利多卡因复合右美托咪定对腹腔镜全子宫切除患者术后恢复质量的影响

目的 观察麻醉诱导前静脉泵注利多卡因复合右美托咪定对腹腔镜全子宫切除患者术中阿片类药物用量和术后恢复质量的影响。
方法 选择择期行腹腔镜全子宫切除患者60例,年龄36～64岁,BMI 20.0~26.0 kg/m²,ASA Ⅰ或Ⅱ级。采用随机数字表法将患者分为两组：利多卡因+右美托咪定组(LD组)与对照组(C组),每组30例。LD组麻醉诱导前10 min 静脉泵注2%利多卡因1.5 mg/kg和右美托咪定0.5 μg/kg,随后分别泵注2%利多卡因1.5 mg·kg^-1·h^-1和右美托咪定0.4 μg·kg^-1·h^-1,手术结束前30 min停止输注。C组麻醉诱导前10 min静脉泵注等容量的生理盐水。两组围麻醉期持续输注瑞芬太尼。记录术中瑞芬太尼和丙泊酚总用量、手术结束前30 min内瑞芬太尼用量。记录术后2、6、12、24 h的VAS疼痛评分和术后补救镇痛例数。记录术前1 d与术后1 d QoR-40量表总分。记录术后24 h恶心、呕吐、口干和嗜睡等不良反应的发生情况。
结果 与C组比较,LD组术中瑞芬太尼和丙泊酚总用量、手术结束前30 min内瑞芬太尼用量明显减少、术后补救镇痛率明显降低(P<0.05),术后6、12、24 h 的VAS疼痛评分和术后恶心、呕吐发生率明显降低(P<0.05),术后1 d QoR-40量表总分和口干、嗜睡发生率明显升高(P<0.05)。
结论 麻醉诱导前静脉泵注利多卡因复合右美托咪定可减少术中阿片类药物用量,并在一定程度上改善腹腔镜全子宫切除患者术后恢复质量,降低术后VAS疼痛评分与恶心、呕吐发生率,但口干和嗜睡发生率升高。     

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。     

意识指数在老年患者胸腔镜肺叶切除术中的应用

目的 比较意识指数（IoC）与脑电双频指数（BIS）用于指导老年患者行胸腔镜肺叶切除术中的效果。

方法 选择2020年9月至2021年2月行胸腔镜肺叶切除术的老年患者64例,男38例,女26例,年龄65～79岁,BMI 18～30 kg/m²,ASA Ⅰ—Ⅲ 级。采用随机数字表法分为两组：IoC组和BIS组,每组32例。两组均采用双腔管全身麻醉。IoC组采用IoC监测,分为IoC1和IoC2,IoC1监测镇静程度,IoC2监测镇痛程度,调整丙泊酚和瑞芬太尼血浆靶浓度,维持IoC1值40～60,IoC2值35～45。BIS组采用BIS监测,调整丙泊酚血浆靶浓度维持BIS值40～60,根据HR和有创动脉压调整瑞芬太尼血浆靶浓度。记录术中丙泊酚、瑞芬太尼用量和血管活性药使用情况,苏醒时间和拔管时间。记录术后1、2和4 h静息和活动（咳嗽）时VAS疼痛评分和术中高血压、低血压、心动过速、心动过缓、术中知晓、体动等不良事件发生情况。

结果 与BIS组比较,IoC组术中瑞芬太尼用量明显减少（P<0.05）,血管活性药物使用率明显降低（P<0.05）。两组术中丙泊酚用量、苏醒时间和拔管时间,不同时点静息和活动时VAS疼痛评分,高血压、低血压、心动过速、心动过缓、术中知晓、体动等不良事件发生率差异无统计学意义。

结论 意识指数IoC1联合IoC2监测用于老年患者行胸腔镜肺叶切除术,可减少术中瑞芬太尼用量和血管活性药物的使用,但不影响丙泊酚用量。     

超声引导下耳大神经阻滞对中耳显微手术中瑞芬太尼血浆靶浓度的影响

目的 探讨超声引导下耳大神经阻滞（GANB）对中耳显微手术中瑞芬太尼血浆靶浓度的影响,评价其在中耳手术围术期少阿片或无阿片麻醉中的应用价值。
方法 选择2019年5月至2021年1月择期行中耳显微手术的患者66例,男35例,女31例,年龄18～60岁,BMI 18～28 kg/m²,ASA Ⅰ或Ⅱ级。采用随机数字表法将患者分为两组：超声引导下GANB组（B组）和对照组（C组）,每组33例。B组在麻醉诱导前10 min超声引导下注射0.5%罗哌卡因2 ml阻滞患侧耳大神经;C组行单纯全麻。两组全麻方案和用药相同。术中维持丙泊酚7 mg·kg^-1·h^-1静脉输注,通过调整瑞芬太尼血浆靶浓度（Cp_remi）维持HR 50～90次/分,SBP 95～125 mmHg。血流动力学指标达标并稳定后,此时Cp_remi为适宜浓度,维持此浓度至术毕。记录切皮后适宜Cp_remi和达到适宜Cp_remi后3 min的BIS,麻醉维持中瑞芬太尼和丙泊酚每小时用量和药物泵注时间,停药至喉罩拔除时间,PACU清醒后5 min、术后2、4、6 h NRS评分,术后6 h内补救镇痛例数。
结果 与C组比较,B组适宜Cp_remi明显降低（P＜0.05）,瑞芬太尼每小时用量明显减少（P＜0.05）,停药至喉罩拔除时间明显缩短（P＜0.05）,PACU清醒后5 min、术后2、4、6 h NRS评分明显降低（P＜0.05）,术后6 h内补救镇痛率明显降低（P＜0.05）。两组达到适宜Cp_remi后3 min的BIS、丙泊酚每小时用量、药物泵注时间差异无统计学意义。
结论 超声引导下GANB可以降低中耳显微手术中瑞芬太尼的血浆靶浓度,减少瑞芬太尼的用量,缩短喉罩拔除时间,同时术后早期镇痛效果更好。     

艾司氯胺酮对合并术前焦虑和认知功能下降妇科恶性肿瘤患者的影响

目的： 探讨艾司氯胺酮对合并术前焦虑和认知功能下降的妇科恶性肿瘤患者术后焦虑及认知功能的影响。
方法： 选择择期行妇科恶性肿瘤切除术患者89例,年龄18～64岁,BMI 18～28 kg/m²,ASA Ⅱ或Ⅲ级,术前1 d医院焦虑抑郁量表（HADS）中焦虑亚量表评分≥8分且蒙特利尔认知评分量表（MoCA）<26分。采用随机数字表法将患者分为两组：艾司氯胺酮组（S组,n=45）和生理盐水组（C组,n=44）。S组麻醉诱导时静注艾司氯胺酮0.2 mg/kg,麻醉维持时泵注艾司氯胺酮0.25 mg·kg^-1·h^-1,术后使用艾司氯胺酮PCIA镇痛。C组在麻醉诱导、维持和PCIA镇痛时予以等容量的生理盐水,其余用药同S组。于术前1 d、术后1、3 d采用HADS及MoCA评估患者焦虑情绪和认知功能。检测术前1 d和术后3 d肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）、S100钙结合蛋白（S100β）、脑源性神经营养因子（BDNF）浓度。记录术中瑞芬太尼用量、麻黄碱使用情况,入PACU后10 min的Ramsay镇静评分、拔管时间、术后48 h内PCIA总按压次数、有效按压次数、术后补救镇痛情况以及术后48 h内高血压、低血压、恶心呕吐、寒战、头晕和发热等不良反应发生情况。
结果： 与C组比较,S组术后1、3 d焦虑发生率明显降低、MoCA认知评分明显升高,TNF-α、IL-6、S100β浓度明显降低,BDNF浓度明显升高,术中瑞芬太尼用量明显减少,Ramsay镇静评分明显升高,术后48 h内PCIA总按压次数、有效按压次数明显减少,术后发热发生率明显降低（P<0.05）。两组麻黄碱使用率、拔管时间、术后补救镇痛率及术后48 h内高血压、低血压、恶心呕吐、寒战和头晕发生率差异无统计学意义。
结论： 艾司氯胺酮可降低炎性因子浓度,减轻神经损伤,缓解妇科恶性肿瘤患者焦虑状态及减轻认知功能损伤。     

吸入和全凭静脉麻醉用于患儿纤维支气管镜检查效果的比较

目的 比较吸入七氟醚保留自主呼吸和丙泊酚-瑞芬太尼静脉麻醉压力控制呼吸两种麻醉管理方式用于患儿纤维支气管镜检查的安全性及有效性。
方法 选择行纤维支气管镜检查患儿72例,男37例,女35例,年龄2～4岁,BMI 12～19 kg/m²,ASA Ⅰ或Ⅱ级,采用随机数字表法将患儿随机分为两组：吸入七氟醚保留自主呼吸组(吸入组)和丙泊酚-瑞芬太尼静脉麻醉压力控制呼吸组(静脉组),每组36例。吸入组给予七氟醚诱导,置入喉罩后持续吸入2.5%～3.0%七氟醚,保留自主呼吸维持麻醉。静脉组经外周静脉给予丙泊酚4 mg/kg+瑞芬太尼1 μg/kg缓慢推注诱导,置入喉罩后静脉泵入丙泊酚9 mg·kg^-1·h^-1、瑞芬太尼0.2 μg·kg^-1·min^-1,压力控制通气维持麻醉。记录麻醉诱导时间、诊疗时间、喉罩拔除时间和完全清醒时间。记录从开始给药到患儿完全清醒过程中低血压、心动过缓、低氧血症、镜检操作反应的发生情况以及镜检医师满意度评分。
结果 静脉组麻醉诱导时间明显短于吸入组［(1.8±0.3)min vs (3.1±0.8)min,P<0.05］,完全清醒时间明显短于吸入组［(11.7±4.6)min vs (13.6±5.1)min,P<0.05］,喉罩拔除时间明显长于吸入组［(5.6±1.2)min vs (0.5±0.2)min,P<0.01］,镜检操作反应发生率明显低于吸入组[14例（39%） vs 25例（69%）,P<0.01]。两组诊疗时间、低血压、心动过缓以及低氧血症的发生率差异无统计学意义。静脉组镜检医师满意度评分明显高于吸入组［8.5(8.1～9.0)分vs 7.4(7.2～7.9)分,P<0.01］。
结论 患儿纤维支气管镜检查中,丙泊酚-瑞芬太尼静脉麻醉压力控制呼吸优于吸入七氟醚保留自主呼吸。     

不同浓度罗哌卡因竖脊肌平面阻滞在腹腔镜下胃癌根治术中的应用效果

目的 观察不同浓度罗哌卡因竖脊肌平面阻滞（ESPB）对腹腔镜下胃癌根治术患者术中镇痛效果和炎性因子的影响。
方法 择期行腹腔镜胃癌根治术患者80例,男54例,女26例,年龄40～65岁,BMI 18～25 kg/m²,ASA Ⅰ或Ⅱ级,采用随机数字表法将患者分为四组,每组20例。S1、S2、S3组行双侧ESPB,每侧分别注射0.25%、0.375%、0.5%罗哌卡因,随后行全身麻醉;C组行单纯全身麻醉。术中采用全凭静脉麻醉,术毕行舒芬太尼PCIA。记录阻滞起效时间和持续时间;记录术后2、8、12、24、48 h静息和运动时VAS疼痛评分;记录术中舒芬太尼用量、术后48 h内镇痛泵有效按压次数和舒芬太尼追加情况。记录术后2、8、12、24 h血清IL-6和IL-10浓度;记录术后呼吸抑制、恶心呕吐、局麻药中毒等不良反应情况。
结果 与S1组比较,S2组、S3组阻滞起效时间明显缩短（P<0.05）;与S2组比较,S3组阻滞起效时间明显缩短（P<0.05）。三组阻滞持续时间差异无统计学意义。与C组比较,S1组、S2组、S3组术后2、8、12 h静息和运动时VAS疼痛评分明显降低（P<0.05）;与S1组比较,S2组、S3组术后8 h静息和运动时VAS疼痛评分明显降低（P<0.05）。与C组比较,S1组、S2组、S3组术中舒芬太尼用量和术后48 h内镇痛泵有效按压次数明显减少（P<0.05）。与S1组比较,S2组、S3组术后48 h内镇痛泵按压次数明显减少（P<0.05）。与C组比较,S2、S3组术后追加舒芬太尼例数明显减少（P<0.05）。与C组比较,术后8、12 h S1组、S2组、S3组IL-6浓度明显降低,IL-10浓度明显升高（P<0.05）。四组术后呼吸抑制、恶心呕吐发生率差异无统计学意义。S3组术后有1例（5%）出现肌肉震颤的局麻药中毒反应。
结论 超声引导下0.375%罗哌卡因ESPB可减少腹腔镜下胃癌根治术的围术期阿片类药物用量,镇痛效果确切,同时减轻胃癌患者术后炎症反应。     

前锯肌平面阻滞对心肺转流下胸腔镜心脏手术患者应激反应和术后镇痛的影响

目的 探讨前锯肌平面阻滞（SAPB）对心肺转流（CPB）下胸腔镜心脏手术患者应激反应和术后镇痛的影响。
方法 选择2018年1月至2019年3月行CPB下胸腔镜心脏手术患者40例,男25例,女15例,年龄18～64岁,BMI 18～28 kg/m²,ASA Ⅲ级。采用随机数字表法分为两组：SAPB组(S组)和对照组(C组),每组20例。S组于麻醉诱导前行超声引导下SAPB,在前锯肌表面缓慢注射0.5%罗哌卡因20 ml,30 min后测定阻滞效果,满意后实施全凭静脉麻醉。C组不做处理。两组采用相同的全凭静脉麻醉方法,术毕均行静脉自控镇痛。分别于麻醉诱导前（T1）、CPB前（T2）、CPB结束时（T3）、手术结束时（T4）、手术结束后24 h（T5）抽取静脉血,测血浆皮质醇（Cor）、肾上腺素（E）、血糖（Glu）、白细胞介素-6（IL-6）、白细胞介素-10（IL-10）的浓度。记录术中及术后24 h舒芬太尼的用量、苏醒时间、气管拔管时间、心胸外科重症监护室（ICU）停留时间、术后24 h的VAS疼痛评分以及术后并发症发生情况。
结果 与T1时比较,T2—T5时两组血清Cor、E、Glu、IL-6浓度明显升高,血清IL-10浓度明显降低（P＜0.05）。与C组比较,T2—T5时S组Cor、E、Glu、IL-6浓度明显降低,IL-10浓度明显升高,术中及术后24 h舒芬太尼用量明显减少,术后24 h静息和活动时VAS疼痛评分明显降低,苏醒时间、气管拔管时间、心胸外科ICU停留时间明显缩短（P＜0.05）。两组术后恶心呕吐、肺部感染、低氧血症、肾功能失代偿等并发症发生率差异无统计学意义。
结论 对心肺转流下胸腔镜心脏手术患者实行超声引导前锯肌平面阻滞联合全凭静脉麻醉,可明显降低应激反应,术后镇痛效果更好。     

咪达唑仑对术前中重度焦虑老年患者结直肠癌根治术后谵妄的影响

目的 探讨术前短期口服咪达唑仑对术前合并中重度焦虑老年患者结直肠癌根治术后谵妄的影响。
方法 选择择期行腹腔镜结直肠癌根治术的老年患者80例，男32例，女48例，年龄65～79岁，BMI 21～27 kg/m²，ASA Ⅱ或Ⅲ级，入院时状态特质焦虑量表（STAI-S）评分≥38分。采用随机数字表法将患者分为两组：对照组和咪达唑仑组，每组40例。咪达唑仑组予咪达唑仑7.5 mg每晚一次，连续服药3～4 d，直到术前1 d；对照组予外观相似的安慰剂半片。记录术前1 d STAI-S评分与术后3 d内谵妄的发生情况，记录入室时、麻醉诱导后30 min、1、2 h、拔管后30 min HR和MAP，记录术中丙泊酚、瑞芬太尼、右美托咪定用量及间羟胺使用情况，记录拔管后30 min、术后24、72 h视觉模拟评分（VAS）、曲马多使用情况以及拔管时间。
结果 与对照组比较，咪达唑仑组术前1 d STAI-S评分、术后谵妄发生率、术中间羟胺使用率、拔管后30 min、术后24 h VAS疼痛评分、曲马多使用率明显降低（P<0.05）。两组术中丙泊酚、瑞芬太尼、右美托咪定用量和拔管时间差异无统计学意义。
结论 术前口服咪达唑仑可有效降低合并术前中重度焦虑老年患者结直肠癌根治术后谵妄的发生。     

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。     

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.