无痛人流术麻醉中七氟醚临床应用效果分析

目的评价七氟醚在无痛人流术麻醉中的效果。方法选取2013-02—2013-08间门诊自愿行无痛人流手术患者156例,随机分为七氟醚组和丙泊酚组。记录两组患者麻醉情况,比较两组患者从手术结束停药到OAA/S镇静评分到达5分的时间和生命体征,记录两组患者并发症。结果七氟醚组麻醉诱导时间长于丙泊酚组,苏醒时间短于丙泊酚组,差异均有统计学意义(P0.05)。七氟醚组患者OAA/S镇静评分到达5分的时间短于丙泊酚组,差异有统计学意义(P0.05)。七氟醚组不良反应率为17.9%,低于丙泊酚组的30.8%(P0.05)。结论无痛人流术应用七氟醚麻醉,具有苏醒快、不良反应率低等优点,更适合应用于无痛人流术的麻醉。     

右美托咪定镇静时BIS与OAA/S评分的相关性研究

目的探讨右美托咪定镇静时BIS与OAA/S评分的相关性。方法选择腰-硬联合麻醉下行单侧膝关节镜手术患者60例,ASAⅠ或Ⅱ级。随机分为三组:右美托咪定组(D组)、丙泊酚组(P组)和咪达唑仑组(M组),每组20例。每组镇静药物均连续三阶段输注,每阶段维持40min。D组:第一阶段负荷量加维持量,负荷量1.0μg/kg,15min恒速输注完毕,维持量0.5μg·kg-1·h-1,第二、三阶段维持量分别为1.0、1.5μg·kg-1·h-1。P组:三阶段效应室靶控浓度分别为1.0、2.0、4.0μg/ml。M组:三阶段药物浓度分别0.05、0.1、0.15mg·kg-1·h-1。三组药物输注的120min内,每隔5分钟记录一次BP、HR、SpO2、BIS值,分析OAA/S评分与BIS的相关性(r)和BIS对OAA/S评分的预测概率(Pk)。结果与基础值比较,OAA/S评分≤3时三组SBP明显降低、OAA/S评分≤4分时D组HR明显减慢(P0.05)。与D组比较,OAA/S评分≤3分时M组SBP明显升高、OAA/S评分≤4分时P组和M组HR明显增快(P0.05)。与OAA/S评分5分时比较,OAA/S评分≤4分时三组患者BIS明显降低(P0.05)。与D组比较,OAA/S评分≤4分时P组和M组BIS值明显升高(P0.05)。三组患者BIS与OAA/S评分呈正相关,且Pk值均大于0.5(P0.05)。结论右美托咪定镇静时BIS与OAA/S评分具有较好相关性,可作为评价右美托咪定镇静深度的重要指标;但其相关性较丙泊酚、咪达唑仑差。     

大脑状态指数在老年人丙泊酚靶控输注镇静深度监测中的应用

目的在丙泊酚靶控输注(TCI)镇静的老年患者,评价大脑状态指数(CSI)在无手术刺激条件下监测镇静深度的准确性及年龄的影响。方法ASAⅠ～Ⅲ级患者40例,按年龄分为老年组(E组),年龄65～79岁;中青年组(Y组),年龄20～55岁,每组20例。所行手术不限,诱导插管前均予以丙泊酚TCI镇静,直至改良清醒/镇静评分(OAA/S)为0分后5min停止,每20秒作改良OAA/S,记录CSI和TCI系统预测效应部位浓度值(CE)每变化0.1μg/ml时的数值及时间。计算在丧失语言反应及意识消失时的CE的CE05、CE50、CE95以及CSI05、CSI50、CSI95。结果随着丙泊酚预测效应部位浓度增加,两组CSI逐渐降低,并与OAA/S有较好的相关性,两组比较差异无统计学意义。当OAA/S≤3分时,E组的CSI明显高于Y组(P<0.05)。结论CSI与预测效应部位浓度、改良OAA/S呈高度相关性,可以较好地监测老年人与中青年人的镇静深度,在相同意识状态下,老年人的预测效应室浓度要低于中青年人,其CSI高于中青年人。     

不同浓度七氟醚复合丙泊酚麻醉对肝脏部分切除术患者术后苏醒质量的影响

目的探讨两种不同浓度的七氟醚复合丙泊酚静-吸复合麻醉对肝脏部分切除术患者术后苏醒质量的影响。方法选择择期行肝脏部分切除术的患者78例,年龄20~70岁,随机分为丙泊酚全凭静脉麻醉组(T组)、0.5MAC七氟醚复合丙泊酚静-吸复合麻醉组(S1组)、1.0MAC七氟醚复合丙泊酚静-吸复合麻醉组(S2组),每组26例。术毕分别记录自主呼吸恢复时间、苏醒时间、拔管时间及改良Aldrete评分达到9分的时间;并于拔管后即刻(T1)、拔管后5min(T2)、15min(T3)、30min(T4)对三组患者进行改良OAA/S评分及改良Aldrete评分;记录苏醒期躁动发生情况。结果 S1、S2组丙泊酚用量明显少于T组,且S2组明显少于S1组(P0.05)。S1、S2组苏醒时间、拔管时间及改良Aldrete评分达到9分的时间明显短于T组(P0.05);S1、S2组T1、T2时改良OAA/S评分、T1时改良Aldrete评分均明显高于T组,且S2组明显高于S1组(P0.05)。结论与丙泊酚全凭静脉麻醉比较,0.5MAC及1.0MAC七氟醚复合丙泊酚静-吸复合麻醉更有助于提高肝脏部分切除术患者术后的苏醒质量,且1.0MAC七氟醚复合丙泊酚静-吸复合麻醉术后苏醒时间较短。     

脑电双频指数和麻醉深度指数用于全麻术中镇静深度的监测

目的 探讨脑电双频指数(BIS)和麻醉深度指数(CSI)应用于全麻手术中镇静深度监测的相关性.方法 88例拟在丙泊酚与雷米芬太尼全麻气管插管下行择期手术的患者,按照雷米芬太尼靶浓度随机均分为四组:R1组(生理盐水)、R2、R3、R4组分别为1.5、3.0、4.5 ng/ml雷米芬太尼.结果 四组患者随着OAA/S评分的降低,BIS、CSI均逐渐降低(P<0.05);相同OAA/S评分下,R2～R4组的BIS、CSI高于R1组(P<0.05).Spearman等级相关分析结果 表明:BIS或CSI与OAA/S评分均明显相关,但各组间相关系数的差异无统计学意义.R2～R4组患者在睫毛反射消失及强直刺激反应消失时的CSI、BIS均高于R1组.结论 CSI与BIS相似,能较好地反映全麻手术患者镇静深度的变化;两者的变化均尚受到血浆镇痛药物浓度改变的影响,与OAA/S评分相关性一致.     

七氟醚麻醉诱导对顺式阿曲库铵起效时间的影响

目的 探讨七氟醚肺活量法吸入诱导和丙泊酚静脉诱导对顺式阿曲库铵起效时间的影响.方法 择期行胸外科或普外科手术的全麻患者60例,ASA Ⅰ或Ⅱ级,年龄18～65岁,随机均分为七氟醚组(S组)和丙泊酚组(P组).麻醉诱导:P组静脉注射咪达唑仑0.05 mg/kg、芬太尼2μg/kg、丙泊酚1 mg/kg;S组采用肺活量吸入法,七氟醚吸入浓度8%.两组患者意识消失后均给予顺式阿曲库铵0.15 mg/kg.监测肌松药起效时间,意识消失时间,血流动力学指标,并评价气管插管条件.结果 患者意识消失时间、顺式阿曲库铵起效时间S组明显短于P组(P<0.05或P<0.01).插管引起的心血管反应S组小于P组(P<0.05).结论 七氟醚吸入诱导能明显缩短顺式阿曲库铵的起效时间,且循环功能稳定.     

麻醉深度指数用于全麻手术期间麻醉深度监测的临床评价

目的 评价麻醉深度指数(CSI)监测麻醉深度的准确性及实用性.方法 ASA Ⅰ或Ⅱ级患者40例随机均分为两组.采用咪唑安定、芬太尼、丙泊酚、维库溴铵诱导和维持.A组以CSI监测数据判断麻醉深度并调整用药,使CSI维持在50±5.B组根据经验用药.常规监测SBP、DBP、HR、ECG、SpO2、CSI,计算用药总量,记录苏醒时间;诱导期进行警觉/镇静(OAA/S)评分,计算CSI对于OAA/S的等级相关系数.结果 麻醉期间,B组的SBP、DBP、HR、CSI波动明显大于A组(P<0.05);A组的苏醒时间明显短于B组,拔管后躁动、嗜睡、恶心、呕吐的病例数少于B组;A组无一例术中知晓,B组有1例发生术中知晓.CSI与OAA/S评分具有显著的等级相关性.结论 CSI可动态反映大脑生理功能的变化,有助于判断全麻深度,指导麻醉用药.     

七氟醚和丙泊酚对老年冠心病患者麻醉诱导期心率变异性的影响

目的 观察七氟醚和丙泊酚对老年冠心病患者全麻诱导期心率变异性(HRV)的影响.方法 40例择期行上腹部手术老年冠心病患者,年龄60～80岁,ASAⅡ或Ⅲ级,随机均分为七氟醚(S组)和丙泊酚(P组):分别予4%七氟醚或靶控输注丙泊酚3μg/ml行麻醉诱导.分别记录麻醉前(基础值)、诱导后5、10、15、20 min SBP、DBP、HR及HRV的变化.结果 与麻醉前比较,诱导后5、10 min两组SBP、DBP下降,HR减慢(P＜0.05).诱导后5、15 min P组SBP、DBP显著低于S组,P组HR快于S组(P＜0.05).在麻醉诱导中,S组主要是低频(LF)逐渐降低,P组则是高频(HF)逐渐降低.结论 与靶控输注丙泊酚麻醉比较,七氟醚吸入麻醉对血流动力学影响较轻,诱导相对平稳,更适合老年冠心病患者的麻醉诱导.     

腔镜手术不同麻醉方法费效的比较:前瞻性、多中心、随机、双盲临床研究

目的 比较腔镜手术患者七氟醚全程吸入麻醉、丙泊酚靶控输注麻醉和静脉注射丙泊酚诱导-吸入七氟醚维持麻醉的费效.方法 本研究为前瞻性、多中心、随机、双盲临床研究.选择全国4个中心的择期行腔镜手术的患者336例,ASA分级Ⅰ或Ⅱ级,性别不限,年龄18～64岁,体重指数16～30 kg/m2,采用随机数字表法,将其分为3组(n=112):七氟醚全程吸入麻醉组(S组)、丙白酚靶控输注麻醉组(P组)及静脉注射丙泊酚诱导-吸入七氟醚维持麻醉组(PS组).麻醉诱导:S组吸入8％七氟醚,氧流量8 L/min;P组靶控输注丙泊酚,血浆靶浓度4 μg/ml; PS组静脉注射丙泊酚1.5 mg/kg,待患者意识消失后,3组均静脉注射芬太尼和维库溴铵,气管插管后行机械通气,氧流量1 L/min,维持PETCO2 30～ 40 mm Hg.麻醉维持:S组和PS组吸入七氟醚,维持呼气末浓度0.8 MAC ～ 1.5 MAC;P组靶控输注丙白酚,血浆靶浓度3～6 μg/ml;3组根据需要间断静脉注射芬太尼和维库溴铵.记录意识消失时间、气管插管时间、自主呼吸恢复时间、苏醒时间、气管拔管时间、定向力恢复时间、改良Aldrete评分≥9分时间和PACU停留时间.记录术中不良反应的发生情况.计算麻醉药物费用.结果 与P组比较,S组意识消失时间、气管插管时间、定向力恢复时间和PACU停留时间缩短,PS组意识消失时间和气管插管时间缩短,S组和PS组七氟醚和/或丙泊酚费用、所有麻醉药物费用、每小时七氟醚和/或丙泊酚费用及每小时所有麻醉药物费用降低(P＜0.05);与S组比较,PS组意识消失时间延长,七氟醚和/或丙泊酚费用、所有麻醉药物费用、每小时七氟醚和/或丙泊酚费用及每小时所有麻醉药物费用降低(P＜0.05).3组间心动过缓、高血压、低血压、呛咳和体动的发生率比较差异无统计学意义(P＞0.05).结论 静脉注射丙泊酚诱导,吸入低流量七氟醚维持麻醉,是腔镜手术患者最经济有效的麻醉方法.     

脑电双频指数指导下不同麻醉诱导方式对喉罩插入条件的影响

目的 观察脑电双频指数(BIS)指导下不同麻醉诱导方式对喉罩插入条件的影响.方法 60例择期行宫腔镜手术患者,ASAⅠ或Ⅱ级,根据诱导方式的不同随机均分为三组:七氟醚复合丙泊酚组(SP组)、七氟醚组(S组)及丙泊酚组(P组).SP组肺活量法吸入七氟醚,待患者意识消失后静脉注射丙泊酚;S组以肺活量法吸入七氟醚;P组静脉泵注丙泊酚.BIS值稳定于40～50超过20 s后插入喉罩.记录诱导开始至成功插入喉罩的时间及成功率;评估下颌松弛度评分和喉罩插入后咳嗽及肢体运动评分.结果 诱导至喉罩插入时间S组＞SP组＞P组(P＜0.05).呼吸暂停发生率P组(40％)明显高于SP和S组(均为0)(P＜0.05).不自主肢体运动发生率P组高于SP和S组(35％ vs 5％和10％,P＜0.05).结论 BIS指导下七氟醚复合丙泊酚诱导较丙泊酚或七氟醚诱导能提供更好的喉罩插入条件.     

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.     

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.     

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.     

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.