足踝手术后连续腓肠肌平面阻滞的镇痛效果

目的：探索连续腓肠肌平面阻滞镇痛用于足踝部手术患者术后镇痛效果。
方法：选择全麻下行足踝部择期手术患者42例,男19例,女23例,年龄18～64岁,BMI 18～28 kg/m²,ASAⅠ—Ⅲ级。将患者随机分为两组：连续腓肠肌平面阻滞镇痛组（CN组）和患者自控静脉镇痛（PCIA）组（I组）,每组21例。CN组术毕行连续腓肠肌平面阻滞镇痛,配方为0.125%罗哌卡因300 ml,背景剂量为3 ml/h,单次给药剂量为 8 ml,锁定时间为25 min。I组术毕使用羟考酮PCIA,配方为羟考酮30 mg、托烷司琼6 mg加生理盐水至150 ml,输注速度0.5 ml/h,单次追加剂量5 ml。观察两组术后0～16、16～24、24～48、0～48 h时段静息和活动时NRS评分曲线下面积（AUC）,1、8、16、24、32、48 h静息和活动时NRS评分,CN组术后胫神经和腓总神经运动功能恢复时间、羟考酮滴定量、术后48 h内补救镇痛药物的吗啡当量累计使用量、补救镇痛次数、补救镇痛率、首次下床活动时间、术后恶心呕吐的发生情况和患者满意度评分。
结果：与I组比较,CN组0～16、16～24、24～48、0～48 h静息和活动时NRS评分AUC明显降低（P<0.01）,术后1、8、16、24、32、48 h NRS评分明显降低（P<0.01）,CN组16 h有10例（50%）患者腓总神经运动功能恢复,24 h有17例（85%）患者腓总神经运动功能恢复,32～48 h所有患者腓总神经运动功能恢复,48 h内所有患者胫神经运动功能正常。与I组比较,CN组吗啡当量累计使用量和补救镇痛次数明显减少（P<0.01）,补救镇痛率明显降低（P<0.01）,患者满意度评分明显升高（P<0.01）。两组羟考酮滴定量、首次下床活动时间,恶心呕吐发生率差异无统计学意义。
结论：超声引导下连续腓肠肌平面阻滞可以实现胫神经运动和感觉阻滞分离,可在足踝手术后提供良好且持续的镇痛效果。     

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。     

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。     

智能化自控静脉镇痛在老年患者腹腔镜结直肠癌根治术后应用的效果

目的 研究智能化患者自控静脉镇痛（Ai-PCIA）在老年患者腹腔镜下结直肠癌根治术后应用的效果。
方法 选择2019年7月至2021年5月择期行腹腔镜结直肠癌根治术的老年患者60例,男40例,女20例,年龄≥65岁,ASA Ⅱ或Ⅲ级。采用随机数字表法将患者分为两组：Ai-PCIA组（A组）和传统PCIA组（C组）,每组30例。A组通过智能化无线镇痛系统+术后每日2次随访进行术后镇痛管理和效果评价,C组通过病房医师反馈+术后每日2次随访的方式进行镇痛管理和效果评价,术后随访在8：00—9：00时和17：00—18：00进行。记录术后2、4、8、12、24、48 h静息和活动时疼痛数字评分（NRS）,术前1 d、术后第1天和第2天理查兹-坎贝尔睡眠量表（RCSQ）评分,术后48 h内镇痛泵总按压次数、有效按压次数、舒芬太尼总用量、补救镇痛例数,术后住院时间,术后48 h内不良反应和心血管不良事件发生情况。
结果 术后8、12、24 h,A组静息时NRS评分明显低于C组（P＜0.05）,术后8、12、24、48 h,A组活动时NRS评分明显低于C组（P＜0.05）。术后第1天、第2天A组RCSQ评分明显高于C组（P<0.05）。两组术后48 h内镇痛泵总按压次数、有效按压次数、舒芬太尼总用量和补救镇痛率差异无统计学意义。A组术后住院时间明显短于C组（P＜0.05）。两组术后48 h内不良反应和心血管不良事件发生率差异无统计学意义。
结论 Ai-PCIA可以提高老年患者腹腔镜结直肠癌根治术后镇痛效果,改善睡眠质量,缩短术后住院时间。     

纳布啡不同镇痛泵参数用于剖宫产术后镇痛的比较

目的：比较三种不同参数纳布啡患者自控静脉镇痛（PCIA）用于剖宫产术后镇痛的效果。
方法：选择剖宫产术后的产妇179例,年龄18～45岁,BMI 20～35 kg/m²,ASA Ⅰ或Ⅱ级,术后均给予PCIA（纳布啡2 mg/kg+托烷司琼8 mg/100 ml,间隔时间15 min,极限量10 ml/h）。将产妇随机分成三组：对照组（C组,背景量2 ml/h,单次按压2 ml,n=60）、低背景量组（L组,背景量1 ml/h,单次按压3 ml,n=62）和无背景量组（N组,背景量0 ml/h,单次按压4 ml,n=57）。记录术后2、6、12、24、48 h静息和活动时VAS疼痛评分、纳布啡消耗量。记录术后48 h内PCIA按压情况、术后首次肛门排气时间、术后住院时间、Ramsay镇静评分和术后恶心呕吐、头晕、感染等不良反应的发生情况。
结果：与C组比较,N组术后6、12 h静息时VAS疼痛评分明显升高（P<0.05）,L组和N组术后24、48 h纳布啡消耗量明显减少,术后首次肛门排气时间明显缩短,头晕发生率明显降低（P<0.05）,N组术后住院时间明显缩短（P<0.05）。与L组比较,N组术后12 h静息和活动时VAS疼痛评分明显升高,术后48 h纳布啡消耗量明显减少,总按压次数和有效按压次数明显增加,术后首次肛门排气时间明显缩短（P<0.05）。三组Ramsay镇静评分和术后恶心呕吐、感染发生率差异无统计学意义。
结论：低背景量（1 ml/h）纳布啡PCIA可在充分镇痛的同时,减少阿片类药物用量,降低相关不良反应发生率,缩短术后首次肛门排气时间,可作为纳布啡PCIA用于剖宫产术后镇痛参数设置的优先选择。     

超声引导下竖脊肌平面阻滞对多发肋骨骨折患者术后早期呼吸功能的影响

目的：探讨超声引导下竖脊肌平面阻滞（ESPB）对多发肋骨骨折（MRFs）患者术后早期呼吸功能和炎性因子的影响。
方法：选择2019年2月至2021年12月择期行多发肋骨骨折手术患者58例,男42例,女16例,年龄18～64岁,BMI 18.5～30.0 kg/m²,ASA Ⅰ或Ⅱ级。采用随机数字表法将患者分为两组：ESPB联合全身麻醉组（E组）和单纯全身麻醉组（G组）,每组29例。E组于麻醉诱导后在侧卧位下实施超声引导下ESPB,给予0.5%罗哌卡因0.4 ml/kg。记录麻醉诱导前、出PACU时、术后24、48 h的用力肺活量（FVC）、动脉血气分析、静息和咳嗽时VAS疼痛评分。记录术后0～24 h、24～48 h的PCIA有效按压次数和补救镇痛情况。记录麻醉诱导前、术后24、48 h的IL-6和TNF-α浓度。
结果：与G组比较,E组出PACU时、术后24、48 h的FVC明显增大（P<0.05）,PaCO₂、静息和咳嗽时VAS疼痛评分明显降低（P<0.05）。与G组比较,E组术后0～24 h、24～48 h的PCIA有效按压次数和补救镇痛率明显降低（P<0.05）。与G组比较,E组术后24、48 h的IL-6和TNF-α浓度明显降低（P<0.05）。
结论：超声引导下ESPB可为MRFs患者提供良好的术后镇痛,促进术后早期呼吸功能的恢复。     

低每搏量变异度指导的液体治疗对老年患者肺叶切除术后恢复质量的影响

目的 探究低每搏量变异度（SVV）指导的液体治疗对老年患者肺叶切除术后恢复的影响。

方法 选择2022年2月至2023年1月择期胸腔镜下肺叶切除术的老年患者100例,男50例,女50例,年龄65～75岁,BMI 18～24 kg/m²,ASA Ⅱ或Ⅲ级。采用随机数表法将患者分为两组：低SVV阈值目标导向液体治疗（GDFT）组（G组）和对照组（C组）,每组50例。G组8%＜SVV≤10%,C组10%＜SVV≤13%。记录麻醉时间、手术时间、单肺通气（OLV）时间,记录入手术室即刻（T₀）、插管即刻（T₁）、OLV开始即刻（T₂）、手术开始即刻（T₃）、OLV结束即刻（T₄）和术毕（T₅）时的HR和MAP。记录术中液体出入量以及各种血管活性药使用情况。记录术前24 h和术后24、48 h血浆胃动素（MTL）、胃泌素（GAS）、肠型脂肪酸结合蛋白（IFABP）浓度。记录术后2、6、12、24、48 h静息时VAS疼痛评分以及术后48 h内PCIA有效按压次数、PCIA总按压次数以及补救镇痛例数。记录术后首次肛门排气时间、首次排便时间、首次下床活动时间、术后住院时间、胃肠道并发症（恶心呕吐、腹胀）发生情况。

结果 与C组比较,G组T₁—T₅时MAP、术后24、48 h血浆MTL和GAS浓度均明显升高（P<0.05）,术后24、48 h血浆IFABP浓度、术中胶体输注量和总液输注量均明显降低（P<0.05）,术后首次肛门排气时间、首次排便时间、首次下床活动时间和术后住院时间均明显缩短（P<0.05）。两组尿量、出血量、术后2、6、12、24、48 h静息时VAS疼痛评分、术后48 h内PCIA有效按压次数、PCIA总按压次数、补救镇痛率差异均无统计学意义。

结论 低SVV阈值（8%＜SVV≤10%）GDFT能很好地促进胃液分泌和肠黏膜屏障功能恢复,对老年患者肺叶切除术后胃肠功能的恢复有积极作用。     

艾司氯胺酮联合胸椎旁神经阻滞对胸腔镜肺癌根治术后恢复质量的影响

目的 探讨艾司氯胺酮联合胸椎旁神经阻滞（TPVB）对胸腔镜肺癌根治术后恢复质量的影响。

方法 选择2021年10月至2022年8月行胸腔镜肺癌根治术患者111例，男50例，女61例，年龄18～64岁，BMI 18～30 kg/m²，ASA Ⅰ或Ⅱ级。采用随机数字表法将患者分为两组：艾司氯胺酮组（S组，n=55）和对照组（C组，n=56）。术前30 min两组均行T4椎旁神经阻滞。S组在麻醉诱导后静注艾司氯胺酮0.1 mg/kg，术中泵注艾司氯胺酮0.12 mg·kg^-1·h^-1至缝皮，术后采用患者自控静脉镇痛（PCIA），镇痛泵配方：羟考酮50 mg、艾司氯胺酮25 mg，生理盐水稀释至100 ml。C组麻醉诱导后和术中给予与S组同等剂量的生理盐水，镇痛泵配方：羟考酮50 mg，加生理盐水稀释至100 ml。记录术前1 d、术后 1、2、3 d 15项恢复质量量表（QoR-15）评分，术中舒芬太尼、瑞芬太尼用量和呼气末七氟醚浓度，拔管时间和PACU停留时间，术后6、12、24、48 h静息和活动（咳嗽）时疼痛数字评分（NRS评分），术后24、48 h羟考酮用量，镇痛泵总按压次数和有效按压次数，术后48 h内头晕、恶心呕吐（PONV）、谵妄、幻觉、噩梦、嗜睡、便秘等不良反应发生情况和患者满意度。

结果 与C组比较，S组术后1、2、3 d QoR-15评分明显升高（P<0.05），术后24、48 h静息时NRS评分、术后6、12、24、48 h活动时NRS评分和羟考酮用量明显下降（P<0.05），术后镇痛泵总按压次数和有效按压次数明显减少（P<0.05），患者满意度明显升高（P<0.05）。两组术中舒芬太尼、瑞芬太尼用量、呼气末七氟醚浓度差异无统计学意义。两组术后48 h内头晕、PONV、谵妄、幻觉、噩梦、嗜睡、便秘等不良反应差异无统计学意义。

结论 在胸腔镜肺癌根治术中，麻醉后应用艾司氯胺酮0.1 mg/kg，术中以0.12 mg·kg^-1·h^-1泵注艾司氯胺酮并在镇痛泵中加入艾司氯胺酮0.25 mg/ml，联合胸椎旁神经阻滞可减轻术后急性疼痛且不增加术后不良反应，提升患者术后恢复质量。     

小剂量氢吗啡酮复合纳布啡用于胃肠道手术后患者自控静脉镇痛的效果

目的 对比小剂量或无背景剂量氢吗啡酮复合纳布啡用于胃肠道手术后患者自控静脉镇痛（PCIA）的效果。

方法 选择择期行胃肠道手术的患者147例，男105例，女42例，年龄18～80岁，BMI 18～35 kg/m²，ASAⅠ—Ⅲ级。采用随机数字表法将患者分为两组：小剂量氢吗啡酮组（SD组，n=76）和无背景剂量氢吗啡酮组（ND组，n=71）。术后48 h内行PCIA，镇痛药配方为氢吗啡酮10 mg、纳布啡40 mg，加生理盐水稀释至100 ml。镇痛泵参数设患者自控镇痛2 ml，锁定时间10 min，SD组设背景剂量1 ml/h，ND组无背景剂量。记录术后24和48 h静息和活动（咳嗽）时VAS疼痛评分、镇痛泵总按压次数和有效按压次数、镇痛泵用药量、术后48 h内补救镇痛情况和补救止吐情况、术后首次肛门排气时间和术后住院时间。使用线性回归模型进行敏感性分析探讨两种术后镇痛方案在性别、年龄、手术部位和手术方式等不同亚组治疗效果的差异，并分析不同亚组间的交互作用。记录恶心呕吐、头晕、嗜睡、呼吸抑制、瘙痒等不良反应发生情况。

结果 与ND组比较，SD组术后24和48 h静息和活动时VAS疼痛评分明显降低(P<0.01)，镇痛泵总按压次数和有效按压次数明显减少（P<0.01），镇痛泵用药量明显升高（P<0.01），术后48 h补救镇痛率明显降低（P<0.05）。两组术后48 h补救止吐率、术后首次肛门排气时间和术后住院时间差异无统计学意义。亚组分析显示行开腹手术的患者更能从小剂量PCIA镇痛方案中获益。两组术后48 h恶心呕吐、头晕和嗜睡发生率差异无统计学意义。两组无一例发生呼吸抑制和瘙痒。

结论 与无背景剂量比较，采用氢吗啡酮0.1 mg/h复合纳布啡0.4 mg/h的小剂量PICA输注模式用于胃肠道手术后镇痛效果更佳，且不增加术后不良反应。     

艾司氯胺酮与硫酸镁用于腹腔镜全子宫切除术后镇痛效果的比较

目的 观察和比较艾司氯胺酮与硫酸镁用于腹腔镜全子宫切除术后镇痛的效果。
方法 选择择期在全麻下行腹腔镜全子宫切除术患者135例，年龄18～64岁，BMI 18.5～28.0 kg/m²，ASA Ⅰ或Ⅱ级。采用随机数字表法将患者随机分为两组：艾司氯胺酮组（E组，n=67）和硫酸镁组（M组，n=68）。E组在手术开始前静脉注射艾司氯胺酮0.25 mg/kg，随后持续静脉泵注0.15 mg·kg^-1·h^-1；M组在手术开始前静脉注射硫酸镁50 mg/kg，随后持续静脉泵注8 mg·kg^-1·h^-1。术后行患者自控静脉镇痛（PCIA），配方为氢吗啡酮0.1 mg/kg+帕洛诺司琼0.25 mg。记录术中丙泊酚、瑞芬太尼用量和苏醒时间。记录术后2、6、12、24、48 h氢吗啡酮消耗量（等效界值为0.25 mg）、静息和活动时VAS疼痛评分。记录术后0~2 h、2~6 h、6~12 h、12~24 h和24~48 h内镇痛泵按压次数。记录术后补救镇痛、术后24 h内不良反应发生情况。
结果 与M组比较，E组术中丙泊酚及瑞芬太尼用量明显增加（P＜0.05），苏醒时间明显延长（P＜0.05）。两组术后2、6、12、24、48 h氢吗啡酮消耗量、静息和活动时VAS疼痛评分、术后0~2 h、2~6 h、6~12 h、12~24 h和24~48 h内镇痛泵按压次数、术后补救镇痛率和术后24 h内不良反应发生率差异无统计学意义。
结论 艾司氯胺酮可为腹腔镜全子宫切除术患者提供与硫酸镁相似的术后镇痛效果。     

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.     

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.