程控硬膜外间歇脉冲注入与持续背景输注用于分娩镇痛的比较

目的比较程控硬膜外间歇脉冲注入(programmed intermittent epidural bolus,PIEB)和持续背景输注(CEI)两种模式联合PCEA用于分娩镇痛的临床效果。方法自愿接受分娩镇痛足月、单胎和头位初产妇200例,随机分为两组,每组100例。在宫口扩张2~3 cm时采用硬膜外阻滞行分娩镇痛。PIEB组背景输注剂量为8 ml/h,给药速度为6 ml/min,每小时给药一次;CEI组以8ml/h的速度持续给药。观察产妇镇痛前(T0)、镇痛后10 min(T1)、30 min(T2)、1 h(T3)、2 h(T4)、宫口开全时(T5)、分娩时(T6)、分娩后1 h(T7)BP、VAS评分、改良Bromage评分;PCEA追加次数、罗哌卡因、舒芬太尼的用量、宫缩情况、胎心率、产程时间、镇痛时间、分娩方式、产妇使用催产素、不良反应、新生儿Apgar评分、产妇满意度评分。结果 T4~T6时PIEB组VAS评分明显低于CEI组(P0.01)。PIEB组PCEA追加次数、药物用量明显少于CEI组(P0.05),PIEB组产妇满意度明显高于CEI组(P0.05)。两组产妇的血压、宫缩持续时间和间隔时间、胎心率、产程、镇痛时间、分娩方式、使用催产素比例、不良反应发生率及新生儿Apgar评分差异无统计学意义。结论与采用CEI+PCEA模式比较,PIEB+PCEA模式的PCEA追加率更低、用药量更少、VAS评分更低、产妇的满意度更高,而不良反应并没有增加。     

低背景剂量联合大剂量PCA在产妇硬膜外分娩镇痛中的应用

目的观察在持续输注联合硬膜外自控给药模式下低背景剂量持续输注联合大剂量PCA的参数设置对分娩镇痛临床效果的影响。方法选择自愿接受分娩镇痛足月、单胎和头位初产妇120例,年龄25~35岁,体重58~86kg,ASAⅠ或Ⅱ级,随机分为两组:常规组(A组)和低背景剂量组(B组)。在宫口扩张2~3cm时采用硬膜外分娩镇痛。每组均事先配置硬膜外注射混合液0.1%罗哌卡因+2μg/ml芬太尼100ml。A组为常规组,背景剂量6ml/h,PCA 5ml,间隔40min;B组为低剂量组,背景剂量2ml/h,PCA 10ml,间隔为40min。记录产妇镇痛前、镇痛后10min、30min、1h、2h、宫口开全时和分娩时VAS评分及改良Bromage评分;记录PCA追加次数;记录爆发痛例数;记录硬膜外混合液的用量;记录镇痛时间、产程时间、分娩方式;记录不良反应的发生情况和新生儿Apgar评分。结果镇痛期间两组产妇VAS评分差异无统计学意义;接受镇痛期间B组混合液用量(40.5±7.5)ml;明显少于A组(60.3±12.0)ml(P0.05);B组PCA实际追加次数(1.6±0.9)次明显少于A组(3.0±1.8)次(P0.05)。两组产妇的产程、镇痛时间、爆发痛例数、不良反应发生率、产妇分娩方式和新生儿Apgar评分差异无统计学意义。结论采用低背景剂量(2ml/h)联合大剂量PCA(10ml,间隔40min)的硬膜外自控镇痛参数设置不仅没有降低镇痛效果,还可减少硬膜外腔用药总量。     

硬膜外不同输注模式用于分娩镇痛的比较

目的 比较规律间断硬膜外泵注（RIEB）和持续性硬膜外输注（CEI）复合病人自控硬膜外镇痛（PCEA）用于分娩镇痛的效果。方法 自愿接受分娩镇痛的初产妇225例,按照随机数字表法分为A、B、C三组,每组75例。所有产妇给予硬膜外分娩镇痛,选取L2~3间隙行硬膜外穿刺,镇痛液配方为0.08%罗哌卡因＋0.4 μg/mL舒芬太尼。A组产妇予以CEI模式镇痛,8 mL/h持续输注镇痛液。B组与C组产妇予以RIEB模式镇痛,自注射首剂开始,每间断1 h给予8 mL镇痛液,其中B组的注射速度为2 mL/min,C组的注射速度为6 mL/min。记录产妇满意度评分,镇痛前（T1）、镇痛后30 min（T2）、1h（T3）、宫口开大7~8 cm时（T4）、宫口开全时（T5）、分娩时（T6）的平均动脉压（MAP）、心率（HR）、疼痛视觉模拟评分（VAS）和改良Bromage评分,观察病人自控硬膜外镇痛（PCEA）有效按压次数、罗哌卡因用量、舒芬太尼用量、产程、镇痛时间、分娩方式、新生儿Apgar评分、不良反应发生情况、产妇满意度评分。结果 三组产妇T1~T3时点VAS评分无统计学差异（P>0.05）;三组产妇T4~T6时点VAS评分,PCEA追加次数,罗哌卡因用量,舒芬太尼用量方面均显示C组B组>A组（P<0.05）;三组患者的平均动脉压,心率,改良Bromage评分,产程,镇痛时间,分娩方式,不良反应发生率,新生儿Apgar评分无统计学差异（P>0.05）。结论 RIEB复合PCEA用于分娩镇痛的效果显著,且泵注速度为6 mL/min的效果最佳,可有效减少PCEA追加次数,罗哌卡因用量和舒芬太尼用量,提高产妇满意度,而不良反应并没有增加。     

硬膜外不同输注模式用于分娩镇痛的比较

目的 比较规律间断硬膜外泵注（RIEB）和持续性硬膜外输注（CEI）复合病人自控硬膜外镇痛（PCEA）用于分娩镇痛的效果。方法 自愿接受分娩镇痛的初产妇225例,按照随机数字表法分为A、B、C三组,每组75例。所有产妇给予硬膜外分娩镇痛,选取L2~3间隙行硬膜外穿刺,镇痛液配方为0.08%罗哌卡因＋0.4 μg/mL舒芬太尼。A组产妇予以CEI模式镇痛,8 mL/h持续输注镇痛液。B组与C组产妇予以RIEB模式镇痛,自注射首剂开始,每间断1 h给予8 mL镇痛液,其中B组的注射速度为2 mL/min,C组的注射速度为6 mL/min。记录产妇满意度评分,镇痛前（T1）、镇痛后30 min（T2）、1h（T3）、宫口开大7~8 cm时（T4）、宫口开全时（T5）、分娩时（T6）的平均动脉压（MAP）、心率（HR）、疼痛视觉模拟评分（VAS）和改良Bromage评分,观察病人自控硬膜外镇痛（PCEA）有效按压次数、罗哌卡因用量、舒芬太尼用量、产程、镇痛时间、分娩方式、新生儿Apgar评分、不良反应发生情况、产妇满意度评分。结果 三组产妇T1~T3时点VAS评分无统计学差异（P>0.05）;三组产妇T4~T6时点VAS评分,PCEA追加次数,罗哌卡因用量,舒芬太尼用量方面均显示C组B组>A组（P<0.05）;三组患者的平均动脉压,心率,改良Bromage评分,产程,镇痛时间,分娩方式,不良反应发生率,新生儿Apgar评分无统计学差异（P>0.05）。结论 RIEB复合PCEA用于分娩镇痛的效果显著,且泵注速度为6 mL/min的效果最佳,可有效减少PCEA追加次数,罗哌卡因用量和舒芬太尼用量,提高产妇满意度,而不良反应并没有增加。     

硬膜外程控间歇脉冲式分娩镇痛对母婴安全的影响

目的探讨硬膜外程控间歇脉冲式分娩镇痛对母婴安全和分娩结局的影响。方法 2017年10月至2018年9月单胎头位初产妇410例,年龄23～32岁,BMI 20～31 kg/m~2,ASAⅡ级。根据计算机产生随机数字的奇偶性分为程控间歇脉冲输注组(PIEB组)和持续输注组(CEI组),每组205例。两组均采用硬膜外自控镇痛(PCEA),PIEB组以每次7 ml(6 ml/min)脉冲式输注,每小时1次;CEI组以7 ml/h的速度持续泵注给药。镇痛泵药物为0.08%罗哌卡因+舒芬太尼0.4μg/ml+生理盐水,总量120 ml,PCA 7 ml,锁定时间60 min。记录产妇镇痛前、镇痛后1、2、3、4、5 h和宫口开全时VAS疼痛评分;记录按压次数、镇痛药用量、产妇镇痛满意度评分;记录第一产程和第二产程时间、催产素、器械助产、会阴侧切、产后出血500 ml发生情况;记录中转剖宫产、新生儿窒息和脐带动脉血血气分析。结果镇痛后2～5 h和宫口开全时PIEB组VAS疼痛评分明显低于CEI组(P0.05)。PIEB组按压次数和镇痛药用量明显少于CEI组(P0.05),产妇镇痛满意度评分明显高于CEI组(P0.05),第一产程时间明显长于CEI组(P0.05),使用催产素明显高于CEI组(P0.05),会阴侧切明显少于CEI组(P0.05)。两组第二产程时间及器械助产、产后出血500 ml发生率差异无统计学意义。两组中转剖宫产、新生儿窒息、脐带动脉血血气分析差异无统计学意义。结论硬膜外程控间歇脉冲式分娩镇痛效果确切,对母婴无明显不良影响。     

程控硬膜外脉冲式注射或连续硬膜外输注复合硬膜外自控镇痛用于分娩镇痛的比较

目的评价不同间隔时间行程控硬膜外脉冲式注射(programmed intermittent epidural bolus,PIEB)或连续硬膜外输注(continuous infusion epiduaral,CEI)复合PCEA用于分娩镇痛的效果。方法选择有分娩镇痛要求的足月初产妇186例,ASAⅠ或Ⅱ级,采用数字表法随机分为三组,每组62例。三组均使用首次剂量(0.125%罗哌卡因+0.4μg/ml舒芬太尼)10 ml,镇痛泵均使用(0.08%罗哌卡因+0.4μg/ml舒芬太尼)100ml。PIEB1组(P1组):5ml/30min,首次剂量注入30min后开始脉冲给药;PIEB2组(P2组):10 ml/60 min,首次剂量注入60 min后开始脉冲给药;CEI组(C组):10ml/h,首次剂量注入后立即开始持续给予背景剂量。三组均设置PCA量5ml,锁定时间30min。记录镇痛期间宫缩疼痛VAS评分、运动阻滞程度Bromage评分、VAS评分3分的例数和(MBS)评分1分的例数;记录最高感觉阻滞平面、镇痛药物用药总量、催产素使用量、PCEA按压次数,第一次追加药物时间、产程时间、分娩方式和产间发热的例数;记录不良反应的发生情况。结果三组在分娩镇痛开始后VAS评分均明显低于镇痛前,P2组VAS3分的比率明显低于P1组和C组(P0.05)。镇痛期间,P1组最高感觉阻滞平面明显高于P2组和C组,P2组单侧阻滞发生率明显低于C组(P0.05)。P2组镇痛药物用药总量、PCEA按压次数明显少于,第一次追加药物时间明显长于P1组和C组(P0.05)。P1组与P2组器械助产与产间发热的例数明显少于C组(P0.05)。结论在分娩镇痛中给予首次剂量后,间隔60min行PIEB模式注射技术,是一种更有效的给药方法。     

肥胖产妇分娩镇痛优化策略：硬脊膜穿破硬膜外阻滞联合程控硬膜外间歇脉冲注入

目的评价肥胖产妇分娩镇痛优化策略:硬脊膜穿破硬膜外阻滞(DPE)联合程控硬膜外间歇脉冲注入(PIEB)。方法选取拟行分娩镇痛初次妊娠、单胎、头位、足月妊娠肥胖初产妇80例, 年龄20～40岁, ASA分级Ⅰ或Ⅱ级, BMI 30～40 kg/m2, 孕37～42周, 宫口扩张2～5 cm, VAS评分≥50 mm。采用随机数字表法分为2组(n=40):DPE+PIEB组(DPEP组)和DPE+持续硬膜外输注组(DPEC组)。DPEP组参数设置:首剂量8 ml, 背景剂量2 ml/12 min, PCEA剂量5 ml, 间隔时间20 min。DPEC组参数设置:首剂量8 ml, 背景剂量10 ml/h, PCEA剂量5 ml, 间隔时间20 min。镇痛泵中均使用0.1%罗哌卡因+0.3 μg/ml舒芬太尼, 记录达到充分镇痛的时间、单位时间罗哌卡因用量、胸段感觉阻滞程度、改良Bromage评分、PCEA有效按压次数、补救镇痛次数、Apgar评分、分娩方式、不良反应发生情况及产妇对分娩镇痛满意度。结果与DPEC组比较, DPEP组达到充分镇痛的时间缩短, 单位时间罗哌卡因用量降低, 补救...     

硬膜外间歇脉冲注入技术用于分娩镇痛的效果

目的 探讨硬膜外间歇脉冲注入技术（PIEB）在产妇自控硬膜外分娩镇痛中的效果及对分娩结局的影响。
方法 选择行硬膜外分娩镇痛的单胎、头位、足月妊娠产妇100例,年龄18～38岁,BMI 20～32 kg/m²,ASA Ⅰ或Ⅱ级,采用随机数字表法分为两组：PIEB组和连续硬膜外输注组（CEI组）,每组50例。两组镇痛药配方均为0.08％罗哌卡因＋0.4 μg/ml舒芬太尼。PIEB组参数设置：脉冲频率每小时1次,剂量10 ml,注药速率400 ml/h,单次剂量10 ml,间隔20 min。CEI组参数设置：背景输注速率10 ml/h,单次剂量10 ml,间隔20 min。记录产妇分娩镇痛前、镇痛后1、2、3、5 h、宫口开全和分娩时的VAS疼痛评分;产妇首次按压时间、按压次数、镇痛泵用药总量、镇痛时间;总产程时间、产后出血量、新生儿Apgar评分、产妇对分娩镇痛效果满意度评分;感觉阻滞平面达T4的例数、改良Bromage评分;以及低血压、恶心呕吐等不良反应发生情况。
结果 与分娩镇痛前比较,分娩镇痛后两组产妇VAS疼痛评分明显降低（P<0.05）。与CEI组比较,PIEB组镇痛后2、3、5 h、宫口开全、分娩时VAS疼痛评分均明显降低（P<0.05）,首次按压时间明显延迟（P<0.01）,按压次数、镇痛泵用药总量明显减少（P<0.01）。与CEI组比较,PIEB组产妇满意度评分明显增高（P<0.01）,感觉阻滞平面达T4的产妇比例明显升高（P<0.05）。两组总产程时间、产后出血量、新生儿Apgar评分差异无统计学意义。两组低血压和恶心呕吐等不良反应发生率差异无统计学意义。
结论 PIEB可安全有效地用于产妇自控硬膜外分娩镇痛,其效果优于连续硬膜外输注,产妇满意度高,且不影响分娩结局。     

产妇分娩时舒芬太尼或芬太尼混合罗哌卡因病人自控硬膜外镇痛的效应

目的比较产妇分娩时舒芬太尼或芬太尼混合罗哌卡因病人自控硬膜外镇痛(PCEA)的效应。方法无产科及硬膜外阻滞禁忌证的阴道分娩单胎初产妇120例,随机分为2组(n：60)：舒芬太尼混合罗哌卡因PCEA组(S组)和芬太尼混合罗哌卡因PCEA组(F组)。当产妇宫口开至3cm时,L_(2,3)间隙硬膜外穿刺置管,S组硬膜外注射0．15%罗哌卡因和0．5μg/ml舒芬太尼混合液试验剂量5 ml,随后追加上述混合液10 ml,30min后以0．1%哌卡因和0．5μg/ml舒芬太尼的混合液行PCEA；F组混合液中以2μg/ml芬太尼替代0．5μg/ml舒芬太尼,其他用药情况均与S组同。两组PCA剂量为6 ml,锁定时间为15 min。记录产妇视觉模拟疼痛评分(VAS)、下肢运动神经阻滞程度、生命体征、产程、分娩方式、不良反应及新生儿Apgar评分。结果两组镇痛期间VAS评分均降低,S组镇痛20～60 min VAS评分均低于F组。两组镇痛起效时间、达最高镇痛平面的时间、最高绝对平面、PCA实际按压次数、有效按压次数差异均无统计学意义。S组皮肤瘙痒的发生率高于F组,舒芬太尼、芬太尼用量分别为16±8、(70±28)μg,比率为1：4．4。两组产程和分娩方式构成比差异无统计学意义。结论产妇分娩时等效剂量的舒芬太尼或芬太尼混合罗哌卡因PCEA均可提供良好的镇痛效果。     

硬膜外分娩镇痛对产妇胃窦排空的影响

目的 观察硬膜外分娩镇痛对产妇胃窦排空的影响。
方法 选择孕足月初产妇87例,年龄20～40岁,BMI 20～40 kg/m²,ASA Ⅱ 或 Ⅲ 级。根据自愿是否需要分娩镇痛分为两组：镇痛组和对照组,其中镇痛组43例,对照组44例。镇痛组在L2-3行硬膜外穿刺置管术,置管成功后连接硬膜外自控镇痛泵,镇痛药物配方为0.08%罗哌卡因+舒芬太尼0.4 μg/ml。对照组不使用分娩镇痛。超声检查胃窦排空后给予碳水化合物饮料300 ml,分娩期间产妇不再进食其他食物饮料。记录胃窦排空即刻、饮用碳水化合物后5、30、60、120 min 和宫口开全时的胃窦横截面积（CSA）、单位体重胃容量（GV_W）和VAS疼痛评分。记录第一和第二产程时间、胃窦再次排空所需时间。记录分娩期间恶心和中转剖宫产情况。记录新生儿1 min和5 min的Apgar评分。记录产后住院时间。
结果 与对照组比较,镇痛组饮用碳水化合物后30、60、120 min和宫口开全时CSA和GV_W明显减小（P<0.05）,胃窦排空即刻、饮用碳水化合物后5、30、60、120 min和宫口开全时VAS疼痛评分明显降低（P<0.05）胃窦再次排空时间明显缩短（P<0.05）。两组第一和第二产程时间、恶心发生率、新生儿出生后1 min和5 min的Apgar评分、产后住院时间差异无统计学意义。
结论 硬膜外分娩镇痛会加快产妇胃窦排空,产程中饮用300 ml的碳水化合物饮品对母婴结局无不良影响。     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

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.