右美托咪定对心脏瓣膜置换术患者肠黏膜损伤的影响

目的研究右美托咪定对心肺转流(CPB)下心脏瓣膜置换术患者肠黏膜损伤的影响及机制。方法择期行心瓣膜置换术的风湿性心脏病患者40例,男17例,女23例,年龄32~64岁,体重40~75kg,ASAⅡ或Ⅲ级,随机均分为右美托咪定组(D组)和对照组(C组)。麻醉诱导前D组静注右美托咪定负荷量1μg/kg持续10min,随后以0.3μg·kg-1·h-1速率持续输注至术毕;C组输注等容量生理盐水。两组麻醉诱导及维持方法相同。测定CPB开始前(T0)、主动脉阻断30min(T1)、停CPB即刻(T2)、术毕(T3)、术后6h(T4)、24h(T5)时血浆丙二醛(MDA)浓度、总抗氧化能力(T-AOC)和肠型脂肪酸结合蛋白(I-FABP)浓度。结果与T0时比较,两组T1~T5时血浆MDA浓度、I-FABP明显升高(P0.05),T1~T4时D组血浆T-AOC明显降低(P0.05)。T1~T5时D组血浆MDA、I-FABP明显低于C组(P0.05),T1~T4时D组血浆T-AOC明显高于C组(P0.05)。结论右美托咪定可以减轻CPB下心脏瓣膜置换术患者肠黏膜损伤,其机制与抑制氧化应激反应有关。     

右美托咪定对颅内肿瘤手术患者脑脊液中氨基酸的影响

目的探讨右美托咪定对颅内肿瘤手术患者脑脊液中兴奋性和抑制性氨基酸的影响和右美托咪定在神经外科手术中的脑保护机制。方法选择择期脑肿瘤手术患者60例,年龄18~64岁,ASAⅠ或Ⅱ级,性别不限,体重50~90kg。随机均分为两组:右美托咪定组(D组)和对照组(C组)。麻醉诱导前D组静脉输注右美托咪定1μg/kg,10min注完,C组静脉注射咪达唑仑0.03~0.05mg/kg。D组持续静脉泵注右美托咪定0.2~0.7μg·kg-1·h-1,C组间断给予咪达唑仑0.03~0.05mg/kg。维持BIS值在40~50。记录麻醉诱导前(T0)、切开硬脑膜(T1)、切除肿瘤时(T2)、手术结束时(T3)的MAP、HR。并于T0、T3、术后6h(T4)、12h(T5)、24h(T6)收集脑脊液,用高效液相色谱法检测脑脊液中兴奋性氨基酸谷氨酸(Glu)、天门冬氨酸(Asp)和抑制性氨基酸γ-氨基丁酸(GABA)的浓度。结果 T1~T3时D组MAP明显低于,HR明显慢于T0时和C组(P0.05)。T3~T6时脑脊液中C组Glu、Asp浓度明显高于T0时和D组(P0.05),GABA浓度明显低于D组(P0.05)。与T0时比较,T3~T5时D组Glu、Asp浓度有升高、GABA浓度有降低趋势,但差异无统计学意义,T6时恢复到T0时水平。结论右美托咪定用于颅内肿瘤手术中可维持血流动力学稳定性,降低脑脊液中兴奋性氨基酸Glu和Asp浓度,有一定的脑保护作用。     

右美托咪定对ARDS机械通气患者炎症因子及肺损伤的影响

目的观察右美托咪定对急性呼吸窘迫综合症(ARDS)机械通气患者炎症因子及肺损伤的影响。方法选择40例ARDS机械通气患者,根据患者使用和未使用右美托咪定,将患者分成右美托咪定组(右美托咪定组,n=20)和对照组(n=20)。前者静脉泵注右美托咪定负荷量1μg/kg 15 min,再以0.2~0.7μg/kg·h速率持续输注48 h;对照组患者静脉泵注丙泊酚3~5 mg/(kg·h)为48 h,两组均复合舒芬太尼0.1~0.2μg/(kg·h)。分别于插管前(T0)、插管后6 h(T1)、12 h(T2)、24 h(T3)、48 h(T4)各时间点抽取静脉血检测IL-6、IL-8、IL-10的浓度,同时记录Pa O2/Fi O2。结果与T0时比较,T1~T4时两组的IL-6、IL-8、IL-10的浓度显著升高(P0.05),D组Pa O2/Fi O2T2~T4时显著增高(P0.05)、C组T1~T4时显著降低(P0.05),HR在T1~T4时D组降低,C组增高(P0.05)。与C组比较,T2~T4时D组IL-6、IL-8显著降低、IL-10显著升高(P0.05);T2~T4时Pa O2/Fi O2升高(P0.05);T1~T4时D组HR降低,T2~T4时MAP升高(P0.05)。结论右美托咪定用于ARDS机械通气治疗患者,可以平衡炎症因子的释放,有利于减轻肺损伤。     

右美托咪定对心脏瓣膜置换术患者的心肌保护作用

目的观察右美托咪定对心脏瓣置换术患者的心肌保护作用。方法风湿性心脏病行二尖瓣置换术患者30例,均择期全麻CPB下手术,年龄18~65岁,ASAⅡ或Ⅲ级。采用随机数字表法均分为右美托咪定组(D组)和生理盐水组(C组)。麻醉诱导后D组开始静注右美托咪定0.5μg/kg,然后静脉持续泵入0.5μg·kg-1·h-1至手术结束;C组静注等量生理盐水。记录用药前(T0)、用药后即刻(T1)、切皮后(T2)、劈胸骨后(T3)、CPB前(T4)、停CPB后10min(T5)、手术结束(T6)的MAP和HR。于T0、T5、T6、术后6h(T7)、24h(T8)抽取中心静脉血ELISA法检测心型脂肪酸结合蛋白(H-FABP)、肌酸激酶(CK-MB)、肌钙蛋白I(cTnI)浓度。结果与T0时比较,T2、T3时两组MAP明显升高,T1、T2和T4时D组HR明显减慢,而T5、T6时两组HR明显增快(P0.05)。与C组比较,T3时D组MAP明显降低、T4时MAP明显升高(P0.05),T1~T3时HR明显减慢(P0.05)。与T0时比较,T5~T8时两组血清H-FABP、CK-MB和cTnI浓度明显升高(P0.05)。与C组比较,T5~T8时D组血清H-FABP浓度,T7、T8时CK-MB和cTnI浓度明显降低(P0.05)。结论麻醉诱导后给予0.5μg/kg负荷量右美托咪定,随后持续静脉输注0.5μg·kg-1·h-1,可维持体外循环前血压稳定,减轻CPB至术后24h心肌损伤。     

右美托咪定对全麻低温心肺转流下冠状动脉旁路移植术围术期的心肌保护作用

目的观察右美托咪定对全麻低温心肺转流(CPB)下冠状动脉旁路移植术患者围术期的心肌保护作用。方法择期行全麻低温CPB下冠状动脉旁路移植术患者80例,男67例,女13例。随机均分为右美托咪定组(A组)和对照组(C组)。在中心静脉置管后,A组静脉泵注右美托咪定4μg·kg-1·h-1持续15min后调节维持剂量0.7μg·kg-1·h-1直到手术结束,C组用同样方案静注等容量生理盐水。记录入室后(T0)、麻醉诱导后(T1)、切皮时(T2)、CPB终止时(T3)和手术结束时(T4)的HR、SBP、DBP和血管活性药物用量。测定T1~T4、术后6h(T5)和术后24h(T6)血浆肌酸激酶同工酶(CK-MB)、心肌肌钙蛋白T(cTnT)、肾上腺素(E)和去甲肾上腺素(NE)浓度。结果与T0时比较,T1时两组HR明显减慢,SBP和DBP明显降低(P0.05)。与T1、T2时比较,T3~T6时两组CK-MB、cTnT、E浓度明显升高(P0.05),T3~T5时A组NE浓度明显下降(P0.05),T6时明显升高(P0.05)。T3~T6时A组CK-MB和cTnT浓度明显低于C组(P0.05)。T3~T5时A组E和NE浓度明显低于C组(P0.05)。两组在围术期均未出现严重不良反应。结论右美托咪定能降低全麻低温CPB下冠状动脉旁路移植术围术期心肌缺血的发生,达到围术期心肌保护的作用。     

右美托咪定对单肺通气患者血浆IL-8、IL-10及肺组织AQP1表达的影响

目的评价右美托咪定对单肺通气(one lung ventilation,OLV)患者血浆IL-8、IL-10及肺组织水通道蛋白(aquaporin,AQP)1表达的影响。方法择期行肺癌根治术患者40例,男23例,女17例,年龄40~75岁,ASAⅠ或Ⅱ级,采用随机数字表法将患者均分为两组:对照组(C组)和右美托咪定组(D组)。麻醉诱导前10 min,D组静注右美托咪定1μg/kg,随后以0.5μg·kg-1·h-1的速率输注至手术结束前30min,C组采用同样的方法静注等容量的生理盐水。于OLV前即刻(T1)、OLV 30min(T2)、60min(T3)、120min(T4)、恢复双肺通气后30min(T5)、术后2h(T6)取桡动脉血,测定血浆IL-8和IL-10的浓度。于OLV前即刻、肺叶离体时取肺组织,测定AQP1的表达。结果 T3~T6时C组及T3~T5时D组IL-8浓度,T2~T5时两组IL-10浓度明显高于T1时(P0.05);D组T3~T6时IL-8浓度明显低于,T2~T5时IL-10浓度明显高于C组(P0.05)。C组肺叶离体时AQP1表达明显低于OLV前即刻和D组(P0.05)。结论给予负荷量1μg/kg的右美托咪定,随后以0.5μg·kg-1·h-1的速率持续输注,可以降低单肺通气患者全身炎症反应,上调肺组织AQP1表达。     

不同剂量右美托咪定对妇科腹腔镜手术围术期炎症因子的影响

目的探讨不同剂量右美托咪定对妇科腹腔镜手术围术期炎症因子的影响。方法选择2012年1月至2013年12月择期妇科腹腔镜手术患者90例,按照随机数字表法将其分为高剂量右美托咪定组(D1组)、低剂量右美托咪定组(D2组)和对照组(C组),每组30例。D1组和D2组分别于麻醉诱导后持续静脉输注右美托咪定0.5和0.2μg·kg-1·h-1,C组则以等容量生理盐水代替。记录麻醉诱导前10 min(T1)、气管插管后1 min(T2)、气腹后1 min(T3)、术毕(T4)的MAP和HR,并检测血清TNF-α、IL-6、IL-10水平。结果与T1时比较,T2~T4时D2组和C组MAP明显升高,D1组HR明显减慢,T2、T3时C组HR明显增快(P0.05)。与C组比较,T2~T4时D1组和D2组MAP明显降低,HR明显减慢(P0.05)。与T1时比较,T2~T4时三组TNF-α、IL-6和IL-10水平明显升高(P0.05)。与C组比较,T2~T4时D1组和D2组TNF-α和IL-6水平明显降低,但D1组IL-10水平明显升高,T2、T3时D2组IL-10水平明显降低(P0.05)。结论持续输注右美托咪定可减轻妇科腹腔镜手术围术期炎症反应,且0.5μg·kg-1·h-1较0.2μg·kg-1·h-1更为明显。     

右美托咪定对全麻下经皮肾镜取石术患者肾功能的影响

目的探讨右美托咪定对肾脏结石患者全麻下经皮肾镜取石术时肾功能的影响。方法选择择期行经皮肾镜取石术患者30例,男25例,女5例,年龄40~70岁,ASAⅠ或Ⅱ级,按分层随机区组设计分为右美托咪定组(D组)和对照组(C组),每组15例。D组在常规麻醉诱导用药前10min经静脉输注右美托咪定1μg/kg,随后以0.5μg·kg-1·h-1的速率静脉输注至手术结束,C组给予等容量的生理盐水。于手术开始前即刻(T0)、手术结束即刻(T1)、术后第1天(T2)和术后第3天(T3)时取静脉血样和留尿液,采用全自动生化分析仪测定血清血尿素氮(BUN)、血肌酐(Scr)、胱抑素C(CYS-C)、视黄醇结合蛋白(RBP)的浓度,采用贝克曼特定蛋白仪测定尿α1-微球蛋白(α1-MG)、尿微量白蛋白、尿转铁蛋白(Tf)及尿液免疫球蛋白G的浓度。结果两组各时点BUN及Scr差异无统计学意义。与T0时比较,T_1~T3时两组CYS-C及RBP明显升高(P0.05);T1~T3时D组CYS-C及RBP明显低于C组(P0.05)。两组各时点尿微量白蛋白、Tf及免疫球蛋白G差异均无统计学意义;与T0时比较,T1~T3时两组尿α1-MG明显升高(P0.05);T1~T3时D组尿α1-MG明显低于C组(P0.05)。结论常规麻醉诱导前静脉输注右美托咪定1μg/kg,随后以0.5μg·kg-1·h-1的速率静脉输注至手术结束,对肾脏结石患者全麻下经皮肾镜取石术产生一定的肾脏保护作用。     

右美托咪定对全麻子宫切除术中血流动力学及应激反应的影响

目的探讨右美托咪定对全麻子宫切除术中血流动力学及应激反应的影响。方法择期行子宫切除术的患者40例,年龄42~58岁,随机均分为右美托咪定组(D组)和对照组(C组)。D组右美托咪定0.2mg用生理盐水稀释至50ml(4μg/ml),麻醉诱导前10min开始以10ml/h持续泵注到子宫标本切下为止,C组给予等容量生理盐水。采用咪达唑仑、舒芬太尼、顺式阿曲库铵、丙泊酚行麻醉诱导,气管插管控制呼吸。麻醉维持:静脉输注丙泊酚、瑞芬太尼,间断静注顺式阿曲库铵。记录给右美托咪定前(T0)、打开腹膜子宫操作开始时(T1)、子宫操作开始10min(T2)、20min(T3)、30min(T4)、子宫切下时(T5)和后腹膜缝合完毕时(T6)的SBP、DBP、HR和血浆肾上腺素、去甲肾上腺素和皮质醇浓度。结果 C组T1~T5时的SBP、DBP明显高于,HR明显快于T0时(P0.05),且SBP、DBP明显高于、HR明显快于D组(P0.05)。C组T1~T5时的肾上腺素、去甲肾上腺素和皮质醇浓度明显高于T0时(P0.05),且明显高于D组(P0.05)。结论右美托咪定用于全麻子宫切除术中,血流动力学稳定,可降低应激反应。     

右美托咪定对颅内肿瘤手术患者血流动力学的影响及脑保护作用

目的探讨右美托咪定对颅内肿瘤手术患者血流动力学的影响及对患者脑保护的作用。方法将60例择期行颅内肿瘤手术患者随机分为右美托咪定组和对照组,每组30例。右美托咪定组患者诱导后静脉注射右美托咪定1μg/kg,10min注射完毕,术中持续静脉泵注右美托咪定0.4μg·kg-1·h-1。对照组诱导后给予等量生理盐水。记录两组患者入室后(T0)、给药后(T1)、插管时(T2)、苏醒时(T3)、拔管时(T4)、出手术室(T5)的SBP、DBP、MAP及HR。并检测T0、手术完成(T6)、术后6h(T7)、术后12h(T8)和术后24h(T9)的血清S100β和NSE水平。结果与对照组比较,右美托咪定组T1~T5时SBP、DBP和MAP明显降低,HR明显减慢(P0.05)。与T0时比较,右美托咪定组T1~T5点MAP水平明显降低(P0.05)。与T0时比较,两组T6~T9时S100β和NSE水平明显增高(P0.05)。与对照组比较,右美托咪定组T6~T9时血清S100β和NSE水平明显降低(P0.05)。结论右美托咪定可较好维持颅内肿瘤患者术中血流动力学的稳定,术中、术后24h内S100β和NSE水平较低。     

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.     

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.