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。     

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。     

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。     

超声引导下腹横筋膜平面阻滞与腹横肌平面阻滞在剖宫产术后镇痛中的效果比较

目的 比较超声引导下腹横筋膜平面(TFP)阻滞与腹横肌平面(TAP)阻滞在剖宫产术后镇痛中的效果。
方法 择期蛛网膜下腔阻滞下行剖宫产术产妇60例,年龄20～35岁,体重50～75 kg,ASA Ⅰ或Ⅱ级,采用随机数字表法分为两组：腹横筋膜平面阻滞组（TFP组）和腹横肌平面阻滞组（TAP组）,每组29例。术毕TFP组行超声引导下双侧腹横筋膜平面阻滞,TAP组行超声引导下双侧腹横肌平面阻滞,两组均每侧注射0.375%罗哌卡因1.25 mg/kg。术后均行曲马多PCIA,若VAS疼痛评分≥4分,肌肉注射曲马多100 mg行补救镇痛。记录术后6、12、24、36、48 h PCIA中曲马多累积用量;记录术后48 h内曲马多补救镇痛情况;记录镇痛期间恶心呕吐、局麻药中毒、呼吸抑制、穿刺部位血肿、穿刺部位感染、腹膜刺穿造成腹腔内注射等不良反应的发生情况。
结果 与TAP组比较,TFP组术后6、12、24、36、48 h PCIA中曲马多累积用量明显减少 （P＜0.05）,术后48 h内曲马多补救镇痛率明显降低 （P＜0.05）。两组镇痛期间恶心呕吐发生率差异统计学意义。两组均无其他不良反应发生。
结论 与超声引导下腹横肌平面阻滞比较,腹横筋膜平面阻滞可减少剖宫产术后阿片类药物用量,镇痛效果更佳。     

超声引导下腹股沟韧带上髂筋膜阻滞对老年患者股骨转子间骨折闭合复位预后的影响

目的 评价超声引导下腹股沟韧带上髂筋膜阻滞对老年股骨转子间骨折闭合复位预后的影响。
方法 选取2018年1月至2020年1月择期行股骨转子间骨折闭合复位手术患者50例,男42例,女8例,年龄78～91岁,BMI 18～25 kg/m²,ASA Ⅱ或Ⅲ级,采用随机数字表法分为两组：全身麻醉联合髂筋膜阻滞组（T组）和全身麻醉组（G组）,每组25例。T组患者在实施全身麻醉前20 min行超声引导下髂筋膜阻滞,于患侧腹股沟韧带上确定好髂筋膜位置,采用平面内操作技术于髂筋膜下给予0.25%罗哌卡因+0.67%利多卡因共30 ml,10～15 min后测定阻滞平面。G组仅接受全身麻醉。术后两组均行PCIA,配方：舒芬太尼150 μg+昂丹司琼24 mg+生理盐水稀释至100 ml,背景剂量2 ml/h,单次剂量0.5 ml,锁定时间15 min。采用VAS评分法评估疼痛程度,VAS疼痛评分≥4分时静脉注射羟考酮0.05 mg/kg行补救镇痛。记录麻醉诱导前（T0）、髓内针固定时（T1）、手术结束即刻（T2）、术后6 h（T3）动脉血乳酸（Lac）和血糖（Glu）浓度。记录手术时间、术中丙泊酚、瑞芬太尼用量、晶体液输入量、胶体液输入量、输液总量、出血量、尿量和去甲肾上腺素使用例数。记录术后6、8、12、24 h静息和运动时VAS疼痛评分,术后24 h内舒芬太尼用量及羟考酮使用例数。记录PACU停留时间、术后住院时间以及恶心呕吐、皮肤瘙痒、肺部炎症、阻滞部位感染等并发症情况。
结果 与G组比较,T1—T3时T组动脉血Lac、Glu浓度明显降低（P<0.05）;T组术中去甲肾上腺素使用率明显降低,术中瑞芬太尼用量、术后24 h内舒芬太尼用量明显减少,羟考酮使用率明显降低（P<0.05）;术后6、8、12 h T组静息及运动时VAS疼痛评分明显降低（P<0.05）;T组PACU停留时间、术后住院时间明显缩短,术后恶心呕吐发生率明显降低（P＜0.05）。两组术中丙泊酚用量、晶体液输入量、胶体液输入量、输液总量、出血量和尿量差异无统计学意义。两组术后皮肤瘙痒、肺部炎症、穿刺部位感染情况差异无统计学意义。
结论 与单独全身麻醉比较,联合超声引导下腹股沟韧带上髂筋膜阻滞降低应激水平,镇痛效果好,减少术后并发症,有助于促进患者术后康复,缩短住院时间。     

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。     

术前连续髂筋膜间隙阻滞对老年髋部骨折患者围术期睡眠质量及术后谵妄的影响

目的 探讨术前超声引导下连续髂筋膜间隙阻滞对老年髋部骨折患者围术期睡眠质量及术后谵妄的影响。
方法 选择老年髋部骨折患者121例,男55例,女66例,年龄65~90岁, BMI 18.5~25.0 kg/m²,ASA Ⅰ—Ⅲ级,采用随机数字表法分为两组：超声引导下连续髂筋膜间隙阻滞组（F组,n=61）和对照组（C组,n=60）。F组于入院后给予经超声引导下连续髂筋膜间隙阻滞,C组常规术前处理。两组采用相同的椎管内麻醉方案实施侧入路股骨头置换术,术后采用相同的术后镇痛方案。采用简易精神状态检查表（MMSE）评估入院后基础认知状态;采用匹兹堡睡眠质量指数（PSQI）评估入院前1个月整体睡眠质量。记录入院时（T1）、髂筋膜间隙阻滞后30 min（C组为入院后相同时间点）（T2）、入室时（T3）、摆放体位时（T4）的疼痛数字评分（NRS）。记录术前及术后7 d每天的里兹睡眠问卷（LSEQ）评分,记录术后7 d内谵妄的发生情况及术后住院时间。记录术后恶心、呕吐、日间嗜睡等不良反应的发生情况。
结果 与C组比较,F组T2—T4时NRS评分明显降低（P<0.05）,术前及术后1~3 d LSEQ评分明显升高（P<0.05）,术后7 d内谵妄发生率明显降低(P<0.05),谵妄持续时间、术后住院时间明显缩短(P<0.05),日间嗜睡发生率明显降低(P<0.05)。
结论 术前超声引导下连续髂筋膜间隙阻滞可改善老年髋部骨折患者围术期睡眠质量,降低术后谵妄发生率及缩短谵妄持续时间。     

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。     

超声引导下横突-胸膜中点阻滞与胸椎旁神经阻滞用于单孔胸腔镜手术后镇痛效果的比较

目的 比较超声引导下横突-胸膜中点阻滞(MTPB)与胸椎旁神经阻滞(TPVB)用于单孔胸腔镜手术术后镇痛的效果。
方法 选择择期行单孔胸腔镜手术患者80例,男36例,女44例,年龄18～65岁,BMI 19～28 kg/m²,ASA Ⅰ―Ⅲ级。采用随机数字表法分为MTPB组（M组）和TPVB组（P组）,每组40例。手术结束后M组行超声引导下MTPB,P组行TPVB,两组均注射0.5%罗哌卡因15 ml。两组患者术后均采用PCIA。记录神经阻滞操作时间、穿刺深度,记录术后2、6、12、24、48 h安静和咳嗽时VAS疼痛评分,记录镇痛泵首次按压时间、总按压次数、舒芬太尼使用量和补救镇痛例数,记录穿刺相关并发症、镇痛不良反应发生情况。
结果 与P组比较,M组神经阻滞操作时间明显缩短（P<0.05）,进针深度明显变浅（P<0.05）。术后2、6、12、24、48 h两组安静和咳嗽时VAS疼痛评分差异无统计学意义。两组患者术后镇痛泵首次按压时间、总按压次数、舒芬太尼用量和补救镇痛率差异无统计学意义。两组患者术后恶心、呕吐等不良反应差异无统计学意义。
结论 MTPB或TPVB联合术后PCIA应用于单孔胸腔镜手术患者,术后均可取得良好的镇痛效果,但MTPB操作简单、安全,可作为单孔胸腔镜手术患者术后镇痛方案的选择。     

超声引导下高位髂筋膜阻滞在经导管主动脉瓣置换术中的应用

目的 探索超声引导下高位髂筋膜阻滞用于经导管主动脉置换术的效果。
方法 收集2016年12月至2020年12月监测麻醉下行经导管主动脉置换术患者资料126例,男85例,女41例,年龄65～90岁,BMI 22～25 kg/m²,ASA Ⅲ或Ⅳ,术前诊断为主动脉瓣重度狭窄,NYHA Ⅲ或Ⅳ级且首次经历心脏手术。按照术中是否进行高位髂筋膜阻滞分为两组：对照组（C组,n=56）和联合组（T组,n=70）。C组仅采用监测麻醉,T组采用监测麻醉联合高位髂筋膜阻滞。采用卡钳法进行倾向值匹配。收集并记录性别、年龄、BMI、ASA分级、主动脉瓣口面积、主动脉瓣平均跨瓣压、合并症（冠心病、高血压、糖尿病）。记录手术时间、术中丙泊酚和舒芬太尼用量、术后补救镇痛情况、苏醒时间、ICU停留时间、术后住院时间、术后30 d死亡例数。记录术中呼吸抑制、术后恶心呕吐、谵妄/脑卒中的发生情况。
结果 44对患者资料匹配成功。匹配后,与C组比较,T组术中丙泊酚和舒芬太尼用量明显减少（P<0.05）,术后补救镇痛率明显降低（P<0.05）,术后苏醒时间、ICU停留时间和术后住院时间明显缩短（P<0.05）,术中呼吸抑制发生率和术后恶心呕吐发生率明显降低（P<0.05）。两组其余指标差异均无统计学意义。
结论 超声引导下高位髂筋膜阻滞用于经导管主动脉置换术可减少术中麻醉药物用量,缩短苏醒时间和ICU停留时间,减少术后补救镇痛和不良反应的发生,有助于早期康复。     

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.     

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.     

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.     

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.