不同麻醉下老年患者静脉输注乳酸钠林格氏液的容量动力学

目的 比较不同麻醉下老年患者静脉输注乳酸钠林格氏液容量动力学的差异.方法 择期行上腹部手术老年患者30例,年龄65～79岁,ASA Ⅰ或Ⅱ级,随机分为2组(n=15):单纯全麻组(GA组)和硬膜外复合全麻组(GE组).GE组经T8.9硬膜外穿刺置管,注入2%利多卡因4 ml使阻滞平面达T4,然后硬膜外给予0.25%布比卡因8～10 ml.2组静脉注射咪达唑仑2 mg、芬太尼3μg/kg、异丙酚1.5 mg,kg和琥珀胆碱1.5 mg/kg麻醉诱导,气管内插管后行机械通气.麻醉诱导后2组经30min静脉输注乳酸钠林格氏液30 ml/kg,随后以0.1 ml·kg-1·min-1的速率继续输注60 min.连续监测心率、平均动脉压、中心静脉压、心脏指数、每搏量指数、胸内血容量指数及血管外肺水容量指数;桡动脉采血测定血红蛋白浓度和红细胞压积;记录试验过程中的尿量;应用容量动力学理论和物质守恒定律,计算中央容量稀释率、血浆容量增加、容量扩张效率、外周容量增加和清除率(K).尿量与Kr进行直线相关分析.结果 GA组和GE组乳酸钠林格氏液分布均符合容量动力学二室模型.与GA组比较,GE组中央容量稀释率、血浆容量增加和容量扩张效率升高,尿量和Kr减少(P<0.05),外周容量增加差异无统计学意义(P>0.05).GA组尿量与Kr呈正相关(r=0.551,P<0.05);GE组尿量与K呈正相关(r=0.531,P<0.05).结论 与单纯全麻比较,老年患者硬膜外复合全麻下静脉输注乳酸钠林格氏液的容量扩张效率增强.     

健康男性志愿者晶体液和胶体液容量动力学的比较

目的 运用容量动力模型分析健康成年男性志愿者输注晶体液或胶体液的动力学特点.方法 健康成年男性志愿者11名,分别接受3次独立的液体输注试验:30 min内随机恒速输注乳酸钠林格氏液20 ml/kg、6%羟乙基淀粉8 ml/kg或4%琥珀酰明胶8 ml/kg,于输液开始前抽取血样2次,测定血红蛋白浓度和红细胞压积,取平均值作为基础值,输液开始后的前120 min,每隔5分钟1次,后120 min,每隔10分钟1次,分别抽取血样2 ml,测定血红蛋白浓度.应用容量动力一室和二室模型分析3种液体的体内动力学过程,计算靶容量(V或V1、V2)和液体清除速率常数(Kr)等参数;拟合输液中及输液后靶容量稀释随时间的变化曲线.结果 输注乳酸钠林格氏液大部分符合二室模型,V1为(3.1±0.7)L,V2为(9±4)L,Kr为(61±39)ml/min;输注胶体液则大多符合一室模型,6%羟乙基淀粉和4%琥珀酰明胶的靶容量(V)分别为(2.6±0.4)L和(2.3±0.3)L,Kr分别为(16±8)ml/min和(17±11)ml/min.结论 容量动力模型可用于比较不同液体的动力学特点;晶体液的体内可扩张液体间隙总量(靶容量)约占整个细胞外液量的85%;相对于晶体液,胶体液较强的扩容效应源于体内较小的靶容量和相对缓慢的清除速率.     

血液稀释对全麻腹腔镜活体肾移植供体围手术期血管外肺水的影响

目的：探讨高容量血液稀释（HHD）、等容量血液稀释（NHD）及常规液体输注（CIT）对全麻腹腔镜活体肾移植供体围手术期肺水的影响。方法：随机将48例健康成年志愿捐肾者分为4组：A组（n=10,对照组,乳酸钠林格氏液,CIT）,B组（n=12,4%琥珀酰明胶4～5ml/kg,NHD）、C组（n=13,4%琥珀酰明胶20ml/kg,HHD）,D组（n=13,4%琥珀酰明胶30ml/kg,HHD）,在全麻腹腔镜下行肾脏摘除手术。B、C、D组于麻醉诱导后至肾动脉阻断前静脉输注4%琥珀酰明胶4～5、20、30ml/kg稀释血液。术中监测麻醉诱导前（T0）、手术开始后30min（T1）、肾动脉阻断时（T2）、肾动脉阻断后15min（T3）、手术结束时（T4）及手术结束后240min（T5）的平均动脉压（MAP）、心率（HR）、心电图（ECG）、脉搏血氧饱和度（SpO2）、中心静脉压（CVP）等指标。于各时点抽取动、静脉血进行血气分析,应用全自动生化分析仪测定血浆胶体渗透压（PCOP）;T2、T4时分别测量供肾者胶体液总量及尿量、晶体液总量。手术期间4组以20ml/（kg.h）速率常规输注乳酸钠林格液。C、D组于大量输注琥珀酰明胶期间静脉持续输注硝酸甘油3～8μg/（kg.h）,于阻断肾动静脉后常规应用速尿40mg。结果：（1）4组ECG、SpO2、晶体液总量及围手术期总出血量等均无显著差异（P〉0.05）;（2）C、D组T1、T2、T3、T4时MAP、CVP、PCOP高于A、B组（P〈0.05）,但均在正常范围;（3）与T0相比,C、D组T2、T3时Hb、Hct降低显著（P〈0.05）,分别达中度（P〈0.05）和重度（P〈0.01）血液稀释水平;T2,T3时A、D组PaO2下降（P〈0.05）,而C组升高（P〈0.05）;（4）T4时C、D组总尿量、胶体液总量大于A、B组（P〈0.05）。结论：不同的血液稀释状态对全麻腹腔镜活体肾移植供体围手术期血管外肺水产生不同的影响,静脉输注琥珀酰明胶20ml/（kg.h）时高容量血液稀释可产生良好的扩容效果     

羟乙基淀粉130/0.4和琥珀酰明胶对SICU患者毛细血管通透性及炎性反应的影响

目的研究羟乙基淀粉130/0.4和琥珀酰明胶对SICU患者毛细血管通透性及炎性反应的影响。方法全麻下行胸腔或腹部手术、失血量超过400ml、术后即入SICU患者100例,年龄50～64岁,体重50～75kg,ASAⅡ级,随机分成5组,每组20例,各组术中分别静脉输注羟乙基淀粉130/0.4 500ml或1 000ml,琥珀酰明胶500ml或1 000ml及乳酸钠林格氏液10ml·kg~(-1)·h~(-1),术后收入SICU。分别于术前、术后入SICU 6h时留取尿液标本,采用ELISA法测定尿白蛋白浓度,酶比色法测定尿肌酐;计算尿白蛋白/尿肌酐比值(MA/CR);抽取10ml深静脉血,采用ELISA法测定血浆IL-6浓度。结果术中静脉输注羟乙基淀粉130/0.4和琥珀酰明胶的MA/CR较静脉输注乳酸钠林格氏液降低(P<0.05);术中输注相同容积羟乙基淀粉和琥珀酰明胶的MA/CR差异无统计学意义(P>0.05);各组入SICU6h时血浆IL-6水平较术前明显升高(P<0.05),5组血浆IL-6水平差异有统计学意义,其中术中静脉输注羟乙基淀粉的最低(P<0.05)。结论静脉输注羟乙基淀粉130/0.4或琥珀酰明胶500 ml有助于改善SICU患者毛细血管的通透性,而羟乙基淀粉130/0.4的抗炎作用明显优于琥珀酰明胶。     

全麻复合硬膜外麻醉患者林格氏溶液的容量动力学

目的 通过确定全麻复合硬膜外时麻醉林格氏溶液的容量动力学模型参数，评价硬膜外复合全麻对晶体液扩容效应的影响。方法择期行肝癌切除术患者20例，随机分为2组：组Ⅰ麻醉诱导前行扩容治疗，组Ⅱ硬膜外复合全麻诱导后行扩容治疗。扩容采用30ml／kg乳酸钠林格氏溶液（LR）恒速输注，30min内输完，输注LR开始后90min内每5min测定血红蛋白（Hb）及红细胞压积（Hct），并记录总尿量及血液动力学数据。用容量动力学数学模型和物质守恒定律处理数据，获得结果。结果 组Ⅱ容量增加量、容量扩张效率、输注结束时液体保留率均高于组Ⅰ（P〈0．05）。一级容量动力学分析结果：组Ⅰ目标容积（V）和清除率（k1）均大于组Ⅱ（P〈0．05）。二级容量动力学分析结果：组Ⅱ的V1、k1、k1均高于组Ⅱ（P〈0．05）。扩容后组Ⅱ的平均动脉压、中心静脉压、心输出量均小于组Ⅰ（P〈0．05）。结论 全麻复合硬膜外麻醉可提高晶体液的容量扩张效率。     

剖宫产术中输注琥珀明胶对母儿血浆内皮素和降钙素基因相关肽水平的影响

目的研究硬膜外麻醉下行剖宫产术中输注琥珀明胶对母儿血浆内皮素和降钙素基因相关肽浓度的影响.方法20个病例随机分为两组对照组(Ⅰ),输乳酸钠林格液15ml·kg-1·h-1;试验组组(Ⅱ),输注琥珀明胶10ml·kg-1·h-1,分别输上述液体500ml后均改为输林格氏液,速率10ml·kg-1·     

不同液体治疗对感染性休克新生兔全身炎性反应的影响

目的 探讨不同液体治疗对感染性休克新生兔全身炎性反应的影响.方法 健康新西兰长耳新生兔100只,采用盲肠结扎穿孔(CLP)法制备感染性休克模型,随机分为5组(n=20):假手术组(S组)、CLP组、乳酸钠林格氏液组(R组)、乳酸钠林格氏液+6%羟乙基淀粉组(R+HES组)和6%羟乙基淀粉组(HES组).CLP后即刻,R组静脉输注乳酸钠林格氏液30 ml/kg 1 h;R+HES组依次静脉输注乳酸钠林格氏液20 ml/kg 40 min和6%羟乙基淀粉10 ml/kg 20 min;HES组静脉输注6%羟乙基淀粉30 ml/kg 1 h.于CLP后即刻、0.5、1、2、4、8 h(T1～6)时记录MAP.于T6时取颈总动脉血样,测定血浆IL-6和IL-10的浓度.结果 与T1时比较,CLP组T4～6时MAP降低,R组T5.6时MAP降低(P＜0.05),其余各组差异无统计学意义(P＞0.05).与S组比较,CLP组MAP降低,血浆IL-6浓度升高,IL-10浓度降低,R组MAP降低,血浆IL-6浓度升高,HES组血浆IL-10浓度升高(P＜0.05).与CLP组比较,R+HES组和HES组血浆IL-6浓度降低,IL-10浓度升高,R组血浆IL-10浓度升高(P＜0.05).结论 新生兔感染性休克早期静脉输注乳酸钠林格氏液与6%羟乙基淀粉(2∶1)治疗,有利于维持促炎细胞因子和抑炎细胞因子的平衡,从而减轻全身炎性反应,其效果优于单独静脉输注乳酸钠林格氏液或6%羟乙基淀粉.     

肠癌根治术病人两种容量治疗方案效果的比较

目的 比较肠癌根治术病人麻醉诱导前6%羟乙基淀粉130/0.4.麻醉诱导后乳酸钠林格氏液血液稀释与麻醉诱导前乳酸钠林格氏液-麻醉诱导后6%羟乙基淀粉130/0.4血液稀释容量治疗的效果.方法 拟行肠癌根治术病人40例,ASA Ⅰ或Ⅱ级,年龄45～64岁,体重42～65 kg,随机分为2组(n=20),Ⅰ组麻醉诱导前经30min静脉输注6%羟乙基淀粉130/0.4 15 ml/kg,麻醉诱导后即刻经30 min静脉输注乳酸钠林格氏液15 ml/kg;Ⅱ组于麻醉诱导前经30 min静脉输注乳酸钠林格氏液15 ml/kg,麻醉诱导后即刻经30 min静脉输注6%羟乙基淀粉130/0.4 15 ml/kg.记录术中胶体液量、晶体液量、出血量、尿量和异体输血情况;于人室后(基础状态,T0)、麻醉诱导后即刻(T1、15 min(T2)、60 min(T3)、120 min(T4)及术毕(T5)时记录平均动脉压(MAP)、中心静脉压(CVP)和心率(HR);于T0、T1、T3、T5时抽取桡动脉血样1 ml行血气分析,并测定血红蛋白浓度(Hb)和红细胞压积(Hct).结果 两组均未输异体血,术中胶体液用量,晶体液用量、出血量、尿量差异无统计学意义(P>0.05);与基础值比较,Ⅰ组术中MAP、HCO-3、血浆乳酸、Na+、K+的浓度差异无统计学意义(P>0.05),CVP升高,HR、Hct、Hb降低,术毕时pH值降低,Ⅱ组术中CVP升高,MAP、HR、pH值降低,术毕时HCO-3降低(P<0.05),血浆乳酸、Na+、K+的浓度差异无统计学意义(P>0.05);与Ⅰ组比较,Ⅱ组术中CVP升高,术毕时血浆乳酸浓度降低(P<0.05).结论 肠癌根治术病人采用麻醉诱导前6%羟乙基淀粉130/0.4-麻醉诱导后乳酸钠林格氏液血液稀释的容量治疗效果较好.     

不同液体对健康成年志愿者扩容效果的比较

目的 比较6%羟乙基淀粉130/0.4、6%羟乙基淀粉200/0.5、琥珀酰明胶及乳酸钠林格氏液对健康成年志愿者的扩容效果.方法 健康成年男性志愿者24名,年龄21～40岁,体重56～78kg,随机分为4组(n=6),以125I法测定血浆容量并结合血细胞比容计算基础血容量;输液前于肘静脉抽血2 ml测定血红蛋白浓度,各组分别在45 min内静脉恒速输注6%羟乙基淀粉130/0.4(A组)、6%羟乙基淀粉200/0.5(B 组)、琥珀酰明胶(C组)和乳酸钠林格氏液(D组)750 ml.输液结束后每隔20分钟抽静脉血2 ml测定血红蛋白浓度,A组、B组和C组至输液后340 min、D组至输液后180 min,计算输液后血容量增加值(△BV)和液体潴留率(FR).结果 与输液前比较,A组和B组输液后80～340 min时血容量增加,C组输液后80～320 min时血容量增加,D组输液后80 min时血容量增加(P＜0.05);与A组比较,C组输液结束时、D组输液结束时至输液结束后180 min时△BV和FR降低(P＜0.05),且输液结束后180 min 时△BV和FR均为0;与B组比较,C组输液结束时、D组输液结束时至输液结束后180 min时△BV和FR降低(P＜0.05);与C组比较,D组输液结束时至输液结束后180 min时△BV和FR降低(P＜0.05);A组、B组和C组液体在血管内存留时间均＞340 min.结论 6%羟乙基淀粉130/0.4、6%羟乙基淀粉200/0.5和琥珀酰明胶较乳酸钠林格氏液的扩容效果好,维持时间长.     

急性高容量血液稀释对患者靶控输注异丙酚时镇静深度的影响

目的 观察急性高容量血液稀释（AHH）对患者靶控输注（TCI）异丙酚时镇静深度的影响。方法 择期全麻患者80例，随机分为4组（n=20）：A组、B组、C组气管插管后5min均开始进行急性高容量血液稀释，静脉输注乳酸钠林格氏液8ml／kg，同时30min内静脉输注6％羟乙基淀粉（HES，200／0．5）15ml／kg。B0组为B组的对照组，只静脉输注乳酸钠林格氏液8ml／kg，不进行急性高容量血液稀释。A组、B组、B0组、C组分别以2、4、4、6μg／ml异丙酚效应室靶浓度实施靶控输注至血液稀释结束。监测各组开始血液稀释即刻、5、10、15、20、25、30min时的BIS、AAI、MAP、HR、SpO2及ECG的变化，采集血标本，检测血液稀释前即刻和血液稀释结束时的Hct、Hb。结果 与B0组比较，B组MAP升高，BIS和AAI降低（P〈0．05或P〈0．01），血液稀释结束时Hct、Hb下降（P〈0．01）。随AHH的进行A组和B组MAP逐渐上升，BIS、AAI逐渐下降（P〈0．05或P〈0．01），Bn组和C组的MAP、BIS、AAI无明显变化，4组HR、SpO2差异无统计学意义（P〉0．05）；与血液稀释前即刻比较，A组、B组、C组在血液稀释结束时的Hct、Hb降低（P〈0．01），Bn组无变化（P〉0．05）。结论 患者以异丙酚2、4μg／ml效应室靶浓度靶控输注时，急性高容量血液稀释可加深镇静深度，当效应室靶浓度升为6μg／ml时，对其镇静深度无明显影响。     

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.     

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.     

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.     

Immunomodulation in Transplantation with Photopheresis

Abstract: Photopheresis is a technique in which peripheral blood mononuclear cells, in the presence of a photoacti-vatable compound, are exposed extracorporeally to ultraviolet A light and reinfused, inducing a host autoregula-tory immune response. Experimental work and ongoing clinical studies are helping to define the role of this novel, safe, and non-toxic immunomodulating technology in the field of transplantation.