顺阿曲库铵的药效学及其对组胺释放的影响

目的 比较全麻诱导期间不同保存条件下顺阿曲库铵和阿曲库铵的药效学及其对组胺释放的影响.方法 择期全麻手术患者45例,ASA Ⅰ或Ⅱ级,年龄16-71岁,随机分为3组(n=15):阿曲库铵冷藏组(ATR冷藏组)、顺阿曲库铵冷藏组(CIS冷藏组)和顺阿曲库铵常温组(CIS常温组).靶控输注异丙酚血浆靶浓度3μg/ml和瑞芬太尼效应室靶浓度3～5 ng/ml行麻醉诱导.ATR冷藏组静脉注射冷藏保存的阿曲库铵0.75 mg/kg,CIS冷藏组和CIS常温组分别静脉注射冷藏或室温保存的顺阿曲库铵0.15 mg/kg.使用肌松监测仪,采用单次颤搐刺激(频率0.1Hz,刺激持续时间0.2ms),测定刺激前臂尺神经拇内收肌的加速度.记录肌颤搐最大抑制程度、起效时间、作用时间和恢复指数.肌颤搐抑制达最大抑制时行气管插管,机械通气,评价气管插管条件.于麻醉诱导前(T0)、给予静脉全麻药后2min(T1)、给予肌松药后2min(T2)和5min(T3)时,记录MAP和HR,观察皮肤情况,同时采集桡动脉血样2ml,采用酶联免疫吸附法测定血浆组胺浓度.结果 CIS冷藏组和ATR冷藏组肌颤搐抑制均可达100%,CIS常温组仅53.33%的患者肌颤搐抑制最大达90%.与ATR冷藏组比较,CIS冷藏组起效时间延长,作用时间缩短(P<0.05),恢复指数差异无统计学意义(P>0.05);与CIS冷藏组比较,CIS常温组起效时间延长,作用时间缩短(P<0.05),恢复指数差异无统计学意义(P>0.05).ATR冷藏组和CIS冷藏组的气管插管条件优于CIS常温组(P<0.05).两组间不同时点血浆组胺浓度、MAP和HR比较差异无统计学意义(P>0.05);与T0时比较,ATR冷藏组T2,3时血浆组胺浓度升高,T1～3时MAP降低,CIS冷藏组T1～3时MAP降低(P<0.05).各组患者皮肤均未发现任何变化.结论 与冷藏保存的阿曲库铵相比,冷藏保存的顺阿曲库铵肌松作用强而起效较慢,作用时间较短,不引起组胺释放,可安全地应用于全身麻醉.但该药在室温下保存120d后,药效稳定性较差.     

恶性肿瘤对顺阿曲库铵肌松效应的影响

目的 探讨恶性肿瘤对顺阿曲库铵肌松效应的影响.方法 选择头颈部肿瘤患者60例,ASA分级Ⅰ或Ⅱ级,年龄18～64岁,分为4组(n=15),良性肿瘤组(B组,3×ED95);45例恶性肿瘤患者按顺阿曲库铵使用剂量分为C1组(2×ED95)、C2组(3×ED95)和C3组(4 × E95).采用TOF-Watch SX型加速度肌松监测仪对尺神经行单次颤搐刺激,监测拇内收肌颤搐情况.麻醉诱导:靶控输注异丙酚(血浆靶浓度3μg//ml)和瑞芬太尼(效应室靶浓度3 ng/ml),患者意识消失后开启加速度肌松监测仪.B组静脉注射顺阿曲库铵0.15 mg/kg行气管插管.C1组、C2组和C3组分别静脉注射顺阿曲库铵0.10、0.15和0.20mg/kg行气管插管.记录顺阿曲库铵起效时间,临床作用时间、T/Tc恢复至75%的时间及其恢复指数.结果 与B组比较,C2组顺阿曲库铵临床作用时间、T/Tc恢复至75%的时间及恢复指数延长(P＜0.05),起效时间差异无统计学意义(P＞0.05).与C1组比较,C2组和C3组顺阿曲库铵起效时间缩短,临床作用时间、T/Tc恢复至75%的时间延长(P＜0.05),恢复指数差异无统计学意义(P＞0.05).与C2组比较,C3组顺阿曲库铵起效时间缩短,临床作用时间、T/Tc恢复至75%时间延长(P＜0.05),恢复指数差异无统计学意义(P＞0.05).结论 恶性肿瘤患者应用顺阿曲库铵肌松效应的维持和恢复时间延长.     

国产顺苯磺酸阿曲库铵在小儿麻醉中的应用

目的观察不同剂量国产顺苯磺酸阿曲库铵用于小儿的药效学。方法45例2~12岁患儿随机均分为三个顺苯磺酸阿曲库铵剂量组:2ED95组(C2组)、3ED95组(C3组)和4ED95组(C4组)。采用TOF-Guard肌松监测仪测定拇内收肌诱发颤搐反应变化,观察气管插管条件及顺苯磺酸阿曲库铵的药效学。结果三组均能完成气管插管。C3组和C4组插管条件评分均为5分;C2组中仅33.3%的患者插管条件评分>5分。随剂量增加,顺苯磺酸阿曲库铵阻滞起效时间相应缩短,肌松作用时间随剂量增加而延长,肌松恢复指数组间差异无统计学意义。所有患儿均无过敏反应发生。结论顺苯磺酸阿曲库铵随剂量的增加起效时间缩短,肌松作用时间延长。3ED95国产顺苯磺酸阿曲库铵剂量作为小儿气管插管较为合适。     

长期糖皮质激素用药对老年患者全麻手术中顺阿曲库铵肌松效应的影响

目的探讨长期糖皮质激素用药对老年全麻手术患者顺阿曲库铵肌松效应的影响。方法择期老年全麻手术患者40例,男28例,女12例,年龄≥65岁,BMI 18~22kg/m2,ASA分级Ⅱ或Ⅲ级,根据患者是否长期糖皮质激素用药分为两组(n=20):对照组(非激素组,C组)和激素组(J组)。静脉注射咪达唑仑0.03mg/kg,面罩吸入8%七氟醚,氧流量为8L,每30s递减2%,直至4%,睫毛反射消失后,静脉注射顺阿曲库铵0.15mg/kg,经1min静脉注射瑞芬太尼2μg/kg,30s后停止吸入七氟醚,气管插管后行机械通气,靶控输注丙泊酚和瑞芬太尼维持麻醉,采用TOFWatch SX加速度仪监测肌松程度,记录顺阿曲库铵起效时间、肌颤搐最大抑制程度、临床作用时间、恢复指数。结果与C组比较,J组顺阿曲库铵起效时间明显延长,肌颤搐最大抑制程度明显降低,临床作用时间明显缩短,恢复指数明显减小(P0.05)。结论长期糖皮质激素用药可减弱老年全麻手术患者顺阿曲库铵肌松效应。     

阻塞性黄疸伴肝功能不全患者顺式阿曲库铵的肌松效应

目的 观察单次静脉注射顺式阿曲席铵在阻塞性黄疸伴有肝功能不全患者的肌松效应.方法 30例择期行上腹部手术的患者均分为阻塞性黄疸伴有肝功能不全(Child-Pugh B级)组(G组)和肝功能正常组(C组).麻醉诱导均采用丙泊酚3 μg/ml、雷米芬太尼3～6 ng/ml、顺式阿曲库铵0.15 mg/kg后气管插管,评估插管条件,记录顺式阿曲库铵的肌松作用指标.结果 G组肌松起效时间较C组明显延长(P＜0.01);两组最大阻滞程度、插管条件、最大效应持续时间、单个颤搐刺激反应强度(T1)10%恢复时间、T125%恢复时间、T175%恢复时间、TOF比(T4/T1)70%恢复时间、恢复指数差异均无统计学意义.结论 阻塞性黄疸伴有肝功能小全患者单次静注顺式阿曲库铵后肌松起效时间明显长于肝功能正常者.     

不同性别患者预注顺阿曲库铵加快起效的半数有效剂量

目的 探讨不同性别患者预注顺阿曲库铵加快起效的半数有效剂量(ED50).方法 择期拟在全身麻醉下行腹部手术的患者90例,年龄18～55岁,分为2组(n=45):男性组(M组)和女性组(F组).采用TOF-Watch SX型加速度肌松监测仪对尺神经行单次颤搐刺激,监测拇内收肌肌颤搐情况.静脉注射咪达唑仑0.04 mg/kg、芬太尼1 μg/kg,患者意识消失后开启加速度肌松监测仪,静脉注射顺阿曲库铵预注剂量,3 min后静脉注射芬太尼5 μg/kg、异丙酚2 mg/kg,静脉注射预注量后4 min,静脉注射顺阿曲库铵剩余插管剂量(3×ED95即0.15 mg/kg减去预注量),当单刺激颤搐值与对照值的比值下降至10%,行气管插管.静脉输注异丙酚、瑞芬太尼,吸入异氟烷维持麻醉.预注量根据序贯法确定,预注量从5μg/kg(10%ED95)开始,各相邻剂量比值为1.2.记录给予预注量后4min时单刺激颤搐值与对照值的比值、90%起效时间、起效时间、最大阻滞程度、临床作用时间.计算预注顺阿曲库铵加快起效的ED50及其95%可信区间(CI).结果 M组90%起效时间长于F组(P＜0.05),其余肌松效应指标两组比较差异无统计学意义(P＞0.05).预注顺阿曲库铵加快起效的ED50:男性为21.36μg/kg,95%CI为20.52～22.23μg/kg;女性为14.53 μg/kg,95%CI为13.77～15.33μg/kg,男性高于女性(P＜0.05).结论 预注顺阿曲库铵加快起效的ED50:男性为21.36μg/kg,女性为14.53 μg/kg,男性高于女性.     

性别因素对七氟醚增强顺阿曲库铵或罗库溴铵肌松效应的影响

目的 探讨性别因素对七氟醚增强顺阿曲库铵或罗库溴铵肌松效应的影响.方法 择期全麻手术患者240例,年龄20～60岁,ASA分级Ⅰ或Ⅱ级,BMI 20～30 kg/m2,随机分为2组(n=120):顺阿曲库铵组和罗库溴铵组,各组按性别和麻醉药再分4个亚组(n=30):女性异丙酚组、男性异丙酚组、女性七氟醚组和男性七氟醚组.各异丙酚组靶控输注异丙酚,血浆靶浓度2～6 μg/ml,各七氟醚组吸入七氟醚,于靶控输注或待呼气末七氟醚浓度稳定于1.71%5 min后,静脉注射顺阿曲库铵0.15 mg/kg或罗库溴铵0.6 mg/kg.记录肌松起效时间、肌松作用峰值时间、T1 25%恢复时间和TOFR25%恢复时间.结果 与异丙酚麻醉比较,女性患者七氟醚麻醉时,罗库溴铵TOFR 25%恢复时间延长,顺阿曲库铵肌松作用峰值时间、T1 25%恢复时间和TOFR 25%恢复时间延长,男性患者七氟醚麻醉时,罗库溴铵起效时间缩短,肌松作用峰值时间、T1 25%恢复时间和TOFR 25%恢复时间延长,顺阿曲库铵肌松作用峰值时间、T1 25%恢复时间和TOFR 25%恢复时间延长(P＜0.05或0.01);七氟醚麻醉时与男性患者比较,女性患者罗库溴铵T1 25%恢复时间和TOFR 25%恢复时间缩短,顺阿曲库铵起效时间缩短(P＜0.05或0.01).结论 七氟醚对罗库溴铵肌松的增强作用存在性别差异,男性强于女性;对顺阿曲库铵肌松的增强作用无明显性别差异.     

二氧化碳气腹对腹腔镜手术患者顺阿曲库铵肌松效应的影响

目的 评价二氧化碳(C02)气腹对腹腔镜手术患者顺阿曲库铵肌松效应的影响.方法 择期子宫切除术患者60例,年龄35 ～ 60岁,BMI 18～ 24 kg/m2,ASA分级Ⅰ或Ⅱ级.采用随机数字表法,将其随机分为2组(n=30):气腹组(P组)和对照组(C组);每组根据肌松拮抗剂使用情况随机分为2个亚组(n=15):非拮抗组(P0组或C0组)和拮抗组(P1组或C1组).静脉注射芬太尼、丙泊酚、顺阿曲库铵麻醉诱导,气管插管后行机械通气.靶控输注丙泊酚和瑞芬太尼维持麻醉.采用TOF-Watch SX加速度仪监测肌松程度,P组于气腹建立后T1恢复达5％时静脉注射顺阿曲库铵0.05mg/kg,术毕P1组和C1组于 T1恢复至25％时静脉注射新斯的明拮抗,P0组和C0组自然恢复.记录气腹建立后追加顺阿曲库铵的临床作用时间和恢复指数.于诱导前即刻、气腹30 min、60 min及术毕时,分别抽取动脉血样行血 气分析.结果 与C0组比较,P0组临床作用时间及恢复指数延长(P＜0.05);与C1组比较,P1组临床作用时间及拮抗恢复指数延长(P＜0.05);与 C0组比较,P0组于气腹30、60 min、术毕时pH值下降,PaCO2升高(P＜0.05);与C1组比较,P1组于气腹30、60 min、术毕时pH值下降,PaCO2升高(P＜0.05).结论 CO2气腹可强化顺阿曲库铵的肌松效应,且可延长拮抗后肌松恢复时间.     

小儿不同剂量顺式阿曲库铵的肌松作用

目的通过观察小儿不同剂量顺式阿曲库铵的肌松作用,评价是否存在封顶效应,探讨小儿合适的麻醉诱导剂量。方法45例择期手术的息儿,年龄15～50月,ASAⅠ或Ⅱ级,随机分为3组(n=15):顺式阿曲库铵0.1 mg/kg组(A组)、顺式阿曲库铵0.15 mg/kg组(B组)、顺式阿曲库铵0.2 mg/kg(C组)。采用TOF-Guard肌松监测仪对尺神经行连续四个成串(TOF)刺激,监测拇内收肌肌颤搐变化;静脉注射异丙酚2 mg/kg、芬太尼2μg/kg及相应剂量顺式阿曲库铵麻醉诱导,吸入O2-N2O和静脉持续输注异丙酚维持麻醉;评价气臂插管条件评估分级,监测诱导期间血液动力学变化,记录起效时间(肌松药注毕至T1达最大抑制的时间)、临床肌松维持时间(肌松药注毕至T1恢复5%的时间)、临床肌松有效作用时间(T1从最大抑制至恢复25%的时间)、恢复指数(T1恢复从25%至75%的时间)、体内肌松作用时间(肌松药注毕至T1恢复95%的时间)。结果3组气管插管条件评估分级比较差异无统计学意义;三组T1达最大抑制时心率、平均动脉压组间和组内比较差异均无统计学意义。与A组相比,B组、C组起效时间较短,临床肌松维持时间、临床肌松有效作用时间、体内肌松作用时间较长(P<0.01);三组恢复指数差异无统计学意义。与B组相比,C组起效时间差异无统计学意义,但临床肌松维持时间、临床肌松有效作用时间、体内肌松作用时间较长(P<0.05或0.01)。结论小儿芬太尼复合异丙酚时,顺式阿曲库铵0.15 mg/kg(3倍ED95)是麻醉诱导的适宜剂量。     

不同剂量顺式阿曲库铵对患者拇内收肌与眼轮匝肌肌松效应的比较

目的 比较不同剂量顺式阿曲库铵对患者拇内收肌与眼轮匝肌的肌松效应.方法 全麻患者25例,ASA Ⅰ或Ⅱ级,年龄42～64岁,体重51～81 kg,随机分为2组,顺式阿曲库铵0.075ms/ks组(Ⅰ组,n=11)和顺式阿曲库铵0.15 mg/kg组(Ⅱ组,n=14).静脉注射咪达唑仑0.035～0.045mg/kg、异丙酚1.5～2 mg/kg、芬太尼0.1～0.2 mg、顺式阿曲库铵0.075 mg/kg或0.15 mg/kg行麻醉诱导,吸入50%氧化亚氮、间断静脉注射芬太尼维持麻醉.采用2台TOF-Watch SX加速度肌松监测仪同步监测眼轮匝肌和拇内收肌的神经肌肉阻滞情况,记录肌松起效时间、无反应期及T25%和T75%恢复时间.于眼轮匝肌肌颤搐抑制75%～80%时行气管插管,并评价气管插管条件.结果 2组气管插管条件良好且差异无统计学意义(P>0.05);与Ⅰ组比较,Ⅱ组拇内收肌和眼轮匝肌肌松起效时间缩短,T25%恢复时间、T75%恢复时间和无反应期延长(P<0.01);与拇内收肌比较,Ⅰ组眼轮匝肌T75%恢复时间缩短,Ⅱ组眼轮匝肌无反应期和T25%恢复时间缩短(P<0.05或0.01).结论 顺式阿曲库铵对拇内收肌和眼轮匝肌的肌松效应呈剂量依赖性,眼轮匝肌对顺式阿曲库铵的敏感性低于拇内收肌;监测顺式阿曲库铵对眼轮匝肌神经肌肉阻滞情况可有效指导气管插管.     

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.