05).结论 复合异丙酚和瑞芬太尼时,静脉输注右美托咪啶0.50 μg·kg-1·h-1用于腹部手术病人麻醉的效果较好.     

右美托咪定复合靶控输注异丙酚-瑞芬太尼用于老年患者纤维支气管镜检查术的效果

目的 探讨右美托咪定复合靶控输注(TCI)异丙酚-瑞芬太尼用于老年患者纤维支气管镜检查术的效果.方法 择期行纤维支气管镜检查术的老年患者40例,性别不限,ASA分级Ⅱ或Ⅲ级,年龄65 ～ 75岁,BMI 20～30 kg/m2,采用随机数字表法,将患者随机分为2组(n=20):生理盐水对照组(C组)和右美托咪定组(D组).麻醉诱导前10 min D组静脉注射右美托咪定负荷剂量0.5μg/kg,随后以0.5 μg·kg-1·h-1的速率维持至检查结束,C组给予等容量生理盐水.麻醉诱导时TCI异丙酚(效应室靶浓度为3 μg/ml),待血浆-效应室浓度平衡后开始TCI瑞芬太尼(效应室靶浓度为4ng/ml),待患者意识消失后置入纤维支气管镜,入镜后调整异丙酚效应室靶浓度至1～3 μg/ml、瑞芬太尼效应室靶浓度至2～4 ng/ml.于麻醉诱导前(T0)、麻醉诱导后即刻(T1)、纤维支气管镜进入声门即刻(T2)、到达隆突即刻(T3)、检查完成即刻(T4)、检查完成后10 min(T)时记录MAP、HR和警觉镇静评分(OAA/S评分),记录异丙酚和瑞芬太尼的用量、检查时间、苏醒时间以及检测期间心血管不良反应、低氧血症、恶心呕吐、反流误吸等不良反应的发生情况.结果 与C组比较,D组T5时OAA/S评分明显升高,异丙酚和瑞芬太尼用量减少,苏醒时间缩短,低血压和低氧血症发生率降低(P＜0.05).2组均未出现恶心呕吐、反流误吸等严重不良反应.结论 右美托咪定(给予负荷剂量0.5 μg/kg后以0.5μg·kg-1·h-1维持输注)复合TCI异丙酚-瑞芬太尼可安全有效地用于老年患者纤维支气管镜检查.     

异丙酚、地氟醚或七氟醚复合瑞芬太尼麻醉对脑功能区手术患者术中唤醒试验的影响

目的 探讨异丙酚、地氟醚或七氟醚复合瑞芬太尼麻醉对脑功能区手术患者术中唤醒试验的影响.方法 择期拟行脑功能区肿瘤切除术患者60例,ASA Ⅰ或Ⅱ级,年龄18～60岁,随机分为3组:异丙酚组(P组)、地氟醚组(D组)及七氟醚组(S组),每组20例.静脉注射依托咪酯0.3mg/kg、芬太尼3 μg/kg、维库溴铵0.1 mg/kg行麻醉诱导,采用1%丁卡因喉头及气管粘膜表面麻醉后行气管插管.P组、D组和S组分别靶控输注异丙酚,血浆靶浓度2.0μg/ml,持续吸入地氟醚、七氟醚1.5 MAC维持麻醉.各组均靶控输注瑞芬太尼,血浆靶浓度2.5 ng/ml,唤醒试验前血浆靶浓度降为0.5 ng/ml,静脉注射曲马多100mg,停用麻醉药,行唤醒试验.记录唤醒时间,观察唤醒试验时躁动及寒颤的发生情况.结果 各组患者唤醒时间差异无统计学意义(P>0.05),P组寒颤发生率较D组和S组高(P<0.05).结论 采用异丙酚、地氟醚或七氟醚复合瑞芬太尼麻醉,脑功能区手术患者术中唤醒时间无差别,地氟醚或七氟醚复合瑞芬太尼麻醉时有关并发症发生率低,更适用于术中唤醒试验.     

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.     

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。     

右美托咪定对脊柱侧弯矫形术患者术中唤醒试验的影响

目的 评价右美托咪定对脊柱侧弯矫形术患者术中唤醒试验的影响.方法 选择拟行脊柱侧弯矫形术患者60例,年龄13～ 18岁,ASA分级Ⅰ级.采用随机数字表法,将患者随机分为2组(n=30)∶舒芬太尼组(S组)和右美托咪定+舒芬太尼组(DS组).两组均采用舒芬太尼、依托咪酯、顺阿曲库铵麻醉诱导,气管插管后机械通气,靶控吸入七氟醚复合靶控输注舒芬太尼维持麻醉.DS组麻醉诱导后静脉输注右美托咪定0.2 μg·kg-1·h-1至术毕,S组以等容量生理盐水替代.唤醒试验前停止输注顺阿曲库铵,下调七氟醚呼气末靶浓度至0;S组、DS组分别下调舒芬太尼Ce至0.1、0.08ng/ml.5 min后开始唤醒试验.记录唤醒时间、唤醒期间呛咳/躁动和心血管事件的发生情况.术后随访患者,记录术中知晓的发生情况.结果 DS组唤醒时无心血管事件发生.与S组比较,DS组唤醒时间缩短,心血管事件、呛咳/躁动的发生率降低(P＜0.05).术后随访无一例发生术中知晓.结论 右美托咪定可用于脊柱侧弯矫形术患者术中唤醒试验,唤醒时间短,血液动力学平稳,不良反应少.     

右美托咪定对丙泊酚或七氟醚全麻患者脑状态指数的影响

目的观察右美托咪定对全麻患者脑状态指数的影响。方法选择择期上腹部手术的全麻患者80例,男39例,女41例,年龄25~65岁,ASAⅠ或Ⅱ级。所有患者分为四组:丙泊酚组(P组),靶控输注丙泊酚血浆浓度3.0~4.0μg/ml;丙泊酚+右美托咪定组(PD组),靶控输注丙泊酚血浆浓度1.5~2.5μg/ml,右美托咪定0.5μg/kg,输注5 min,再持续输注0.6μg·kg~(-1)·h~(-1);七氟醚组(S组),吸入1.5%~2.5%七氟醚;七氟醚+右美托咪定组(SD组),吸入1%~1.5%七氟醚,右美托咪定0.5μg/kg,输注5min,再持续输注0.6μg·kg~(-1)·h~(-1)。术中所有患者镇静指数维持在45~55。分别于麻醉前、右美托咪定持续输注30、60min测定脑状态指数(记忆加工指数、谵妄指数)。结果麻醉前四组脑状态指数差异无统计学意义。右美托咪定持续输注30、60 min时PD组记忆加工指数和谵妄指数均明显低于P组(P0.05),SD组均明显低于S组(P0.05)。结论全麻中复合应用右美托咪定能够降低患者的脑状态指数。     

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.     

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.     

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.