右美托咪定对经皮冠状动脉介入治疗患者氧化应激的影响

目的评价右美托咪定对经皮冠状动脉介入治疗(percutaneous coronary intervention,PCI)患者氧化应激的影响。方法选择急性心肌梗死需行急诊PCI患者50例,男39例,女11例,年龄47~79岁,体重45~83kg,ASAⅢ或Ⅳ级,采用随机数字表法将患者分为右美托咪定组(D组)和对照组(C组),每组25例。D组麻醉诱导前30min静脉泵注负荷剂量右美托咪定0.5μg/kg,泵注时间10min,随后持续静脉泵注右美托咪定0.2~1.0μg·kg~(-1)·h~(-1)至术毕;C组采用同样方法静脉泵注等量生理盐水。根据RASS镇静程度评估表,维持RASS评分-2~2分。于麻醉诱导前(T_0)、术毕(T_1)、术后6h(T_2)和24h(T_3)采集颈静脉血4ml,分别进行中性粒细胞(PMN)计数、血清丙二醛(MDA)浓度和超氧化物歧化酶(SOD)活性测定。记录术中低血压、心动过缓和低氧血症等不良反应的发生情况。结果与T_0时比较,T_1~T_3时两组血清PMN计数、MDA浓度均明显升高,血清SOD活性明显降低(P0.01或P0.05);T_1~T_3时D组PMN计数、MDA浓度均明显低于C组,血清SOD活性明显高于C组(P0.05)。两组患者术中低血压、心动过缓和低氧血症的发生率差异无统计学意义。结论持续静脉泵注右美托咪定0.5μg/kg,可以更好地抑制PCI患者的氧化应激反应,有助于减轻心肌缺血-再灌注损伤。     

右美托咪定对心肺转流患者中性粒细胞明胶酶脂质运载蛋白和胱抑素C的影响

目的评价右美托咪定对心肺转流(CPB)患者的中性粒细胞明胶酶脂质运载蛋白(NGAL)、胱抑素C(Cys C)的影响。方法择期拟行CPB下心血管手术患者60例,ASAⅡ或Ⅲ级,NYHA心功能分级Ⅱ或Ⅲ级,年龄23~64岁,体重48~85kg,采用随机数字表法均分为两组:右美托咪定组(D组)和对照组(C组)。D组麻醉诱导前10 min静脉缓慢泵注右美托咪定0.8μg/kg,继之以0.2~0.7μg·kg-1·h-1持续泵注至术毕,C组给予等容量生理盐水。于术前1d(T0)和CPB开始后6h(T1)、12h(T2)、24h(T3)、48h(T4)和72h(T5)时测定血清和尿的NGAL和Cys C的浓度。结果与T0时比较,两组T2、T3时血清NGAL和Cys C浓度、T1~T3时尿NGAL和Cys C浓度明显升高(P0.05)。与C组比较,D组T2、T3时血清NGAL和Cys C浓度、T1~T3时尿NGAL浓度、T1、T2时尿Cys C浓度明显降低(P0.05)。结论右美托咪定可降低心血管手术CPB患者NGAL和Cys C水平,减轻CPB诱发的肾损伤。     

不同剂量右美托咪定对腹腔镜下胃肠手术老年患者围术期应激反应的影响

目的观察不同剂量右美托咪定对腹腔镜下胃肠手术老年患者围术期应激反应的影响。方法择期行腹腔镜下胃肠手术老年患者80例,性别不限,年龄≥65岁,ASAⅠ或Ⅱ级。随机分为四组,每组20例。所有患者均采用全凭静脉麻醉。D1、D2组和D3组麻醉诱导前10min静脉泵注右美托咪定0.5μg/kg,插管后分别静脉泵注右美托咪定0.2、0.5、0.8μg·kg~(-1)·h~(-1)至术毕前30min;C组麻醉诱导前10min静脉泵注7ml生理盐水,插管后静脉泵注生理盐水10ml/h至术毕前30min。记录术中麻醉药物用量,记录给药前(T_0)、气管插管后即刻(T_1)、气腹后5min(T_2)、气腹后60min(T_3)、拔管后即刻(T_4)和拔管后10min(T_5)的HR、SBP、DBP,分别于T_0、T_1、T_3、T_5时抽取桡动脉血,测定Glu、Cor、E和NE浓度。结果 D1组、D2组和D3组术中瑞芬太尼的用量明显少于C组,且D2组和D3组明显少于D1组(P0.05)。与T_0时比较,T_1~T_5时C组HR明显增快(P0.05)。T_2~T_5时,D2组和D3组的HR明显慢于C组和D1组,SBP明显低于C组(P0.05);T_1时D2组和D3组Cor和NE浓度也明显低于C组(P0.05)。T_3和T_5时,D2组和D3组Glu、Cor、E和NE浓度明显低于C组,D2组和D3组Cor和NE浓度明显低于D1组(P0.05)。结论与0.2和0.8μg·kg~(-1)·h~(-1)右美托咪定静脉泵注维持比较,0.5μg·kg~(-1)·h~(-1)能更有效抑制腹腔镜下胃肠手术老年患者围术期应激反应。     

不同剂量右美托咪定滴鼻用于后路腰椎管减压内固定术患者术前镇静效果的比较

目的探讨经鼻给予不同剂量右美托咪定用于后路腰椎管减压内固定术患者术前镇静的效果。方法选择择期后路单间隙腰椎管减压内固定术患者80例,男46例,女34例,年龄18～65岁,BMI 18～25 kg/m~2,ASAⅡ或Ⅲ级。随机分为右美托咪定1.0μg/kg组(D1.0组)、右美托咪定1.5μg/kg组(D1.5组)、右美托咪定2.0μg/kg组(D2.0组)和对照组(C组)。患者入手术室后,D1.0组、D1.5组、D2.0组分别经鼻滴注右美托咪定1.0、1.5、2.0μg/kg,C组用生理盐水滴鼻,容量均为2 ml。记录滴鼻前(T_0)、滴鼻后10 min(T_1)、20 min(T_2)和30 min(T_3)的HR、MAP、SpO_2、自发痛VAS评分、Ramsay镇静和焦虑评分。滴鼻后30 min行左侧上肢肘正中静脉穿刺和桡动脉穿刺置管,记录患者穿刺时VAS评分和满意度评分,并抽取桡动脉血行血气分析。结果 T_3时D2.0组HR明显慢于C组(P0.05),MAP明显低于C组(P0.05)。T_3时D1.0、D1.5和D2.0组自发痛VAS评分明显低于C组(P0.05),Ramsay镇静评分明显高于C组(P0.05),T_3时D1.0和D1.5,T_2、T_3时D2.0组焦虑评分明显低于C组(P0.05)。D1.5组和D2.0组静脉穿刺和桡动脉穿刺VAS评分明显低于C组(P0.05),D1.0、D1.5和D2.0组满意度明显高于C组(P0.05)。结论后路腰椎管减压内固定术患者术前给予右美托咪定1.5μg/kg滴鼻可获得良好的镇静效果,提高患者的满意度。     

右美托咪定经鼻腔给药对妇科全麻围拔管期应激反应的影响

目的观察不同剂量右美托咪定经鼻腔给药对妇科全麻围拔管期应激反应的影响,并探讨最佳剂量。方法择期妇科手术患者80例,随机分为对照组(C组)和不同剂量右美托咪定滴鼻组(D1组、D2组、D3组)。手术结束前30 min,D1、D2、D3组分别经鼻滴注右美托咪定0.6、1.2、1.8μg/kg,C组用生理盐水滴鼻。记录给药前即刻(T_1)、手术结束时(T_2)、患者可唤醒时(T_3)、拔管时(T_4)、拔管后1min(T_5)、5min(T_6)、10min(T_7)的HR、MAP、SBP与HR乘积(RPP);检测T_1、T_2、T_4、T_6时血浆去甲肾上腺素(NE)和皮质醇(Cor)浓度。记录患者术后恢复指标。结果与C组比较,T_3~T_5时D1组、T_2~T_7时D2、D3组MAP和RPP均明显降低,HR明显减慢(P0.05);T_4、T_6时D1组、T_2、T_4和T6时D2、D3组血浆NE、Cor浓度明显降低(P0.05)。C组、D1组和D2组唤醒时间、拔管时间及PACU留观时间均明显短于D3组(P0.05)。结论手术结束前30min给予右美托咪定1.2μg/kg滴鼻可有效抑制全麻手术拔管期的应激反应,同时不影响术后恢复。     

右美托咪定对腭咽成形术患者围术期应激反应的影响

目的观察右美托咪定对腭咽成形术(uvulopalatopharyngoplasty,UPPP)患者围术期应激反应的影响。方法选择择期行腭咽成形术的男性患者60例,年龄18~65岁,ASAⅠ或Ⅱ级,随机分为右美托咪定组(D组)和对照组(C组),每组30例。D组气管插管前先予负荷剂量右美托咪定1.0μg/kg 10min,术中及入ICU后持续静脉泵注右美托咪定0.5μg·kg~(-1)·h~(-1);C组持续泵入等容量生理盐水。记录入室(T_0)、气管插管成功即刻(T_1)、手术开始30min(T_2)、入ICU即刻(T_3)、拔除气管导管即刻(T_4)的MAP、HR;检测T_0~T_4时动脉血PaO_2、PaCO_2及去甲肾上腺素(NE)、肾上腺素(E)、皮质醇(Cor)、IL-6、T_NF-α的浓度;记录入ICU后苏醒时间、拔管时间、ICU停留时间及呛咳反应的发生情况。结果 T_1~T_4时D组HR明显慢于C组,MAP明显低于C组(P0.05);T_1~T_4时D组NE、E、Cor、IL-6、T_NF-α浓度明显低于C组(P0.05);D组拔管期呛咳发生率为9例(30%),明显低于C组的21例(70%)(P0.05)。两组苏醒时间、拔管时间及ICU停留时间差异无统计学意义。结论围术期静脉泵注右美托咪定可有效抑制腭咽成形术患者的应激反应,维持循环稳定,且不延长患者苏醒时间、拔管时间及ICU停留时间。     

右美托咪定对胃癌手术老年患者红细胞糖代谢限速酶和血糖及丙二醛浓度的影响

目的观察右美托咪定对胃癌手术老年患者红细胞糖代谢限速酶活性和血糖及丙二醛(MDA)浓度的影响。方法选择胃癌手术老年患者60例,男38例,女22例,年龄60~80岁,ASAⅠ或Ⅱ级,随机分为两组,每组30例。右美托咪定组(D组)术前10 min静脉泵注右美托咪定0.5μg/kg,术中右美托咪定静脉维持0.3μg·kg~(-1)·h-1,对照组(C组)术前、术中静脉泵注等量的生理盐水。分别于麻醉前(T_0)、手术60min(T_1)、术后60 min(T_2)、术后1d晨(T_3)和术后2d晨(T_4)抽取肘静脉血,测定红细胞磷酸果糖激酶(PFK)、葡萄糖-6-磷酸脱氢酶(G-6PD)和醛糖还原酶(AR)的活性及血糖和血浆丙二醛(MDA)的浓度。结果与T_0时比较,T_3时两组PFK活性明显降低(P0.05),G-6PD和AR活性明显升高(P0.05或P0.01),且D组PFK活性明显高于、G-6PD和AR活性明显低于C组(P0.05)。T_1时两组血糖浓度开始升高(P0.01),至T_3时达峰值(P0.01);T_1~T_3时D组血糖浓度均明显低于C组(P0.05)。与T_0时比较,T_3时两组血浆MDA浓度在T_3时明显升高(P0.01),D组MDA浓度明显低于C组(P0.05)。结论右美托咪定可降低胃癌手术老年患者围术期血糖浓度,减轻氧化应激,改善红细胞糖代谢状态。     

ZP123可预防右美托咪定延长心肌复极时程所致的负性变频效应

目的探讨缝隙连接改造剂ZP123对右美托咪定诱发鼠离体心脏复极时程延长所致的负性变频效应。方法健康成年SD大鼠18只,雌雄不拘,体重(300±30)g,制备Langendorff离体心脏灌注模型,K-H液平衡灌注15min后,随机分为三组,每组6只:空白对照组(C组)继续灌注37℃K-H液30min;右美托咪定组(D组)灌注含50ng/ml右美托咪定的K-H液30min,右美托咪定+ZP123组(ZD组)灌注含50ng/ml右美托咪定+80nmol/L ZP123的K-H液30 min。于平衡灌注15 min(T_o)、继续灌注15 min(T_1)、30 min(T_2)时记录HR和左心室心肌单相动作电位(MAP),计算MAP复极50%、90%的时程(MAPD50、MAPD90)、单相动电位振幅(MAPA)和最大去极化速度(Vmax)。结果与T_0时比较,T_1、T_2时D组HR明显减慢(P0.05),T_1、T_2时D组HR明显慢于C组和ZD组(P0.05)。与T_0时比较,T_1、T_2时D组心肌MAPD50、MAPD90明显延长(P0.05);T_1、T_2时D组心肌MAPD50、MAPD90明显长于C组和ZD组(P0.05)。三组心肌内外两层膜MAPA和Vmax组间组内差异均无统计学意义。结论缝隙连接改造剂ZP123通过缩短心肌单相动作电位复极的时程从而拮抗右美托咪定诱发的鼠离体心脏的负性变频效应。     

右美托咪定通过腺苷A1受体调节大鼠压力反射敏感性

目的观察腺苷A1受体在右美托咪定调节压力反射敏感性(baroreflex sensitivity,BRS)中的作用。方法健康成年雄性SD大鼠32只,体重240~280g,按随机数字表随机分为四组:对照组(C组)、选择性腺苷A1受体阻断剂组(P组)、右美托咪定组(D组)、选择性腺苷A1受体阻断剂+右美托咪定组(PD组),每组8只。C组泵注生理盐水40 ml·kg~(-1)·h~(-1)负荷量15 min,维持泵注10 ml·kg~(-1)·h~(-1);P组腹腔注射选择性腺苷A1受体阻断剂8-环戊基-1,3-二丙基黄嘌呤(DPCPX)1mg/kg,泵注同C组方案的生理盐水;D组右美托咪定负荷量100μg/kg,维持量100μg·kg~(-1)·h~(-1)持续泵注;PD组腹腔注射DPCPX 1mg/kg并泵注右美托咪定,泵注剂量同D组。采用苯肾上腺素升压法于泵注前(T_0)、泵注后60min(T_1)和泵注后120min(T_2)测定BRS。结果与T_0时比较,T_1和T_2时D组和PD组BRS明显升高(P0.05)。与C组和P组比较,T_1和T_2时D组和PD组BRS均明显升高(P0.05)。与D组比较,T_1和T_2时PD组BRS明显降低(P0.05)。结论右美托咪定可能通过腺苷A1受体增加大鼠BRS。     

不同负荷剂量右美托咪定对心脏传导系统的影响

目的探讨单次泵注不同负荷剂量右美托咪定对心脏传导系统的影响。方法择期行骨科手术男性患者80例,年龄20~65岁,ASAⅠ或Ⅱ级,随机分为四组,每组20例。D1、D2、D3组分别采用微量泵输注右美托咪定0.3、0.5和0.8μg/kg,C组以同样方式输注等容量生理盐水,输注时间为10min。记录泵注前(T_1)、泵注后5min(T_2)、10min(T_3)、泵注结束后10min(T_4)时患者MAP、HR、SpO_2和12导联ECG,计算P波时限、P-R间期、QRS时限和QTc值。结果 T_2~T_4时D2、D3组MAP明显低于,HR明显慢于T_1时和C组(P0.05)。T_2~T_4时D2、D3组QTc值明显短于T_1时和C组(P0.05)。四组P波时限、P-R间期和QRS时限组间组内差异无统计学意义。结论右美托咪定不影响心脏传导系统,0.5及0.8μg/kg负荷剂量右美托咪定可有效缩短QT间期,但可能对基础心率偏慢患者宜选用不超过0.5μg/kg负荷剂量右美托咪定,避免严重心动过缓。     

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.