右美托咪定对二尖瓣置换术患者左右心室收缩和舒张功能的影响

目的 观察右美托咪定对心肺转流（CPB）下行二尖瓣置换术患者左右心室收缩和舒张功能的影响。方法 择期CPB下行二尖瓣置换术患者32例,男9例,女23例,年龄42～70岁,BMI 18~28 kg/m²,ASA Ⅱ或Ⅲ级。采用随机数字表法分为两组:右美托咪定组（D组）和对照组（C组）。两组术中麻醉维持均采用静脉复合麻醉,D组于切皮后经微量注射泵静脉注射右美托咪定负荷剂量1 μg/kg,10 min内注射完后以0.5 μg·kg^-1·h^-1维持给药至术毕,C组静脉注射等量生理盐水。于麻醉诱导后（T0）、CPB停机后30 min(T1)、60 min(T2)记录HR、MAP、CVP、心脏指数（CI）、左心室射血分数(LVEF)等血流动力学指标,并于同时点记录二尖瓣瓣环等容收缩期峰值速度（Sm1）、射血期峰值速度（Sm2）、二尖瓣舒张早期血流峰值速度与二尖瓣瓣环舒张早期峰值速度的比值（E/Ea-MV）、三尖瓣瓣环等容收缩期峰值速度（St1）、射血期峰值速度（St2）、三尖瓣舒张早期峰值速度与三尖瓣瓣环舒张早期血流峰值速度的比值（E/Ea-TV）。结果 与T0时比较,T1—T2时两组HR明显增快（P<0.05）,MAP明显降低（P<0.05）,CVP、CI明显升高（P<0.05）。T0—T2时两组HR、MAP、CVP、CI、LVEF差异均无统计学意义。T0—T2时两组Sm1、Sm2、E/Ea-MV组内组间差异均无统计学意义。与T0时比较,T1—T2时C组E/Ea-TV明显升高,T2时D组E/Ea-TV明显升高（P<0.05）。T0—T2时两组St1、St2、E/Ea-TV差异无统计学意义。结论 右美托咪定并不能改善左右心室舒张功能受损的程度,亦未增加心肌受损程度。     

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。     

气管导管套囊充气前后气管横径变化值与套囊压的相关性

目的 探讨超声测量气管导管（ETT）套囊充气前后的气管横径变化值（ΔTD）与ETT套囊压（CP_ETT）的相关性。
方法 选择2020年6月—2021年8月行气管插管全身麻醉的男性患者,年龄18～60岁,BMI 18～25 kg/m ²,ASA Ⅰ至Ⅲ级。研究分为两个部分。第1部分拟招募90例符合纳入标准的患者,用指压法进行ETT套囊充气,分别在充气前后用超声测量胸骨上窝水平的气管横径,计算ΔTD。然后用压力表测量套囊压力（CP_ETT）。采用受试者工作特征（ROC）曲线求取ΔTD截断值并分析其预测效能。第2部分拟招募46例患者,按照ETT套囊充气
方法 随机分为指压组和超声组,每组23例。指压组使用指压法为套囊充气,超声组使用超声结合ΔTD截断值指导套囊充气。两组充气后均用压力表测量CP_ETT。
结果 当CP_ETT不高于110 cmH₂O时,CP_ETT与ΔTD呈明显正相关（r=0.78, P<0.05）。ΔTD的ROC曲线下面积（AUC）为0.85,ΔTD截断值为1.25 mm,敏感性为70.5%,特异性为84.2%。与指压组比较,超声组正常CP_ETT占比明显升高（P<0.05）。
结论 当CP_ETT不高于110 cmH₂O时,CP_ETT与ΔTD呈明显正相关;超声法测量ΔTD指导ETT套囊充气明显优于指压法。     

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。     

小剂量艾司氯胺酮对环泊酚用于无痛胃肠镜检查麻醉诱导半数有效剂量的影响

目的： 探讨小剂量艾司氯胺酮对环泊酚用于无痛胃肠镜检查麻醉诱导半数有效剂量（ED₅₀）的影响。
方法： 选择择期行无痛胃肠镜检查患者59例,男26例,女33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：艾司氯胺酮联合环泊酚组（EC组,n=29）和环泊酚组（C组,n=30）。EC组给予环泊酚前2 min静注艾司氯胺酮0.3 mg/kg,C组于相同时点静注等量生理盐水。麻醉诱导环泊酚初始剂量为0.4 mg/kg,剂量调整梯度为0.04 mg/kg,检查时若出现阳性反应则下一例患者环泊酚诱导剂量增加0.04 mg/kg,阴性反应则下一例患者环泊酚诱导剂量减少0.04 mg/kg。阳性反应为麻醉诱导后2 min患者BIS无法降至60或置入胃镜时出现呛咳或体动反应2级及以上。记录环泊酚总用量、苏醒时间、出室时间、术中及术后不良反应发生情况。采用Probit概率回归分析法计算ED₅₀、95%有效剂量(ED₉₅)和95%可信区间（CI）。
结果： 与C组比较,EC组检查过程中环泊酚总用量、低血压发生率及血管活性药物使用率均明显降低（P<0.05）。EC组使用环泊酚行无痛胃肠镜检查的麻醉诱导ED₅₀为0.21 mg/kg（95%CI 0.12～0.25 mg/kg）,ED₉₅为0.32 mg/kg（95%CI 0.26～0.39 mg/kg）,C组使用环泊酚行无痛胃肠镜检查的麻醉诱导ED₅₀为0.37 mg/kg（95%CI 0.32～0.40 mg/kg）,ED₉₅为0.48 mg/kg（95%CI 0.43～0.54 mg/kg）。与C组比较,EC组使用环泊酚行无痛胃肠镜检查的麻醉诱导ED₅₀、ED₉₅明显降低（P<0.05）。两组其他不良反应发生率差异无统计学意义。
结论： 联合艾司氯胺酮0.3 mg/kg可降低环泊酚用于无痛胃肠镜检查麻醉诱导时的ED₅₀并减少检查过程中环泊酚总用量,术中循环稳定,可安全用于无痛胃肠镜检查。     

内镜喉罩对胃内镜黏膜下剥离术气道管理和术后恢复的影响

目的： 评价内镜喉罩用于胃内镜黏膜下剥离术（ESD）患者围术期气道管理和术后恢复的效果。
方法： 选择择期行胃ESD的患者90例,男48例,女42例,年龄18～64岁,BMI 18～25 kg/m²,ASA Ⅰ或Ⅱ级。将患者随机分为两组：内镜喉罩组（E组）和气管插管组（C组）,每组45例。麻醉诱导后E组行内镜喉罩通气,消化内镜从喉罩的内镜通道置入;C组则采取气管内插管通气,消化内镜经口置入。记录插管情况（插管成功时间、插管一次性成功例数）、消化内镜置入情况（消化内镜置入时间和退镜例数）、手术时间、拔管时间以及PACU停留时间。记录入室时（T₀）、置入喉罩或气管插管后即刻（T₁）、消化内镜置入时（T₂）、内镜退出时（T₃）、拔除喉罩或气管导管后即刻（T₄）、离开PACU时（T₅）的HR、MAP。记录T₁—T₃时的平均气道压和气道峰压。记录E组改变体位前后、手术结束时的气道密封压和内窥镜显露分级（EVGS）。记录不良反应发生情况以及麻醉科医师和消化内镜医师的满意度。
结果： 与T₀时比较,T₁、T₄时两组HR和MAP明显升高（P＜0.05）。与C组比较,E组置入喉罩成功时间、拔除喉罩时间及PACU停留时间明显缩短,T₁、T₄时HR和MAP明显降低,围拔管期呛咳以及术后咽痛、声嘶发生率明显降低（P＜0.05）。两组插管或置入喉罩一次性成功率、消化内镜置入时间和退镜率差异无统计学意义。E组内镜喉罩的密封性和对位良好。
结论： 内镜喉罩可缩短胃ESD患者的人工气道建立成功时间,对消化内镜操作不造成干扰,缩短拔管时间和PACU停留时间,加快患者术后恢复。     

尼卡地平对冠状动脉旁路移植术患者脑血流和功能的影响

目的 探讨冠状动脉旁路移植术（CABG）患者在心肺转流（CPB）期间输注小剂量尼卡地平对脑血流和功能的影响。

方法 选择CPB下CABG患者64例,男41例,女23例,年龄60～79岁,BMI 18～29 kg/m²,ASA Ⅱ或Ⅲ级,NYHA分级Ⅱ或Ⅲ级,左室射血分数≥50%。采用随机双盲数字表法将患者分为两组：尼卡地平组（N组）和生理盐水组（C组）,每组32例。N组在CPB开始后输注尼卡地平0.2～0.5 μg·kg^-1·min^-1,于CPB停机后停止输注。C组于相同时点输注同等容量生理盐水。记录麻醉诱导前（T₀）、外科切皮时（T₁）、CPB 30 min（T₂）、60 min（T₃）、停CPB 30 min（T₄）、60 min（T₅）的动脉血气、心输出量（CO）、颈内动脉血流量（Q-ICA）、颈内动脉直径（D-ICA）和局部脑氧饱和度（rScO₂）。记录术中去氧肾上腺素用量、术后拔管时间、ICU停留时间和术后住院时间。

结果 与C组比较,T₂—T₅时N组Q-ICA和D-ICA明显增加,rScO₂明显升高（P＜0.05）。两组T₀—T₅时动脉血气指标、T₀、T₁时Q-ICA、D-ICA和rScO₂、术中去氧肾上腺素用量、术后拔管时间、ICU停留时间和术后住院时间差异均无统计学意义。

结论 在CABG患者CPB期间输注小剂量尼卡地平可以增加颈内动脉血流量,升高rScO₂,减轻围术期神经功能损伤。     

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。     

丙泊酚与七氟醚对妇科腹腔镜患者视神经鞘直径的影响

目的 应用超声测量视神经鞘直径（ONSD）方法评价丙泊酚与七氟醚对妇科腹腔镜患者颅内压的影响。
方法 选择择期行妇科腹腔镜手术患者40例,年龄20～60岁,BMI 18～27 kg/m²,ASAⅠ或Ⅱ级。采用随机数字表法分为丙泊酚组（P组）和七氟醚组（S组）,每组20例。麻醉维持：P组静脉泵注丙泊酚4～12 mg·kg^-1·h^-1,S组吸入1%～2%七氟醚。使用容量控制模式,V_T6～8 ml/kg,FiO₂ 50%,I∶E 1∶2,RR 12～20次/分。记录麻醉诱导后5 min（T₀）、气腹开始后头低脚高位5 min（T₁）、气腹开始后头低脚高位30 min（T₂）、气腹开始后头低脚高位60 min（T₃）时的HR、MAP、气道峰压（Peak）、气道平台压（Plat）、P_ET CO₂ 和ONSD。
结果 与T₀时比较,T₁—T₃时P组MAP明显降低,T₂—T₃时S组MAP明显降低（P＜0.05）,T₁—T₃时两组Peak、Plat明显升高（P＜0.05）,T₁—T₃时两组ONSD明显升高（P＜0.05）。T₁时P组MAP明显低于S组（P＜0.05）。T₃时P组ONSD明显低于S组（P＜0.05）。
结论 在妇科腹腔镜手术中,与单纯使用七氟醚比较,应用丙泊酚维持可一定程度减轻颅内压的升高。     

复合羟考酮时环泊酚用于无痛人工流产术的半数有效剂量

目的 探讨复合羟考酮时环泊酚用于无痛人工流产术的半数有效剂量（ED₅₀）。
方法 选择择期行无痛人工流产术患者23例，年龄22～40岁，BMI 20～30 kg/m²，ASA Ⅰ或Ⅱ级。麻醉诱导前静脉推注羟考酮0.08 mg/kg，环泊酚剂量采用序贯法。第1例患者环泊酚剂量为0.6 mg/kg，阳性反应定义为术中发生体动反应，若出现阳性反应则升高一个剂量等级，相邻剂量相差为0.05 mg/kg，若出现阴性反应则降低一个剂量等级，直至出现第7个拐点终止研究。计算复合羟考酮时环泊酚用于无痛人工流产术的ED₅₀和95%有效剂量（ED₉₅）及其95%可信区间（CI）。根据术中是否发生体动将患者分为两组：阳性组和阴性组。记录睫毛反射消失时间、手术时间、苏醒时间。记录术中恶心、呕吐、注射痛、呼吸抑制、过敏的发生情况。
结果 复合羟考酮时环泊酚用于无痛人工流产术的ED₅₀为0.469 mg/kg（95%CI 0.453～0.486 mg/kg），ED₉₅为0.542 mg/kg（95%CI 0.519～0.583 mg/kg）。与阴性组比较，阳性组苏醒时间明显延长（P<0.05）。两组无一例出现恶心、呕吐、注射痛、呼吸抑制、过敏等不良反应。
结论 复合羟考酮时环泊酚用于无痛人工流产术的ED₅₀为0.469 mg/kg（95%CI 0.453～0.486 mg/kg），ED₉₅为0.542 mg/kg（95%CI 0.519～0.583 mg/kg）。     

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.     

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.     

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.