右美托咪定复合氟哌利多对七氟醚全麻胸科手术老年患者苏醒期躁动的影响

目的评价右美托咪定复合氟哌利多治疗七氟醚全麻胸科手术老年患者苏醒期躁动的有效性及安全性。方法选取七氟醚全麻下普胸外科术后严重躁动老年患者60例,男48例,女12例,年龄66～75岁,ASAⅡ或Ⅲ级,按照随机数字表分为三组:氟哌利多组(F组)、右美托咪定组(D组)和右美托咪定复合氟哌利多组(DF组)。被诊断为苏醒期严重躁动后,F组静脉推注氟哌利多0.06 mg/kg;D组右美托咪定1μg/kg泵注10 min,继以0.2μg·kg~(-1)·h~(-1)维持泵注1 h;DF组静脉推注氟哌利多0.03 mg/kg,同时给予右美托咪定0.5μg/kg泵注10 min,继以0.2μg·kg~(-1)·h~(-1)维持泵注1 h。观察并记录躁动评分、Ramsay镇静评分、PaCO_2变化以及恶心、呕吐等不良反应的发生情况。结果给药后5、10、15、20 min DF组躁动评分明显低于D组(P0.05);给药后60、90、120 min DF组躁动评分明显低于F组(P0.05)。给药后60、120 min三组PaCO_2差异无统计学意义。DF组和D组过度镇静比例明显低于F组(P0.05)。三组恶心、呕吐、心动过缓、高血压、低血压发生率差异无统计学意义。结论右美托咪定复合氟哌利多用于老年患者七氟醚全身麻醉苏醒期躁动的治疗效果确切,安全性好,可以规避右美托咪定不能快速推注同时避免氟哌利多导致过度镇静的缺点。     

右美托咪定用于预防腹腔镜胆囊切除术后恶心呕吐的效果

目的观察右美托咪定预防腹腔镜胆囊切除术后恶心呕吐的效果。方法选择择期行腹腔镜胆囊切除术的患者70例,男17例,女53例,年龄20~65岁,ASAⅠ或Ⅱ级。随机分为两组:右美托咪定组(R组)和地塞米松组(D组),每组35例。R组于麻醉诱导前静脉注射右美托咪定,背景剂量为0.5μg/kg,10min内注射完毕,后以0.5μg·kg~(-1)·h~(-1)维持输注。D组给予地塞米松8mg静脉注射。观察患者入室(T_1)、插管前(T_2)、插管后5min(T_3)、手术开始后5 min(T_4)、手术开始后30min(T_5)、缝皮时(T_6)、拔管后5min(T_7)的血压和心率。记录术中七氟醚的吸入浓度、停七氟醚至拔管的时间、手术时间及麻醉时间。观察患者8、24、48h内有无发生恶心呕吐。结果两组患者术后8、24、48h的恶心发生率和呕吐发生率差异无统计学意义。T2~T7时R组HR明显低于D组(P0.05),两组间MAP差异无统计学意义。结论与静脉注射地塞米松8mg比较,静脉注射右美托咪定负荷量0.5μg/kg(10min),维持量0.5μg·kg~(-1)·h~(-1),对减少腹腔镜胆囊术后恶心呕吐的发生有相同的效果。     

右美托咪定对全麻下脑功能区肿瘤切除术唤醒试验中应激反应的影响

目的评价右美托咪定对丙泊酚联合瑞芬太尼全麻下脑功能区肿瘤切除术患者唤醒试验中应激反应的影响。方法拟行术中唤醒试验的脑功能区肿瘤切除术患者48例,随机均分为右美托咪定组和对照组,右美托咪定组麻醉诱导前10min将负荷量0.8μg/kg右美托咪定进行静脉输注,继以0.4μg·kg-1·h-1进行维持;对照组采用等量生理盐水进行静脉输注。丙泊酚和瑞芬太尼靶控输注进行麻醉诱导与维持,于唤醒试验前30min停用丙泊酚和肌松药,调整瑞芬太尼血浆浓度为1ng/ml,右美托咪定组输注速率0.1μg·kg-1·h-1。记录两组患者唤醒前麻醉时间、麻醉药用量和唤醒时间,分别于唤醒前30min(T1)、唤醒时(T2)、唤醒后5min(T3)和研究结束后加深麻醉10min(T4)时,记录两组患者MAP、HR和BIS值,及血浆中去甲肾上腺素(NE)和肾上腺素(E)浓度,记录两组患者唤醒期间不良反应发生情况。结果两组患者唤醒时间、唤醒前麻醉时间和顺阿曲库铵用量差异无统计学意义。与对照组比较,右美托咪定组患者唤醒前丙泊酚和瑞芬太尼用量明显减少(P0.05)。与T1时比较,T2和T3时两组患者MAP和BIS均明显升高、HR明显增快(P0.05)。与对照组比较,T2和T3时右美托咪定组MAP明显降低(P0.05),T1~T4时HR明显减慢(P0.05),T1~T4时右美托咪定组患者NE和E浓度明显降低(P0.05),右美托咪定组患者躁动、心动过速、呛咳和高血压发生率均明显降低(P0.05)。各时点两组BIS值差异无统计学意义。结论右美托咪定对丙泊酚联合瑞芬太尼全麻下脑功能区肿瘤切除术唤醒试验中应激反应有较好的抑制作用,能够降低血浆NE和E浓度,对血流动力学影响较小,不良反应发生率降低。     

右美托咪定对丙泊酚复合瑞芬太尼麻醉下脑功能区手术患者唤醒试验质量的影响

目的 评价右美托咪定对丙泊酚复合瑞芬太尼麻醉下脑功能区手术患者唤醒试验质量的影响.方法 拟行术中唤醒的脑功能区手术患者27例,性别不限,年龄17 ～ 43岁,BMI 20～ 24kg/m2,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将患者随机分为2组∶对照组(C组,n=13)和右美托咪定组(D组,n=14).麻醉诱导后气管插管,麻醉维持:2组均靶控输注丙泊酚和瑞芬太尼,丙泊酚血浆靶浓度3 ～5 μg/ml,调整丙泊酚血浆靶浓度维持BIS值55 ～ 65,瑞芬太尼效应室靶浓度2～6ng/ml.打开硬脑膜后,D组停止输注丙泊酚和瑞芬太尼,经15 min静脉输注右美托咪定负荷量0.3μg/kg,随后以0.2 μg-1·kg·h-1速率维持;C组打开硬脑膜后15 min将丙泊酚血浆靶浓度降至0.5μg/ml,将瑞芬太尼效应室靶浓度降至0.5 ng/ml.记录唤醒时间、唤醒试验期间心血管事件、头痛、躁动、谵妄和术中知晓等的发生情况.结果 所有患者均成功实施唤醒,并顺利完成手术.与C组比较,D组唤醒试验期间高血压、心动过速、头痛和术中知晓的发生率均降低(P＜0.05),唤醒时间差异无统计学意义(P＞0.05),2组未见躁动和谵妄的发生.结论 右美托咪定可提高丙泊酚复合瑞芬太尼麻醉下脑功能区手术患者唤醒试验的质量.     

右美托咪定和丙泊酚对癫痫病灶切除术中皮层脑电图的影响

目的观察不同剂量右美托咪定和丙泊酚对癫痫病灶切除术中皮层脑电图(electrocorticography,ECoG)的影响。方法择期行癫痫病灶切除术患者100例,随机分为五组,每组20例。在切开硬脑膜暴露脑皮质后,C1组和C2组将丙泊酚靶浓度分别调至1.5和5.0μg/ml,稳定15min后观察描记脑电图。其余三组于ECoG监测开始前15min停用丙泊酚,静脉注射负荷量右美托咪定0.5μg/kg,维持剂量分别为0.25μg·kg~(-1)·h~(-1)(D1组)、0.5μg·kg~(-1)·h~(-1)(D2组)、1.0μg·kg~(-1)·h~(-1)(D3组),维持30min后观察描记脑电图至监测结束。结果五组患者术中ECoG均有棘波出现。与C2组比较,其他四组ECoG的α波、β波明显增加,δ波明显减少,棘慢波明显增加(P0.05),但没有被完全抑制,偶尔可见丙泊酚引起的爆发抑制。D1、D2、D3组患者术中随着右美托咪定剂量的增加,术中ECoG的α波、β波逐渐减少,δ波逐渐增加(P0.05)。结论丙泊酚对癫痫患者ECoG的影响呈剂量依赖性,1.5μg/ml浓度不影响ECoG对癫痫波的描记。右美托咪定对ECoG监测定位影响较丙泊酚小,0.25~0.5μg·kg~(-1)·h~(-1)剂量对癫痫波未产生明显抑制作用,可安全用于癫痫手术麻醉。     

右美托咪定对预防老年手术患者七氟醚麻醉苏醒期躁动的效果

目的观察右美托咪定对预防老年手术患者七氟醚麻醉苏醒期躁动的效果。方法随机将接受七氟醚麻醉下行择期手术的96老年患者分为2组,各48例。手术结束前10 min,观察组静脉输注右美托咪定1.0μg/kg,对照组静脉输注等容量的生理盐水。输注时间均为10 min。比较2组苏醒期躁动发生率,及拔管时(T_0)和拔管后5 min(T_1)、10 min(T_2)、20 min(T_3)的Ramsay镇静评分。结果观察组患者苏醒期躁动发生低于对照组;各时点镇静评分优于对照组,差异均有统计学意义(P0.05)。结论在老年患者七氟醚麻醉手术结束前静脉输注右美托咪定,可有效降低苏醒期患者的躁动发生率,并可显著改善镇静评分。     

右美托咪定和七氟醚改善冠心病非心脏手术患者围术期心肌缺血的比较

目的观察和比较右美托咪定和七氟醚对冠心病非心脏手术患者围术期心肌保护的效应。方法选择择期合并冠心病的腔镜下胸腹部手术患者135例,男90例,女45例,年龄45~82岁,ASAⅡ或Ⅲ级。采用随机数字表法将患者分为三组:对照组(C组),右美托咪定组(D组)和七氟醚组(S组),每组45例。采用依托咪酯0.2mg/kg、丙泊酚0.5mg/kg、顺苯磺酸阿曲库铵0.2~0.3mg/kg和芬太尼5.0~6.0μg/kg进行麻醉诱导和维持,D组诱导前10min开始至手术结束持续泵注右美托咪定。C组给予等容量生理盐水。S组从麻醉诱导后开始持续吸入七氟醚至手术结束前30min停用。记录术中和术后72h内心肌缺血的发生情况。结果术中C组心肌缺血的发生率[12例(26.7%)]明显高于D组[3例(6.7%)]和S组[4例(8.9%)](P0.05);术后72h内C组、D组和S组心肌缺血的发生率分别为6例(13.3%)、4例(8.9%)和4例(8.9%),差异无统计学意义。结论右美托咪定和七氟醚均能通过改善心肌血氧供需平衡,降低冠心病非心脏手术患者心肌缺血的发生率。     

右美托咪定在颅脑肿瘤手术中的应用

目的探讨右美托咪定在丙泊酚复合芬太尼麻醉下行颅脑肿瘤手术中的优化作用。方法拟行择期手术的小脑幕上肿瘤患者42例,ASAⅠ或Ⅱ级,随机均分为两组。麻醉诱导前,右美托咪定组(D组)于20min内静脉输注右美托咪定负荷剂量1μg/kg,随后静脉输注0.4μg·kg-1·h-1维持至手术结束;对照组(C组)静脉输注等量生理盐水。以丙泊酚、芬太尼、顺阿曲库铵完成麻醉诱导,气管插管。术中以BIS为指导,七氟醚静吸复合维持麻醉。记录麻醉诱导前(T0)、气管插管时(T1)、打开硬脑膜(T2)、关上硬脑膜(T3)、拔除气管插管即刻(T4)时MAP、HR、颅内压(ICP)的变化。记录呼气末七氟醚浓度和术中芬太尼总量、手术时间、术后拔管时间、术后止吐药的使用情况。结果 T1~T3时C组ICP,T1~T4时MAP明显高于T0时和D组,T4时两组ICP明显低于T0时,且D组明显低于C组(P0.01);T1~T4时D组HR明显慢于T0时和C组(P0.01)。D组芬太尼总量、呼气末七氟醚浓度明显低于C组,拔管时间明显短于C组(P0.01)。D组血管活性药物使用率明显低于C组(P0.01)。结论在颅脑肿瘤手术中,右美托咪定在稳定血流动力学、控制颅内压及术后复苏方面显著优化了常用的丙泊酚复合芬太尼全麻方案,同时减少了阿片药物及吸入麻醉药物用量。     

右美托咪定预防静吸全麻下宫颈癌根治术后苏醒期寒战

目的 评价右美托咪定预防静吸全麻下宫颈癌根治术后苏醒期寒战的临床效果.方法 择期宫颈癌根治术患者50例,ASA Ⅰ或Ⅱ级,随机均分为右美托咪定组(D组)和生理盐水对照组(N组),两组麻醉诱导方法相同:均依次静脉注射丙泊酚1.5mg/kg、芬太尼4μg/kg、苯磺酸阿曲库铵0.3 mg/kg,插管成功后行间歇正压通气.麻醉维持:吸入1％～4％七氟醚,静脉微量泵注瑞芬太尼4～8 μg·kg-1·h-1和苯磺酸阿曲库铵0.2 mg·kg-1·h-1.D组气管插管后静脉输注右美托咪定0.5 μg·kg-1·h-1至术毕前1h,N组则在相同时段内静脉输注等容量生理盐水.两组BIS值均维持在40～55.记录两组手术时间、术中输液量、腹腔冲洗量、拔管时间;记录术中瑞芬太尼、七氟醚用量和阿托品使用率;记录苏醒期2h内寒战发生情况.结果 两组患者手术时间、术中输液量、腹腔冲洗量及拔管时间差异无统计学意义.D组术中瑞芬太尼、七氟醚用量均明显低于N组(P＜0.05),D组阿托品使用率明显高于N组(P＜0.01).D组和N组寒战发生率分别为16％和64％,D组明显低于N组,且寒战程度减轻(P＜0.05).结论 宫颈癌静吸全麻维持期辅助静脉输注右美托咪定,能有效预防苏醒期寒战发生,不影响苏醒时间,但应注意心动过缓的发生.     

右美托咪定用于舒芬太尼伴七氟烷全麻在腹腔镜手术中的随机对照研究

目的探讨右美托咪定用于舒芬太尼靶控输注伴七氟烷全麻的效果。方法 2017年8月～2018年1月,择期全麻下腹腔镜手术40例(18～68岁,ASAⅠ级或Ⅱ级),随机分为观察组和对照组,每组20例。观察组麻醉诱导前静脉输注右美托咪定0.3μg/kg(10 min输注完成),对照组静脉输注等量生理盐水。麻醉诱导采用靶控输注舒芬太尼、丙泊酚和罗库溴铵静脉注射。麻醉维持采用靶控输注舒芬太尼复合吸入七氟烷,间断静脉注射罗库溴铵维持肌肉松弛。比较2组基础值、右美托咪定或生理盐水输注完成即刻、气管插管后1 min、气腹后10 min、开始关伤口时、气管拔管前即刻和拔管后1 min时的平均动脉压、心率、脑电双频指数(BIS),以及麻醉后苏醒情况和术后24 h内不良反应。结果围术期2组平均动脉压和心率平稳(在基础值上下20%之内),BIS值适宜(术中40～60,麻醉苏醒、镇静至清醒状态70～100)。右美托咪定或生理盐水输注完成即刻,观察组心率[(70.0±9.2)次/min]慢于对照组[(79.6±10.7)次/min](t=-3.015,P=0.005),观察组BIS值(92.3±0.8)低于对照组(96.4±0.9)(t=-15.265,P=0.000)。2组均无肌肉僵直、躁动、呼吸抑制或术中知晓发生,2组术后拔管时间、恶心呕吐及使用镇痛药例数差异无显著性(P0.05)。结论麻醉诱导前将右美托咪定0.3μg/kg用于舒芬太尼靶控输注伴七氟烷吸入的国人全麻手术安全有效。     

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.     

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.