超声引导下胸腰筋膜平面阻滞在脑瘫患儿选择性脊神经后根切断术中的应用

目的 探讨超声引导下胸腰筋膜平面（TLIP）阻滞在脑瘫患儿选择性脊神经后根切断术（SPR）中的应用效果。

方法 选择行SPR的脑瘫患儿56例，男31例，女25例，年龄6～12岁，体重18～47 kg，ASA Ⅰ或Ⅱ级。采用随机数字表法将患儿分为两组：超声引导下TLIP阻滞联合全麻组（T组）和单纯全麻组（C组），每组28例。所有患儿静脉全麻用药方案一致。T组插管翻身后行超声引导下双侧TLIP阻滞，0.2%罗哌卡因 0.5 ml/kg，最大用量小于20 ml，30 min后开始手术。C组不行阻滞。记录术中丙泊酚和瑞芬太尼用量，镇痛泵首次按压时间、术后24 h内镇痛泵总按压次数和有效按压次数，术后2、6、12、24 h静息和活动时VAS疼痛评分，术后住院时间、补救镇痛情况、患儿家属满意情况，皮肤瘙痒、低氧血症、恶心呕吐等不良反应发生情况。

结果 与C组比较，T组术中丙泊酚和瑞芬太尼用量均明显减少（P＜0.05），镇痛泵首次按压时间明显延长（P＜0.05），术后24 h内镇痛泵按压的总次数和有效按压次数明显减少（P＜0.05），术后2、6、12 h静息和活动时VAS疼痛评分明显降低（P＜0.05），术后住院时间明显缩短（P＜0.05），补救镇痛率明显降低（P＜0.05），患儿家属满意率明显升高（P＜0.05）。两组皮肤瘙痒、呼吸抑制、恶心呕吐等不良反应的发生率差异无统计学意义。

结论 超声引导下TLIP阻滞可为行SPR的脑瘫患儿提供较为完善的镇痛，减少全麻药用量，加速术后康复。     

超声引导下隐神经阻滞联合帕瑞昔布用于胫骨高位截骨术后精准镇痛的临床应用研究

目的 探讨超声引导下隐神经阻滞联合帕瑞昔布用于胫骨高位截骨术后镇痛的临床疗效。方法 选取2020年1月至2021年3月于我院行胫骨高位截骨手术的病人,按照时间顺序进行分组研究,将病人分为三组：2020年1月至2020年5月超声引导隐神经阻滞（罗哌卡因）联合术后静脉注射帕瑞昔布者纳入A组;2020年6月至2020年10月超声引导隐神经阻滞（罗哌卡因）联合术后静脉镇痛泵（舒芬太尼）者纳入B组;2020年11月至2021年3月术后静脉镇痛泵（舒芬太尼）者纳入C组。统计分析三组病人疼痛、功能、并发症方面的差异。结果 静息状态下,术后4 h、12 h,A组疼痛视觉模拟量表（visual analogue scale,VAS）评分均明显低于B组和C组;术后4 h、12 h、24 h,A组、B组VAS评分均明显低于C组;术后48 h、6 d,A组明显低于C组,差异有统计学意义（P＜0.05）。屈曲45°活动状态下,术后4 h、12 h、24 h、48 h,A组和B组的VAS评分均明显低于C组;术后6 d,A组明显低于B组和C组,差异均有统计学意义（P均＜0.05）。术后24 h、48 h,A组膝关节功能Lysholm评分优于B组和C组;术后6 d,A组优于C组;术后24 h时,B组优于C组,差异均有统计学意义（P＜0.05）。术后1、3、6个月,三组病人在静息状态、活动状态的VAS评分及膝关节功能Lysholm评分方面的差异均无统计学意义（P＞0.05）。术后3 d,A组术后镇痛满意度优于B组和C组,B组优于C组,差异有统计学意义（P＜0.05）;术后6 d,A组和B组优于C组,差异有统计学意义（P＜0.05）。A组术后住院时间短于C组,差异有统计学意义（P＜0.05）。三组并发症的差异无统计学意义（P＞0.05）。结论 超声引导下隐神经阻滞可以提高阻滞的成功率,降低穿刺相关性并发症,可重复性强。通过超声引导下隐神经阻滞联合帕瑞昔布的镇痛方案可改善手术后病人的不愉快体验,显著减轻病人术后疼痛,实现快速康复,减少镇痛泵的使用,符合精准医疗理念,操作较简单,便于推广。     

高位胸椎竖脊肌平面阻滞与臂丛上干阻滞在全身麻醉肩关节镜手术中应用的比较

目的 比较高位胸椎竖脊肌平面阻滞（high thoracic erector spinae plane block，HT-ESPB）与臂丛上干阻滞（superior trunk block，STB）在肩关节镜手术围手术期的镇痛效果。方法 纳入择期全身麻醉下行肩关节镜肩袖修补术病人共计60例，采用随机数字法将其分为HT-ESPB组（30例）与STB组（30例）。记录两组术中镇痛药物用量、拔管时间、膈肌阻滞发生率、相关并发症；术后2、6、12、24、48、72 h时静息和活动时的疼痛视觉模拟量表（VAS）评分，术后曲马多镇痛补救情况，病人术后镇痛满意度评分，术后24、48、72 h的15项恢复质量量表（QoR-15）评分以及不良反应发生情况。结果 HT-ESPB组术中舒芬太尼用量高于STB组［（21.5±11.1） μg vs. （15.6±10.3） μg，P=0.037］，术后曲马多用量高于STB组［（36.9±10.2） mg vs. （25.4±9.5） mg，P＜0.001］，膈神经阻滞发生率低于STB组（0 vs. 80%，P＜0.001），术后24 h QoR-15评分显著高于STB组［（76.3±12.2）分 vs. （66.4±11.6）分，P=0.003］；两组病人静息和活动时VAS评分、镇痛满意度评分、并发症发生率差异无统计学意义（P＞0.05）。结论 肩关节镜手术中应用HT-ESPB能达到与STB类似的麻醉和镇痛效果，且膈神经阻滞发生率更低，尽管其镇痛药补救需求更多，仍是STB一种可行的替代方案。     

改良经肋软骨膜入路胸腹神经阻滞与腹横肌平面阻滞用于腹腔镜袖状胃切除术的比较

目的 比较改良经肋软骨膜入路胸腹神经阻滞（M-TAPA）与腹横肌平面阻滞（TAPB）用于病态肥胖患者腹腔镜袖状胃切除术（LSG）的镇痛效果。
方法 选择2020年12月至2021年8月择期行LSG患者60例,男15例,女45例,年龄18～64岁,BMI≥35 kg/m²,ASA Ⅰ或Ⅱ级。采用随机数字表法分为三组：单纯全麻组（C组）、TAPB组（T组）和M-TAPA组（M组）,每组20例。全麻诱导前,T组和M组予0.25%罗哌卡因行神经阻滞操作,每侧30 ml。术后均行舒芬太尼PCIA。记录术中瑞芬太尼用量、术后48 h内镇痛泵舒芬太尼用量和术后补救镇痛例数。记录拔管后即刻及术后2、4、6、12、24、48 h静息和活动时VAS疼痛评分。记录术后首次肛门排气时间、术后首次下床活动时间。记录术后恶心呕吐、呼吸抑制等不良反应的发生情况。
结果 与C组比较,T组和M组术中瑞芬太尼用量、术后48 h内镇痛泵舒芬太尼用量明显减少,术后补救镇痛率明显降低,术后2、4、6、12 h静息和活动时VAS疼痛评分明显降低,术后首次肛门排气时间、术后首次下床活动时间明显缩短（P＜0.05）。与C组比较,术后24、48 h M组静息和活动时VAS疼痛评分明显降低（P＜0.05）。术后24、48 h C组和T组静息和活动时VAS疼痛评分差异无统计学意义。三组不良反应发生率差异无统计学意义。
结论 改良经肋软骨膜入路胸腹神经阻滞与腹横肌平面阻滞均可为腹腔镜袖状胃切除术后提供良好的镇痛效果,不升高不良反应发生率,且改良经肋软骨膜入路胸腹神经阻滞较腹横肌平面阻滞的镇痛持续时间更长。     

超声引导下罗哌卡因复合地塞米松腰方肌阻滞对全髋关节置换术患者术后镇痛的影响

目的 研究超声引导下腰方肌阻滞中罗哌卡因复合地塞米松对全髋关节置换术后镇痛的疗效。
方法 选择2019年12月至2020年12月行全髋关节置换术的患者90例,男40例,女50例,年龄65～78岁,ASA Ⅰ或Ⅱ级。采用随机分组的方法分成罗哌卡因复合地塞米松组（D组）,罗哌卡因组（Y组）和单纯静脉自控镇痛（PCIA）组（R组）,每组30例。D组术后以罗哌卡因100 mg复合地塞米松0.1 mg/kg为药液行腰方肌阻滞同时联合PCIA作为术后镇痛,Y组术后以单纯罗哌卡因100 mg为药液行腰方肌阻滞并联合PCIA为术后镇痛,R组则采用单纯PCIA作为对照。记录三组术后4、6、12、24和48 h静息和活动时VAS疼痛评分以及术后48 h内镇痛泵按压次数及曲马多补救例数。同时记录术后48 h内恶心呕吐、呼吸抑制和术后谵妄等不良反应发生情况,记录患者对术后镇痛的满意度。
结果 术后4、6、12、24和48 h D组和Y组静息和活动时VAS疼痛评分明显低于R组（P<0.05）,术后12、24 h D组的静息和活动时VAS疼痛评分明显低于Y组（P<0.05）。术后48 h D组和Y组内镇痛泵按压次数和曲马多补救例数明显少于R组（P<0.05）,且D组明显少于Y组（P<0.05）。术后48 h内D组和Y组恶心呕吐发生率明显低于R组（P<0.05）,且D组明显低于Y组（P<0.05）。三组均未发生呼吸抑制和术后谵妄。D组术后镇痛的满意度评分明显高于Y组和R组（P<0.05）。
结论 超声引导下罗哌卡因复合地塞米松腰方肌阻滞对全髋关节置换术患者术后镇痛的效果好,不良反应少,提高患者对术后镇痛的满意度。     

不同层面腰方肌阻滞对剖宫产产妇术后镇痛的影响

目的 探讨超声引导下前层胸腰筋膜下和前层胸腰筋膜外实施腰方肌阻滞（QLB）对剖宫产术后镇痛的影响。
方法 选择择期腰-硬联合麻醉下行剖宫产手术的产妇113例,年龄23～39岁,体重50～90 kg,ASA Ⅰ或Ⅱ级,孕期>37周。采用随机数字表法将产妇分为两组：前层胸腰筋膜下阻滞组（S组,n=57）和前层胸腰筋膜外阻滞组（E组,n=56）。所有产妇腰-硬联合麻醉用药相同,术毕连接患者自控静脉镇痛（PCIA）泵,S组术毕行超声引导下前层胸腰筋膜下阻滞,E组行超声引导下前层胸腰筋膜外阻滞。记录首次按压PCIA时间,术后24 h内PCIA有效按压次数以及布托啡诺用量。记录QLB实施后6、9、12、24、48 h静息和活动时VAS疼痛评分、BCS舒适度评分以及阻滞平面存在情况。记录头晕、恶心呕吐、肌力减退等不良反应发生情况。
结果 两组首次按压PCIA时间差异无统计学意义。S组术后24 h内PCIA有效按压次数、布托啡诺用量明显少于E组（P＜0.05）。QLB阻滞实施后不同时点静息和活动时VAS疼痛评分、BCS舒适度评分差异均无统计学意义。S组QLB实施后24 h阻滞平面存在的产妇比例明显高于E组（P＜0.05）。S组头晕发生率明显低于E组（P＜0.05）。
结论 超声引导下前层胸腰筋膜下实施腰方肌阻滞应用于剖宫产术后镇痛效果好,不良反应少,是剖宫产术后镇痛更适宜的阻滞层面。     

小剂量艾司氯胺酮复合舒芬太尼在脊柱矫形术后持续静脉镇痛中的应用

目的 探讨小剂量艾司氯胺酮复合舒芬太尼在脊柱矫形术后持续静脉镇痛中的应用效果。
方法 选择2020年6月至2021年6月择期行脊柱矫形术患者36例,男18例,女18例,年龄18～64岁,BMI 17～29 kg/m²,ASA Ⅰ—Ⅲ级。采用完全随机设计法将患者分为两组：艾司氯胺酮复合舒芬太尼组（ES组）和单纯舒芬太尼组（S组）,每组18例。ES组静注艾司氯胺酮0.25 mg/kg复合舒芬太尼1.5 μg/kg行PCIA,S组静注舒芬太尼2 μg/kg行PCIA。记录术后2、4、8、12、24、48、72 h静息和活动时NRS评分和Ramsay镇静评分。记录PCIA总按压次数、有效按压次数、PCIA中舒芬太尼总用量。记录术后住院时间、术后0～24、24～48、48～72 h头晕、恶心呕吐、尿潴留等不良反应发生情况。
结果 与S组比较,ES组术后2、4、8、12、24、48、72 h静息和活动时NRS评分明显降低（P＜0.05）,术后2、4、8、12 h Ramsay镇静评分明显升高（P＜0.05）,PCIA总按压次数、有效按压次数、PCIA中舒芬太尼总用量明显减少（P＜0.05）,术后0～24 h恶心呕吐发生率明显降低（P＜0.05）。
结论 小剂量艾司氯胺酮复合舒芬太尼用于脊柱矫形术后可以提供更好的镇痛、镇静作用,减少持续静脉镇痛舒芬太尼总用量,降低术后恶心呕吐发生率。     

腹股沟韧带上髂筋膜阻滞联合经静脉患者自控镇痛在老年髋关节置换术后的应用

目的：比较经静脉患者自控镇痛(patient controlled intravenous analgesia,PCIA)与腹股沟韧带上髂筋膜阻滞联合PCIA在老年髋关节置换术后的应用效果。方法：2019年6月至2021年6月84例老年患者接受髋关节置换术,其中42例以PCIA镇痛作为对照组,男18例,女24例;年龄60~78(70.43±3.67)岁;股骨颈骨折28例,股骨头坏死14例;另42例以腹股沟韧带上髂筋膜阻滞联合PCIA镇痛作为研究组,男20例,女22例;年龄61~76(69.68±3.74)岁;股骨颈骨折25例,股骨头坏死17例。分别于术后2、6、12、24、48 h进行疼痛视觉模拟评分(visual analogue scale,VAS)及Ramesay镇静评分。观察比较两组术后48 h的舒芬太尼总消耗量、PCIA总按压次数、术后首次下地时间、住院时间、不良反应发生率、镇痛满意度等随访结果。结果：两组术后随访9~24(13.85±2.67)个月。两组手术时间和术中出血量比较,差异无统计学意义(P＞0.05)。两组术后2 h的VAS比较,差异无统计学意义(P＞0.05),研究组术后6、12、24、48 h的VAS均低于对照组(P＜0.05)。研究组术后2、6、12 h的Ramesay镇静评分均高于对照组(P＜0.05),两组术后24、48 h的Ramesay评分比较差异无统计学意义(P＞0.05)。研究组术后48 h内舒芬太尼消耗量、PICA按压次数少于对照组(P＜0.05),术后首次下地时间早于对照组(P＜0.05)。研究组镇痛满意度高于对照组(P＜0.05)。两组住院时间、不良反应发生率、随访期间并发症比较差异无统计学意义(P＞0.05)。结论：腹股沟韧带上髂筋膜阻滞联合PCIA在老年髋关节置换术后镇痛和镇静效果显著,可减少舒芬太尼使用量及PCIA总按压次数,有利于患者早期下床活动,提高镇痛满意度。     

超声引导下髂筋膜间隙阻滞在老年患者全髋关节置换术中的应用

目的 探讨术前行超声引导下髂筋膜间隙阻滞在老年患者全髋关节置换术中的应用效果。
方法 回顾性分析择期在全身麻醉下行全髋关节置换术的老年患者98例,男40例,女58例,年龄≥65岁,BMI 16～28 kg/m²,ASA Ⅱ或Ⅲ级。根据术前是否行髂筋膜间隙阻滞分为两组：髂筋膜间隙阻滞组（F组,n=43）和对照组（C组,n=55）。根据性别、年龄、BMI、ASA分级、基础疾病、手术方式进行倾向评分匹配。收集手术时间、麻醉时间、术中出血量、术中舒芬太尼和瑞芬太尼用量、术后2、6、12、24、48 h静息和活动时NRS评分、首次下床活动时间、住院时间、术后48 h镇痛满意度评分、术后48 h内患者自控静脉镇痛（PCIA）有效按压次数以及术后48 h内PCIA舒芬太尼用量。记录术后输血、入ICU以及相关不良反应（包括肺部感染、尿路感染、心律失常、术后恶心呕吐、尿潴留、瘙痒、呼吸抑制、嗜睡）的发生情况。
结果 匹配后F组和C组各纳入患者43例。F组术中舒芬太尼和瑞芬太尼用量明显少于C组（P＜0.05）。F组术后2、6 h静息时NRS评分以及术后2、6、12、24、48 h活动时NRS评分明显低于C组（P＜0.05）。F组首次下床活动时间、住院时间明显短于C组（P＜0.05）,F组术后48 h镇痛满意度评分明显高于C组（P＜0.05）,F组术后48 h内PCIA有效按压次数以及PCIA舒芬太尼用量明显少于C组（P＜0.05）。F组术后恶心呕吐及尿潴留的发生率明显低于C组（P＜0.05）。两组手术时间、麻醉时间、术中出血量、术后12、24、48 h静息时NRS评分、术后输血、入ICU以及肺部感染、尿路感染、心律失常、术后瘙痒、嗜睡发生率差异均无统计学意义。
结论 术前行超声引导下髂筋膜间隙阻滞能为老年患者全髋关节置换术后提供良好镇痛,减少镇痛药物的使用,提高镇痛满意度,同时促进患者术后早期恢复。     

不同浓度罗哌卡因收肌管阻滞对全膝关节置换术后镇痛效果及股四头肌肌力的影响

目的 比较超声引导下采用不同浓度罗哌卡因行收肌管阻滞（ACB）对全膝置换术（TKA）后镇痛效果及股四头肌肌力的影响。
方法 选取拟在喉罩全麻下行单侧膝置换手术患者60例,男33例,女27例,年龄50~75岁,BMI 17~25 kg/m²,ASA Ⅰ—Ⅲ级,随机分为三组：0.25%罗哌卡因组（R1组）、0.375%罗哌卡因组（R2组）和0.5%罗哌卡因组（R3组）,每组20例。患者均于术毕即刻于超声下行术侧ACB。记录术后4、8、12、24、48 h静息和运动时的VAS评分,记录术前1 d、术后4、8、12、24、48 h的股四头肌肌力分级,记录术前1 d、术后24、48 h膝关节活动度（ROM）,并记录术后48 h内PCIA内舒芬太尼使用量,补救镇痛次数,恶心呕吐、尿潴留等并发症的发生情况。
结果 与术后4 h比较,术后12、24、48 h R1组静息和运动VAS疼痛评分明显升高（P＜0.05）。与R1组比较,术后12、24、48 h R2、R3组静息和运动VAS疼痛评分明显降低（P＜0.05）。与术前1 d比较,术后4、8、12、24 h R1组、R2组股四头肌肌力明显降低（P＜0.05）;术后4、8、12、24、48 h R3组股四头肌肌力明显降低（P＜0.05）。与R3组比较,术后48 h R1组、R2组股四头肌肌力明显升高（P＜0.05）。与术前1 d比较,术后24、48 h三组ROM明显降低（P＜0.05）;与R1组比较,术后24、48 h R2、R3组ROM明显升高（P＜0.05）。与R1组比较,R2、R3组术后48 h内PCIA内舒芬太尼使用量明显减少,补救镇痛率、恶心呕吐和尿潴留发生率明显降低（P＜0.05）。
结论 全膝关节置换术后镇痛采用0.375%罗哌卡因收肌管阻滞较0.25%浓度镇痛效果明显,减少术后阿片类药物使用量及并发症,较0.5%浓度有更强的股四头肌肌力及更高的膝关节活动度,有助于患者的术后快速康复。     

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.     

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.     

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.