双气道喉管用于中心气道狭窄气管支架置入术的效果

目的 评价双气道喉管用于中心气道狭窄气管支架置入术的效果。
方法 选择择期行中心气道狭窄气管支架置入术患者42例,男28例,女14例,年龄18~64岁,ASA Ⅱ或Ⅲ级。采用随机数字表法分为两组：双气道喉管组（D组）和普通喉罩组（C组）,每组21例。麻醉诱导后,D组、C组分别置入双气道喉管和普通喉罩,行机械通气。记录麻醉诱导前（T1）、置入喉管/喉罩开始通气时（T2）、手术开始（T3）、支架置入时（T4）及术毕停止麻醉药后5 min（T5）的MAP、HR和SpO₂。分别于支架置入前和置入后抽取动脉血样行血气分析,记录pH值、PaO₂和PaCO₂。记录手术时间和支架置入调整例数。记录气管黏膜损伤、术后声嘶和术后咽痛的发生情况。
结果 T1—T5时两组MAP、HR和SpO₂差异无统计学意义。与C组比较,D组支架置入后pH值、PaO₂明显升高,PaCO₂明显降低,手术时间明显缩短,支架置入调整例数明显减少,气管黏膜损伤、术后声嘶和术后咽痛发生率明显降低（P<0.05）。
结论 双气道喉管用于中心气道狭窄气管支架置入术,可有效减少并发症的发生。     

环泊酚用于老年患者经内镜逆行胰胆管造影术的效果

目的 评价环泊酚用于老年患者经内镜逆行胰胆管造影术（ERCP）麻醉的有效性及安全性。

方法 选择2021年10月至2022年4月择期行ERCP的老年患者284例，男145例，女139例，年龄65～90岁，BMI 18～30 kg/m²，ASA Ⅱ或Ⅲ级。采用随机数字表法将患者分为两组：环泊酚组（C组）与丙泊酚组（P组），每组142例。记录镇静成功例数，入室前（T₀）、诱导后（T₁）、进镜时（T₂）、置入十二指肠乳头时（T₃）、退镜时（T₄）、苏醒时（T₅）的HR、MAP、SpO₂。记录镇静诱导成功时间、苏醒时间和离室时间。记录注射痛的发生情况。

结果 两组镇静成功率均为100%。与P组比较，T₁—T₅时C组HR明显增快，MAP、SpO₂明显升高（P<0.05），镇静诱导成功时间明显延长（P<0.05），苏醒时间和离室时间明显缩短（P<0.05），注射痛发生率明显降低（P<0.05）。

结论 丙泊酚与环泊酚均可安全有效用于老年患者ERCP手术麻醉，与丙泊酚比较，采用环泊酚患者苏醒时间、离院时间更短，注射痛发生率更低。     

不同剂量环泊酚用于无痛胃镜检查的效果

目的 比较不同剂量环泊酚应用于无痛胃镜检查的效果。
方法 选择择期行无痛胃镜检查患者160例,男78例,女82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四组：环泊酚0.4 mg/kg组（C1组,n=40）、环泊酚0.5 mg/kg组（C2组,n=40）、环泊酚0.6 mg/kg组（C3组,n=40）和丙泊酚2 mg/kg组（P组,n=39）。C1组、C2组和C3组分别静脉注射环泊酚0.4、0.5、0.6 mg/kg,P组则静脉注射丙泊酚2 mg/kg。若检查过程中发生呛咳或体动,C1组、C2组和C3组追加环泊酚0.1 mg/kg,P组追加丙泊酚0.5 mg/kg。10 min内追加次数≤1次,则为镇静成功。记录镇静成功例数、环泊酚或丙泊酚追加例数、胃镜检查时间、苏醒时间和离院时间。记录麻醉前即刻（T₀）、进镜前即刻（T₁）、内镜到达十二指肠降部时（T₂）、内镜退出咽腔时（T₃）的HR、SBP、DBP、SpO₂。记录检查过程中呛咳、体动、注射痛和低氧血症（SpO₂＜90%）等不良反应的发生情况。
结果 与C1组比较,C2组、C3组和P组镇静成功率明显升高（P＜0.05）。与C2组比较,C1组环泊酚追加比例明显升高,C3组环泊酚追加比例明显降低（P＜0.05）。与T₀比较,T₁、T₂时四组HR明显减慢,SBP和DBP明显降低,C3组SpO₂明显降低（P＜0.05）。与C3组比较,T₁、T₂时C1组、C2组和P组SpO₂明显升高（P＜0.05）。与C1组比较,C2组、C3组和P组的呛咳、体动发生率明显降低,P组注射痛发生率明显升高（P＜0.05）。与C3组比较,C1组和C2组的低氧血症发生率明显降低（P＜0.05）。
结论 静脉注射环泊酚0.5 mg/kg镇静成功率高,呼吸抑制及注射痛发生率低,可安全有效地应用于胃镜检查。     

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。     

术前容量治疗对微创冠状动脉搭桥患者微血管反应性的影响

目的 探讨术前容量治疗对微创冠状动脉搭桥（MIDCAB）患者微血管反应性的影响。

方法 选择择期行MIDCAB患者82例，男57例，女25例，年龄≥18岁，BMI 15～31 kg/m²，ASA Ⅲ级，NYHA分级Ⅰ或Ⅱ级。采用随机序列号法将患者分为两组：容量治疗组（T组）和对照组（C组），每组41例。T组麻醉诱导前根据被动抬腿试验，以ΔSV≥16%为目标进行术前容量治疗；C组术前不进行容量治疗。记录麻醉诱导前30 min、麻醉诱导后30 min的组织氧饱和度（StO₂）、组织氧恢复时间（tM）、组织氧恢复斜率（RecStO₂）、组织氧下降斜率（DesStO₂）、SBP、DBP、MAP、Hb、静脉血氧饱和度（SvO₂）、动脉血氧饱和度（SaO₂）、动脉血氧含量（CaO₂）、静脉血氧含量（CvO2）、氧摄取率（OER）、pH和Lac。

结果 与麻醉诱导前30 min比较，麻醉诱导后30 min T组MaxStO₂和MinStO₂明显升高，tM明显缩短，DesStO₂明显降低（P<0.05）；C组MaxStO₂和MinStO₂明显升高，tM明显延长，RecStO₂和DesStO₂明显降低（P<0.05）。麻醉诱导前后30 min两组BaseStO₂差异无统计学意义。与C组比较，麻醉诱导后30 min T组tM明显缩短，RecStO₂明显升高，SBP、DBP、MAP明显升高，Lac明显降低（P<0.05）。

结论 基于被动抬腿试验的术前容量治疗可改善麻醉诱导后微创冠状动脉搭桥患者微血管反应性。     

预注不同负荷剂量右美托咪定在腹腔镜胆囊切除术中的应用

目的 比较麻醉诱导前预注不同负荷剂量右美托咪定在腹腔镜胆囊切除术中的应用效果。
方法 选择2019年12月至2020年12月择期全麻下行腹腔镜胆囊切除术的患者120例,男52例,女68例,年龄18～64岁,BMI 20～35 kg/m²,ASA Ⅰ或Ⅱ级。采用随机数字表法将患者分为四组：生理盐水组（C组）、右美托咪定0.5 μg/kg组（L组）、右美托咪定0.75 μg/kg组（M组）和右美托咪定1.0 μg/kg组（H组）,每组30例。C组麻醉诱导前10 min恒速静脉泵注生理盐水0.5 ml/kg,L组、M组和H组麻醉诱导前10 min分别恒速静脉泵注右美托咪定0.5、0.75和1.0 μg/kg。所有患者为全凭静脉麻醉,麻醉用药相同。记录输注生理盐水/右美托咪定前即刻（T₁）、麻醉诱导前即刻（T₂）、气管插管后即刻（T₃）、手术切皮即刻（T₄）、气腹开始即刻（T₅）、气腹后10 min（T₆）、缝合完毕即刻（T₇）、气管拔管后即刻（T₈）的HR和MAP。记录术中丙泊酚、瑞芬太尼用量、阿托品使用例数、苏醒时间、拔管时间、术后1、4 h咳嗽时VAS疼痛评分。记录苏醒期躁动、术后心动过缓、术后低血压、术后48 h内恶心呕吐等不良反应发生情况。
结果 与C组比较,L组、M组和H组T₂—T₈时HR明显减慢（P<0.05）,T₃—T₈时MAP明显降低（P<0.05）,术中丙泊酚和瑞芬太尼用量明显减少（P<0.05）,术后1、4 h咳嗽时VAS疼痛评分明显降低（P<0.05）,苏醒期躁动、术后恶心呕吐发生率明显降低（P<0.05）;M组苏醒时间、拔管时间明显缩短（P<0.05）;H组阿托品使用率明显升高（P<0.05）,苏醒时间、拔管时间明显延长（P<0.05）,术后心动过缓和低血压发生率明显升高（P<0.05）。与L组比较,H组T₂—T₆时HR明显减慢（P<0.05）,M组和H组术后1、4 h咳嗽时VAS疼痛评分明显降低（P<0.05）。
结论 腹腔镜胆囊切除术全麻诱导前预注右美托咪定0.75 μg/kg可以有效维持围术期血流动力学稳定,减少麻醉药物用量,缩短苏醒时间,减少术后并发症,有利于患者术后恢复。     

环泊酚和丙泊酚在老年患者纤维结肠镜治疗中镇静效果比较

目的 比较环泊酚和丙泊酚在老年患者纤维结肠镜治疗中的镇静效果。

方法 选择行纤维结肠镜治疗的老年患者330例,男179例,女151例,年龄65～84岁,BMI 18～29 kg/m²,ASA Ⅰ或Ⅱ级。随机分为两组：环泊酚组（C组,n=160）和丙泊酚组（P组,n=162）。C组麻醉诱导给予环泊酚0.4 mg/kg,麻醉维持泵注环泊酚1～1.5 mg·kg^-1·h^-1,P组麻醉诱导给予丙泊酚2 mg/kg,麻醉维持泵注丙泊酚4～6 mg·kg^-1·h^-1。记录镇静成功率、诱导时间、完全清醒时间,麻醉诱导前（T0）、进镜时（T1）、进镜后10 min（T2）、完全清醒时（T3）时SBP、DBP、BIS,术中心动过缓、低血压、低氧血症、注射痛、体动,气道干预、术中追加镇静和术后恶心呕吐发生情况。

结果 与P组比较,C组T2时SBP、DBP明显升高（P<0.05）,T2和T3时BIS明显降低（P<0.05）,术中低氧血症和注射痛发生率明显降低（P<0.05）。两组镇静成功率、诱导时间、完全清醒时间,术中心动过缓、低血压、体动发生率,气道干预、术中追加镇静和术后恶心呕吐发生率差异无统计学意义。

结论 与丙泊酚比较,环泊酚在老年患者纤维结肠镜治疗中有同样的镇静效果,且有着更低的低氧血症和注射痛发生率,值得临床推广。     

术中持续输注胰岛素对心肺转流心脏手术患者心肌血流灌注的影响

目的： 探讨术中持续输注胰岛素对心肺转流（CPB）心脏手术患者心肌血流灌注的影响。
方法： 选择择期行CPB心脏手术患者48例,男21例,女27例,年龄55～80岁,BMI 18～28 kg/m²,ASA Ⅱ—Ⅳ级。将患者随机分为两组：胰岛素组（I组,n=25）和对照组（C组,n=23）。两组采用相同麻醉方案。麻醉诱导后I组静脉输注胰岛素30 mU·kg^-1·h^-1、葡萄糖0.12 g·kg^-1·h^-1、氯化钾0.06 mmol·kg^-1·h^-1混合液,C组予以生理盐水10 ml/h输注,均输注至术毕。术中目标血糖值为6.1～11.1 mmol/L。于麻醉诱导后10 min（T₂）和术毕（T₆）行经食管超声心动图（TEE）检测,记录冠状静脉窦（CS）血流频谱、直径及肺静脉血流频谱,并计算CS净向前血流流速时间积分（VTI）。记录T₂、CPB前2 min（T₃）、CPB结束时（T₅₂）和T6时的股动脉平均动脉压（MAP）、中心静脉压（CVP）、每搏量（SV）、心脏指数（CI）及外周血管阻力指数（SVRI）。记录麻醉诱导前5 min（T₁）、T₃、CPB后30 min（T₄）、T₅、T₆、术后6 h（T₇）、术后12 h（T₈）及术后24 h（T₉）时血糖及乳酸浓度。记录术前1 d、术后1、2 d时超敏C反应蛋白（hs-CRP）、高敏肌钙蛋白I（hs-TnI）和肌酸激酶同工酶（CK-MB）水平。
结果： 与C组比较,I组T₆时CS净前向血流VTI及每分钟CS血流量均明显增加（P<0.05）,肺静脉心房收缩期峰值流速（ARp）明显减小（P<0.05）,T₅、T₆时SV和CI明显增大、SVRI明显降低（P<0.05）,T₇、T₈时乳酸浓度明显降低（P<0.05）,术后1、2 d时hs-CRP和CK-MB水平明显降低（P<0.05）,术后2 d时hs-TnI明显降低（P<0.05）。
结论： CPB心脏手术中持续输注胰岛素,同时维持血糖6.1～11.1 mmol/L,可改善心肌血流灌注,减轻术后炎症反应及心肌损伤。     

环泊酚或丙泊酚复合瑞芬太尼用于无痛纤维支气管镜检查的比较

目的 探讨环泊酚或丙泊酚复合瑞芬太尼用于无痛纤维支气管镜检查的麻醉效果及对梦境状态的影响。
方法 选择择期行全麻下无痛纤维支气管镜检查的患者60例，男27例，女33例，年龄18～75岁，BMI 20～30 kg/m²，ASA Ⅰ或Ⅱ级。将患者随机分为两组：丙泊酚组（P组）和环泊酚组（C组），每组30例。麻醉诱导：P组静注丙泊酚2.5 mg/kg和瑞芬太尼1 μg/kg；C组静注环泊酚0.4 mg/kg和瑞芬太尼1 μg/kg。麻醉维持：P组泵注丙泊酚4～6 mg·kg^-1·h^-1；C组泵注环泊酚0.8～1.2 mg·kg^-1·h^-1。记录低血压的发生情况、麻黄碱用量，麻醉诱导前5 min（T₀）、插入喉罩即刻（T₁）、纤维支气管镜进至隆突时（T₂）、镜检完毕（T₃）及拔除喉罩时（T₄）的HR、MAP和SpO₂。记录呛咳评分、利多卡因用量、手术时间、苏醒时间、定向力恢复时间、梦境的发生情况和状态、静脉注射痛、心动过缓、呼吸暂停、呛咳及恶心呕吐等相关不良事件的发生情况。
结果 与T₀时比较，T₁时两组MAP均明显降低（P<0.05）。与P组比较，C组低血压的发生率明显降低（P<0.05），麻黄碱用量明显减少(P<0.05)，T₁和T₃时MAP明显升高(P<0.05)，梦境的情绪评分明显升高(P<0.05)，静脉注射痛及呼吸暂停相关不良事件的发生率明显降低(P<0.05)。两组呛咳评分、利多卡因用量、手术时间、苏醒时间、定向力恢复时间、梦境发生率、心动过缓、呛咳及恶心呕吐相关不良事件的发生率差异无统计学意义。
结论 与丙泊酚比较，环泊酚复合瑞芬太尼在无痛纤维支气管镜检查中对循环呼吸影响小，不良事件发生率更低，同时可产生更优情绪的梦境状态。     

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.     

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.     

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.     

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.     

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.