控制性降压对颅内动脉瘤夹闭术中脑氧饱和度和术后神经认知功能的影响

目的研究近红外光谱监测下两种控制性降压方式对颅内动脉瘤夹闭术中脑氧饱和度(rSO_2)和术后神经认知功能的影响。方法选择行颅内动脉瘤夹闭术患者108例,男50例,女58例,年龄30～74岁,ASAⅠ或Ⅱ级,随机分为硝酸甘油降压组(N组)、七氟醚降压组(S组)和非降压组(C组),每组36例。N组和S组在开始剥离动脉瘤时开始控制性降压,于动脉瘤夹闭后停止降压。记录诱导前(T_0)、开始降压时(T_1)、降压后10 min(T_2)、30 min(T_3)、停止降压即刻(动脉瘤夹闭完成,T_4)、停止降压后10 min(T_5)、30 min(T_6)、手术结束时(T_7)和拔管时(T_8)的rSO_2。分别于术前和术后1、3、7 d采用简易精神状态量表(MMSE)和蒙特利尔认知功能评估量表(MoCA)评估患者认知功能。术后3个月随访并记录新发神经系统并发症及重要脏器并发症的情况。结果与T_0时比较,T_2—T_6时N组和S组rSO_2明显降低(P0.05)。T_2—T_6时N组和S组rSO_2明显低于C组(P0.05)。N组和S组不同时点rSO_2差异无统计学意义。三组不同时点MMSE评分及MoCA评分差异无统计学意义。三组术后并发症发生率差异无统计学意义。结论颅内动脉瘤夹闭术中应用七氟醚和硝酸甘油行控制性降压会降低脑氧饱和度,但不影响术后3个月内的神经认知功能。     

不同血压调控水平对老年患者髋关节置换术中局部脑氧饱和度及术后谵妄的影响

目的探讨术中不同血压调控水平对老年患者髋关节置换术中局部脑氧饱和度(rSO_2)及术后谵妄的影响。方法择期全麻下行髋关节置换术患者150例,男54例,女96例,年龄65～80岁,ASAⅡ或Ⅲ级,采用随机数字表法分为三组:A组术中MAP维持在基础值的80%～90%,B组MAP维持在基础值的90%～100%,C组MAP维持在基础值的100%～110%。记录术前(T_0)、麻醉后5 min (T_1)、手术开始后5 min(T_2)、30 min (T_3)、60 min (T_4)、手术结束时(T_5)、手术结束后5 min(T_6)的MAP、HR和rSO_2。记录术后3 d内谵妄发生情况以及PACU停留时间、住院时间和术后并发症等。结果与C组比较,T_2—T_6时A组和B组rSO_2明显降低(P0.05)。A组术后谵妄有10例(20%),B组有8例(16%),C组有1例(2%),A、B组发生率明显高于C组(P0.05)。与C组比较,A、B组PACU停留时间及住院时间明显延长(P0.05)。A、B组苏醒期躁动发生率明显高于C组(P0.05)。结论 MAP维持于基础值的100%～110%有助于降低术后谵妄及苏醒期躁动发生率,缩短住院时间,可能与术中局部脑氧饱和度升高有关。     

超声引导下星状神经节阻滞对局部脑氧饱和度及血流动力学的影响

目的观察超声引导下星状神经节阻滞(stellate ganglion block,SGB)对患者双侧局部脑氧饱和度(rSO_2)及血流动力学的影响,为SGB是否改善脑氧代谢及是否有围术期脑保护作用等研究提供参考。方法选择郑州大学第一附属医院疼痛科2018-06—10间收治的45例头、面部疼痛或躯体形式疼痛障碍患者,均接受超声引导下单侧SGB(颈6水平注射0.2%盐酸罗哌卡因4 mL)。利用近红外光谱局部脑氧饱和度监测仪观察SGB前(T_0)及SGB后5 min(T_1)、10 min(T_2)、15 min(T_3)、20 min(T_4)、25 min(T_5)、30 min(T_6)的阻滞侧rSO_2(b-rSO_2)与非阻滞侧的rSO_2(nb-rSO_2)。记录患者上述时间点的SBP、DBP、MAP、HR、SpO_2。结果 T_(1～6)的b-rSO_2较T_0均升高,差异有统计学意义(P0.05);T_(1～6)的nb-rSO_2与T_0差异无统计学意义(P0.05)。T_(1～6)的b-rSO_2均较同时间点的nb-rSO_2升高,差异有统计学意义(P0.05)。T_(1～6)的SBP、DBP、MAP、HR、SpO_2与T_0差异无统计学意义(P0.05)。结论超声引导下SGB后b-rSO_2升高,nb-rSO_2无明显变化。超声引导下SGB可改善脑氧代谢,可能在围术期脑保护方面有积极作用;对无心血管疾病的清醒患者血流动力学影响较小。     

目标导向液体治疗对脊柱侧弯矫形手术患者术中局部脑氧饱和度和术后并发症的影响

目的观察目标导向液体治疗(GDFT)对脊柱侧弯矫形手术患者术中局部脑氧饱和度(rSO_2)和术后并发症的影响。方法择期全麻下行脊柱侧弯矫形手术患者60例,男12例,女48例,年龄48～75岁,BMI 19～28 kg/m~2,ASAⅡ或Ⅲ级。采用随机数字表法分为观察组和对照组。对照组采取传统液体管理方法维持MAP基础值的80%,CVP 8～12 mmHg,尿量0.5 ml·kg~(-1)·h~(-1)。观察组通过桡动脉连接FloTrac/Vigileo监测系统,并在每博量变异度(SVV)指导下行GDFT,维持CI2.5 L·min~(-1)·m~(-2)。记录麻醉诱导前(T_0)、麻醉诱导后5 min(T_1)、俯卧位时(T_2)、切皮时(T_3)、内固定时(T_4)、矫形时(T_5)、术毕(T_6)的rSO_2,并计算rSO_2平均值■、rSO_2最小值(rSO_(2min))以及rSO_2较基础值下降的最大百分比(rSO_(2%max))。记录术中晶体液和胶体液用量、总输液量、出血量、尿量及去甲肾上腺素的使用情况。记录术后住院期间肺部炎症、恶心呕吐、心律失常、发热及低血压等并发症的发生情况。结果与对照组比较,观察组术中晶体液用量、总尿量明显减少(P0.05),胶体液用量明显增加(P0.05),去甲肾上腺素使用量明显减少(P0.05),术中■、rSO_(2min)明显升高(P0.05),术后住院期间肺部炎症及恶心呕吐发生率明显降低(P0.05)。结论目标导向液体治疗可以升高脊柱侧弯矫形手术患者术中rSO_2,减少术后住院期间肺部炎症及恶心呕吐的发生。     

超声引导下喉上神经阻滞用于支撑喉镜下声带息肉摘除术中的效果

目的探讨超声引导下不同浓度利多卡因喉上神经阻滞在支撑喉镜下声带息肉摘除术中的临床效果。方法择期行支撑喉镜下声带息肉摘除术患者60例,性别不限,年龄18～65岁,ASAⅠ或Ⅱ,随机分为三组,每组20例。A组:超声引导下2%利多卡因双侧喉上神经阻滞联合静脉全麻;B组:超声引导下1%利多卡因双侧喉上神经阻滞联合静脉全麻;C组:传统定位2%利多卡因双侧喉上神经阻滞联合静脉全麻。记录入室时(T_0)、气管插管进入声门即刻(T_1)、支撑喉镜置入成功即刻(T_2)、支撑喉镜置入成功后5min(T_3)、拔管即刻(T_4)、拔管后5min(T_5)的HR、MAP、SpO_2及血浆NE浓度;记录拔管时间和拔管后2h出现喉上神经阻滞并发症(吞咽困难、呼吸困难)的情况。结果与T_0时比较,T_1～T_5时三组HR明显增快,MAP明显升高(P0.05),但A、B组HR明显慢于C组,MAP明显低于C组(P0.05)。与C组比较,T_1～T_5时A、B组NE浓度明显降低(P0.05)。A、B组拔管时间明显短于C组(P0.05)。结论超声引导下1%利多卡因双侧喉上神经阻滞效果确切,可减少支撑喉镜术中应激反应,缩短拔管时间,减少患者术后不适。     

超声引导下单点和两点胸椎旁神经阻滞对胸腔镜手术患者血流动力学和应激反应的影响

目的比较单点和两点椎旁神经阻滞对胸腔镜手术患者血流动力学和应激反应的影响。方法选择拟在本院行胸腔镜下肺癌切除患者60例,男26例,女34例,年龄55～75岁,BMI 18～25 kg/m~2,ASA I—III级。随机分为单点椎旁注射组(S组)、两点椎旁注射组(D组)和对照组(C组),每组20例。S组患者超声引导下在T_(4～5)椎旁间隙注射0.75%罗哌卡因15 ml和2%利多卡因5ml混合溶液,D组患者分别在T_(3～4)和T_(5～6)椎旁间隙注射0.75%罗哌卡因7.5 ml和2%利多卡因2.5 ml混合溶液,C组患者不予穿刺给药。记录三组患者术中麻醉诱导前(T_0)、单肺通气1 h(T_1)、单肺通气结束时(T_2)、术毕(T_3)、术后1 h(T_4)、4 h(T_5)和24 h(T_6)的HR和MAP;采集三组患者T_0、T_1、T_2和T_3时桡动脉血,检测血液中血糖(Glu)、皮质醇(Cor)和8-异前列腺素F_(2α)(8-iso-PGF_(2α),8-iso)浓度;随访记录术后1、4、24和48 h静息和咳嗽时VAS评分;记录穿刺部位血肿、气胸、感染等阻滞相关并发症发生情况;记录术后48 h内恶心呕吐、头晕、低血压、皮肤瘙痒等镇痛不良反应发生情况。结果三组不同时点HR和MAP差异无统计学意义。与C组比较,T_2和T_3时D组Glu明显降低(P0.05),T_3时D组8-iso明显降低(P0.05),术后1、4、24、48 h S组和D组静息和咳嗽时VAS评分明显降低(P0.05),S组和D组不同时点静息和咳嗽时VAS评分差异无统计学意义。三组无一例发生穿刺部位血肿、气胸、感染等阻滞相关并发症。三组术后48 h内恶心呕吐、头晕、低血压发生率差异无统计学意义,无一例皮肤瘙痒发生。结论超声引导下两点胸椎旁神经阻滞较单点胸椎旁神经阻滞更能阻断胸腔镜手术中外周伤害性刺激向中枢的传导,减少应激类物质的产生,降低应激反应程度。     

超声引导下髋关节囊周神经丛阻滞对股骨颈骨折老年患者摆放侧卧位时疼痛的影响

目的比较超声引导下髋关节囊周神经丛阻滞(PENGB)和腹股沟上髂筋膜间隙阻滞(S-FICB)对股骨颈骨折患者麻醉前摆放侧卧位时疼痛的影响。方法择期腰-硬联合麻醉下行髋关节置换术的股骨颈骨折患者42例,男18例,女24例,年龄≥65岁,BMI 18～28 kg/m~2,ASAⅡ或Ⅲ级,所有患者在腰-硬联合麻醉体位变动之前,在超声引导下进行单次神经阻滞,根据神经阻滞入路不同,随机分为两组,每组21例。P组行PENGB,S组行S-FICB,两组均给予0.25%罗哌卡因30 ml。记录阻滞前(T_1)和阻滞后5 min(T_2)、10 min(T_3)、15 min(T_4)及摆放侧卧位即刻(T_5)和侧卧位后即刻(T_6)的VAS疼痛评分、MAP和HR,记录超声成像时间、穿刺注药时间、超声成像清晰度评分、患者满意度和配合度评分及相关并发症。结果与T_1时比较,T_2—T_6时两组VAS疼痛评分明显降低(P0.05)。与S组比较,T_2—T_6时P组VAS疼痛评分明显降低(P0.05)。与T_1时比较,T_2—T_4和T_6时两组MAP明显降低(P0.05)。与T_1时比较,T_3、T_4时P组HR明显减慢(P0.05)。与S组比较,P组超声成像时间明显缩短(P0.05),镇痛满意度评分明显提高(P0.05)。两组穿刺注药时间、超声成像清晰度评分和配合度评分差异无统计学意义。两组均无一例穿刺相关并发症。结论超声引导下PENGB和S-FICB对股骨颈骨折患者术前摆放侧卧位时都有良好的镇痛效果,PENGB超声成像时间更短,起效更快,患者满意度更高。     

连续前锯肌平面阻滞对胸腔镜下肺癌根治术患者术后肺氧合功能的影响

目的比较连续前锯肌平面阻滞(SAPB)和静脉自控镇痛(PCIA)两种镇痛方式在胸腔镜下肺癌根治术患者术后减少肺部并发症、改善肺氧合功能方面的有效性。方法择期行胸腔镜下肺癌根治术患者126例,年龄18～70岁,BMI 18.5～30.0 kg/m~2,ASAⅠ–Ⅲ级,随机分为两组:连续SAPB组(S组)和PCIA组(P组),每组63例。术毕S组行超声引导下前锯肌平面阻滞,注入0.375%罗哌卡因20 ml,留置导管予0.2%罗哌卡因行自控镇痛;P组行舒芬太尼常规PCIA。麻醉诱导前(T_0)、术毕即刻(T_1)、拔管后2 h(T_2)、拔管后6 h(T_3)、拔管后24 h(T_4)抽取桡动脉血记录PaO_2并计算氧合指数(OI)。记录T_2—T_4时静态和活动VAS评分,并记录肺部并发症发生情况。结果与T_0时比较,T_2、T_3时两组OI明显降低,且P组明显低于S组(P0.05)。T_2—T_4时S组VAS评分明显低于P组(P0.05),但两组补救镇痛例数差异无统计学意义。与P组比较,S组低氧血症、肺不张、恶心、呕吐的发生率明显降低(P0.05)。结论连续SAPB较PCIA能够改善胸腔镜下肺癌根治术患者肺氧合功能。     

不同肌松程度对腹腔镜胆囊切除联合胆总管探查术患者视神经鞘直径的影响

目的观察不同肌松程度下腹腔镜胆囊切除联合胆总管探查术患者视神经鞘直径(ONSD)的变化。方法选择2020年6—12月择期全麻下行腹腔镜胆囊切除联合胆总管探查术的患者60例,男33例,女27例,年龄18～64岁,BMI 18～28 kg/m~2,ASAⅡ级。采用随机数字表法将患者分为两组:深度肌松组(S组)和中度肌松组(Z组),每组30例。术中根据TOF-Watch肌松监测仪,S组维持TOF计数为0且PTC计数1～2,Z组维持TOF计数1～2。记录手术时间、麻醉时间、罗库溴铵用量以及TOFr 0.9时间。记录诱导前即刻(T_0)、切皮前即刻(T_1)、气腹后30 min(T_2)、气腹后1 h(T_3)、放气后10 min(T_4)、出手术室前即刻(T_5)MAP、BIS、HR、ONSD及T_1—T_4时P_(ET)CO_2、PaCO_2、CVP。记录术后1 d恶心呕吐、头痛发生情况。结果两组手术时间、麻醉时间以及T_0—T_5时MAP、HR、BIS、P_(ET)CO_2、PaCO_2差异无统计学意义。与T_0时比较,T_2—T_5时两组ONSD明显增大(P0.05)。与T_1时比较,T_2—T_4时两组P_(ET)CO_2、PaCO_2、CVP均明显升高(P0.05)。与Z组比较,T_2—T_5时S组ONSD明显减小(P0.05),T_2—T_3时CVP明显降低(P0.05),TOFr 0.9时间明显延长(P0.05)。两组术后1 d恶心呕吐、头痛发生率差异无统计学意义。结论与中度肌松比较,深度肌松更能在一定程度上缓解腹腔镜胆囊切除联合胆总管探查术患者术中视神经鞘直径的增大。     

右美托咪定对腹腔镜前列腺癌根治术老年患者局部脑氧饱和度和术后认知功能的影响

目的观察右美托咪定对腹腔镜前列腺癌根治术老年患者对局部脑氧饱和度(rSO_2)和术后认知功能的影响。方法选择择期行腹腔镜前列腺癌根治手术的老年患者60例,年龄65~80岁,ASA分级Ⅰ~Ⅲ级,随机均分为两组:右美托咪定组(D组)在全麻诱导插管后泵注右美托咪定0.5μg/kg,10min泵注完毕,然后以0.5μg·kg~(-1)·h~(-1)的速度持续泵注至手术结束前30min,对照组(C组)泵入等量的生理盐水。术中使用FORE-SIGHT_脑氧饱和度监测仪监测rSO_2。记录入室时(T_0)、诱导插管后(T_1)、气腹后60min(T_2)和苏醒后(T_3)的rSO_2、MAP、PaCO_2和PaO_2。记录丙泊酚和瑞芬太尼的使用情况、术后躁动和恶心呕吐的发生情况。于术前1d、术后1d和3d使用蒙特利尔认知功能评分量表(MoCA)进行评分,记录患者术后认知功能障碍(POCD)发生情况。结果T_2时两组rSO_2、PaCO_2明显高于T_1时(P0.05)。D组患者丙泊酚和瑞芬太尼用量明显少于C组(P0.05)。D组MoCA评分明显高于C组(P0.05);D组2例(6.7%)患者发生POCD,明显低于C组的9例(30%)(P0.05)。结论右美托咪定用于老年患者腹腔镜前列腺癌根治手术对rSO_2未见明显影响,但可以减少POCD的发生。     

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.     

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.     

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.     

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.     

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.