复合丙泊酚时阿芬太尼抑制患儿无痛皮肤磨削术中体动反应的半数有效剂量

目的 探讨复合丙泊酚时阿芬太尼抑制患儿无痛皮肤磨削术中体动反应的半数有效剂量（ED₅₀）。
方法 选择2021年7—11月择期行无痛皮肤磨削术患儿24例，男11例，女13例，年龄5～10岁，BMI 12～20 kg/m²，ASA Ⅰ或Ⅱ级。所有患儿均给予丙泊酚2 mg/kg复合阿芬太尼静脉麻醉。采用Dixon序贯法进行研究，阿芬太尼初始剂量10 μg/kg，下一例患儿剂量由上一例患儿体动反应决定，若术中体动反应阳性，下一例患儿阿芬太尼剂量增加1 μg/kg；若术中体动反应阴性，则下一例患儿阿芬太尼剂量减少1 μg/kg，重复此过程直到出现7个拐点终止研究。采用Probit法计算阿芬太尼的ED₅₀、95%有效剂量（ED₉₅）及其95%可信区间（CI）。
结果 复合丙泊酚时阿芬太尼抑制体动反应的ED₅₀为9.58 μg/kg（95%CI 8.97～10.21 μg/kg），ED₉₅为10.74 μg/kg（95%CI 10.12～14.01 μg/kg）。
结论 复合丙泊酚2 mg/kg时阿芬太尼用于患儿无痛皮肤磨削术的ED₅₀为9.58 μg/kg(95%CI 8.97~10.21 μg/kg)。     

艾司氯胺酮对保留自主呼吸全身麻醉胸腔镜肺结节切除术中低氧血症的影响

目的 探讨艾司氯胺酮对保留自主呼吸全身麻醉下行胸腔镜周围性肺结节切除术患者呼吸、循环和急性期炎性因子的影响。

方法 选择择期拟在全身麻醉下行胸腔镜周围性肺结节楔形切除术的患者84例,男45例,女39例,年龄18～64岁,BMI 18～25 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（E组）和舒芬太尼组（S组）,每组42例。两组麻醉诱导前 10 min分别恒速静脉泵注右美托咪定0.4 μg/kg,首量泵注结束后行胸椎旁神经阻滞（TPVB）。E组麻醉诱导给予艾司氯胺酮0.5 mg/kg,术中维持艾司氯胺酮0.5 mg·kg^-1·h^-1持续泵注。S组麻醉诱导给予舒芬太尼0.1 μg/kg,术中维持瑞芬太尼0.05 μg·kg^-1·min^-1持续泵注。两组其余麻醉诱导和维持药物一致。记录术中低氧血症、心动过缓、低血压和体动发生情况。记录麻醉诱导前（t0）、置入喉罩后（t1）、打开胸膜后30 min（t2）、拔除喉罩前（t3）、送返病房前（t4）的HR、MAP、SpO₂、PaCO₂和PaO₂。记录t1、t2、t3 时VT、RR。于t0 及术后24 h（t5）时抽取肘正中静脉血3 ml,检测TNF-α、IL-6浓度。记录术后恶心呕吐、幻觉、谵妄、噩梦发生情况,口腔分泌物量和术后住院时间。

结果 与S组比较,E组术中低氧血症、心动过缓、低血压和体动发生率明显降低（P＜0.05）。与t0 时比较,S组t1时HR明显减慢,MAP明显降低,t1、t2、t3 时SpO₂明显降低（P＜0.05）。与S组比较,E组t1、t2、t3时SpO₂明显升高（P＜0.05）,t1、t2、t3、t4 时PaCO₂明显降低、PaO₂明显升高（P＜0.05）,t1、t2 时VT明显增大、RR明显增快（P＜0.05）, t5 时静脉血TNF-α和IL-6浓度明显降低（P＜0.05）,恶心呕吐发生率明显降低,术后住院时间明显缩短（P＜0.05）。两组幻觉、谵妄、噩梦发生率和口腔分泌物量差异无统计学意义。

结论 艾司氯胺酮可以降低保留自主呼吸全身麻醉下周围性肺结节切除术患者术中呼吸抑制的发生率,维持血流动力学稳定,减轻急性期炎症反应,缩短术后住院时间。     

复合不同剂量艾司氯胺酮时舒芬太尼引起呼吸抑制半数有效剂量的比较

目的 比较复合不同剂量艾司氯胺酮时舒芬太尼引起全麻患者呼吸抑制的半数有效剂量（ED₅₀）。
方法 选择2022年2—10月择期行气管插管全麻手术的患者150例，男86例，女64例，年龄20～50岁，BMI 18～24 kg/m²，ASA Ⅰ或Ⅱ级。将患者随机分为三组：A组、B组和C组，每组50例。A组静注咪达唑仑0.03 mg/kg；B组静注咪达唑仑0.03 mg/kg和亚麻醉剂量艾司氯胺酮0.25 mg/kg；C组静注咪达唑仑0.03 mg/kg和麻醉剂量艾司氯胺酮0.5 mg/kg；5 min后三组单次静注舒芬太尼。舒芬太尼单次注射剂量按Dixon序贯法确定，初始剂量0.05 μg/kg，相邻剂量梯度为0.025 μg/kg。若出现呼吸抑制，则下一例患者舒芬太尼降低一个剂量梯度；若未出现呼吸抑制，则下一例升高一个剂量梯度。呼吸抑制标准为SpO₂≤92％或RR<10次/分。计算复合不同剂量艾司氯胺酮时舒芬太尼引起呼吸抑制的ED₅₀及95％可信区间（CI）。
结果 A组出现呛咳3例，C组出现HR＞100次/分2例，经相应处理后未影响研究进行。A组、B组和C组达到呼吸抑制时舒芬太尼的ED₅₀及95%CI分别为0.152 μg/kg（95%CI 0.142～0.164 μg/kg）、0.199 μg/kg（95%CI 0.186～0.212 μg/kg）和0.109 μg/kg（95%CI 0.100～0.118 μg/kg）。
结论 咪达唑仑0.03 mg/kg辅助镇静时，单用舒芬太尼静脉注射致呼吸抑制的ED₅₀为0.152 μg/kg；复合艾司氯胺酮0.25 mg/kg可以提高舒芬太尼静脉注射致呼吸抑制的ED₅₀；复合艾司氯胺酮0.5 mg/kg可以降低舒芬太尼静脉注射致呼吸抑制的ED₅₀。     

复合丙泊酚时阿芬太尼抑制稽留流产清宫术扩宫痛的半数有效剂量

目的 评估复合丙泊酚时阿芬太尼抑制稽留流产清宫术扩宫痛的半数有效剂量（ED₅₀）。
方法 选择择期全麻下行稽留流产清宫术患者29例,年龄24～45岁,孕期8～14周,BMI 18～28 kg/m ²,ASAⅠ或Ⅱ级。采用改良序贯法进行研究。阿芬太尼初始用量为10 μg/kg,静注时间不短于30 s,再给予丙泊酚1.5 mg/kg。判断患者意识与睫毛反射情况,待消失后进行稽留流产清宫术。手术期间,有体动则继续推注丙泊酚1 mg/kg。若扩宫痛阳性,下一例增加阿芬太尼用量;反之,则减少用量。增减梯度比为1∶1.2。扩宫痛阳性标准：扩宫时发生体动或出现痛苦表情。计算阿芬太尼抑制扩宫痛的ED₅₀、ED₉₅和95%可信区间（CI）。记录术中轻度低氧、中度低氧、重度低氧、心动过缓、低血压、呛咳,术后头痛、头晕、恶心、呕吐等不良反应发生情况。
结果 阿芬太尼抑制稽留流产清宫术疼痛的ED₅₀为7.4 μg/kg（95%CI 4.0～9.3 μg/kg）,ED₉₅为11.5 μg/kg（95%CI 9.5～37.5 μg/kg）。29例患者术中无一例重度低氧、心动过缓、呛咳、呕吐,轻度低氧1例,中度低氧4例,给予托下颌后及时缓解。术后头晕2例,恶心3例。
结论 复合丙泊酚静脉麻醉时,阿芬太尼抑制稽留流产清宫术扩宫痛的ED₅₀为7.4 μg/kg。     

不同剂量艾司氯胺酮对产妇剖宫产术后镇痛和产后抑郁的影响

目的 观察不同剂量艾司氯胺酮复合舒芬太尼用于术后静脉自控镇痛（PCIA）对剖宫产术后镇痛效果及产后抑郁（PPD）的影响。
方法 选择择期行剖宫产术的产妇120例,单胎足月妊娠,年龄22～35岁,BMI 25～30 kg/m²,ASA Ⅱ级。所有产妇采用腰-硬联合麻醉,蛛网膜下腔使用0.5%布比卡因8～10 mg,硬膜外腔头端置管备用。采用随机数字表法将产妇分为四组：C组(n=29)、S₁组(n=28)、S₂组(n=30)和S₃组(n=29)。C组镇痛泵配方为舒芬太尼1.5 μg/kg+托烷司琼4 mg,用生理盐水稀释至150 ml;S₁组、S₂组和S₃组分别在C组配方基础上加入艾司氯胺酮0.1、0.2和0.4 mg/kg。镇痛泵参数设置：负荷剂量5 ml,持续输注量2 ml/h,单次剂量1 ml,锁定时间15 min,镇痛持续时间48 h。记录术后48 h舒芬太尼用量、艾司氯胺酮用量、镇痛泵有效按压次数、总按压次数、术后镇痛补救例数、术后1周及6周爱丁堡产后抑郁量表（EPDS）评分情况和PPD的发生情况。记录术后48 h内恶心呕吐、皮肤瘙痒、噩梦等不良反应发生情况。
结果 与C组比较,S₁组、S₂组和S₃组术后48 h内舒芬太尼用量、镇痛泵有效按压次数、总按压次数明显减少（P＜0.05）。S₁组、S₂组和S₃组术后48 h内舒芬太尼用量、镇痛泵有效按压次数、总按压次数差异无统计学意义。与C组比较,S₁组、S₂组和S₃组术后1周和6周EPDS评分与PPD发生率明显降低（P＜0.05）。与S₁组比较,S₂组和S₃组术后1周和6周EPDS评分与PPD发生率明显降低（P＜0.05）。与C组比较,S₁组、S₂组和S₃组产妇术后48 h内恶心呕吐发生率明显降低（P＜0.05）。四组产妇术后48 h内补救镇痛比例和皮肤瘙痒、噩梦等不良反应发生率差异无统计学意义。
结论 剖宫产产妇术后PCIA复合使用艾司氯胺酮可减少阿片类药物的用量,提高术后镇痛效果,降低术后PPD的发生率,其中复合艾司氯胺酮0.2、0.4 mg/kg效果优于艾司氯胺酮0.1 mg/kg。     

艾司氯胺酮与右美托咪定在中老年患者全髋关节置换术中的比较

目的 比较艾司氯胺酮与右美托咪定在中老年患者全髋关节置换术中的应用效果。
方法 选择择期行单侧全髋关节置换术的中老年患者60例,男17例,女43例,年龄60～80岁,BMI 18～28 kg/m²,ASA Ⅱ或Ⅲ级。将患者随机分为两组：右美托咪定组（D组,n=30）和艾司氯胺酮组（S组,n=30）。选择L2-3间隙行腰-硬联合麻醉（CSEA）,维持平面T₆—T₁₀。D组：静脉注射咪达唑仑0.04 mg/kg,5 min后静脉注射右美托咪定0.25 μg/kg,后维持0.2～0.7 μg·kg^-1·h^-1。S组：静脉注射咪达唑仑0.04 mg/kg,5 min后静脉注射艾司氯胺酮0.35 mg/kg,后维持0.3～0.4 mg·kg^-1·h^-1。记录入室时、椎管内麻醉10 min后、静注咪达唑仑后10、30、60 min的HR和MAP。记录术中血管活性药物使用情况。记录静注咪达唑仑30、90 min以及开始缝皮时的Ramsay镇静评分。记录术中及术后不良反应的发生情况。
结果 与D组比较,静注咪达唑仑后30、60 min,S组HR明显增快（P＜0.05）,术中麻黄碱、阿托品、去甲肾上腺素的使用率明显降低（P＜0.05）。两组不同时点Ramsay镇静评分、术中及术后不良反应发生率差异均无统计学意义。
结论 艾司氯胺酮与右美托咪定均可安全有效地应用于中老年患者全髋关节置换术,但艾司氯胺酮术中血流动力学更加稳定,且不增加不良反应的发生。     

罗哌卡因在老年患者全髋关节置换术中髋关节囊周围神经阻滞的半数有效浓度

目的 测定全麻联合髋关节囊周围神经（PENG）阻滞用于全髋关节置换术老年患者的罗哌卡因半数有效浓度（EC₅₀）。

方法 选择择期行全髋关节置换术的老年患者36例,男20例,女16例,年龄65～80岁,BMI 18～30 kg/m²,ASA Ⅱ或Ⅲ级。在超声引导下行PENG阻滞,设定罗哌卡因容量为20 ml,浓度由序贯法确定,初始浓度为0.375%,若神经阻滞20 min后,静息NRS评分较阻滞前下降≥2分且活动时NRS评分较阻滞前下降≥3分时,则视为阻滞成功,反之则视为失败,阻滞失败则下1例患者提高1个浓度梯度,阻滞成功则下1例患者降低1个浓度梯度,相邻浓度比值为1.0∶1.2,直至出现7个拐点。采用Probit概率法计算罗哌卡因的EC₅₀及其 95%可信区间（CI）。记录PENG阻滞前（阻滞前）、阻滞后20 min和术后2、6、12、24 h静息和活动（被动抬髋15°）时NRS评分,术后穿刺部位感染、血肿、神经损伤、局麻药中毒、恶心、呕吐、头晕等发生情况。

结果 罗哌卡因用于老年患者全髋关节置换术前行PENG阻滞的EC₅₀为0.185%（95%CI 0.154%～0.213%）。无一例患者穿刺部位感染、血肿、神经损伤、局麻药中毒并发症。

结论 罗哌卡因用于老年患者全髋关节置换术中PENG阻滞的EC₅₀为0.185%（95%CI 0.154%～0.213%）。     

艾司氯胺酮对重度抑郁症患者电休克治疗后认知功能的影响

目的： 探讨艾司氯胺酮对电休克治疗（ECT）重度抑郁症患者改善抑郁和术后认知功能的影响。
方法： 选择接受ECT的重度抑郁症患者115例,男37例,女78例,年龄≥12岁,BMI 18～30 kg/m²,ASA Ⅰ或Ⅱ级,采用随机数字表将患者随机分为两组：艾司氯胺酮组（E组,n=56）和对照组（C组,n=59）。E组在麻醉诱导时使用艾司氯胺酮0.3~0.5 mg/kg、丙泊酚0.3~1.0 mg/kg和琥珀胆碱0.5~1.25 mg/kg,C组在麻醉诱导时使用丙泊酚1~2 mg/kg和琥珀胆碱0.5~1.25 mg/kg。每次ECT过程中记录ECT指标（包括EEG抽搐时间、总抽搐时间、刺激强度和抽搐能量指数）。在ECT前和ECT疗程结束后采用蒙特利尔认知评估量表（MoCA）和简易认知状态评价量表（MMSE）评价认知功能,使用汉密尔顿抑郁量表（HAMD）进行抑郁评分。记录头疼、恶心、呕吐、头晕、谵妄等不良反应的发生情况。
结果： 与C组比较,E组EEG抽搐时间明显延长（P<0.05）,ECT疗程结束后MoCA评分下降≥1分和MMSE评分下降≥1分比例明显降低（P<0.05）,恶心、呕吐和头晕发生率明显降低（P<0.05）。
结论： 艾司氯胺酮用于ECT重度抑郁症患者可改善治疗后的认知功能。     

丙泊酚在克罗恩病患者无痛胃肠镜检查中的半数有效剂量

目的 采用序贯法测定丙泊酚在克罗恩病患者无痛胃肠镜检查中的半数有效剂量（ED₅₀ ）。

方法 选择克罗恩病患者24例（D组）和正常体检患者23例（C组），男23例，女24例，年龄18～64岁，BMI 18～30 kg/m²，ASA Ⅰ或Ⅱ级。常规行HR、BP、SpO₂和BIS监测，静脉推注丙泊酚行无痛胃肠镜检查。根据序贯法确定D组丙泊酚初始剂量2.2 mg/kg，C组初始剂量2.4 mg/kg。当BIS为60时进镜，若出现阳性反应，则下一例剂量增加0.2 mg/kg，否则减少0.2 mg/kg。阳性反应定义为麻醉诱导后患者BIS无法降至60，或入镜时出现呛咳或体动反应2级及以上。记录既往行无痛胃肠镜和全麻次数以及低血压和呼吸抑制的发生情况。采用概率回归分析法计算两组的ED₅₀、ED₉₅和95%可信区间（CI），比较两组ED₅₀和ED₉₅。

结果 与C组比较，D组既往行无痛胃肠镜和全麻的次数明显增多（P＜0.05）。D组使用丙泊酚行无痛胃肠镜检查的ED₅₀为2.80 mg/kg（95%CI 2.72～2.88 mg/kg），ED₉₅为3.20 mg/kg（95%CI 3.12～3.32 mg/kg），C组使用丙泊酚行无痛胃肠镜检查的ED₅₀为2.42 mg/kg（95%CI 2.38～2.46 mg/kg），ED₉₅为2.60 mg/kg（95%CI 2.51～2.70 mg/kg）。D组使用丙泊酚行无痛胃肠镜检查的ED₅₀、ED₉₅明显高于C组（P＜0.05）。两组低血压和呼吸抑制发生情况差异无统计学意义。

结论 丙泊酚在克罗恩病患者行无痛胃肠镜检查中的ED₅₀为2.80 mg/kg（95%CI 2.72～2.88 mg/kg），体检患者的ED₅₀为2.42 mg/kg（95%CI 2.38～2.46 mg/kg）。克罗恩病患者可能因曾反复多次行丙泊酚麻醉导致其使用丙泊酚行无痛胃肠镜的用药量高于体检患者，需要增加丙泊酚用量才能满足临床镇静需求。     

不同剂量阿芬太尼复合丙泊酚在胃镜检查中的应用

目的 探讨不同剂量阿芬太尼复合丙泊酚在胃镜检查中的应用效果。
方法 选择门诊无痛胃镜检查患者60例,男28例,女32例,年龄18～64岁,BMI 18～25 kg/m²,ASA Ⅰ或Ⅱ级。采用随机数字表法将患者分为三组：丙泊酚组 （P组）、阿芬太尼7 μg/kg复合丙泊酚组（A1组）和阿芬太尼10 μg/kg复合丙泊酚组（A2组）,每组20例。A1组静脉注射阿芬太尼7 μg/kg,A2组静脉注射阿芬太尼10 μg/kg,P组静脉注射等容量生理盐水20 ml。静脉泵注丙泊酚2.0 mg·kg^-1·min^-1至改良警觉/镇静评分（MOAA/S）为0分时开始胃镜操作。记录入室时（T0）、给药后MOAA/S评分为0分时（T1）、胃镜通过咽喉部（T2）、胃镜抵达十二指肠降部（T3）、胃镜检查结束时（T4）、胃镜检查结束后MOAA/S评分为5分时（T5）、离院时（T6）的MAP、HR、SpO₂。记录丙泊酚诱导量、追加情况、总用量、胃镜操作时间、清醒时间和离院时间。记录麻醉期间亚临床呼吸抑制例数。记录T0、T5、T6和离院后24 h（T7）的Christensen疲劳评分。记录胃镜操作过程中体动、低血压、高血压、心动过缓、反流误吸等并发症的发生情况。
结果 与T0时比较,T1—T4时三组MAP明显降低、HR明显减慢（P<0.05）,T5、T6时三组Christensen疲劳评分降低（P＜0.05）。与P组比较,T1、T2时A1组MAP明显升高（P<0.05）,T1—T4时A2组MAP明显升高（P<0.05）;A1组和A2组丙泊酚诱导量和总用量明显减少、追加率明显降低（P<0.05）,清醒时间和离院时间明显缩短（P<0.05）,亚临床呼吸抑制发生率明显降低（P<0.05）,T5、T6时A1组和A2组Christensen疲劳评分明显降低（P<0.05）,A1组和A2组体动发生率明显降低（P<0.05）,A2组低血压发生率明显降低（P<0.05）。与A1组比较,T3、T4时A2组MAP明显升高（P<0.05）,A2组丙泊酚追明显降低、总用量明显减少,清醒时间、离院时间明显缩短（P<0.05）,T6时A2组Christensen疲劳评分明显降低（P<0.05）。
结论 与单纯应用丙泊酚镇静比较,阿芬太尼复合丙泊酚应用于无痛胃镜检查,可降低亚临床呼吸抑制发生率,缩短清醒时间和离院时间,提高恢复质量,阿芬太尼10 μg/kg较7 μg/kg复合丙泊酚效果更优。     

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.     

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.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

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.