腰-硬联合麻醉患者异丙酚不同镇静深度下半数有效的浓度、脑电双频指数和听觉诱发电位指数

目的测定腰-硬联合麻醉期间异丙酚靶控输注清醒镇静时患者不同镇静深度的半数有效浓度(EC50)、半数有效BIS(BIS50)和半数有效AAI(AAI50)。方法择期腰-硬联合麻醉下行下腹部或下肢手术患者45例,ASAⅠ级。腰麻阻滞完善后,异丙酚靶控输注清醒镇静,以患者OAA/S评分为镇静指标,采用二项Logistic回归方法计算不同镇静深度(OAA／S评分)的EC50、BIS50和AAI50。结果患者OAA/S4分时EC50为0.6μg／ml、BIS50为85和AAI50为72,OAA/S3分时EC50为1.0μg/ml、BIS50为75和AAI50为59,OAA／S2分时EC50为1.3μg/ml、BIS50为67和AAI50为39,OAA/S1分时EC50为1.6μg／ml、BIS50为61和从AAI50为30,OAA／S0分时EC50为2.5μg／ml、BIS50为41和.AAI50为12。结论EC50、BIS50和AAI50对患者腰-硬联合麻醉期间清醒镇静有重要的临床指导价值。     

高龄病人异丙酚分步TCI时效应室浓度及BIS的变化

目的 研究高龄病人异丙酚分步靶控输注(TCI)时效应室浓度变化的规律及其相应镇静程度和双频指数(BIS)的变化。方法10例年龄67～77岁病人,进行异丙酚分步TCI,靶浓度(Ct)由1μg/ml,分6步渐增加至4μg/ml。观察效应室浓度(Ce)、BIS和镇静警觉评分(OAA/S),并于Ct分别为1、2、3和4μg/ml时取桡动脉血测异丙酚浓度(Cb)。结果①Ce随Ct增加而增加,但较Ct明显滞后,Ce达到4μg/ml较Ct滞后时间为(14.4±0.5)min。②Cb均高于Ct。PE、MDPE和MDAPE分别为16.3％,9.7％和11.2％。③BIS与Ct和Ce均呈显著负相关(r=-0.878和-0.888,P<0.01)。OAA/S与BIS呈显著正相关(r=0.913,P<0.01),与Ct、Ce均呈显著负相关(r=-0.876和-0.893,P<0.01)。④意识和痛刺激反应消失时BIS值分别为64.6±10.6和43.6±8.1,Ce分别为(1.67±0.49)μg/ml和(2.78±0.46)μg/ml。结论 高龄病人 Ce变化较Ct明显滞后,高龄病人BIS监测可很好反映异丙酚麻醉的深度。     

异丙酚病人自控镇静与靶控镇静的对比研究

目的 比较异丙酚病人自控镇静术（PCS）与靶控镇静术（TCI）在硬膜外麻醉中的应用价值。方法 32例行下肢或下腹部手术的成年患者,硬膜外麻醉满意后,随机分成两组,PCS组行病人自控镇静,单次剂量0.3mg/kg,锁定时间2min;TCI组行靶控输注,术中维持镇静深度于OAA/S镇静评分3分。监测不同时点的镇静评分、双频谱指数（BIS）、边缘频率（95％SEF）、异丙酚靶浓度（CP）及血药浓度（Cm）、术中遗忘及镇静满意程度,并比较BIS、95％SEF及Cm与镇静评分的相关性。结果 所有患者均对镇静效果满意,PCS组镇静深度较浅,异丙酚用药量较TCI组少（分别为 2.5mg·kg-1·h-1与 3.8mg·kg-1·h-1,P<0.01）,且个体差异明显。TCI组血药浓度平稳,并与靶浓度基本相符,术中及术后遗忘率较自控镇静组高（分别为31％与69％,P<0.01）。BIS与镇静评分的相关性（γ=0.73）较95％SEF及Cm高。结论 两种方法镇静效果均满意,但又各具特点。自控镇静体现了个体化给药原则,用药量较少,其合理的设置至关重要。靶控镇静的深度平稳且易于调控,遗忘良好,但由于其治疗窗较窄,需要有良好的监测。BIS是监测硬膜外麻醉中镇静深度的较敏感指标。     

麻醉深度指数与脑电双频谱指数测定靶控输注异丙酚患者镇静时镇静深度的比较

目的对异丙酚靶控输注(TCI)镇静的患者,比较麻醉深度指数(CSI)与脑电双频谱指数(BIS)在无手术刺激条件下监测镇静深度的准确性。方法 ASA Ⅰ或Ⅱ级患者20例,手术种类不限,诱导插管前以异丙酚TCI镇静,靶浓度从0．5 μg/ml开始,输注5 min后递增,递增梯度为0．5 μg/ml, 直至改良清醒镇静评分(OAA/S)为0分后5 min停止,试验中监测并记录患者CSI及BIS,每间隔20 s 行改良OAA/S评分,记录TCI系统预测效应部位浓度值每变化0．1 μg/ml时的数值及时间。计算CSI 及BIS预测不同改良OAA/S评分的预测概率(Pk)。结果 CSI及BIS与改良OAA/S评分均有较好的相关性,患者在不同改良OAA/S评分时的镇静深度均表现出较高的Pk值(Pk>0．9),且二者比较差异无统计学意义。语言反应消失时的BIS05与CSI05、BIS50与CSI50、BIS95与CSI95分别为79．2与74．9、69．2 与65．9、59．2与56．8。意识消失时的BIS05与CSI05、BIS50与CSI50、BIS95与CSI95分别为73．6与65．2、57．1 与54．8、40．6与44．3。结论异丙酚TCI镇静时CSI同BIS一样能够较好的反映患者的镇静深度变化,CSI监测用于观察患者语言反应消失和意识消失的能力优于BIS监测。     

咪唑安定靶控输注时清醒镇静的临床观察

目的 探讨在腰一硬联合麻醉下用脑电双频指数(BIS)监测靶控输注(TCI)咪唑安定清醒镇静时,咪唑安定适宜的目标血药浓度.方法 选择60例腰一硬麻醉下行妇科手术患者,年龄45～65岁,ASA Ⅰ或Ⅱ级,随机均分为A、B、C三组.A、B、C组咪唑安定血浆靶控浓度分别为30、40、50 ng/ml.记录患者TCI眯唑安定30 min时BIS,同时记录咪唑安定不同血浆靶控浓度下警觉/镇静评分(0AA/S).维持术中BP、HR、SpO2至满意水平,记录术中、术后的感受情况、遗忘程度、麻醉的满意度.结果 A组患者术中BIS为89.5,OAA/S 4～5分.B组患者术中BIS为76.5,OAA/S 3分.C组患者术中BIS为68,OAA/S 1～2分.结论 腰一硬联合麻醉下手术患者咪唑安定以40ng/ml血浆靶控输注BIS在73～80.0AA/S 3分,术中镇静及顺行性遗忘效果好,安全性高,不良反应小,但应注意阻滞效果不完善时患者易引起极度躁动.     

靶控输注异丙酚时脑电双频谱指数与皮肤电传导监测患者镇静深度准确性的比较

目的 比较靶控输注异丙酚时脑电双频谱指数(BIS)与皮肤电传导(SC)监测患者镇静深度的准确性.方法 拟在硬膜外麻醉下行下肢手术的患者30例,年龄21～56岁,体重52～85 kg,ASA分级Ⅰ或Ⅱ级.异丙酚初始血浆靶浓度0.8 μg/ml,待血浆靶浓度与效应室浓度平衡后.以0.5～0.8 μg/ml血浆靶浓度递增,直至警觉/镇静评分(OAA/S评分)为1分时停止给药,靶控输注异丙酚前记录BIS和SC,作为基础值,异丙酚靶控输注期间记录OAA/S评分、BIS和SC,计算SC变化值(△SC).OAM/S评分与BIS和△SC行Spearman等级相关分析,绘制BIS和△SC判断OAA/S评分及意识消失的受试者工作特征曲线,计算曲线下面积(AUC,分别为AUCBIS和AUC△SC);逻辑回归分析计算BIS和△SC正确判断意识消失的概率.结果 随OAA/S评分的升高,BIS值逐渐升高(P＜0.01),OAA/S评分1分与2分时△SC比较差异无统计学意义(P＞0.05),OAA/S评分3～5分时△SC低于OAA/S评分1分或2分,OAA/S评分3～5分时△SC逐渐降低(P＜0.01),OAA/S评分与BIS呈正相关(r=0.920,P＜0.01),与△SC呈负相关(r=-0.859,P＜0.01);与AUCBIS比较,OAA/S评分5→4分、4→3分时AUC△SC升高,OAA/S评分3→2分、2→1分和意识消失时降低AUC△SC(P＜0.05);BIS与ASC正确判断意识消失的概率分别为93%和82%.结论 靶控输注异丙酚时,患者意识消失前SC监测镇静深度的准确性高于BIS,意识消失后低于BIS;BIS判断患者意识消失的准确性高于SC.

Abstract：

Objective To compare the accuracy of BIS and skin conductance (SC) for assessment of the depth of sedation induced by target-controlled infusion (TCI) of propofol. Methods Thirty ASA Ⅰ orⅡpatients aged 21-56 yr weighing 52-85 kg undergoing orthopedic operation on the lower limb under epidural anesthesia were enrolled in this study.After the onset of epidural anesthesia, TCI of propofol was started at an initial target plasma concentration (Cp) of 0.8 μg/ml. Th Cp was increased by 0.5-0.8 μg/ml every 3 min until OAA/S score=1. OAA/S score, BIS and SC values were recorded, SC change value (△SC) was calculated. Spearman rank-order correlation, receiver operating characteristic curve (area under curve "AUC" was calculated) and logistic regression were used to analyze the relationship of OAA/S score to BIS and △SC.Results BIS and △SC were significantly correlated with OAA/S scores (r were 0.920 and-0.859 respectively). The AUC of △SC (0.919, 0.946) was significantly better correlated with OAA/S score (5→4, 4→3) than that of BIS (0.761, 0.507), while BIS was better correlated (0.781, 0.959) with OAA/S score (3→2, 2→1) than ASC (0.577, 0.630). Logistic regression correctly predicted loss of consciousness. The accuracy of prediction was 93% for BIS and 82% for △SC. Conclusion The accuracy of SC for assessment of the depth of sedation induced by propofol TCI ishigher than that of BIS before loss of consciousness,while lower than that of BIS after loss of consciousness. BIS is more accurate in monitoring the loss of consciousness.     

硬膜外阻滞辅以丙泊酚闭环靶控镇静

目的对硬膜外阻滞中以脑电双频指数(BIS)作为反馈的闭环靶控输注丙泊酚镇静的效果和性能进行评价。方法11例ASAⅠ～Ⅱ级择期行下腹部或下肢手术患者，男5例，女6例，年龄28～67岁。硬膜外阻滞期间采用以BIS作为反馈的闭环靶控输注(CLTCI)丙泊酚进行镇静，开始的靶浓度设定为1．5μg／ml，然后每分钟逐步增加或减少0．5μg／ml，直到患者的镇静深度稳定于OAA／S评分3分以下，这时候的BIS值作为反馈变量，通过CLTCI系统自动输注丙泊酚。每5分钟记录血压、心率、BIS和OAA／S评分。记录诱导时间及丙泊酚诱导剂量、丙泊酚总用量、苏醒时间及不良反应，并评价CLTCI系统的性能。结果所有患者镇静期间血液动力学平稳，无严重呼吸抑制。OAA／S评分3分时平均BIS值76．6。CLTCI系统的偏离性1．9％，精确度7．1％，摆动度4．1％。结论在硬膜外麻醉期间以BIS为反馈的闭环靶控输注丙泊酚进行清醒镇静是可行的。该系统性能稳定，有临床推广价值。     

咪唑安定靶控输注时镇静深度的预测

目的　探讨咪唑安定 (MDZ)靶控输注镇静时目标血药浓度、效应室浓度与脑电指标双频指数 (BIS)、95 %边缘频率 (95 %SEF)预测镇静深度的临床价值及MDZ在区域麻醉靶控输注镇静中的适宜目标浓度。方法　选择ASAⅠ～Ⅱ级的择期手术患者 14例 ,以血药浓度作为靶控输注目标浓度。第一阶段靶浓度为 5 0ng/ml,继以 5 0ng/ml浓度梯度递增 ,每一阶段维持 15分钟 ,至镇静评分 (OAA/S评分法 )达 1分后停药 ,观察并双盲记录目标血药浓度、效应室浓度、BIS、95 %SEF、血液动力学和镇静评分各指标至患者清醒 ,用Spearman’s等级相关进行相关分析。 结果　镇静起效期(0AA/S5～ 1)OAA/S与BIS、95 %SEF、目标血药浓度、效应室浓度的相关系数分别为r =0 735、0 4 15、- 0 4 87和 - 0 6 89(P值均 <0 0 0 1)。镇静恢复期 (0AA/S1～ 5)分别为r =0 6 14、0 2 94、-0 5 5 1和 - 0 4 97(P值均 <0 0 1)。不同镇静评分时各指标变化有显著差异。血液动力学指标未见与镇静评分相关。结论　MDZ靶控输注镇静时 ,目标血药浓度、效应室浓度、BIS和 95 %SEF均可用于镇静深度的预测 ,镇静评分与BIS相关最好 ,镇静深度宜维持在OAA/S评分 2～ 3分 ,目标血药浓度 10 0ng/ml左右 ,BIS在 77～ 81之间。     

日间与夜间靶控输注异丙酚镇静效果的比较

目的 通过比较日间与夜间靶控输注异丙酚的镇静效果,探讨近日节律对异丙酚镇静效果的影响.方法 局部或臂丛神经阻滞下行急诊手部小手术的男性患者65例,ASA分级Ⅰ或Ⅱ级,年龄18～55岁,BMI 18.5～ 24.9 kg/m2,根据患者手术时间分为日间组(07:01至19:00)和夜间组(19:01至07:00).行臂丛或局部神经阻滞,确认麻醉效果完善后开始靶控输注异丙酚,靶控输注过程采用阶梯给药方式,设定4个目标效应室靶控浓度,依次为0.8、1.2、2.0和4.0 μg/ml.当异丙酚效应室浓度达到预设值后,维持5 min,记录该浓度下的BIS值.靶控输注过程中每分钟进行1次警觉镇静评分(OAA/S评分),并记录OAA/S评分为2分(患者意识消失)时的BIS值和异丙酚效应室浓度.结果 共有58例患者完成研究,其中日间组28例,夜间组30例.与日间组比较,夜间组BIS基础状态、异丙酚效应室浓度1.2和2.0 μg/ml时BIS值降低(P＜0.05),异丙酚效应室浓度0.8和4.0 μg/ml时BIS值差异无统计学意义(P＞0.05),OAA/S 2分时异丙酚效应室浓度降低(P＜0.05)而BIS值差异无统计学意义(P＞0.05).结论 近日节律可影响患者异丙酚的镇静效果,表现为夜间镇静效果强于日间.     

状态熵指数监测患者靶控输注异丙酚全麻诱导时镇静深度的准确性

目的评价状态熵指数(SE)监测患者靶控输注异丙酚全麻诱导时镇静深度的准确性。方法择期全麻手术患者17例,年龄21～64岁,ASAⅠ级或Ⅱ级,靶控输注异丙酚行全麻诱导,初始效应室靶浓度设定为1.5μg/ml,效应室靶浓度达到设定浓度后1 min以0.5μg/ml的浓度梯度递增,靶控输注开始后每30秒进行1次警觉,镇静评分(OAA/S评分),直至患者意识消失(OAA/S评分≤1分),记录每次OAA/S评分即刻的SE及BIS。分析SE和BIS与OAA/S评分的相关性,计算SE和BIS的镇静深度预测概率(P_K)、患者意识消失时SE_(50)、SK_(90)、BIS_(50)、BIS_(90)及其95%可信区间。结果BIS、SE与OAA/S评分的相关系数分别为0.726(P<0.05)和0.824(P<0.05);BIS与SE的相关系数为0.855 (P<0.05);SE的镇静深度P_K(0.874±0.021)高于BIS(0.820±0.028)(P<0.05)。SE_(50)和BIS_(50)分别为59(48～65)、62(53～67),SE_(90)和BIS_(90)分别为39(16～49)、44(23～53)。结论SE监测患者靶控输注异丙酚全麻诱导时镇静深度的准确性高于BIS。     

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 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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.