雷米芬太尼静脉全麻诱导期血流动力学变化

目的 比较霄米芬太及芬太尼静脉全麻诱导对患者血流动力学的影响.方法 60例ASA.Ⅰ或Ⅱ级的择期手术患者,年龄18～65岁.随机均分成雷米芬太尼组(R组)和芬太尼组(F组),分别以雷米分太尼1 μg/kg或芬太尼3/μg/kg进行麻醉诱导,用胸阻抗法监测麻醉诱导前(T0)、插管前(T1)、插管即刻(T2)、插管后1 min(T3)、5 min(T4)时的HR、SBP、DBP、心排血量(CO)、外周血管阻力(SVR)、加速度指数(ACI)、胸腔液体水平(TFC)和左心作功(LCW)的变化.结果 T1时两组HR、SBP、DBP、CO、SVR、LCW均低于T0时(P<0.05或P<0.01),T4时F组HR、SBP、DBP、CO、LCW显著低于T0时和R组(P<0.05或P<0.01).R组T2、T3时,F组T2～T4时SVR均高于T0时(P<0.05).结论 1μg/kg雷米芬太尼较3 μg/kg芬太尼更能有效维待全麻诱导期气管插管血流动力学平稳.     

老年冠心病患者全麻恢复期血液动力学变化

目的观察老年冠心病患者于雷米芬太尼-丙泊酚或七氟醚-N2O全麻恢复期血液动力学变化,寻求合理处理,减少老年冠心病患者非心脏手术后心肌再损害。方法32例65~82岁经本院心内科诊断的冠心病患者,ASAⅡ级,分别七氟醚-N2O-O2(SE)吸入或雷米芬太尼-丙泊酚(RP)静脉维持麻醉。芬太尼3μg/kg、咪唑安定0·05mg/kg并吸入纯氧和5%国产七氟醚诱导,琥珀胆碱2mg/kg后,置入LMA-ProSeal喉罩,分别吸入国产七氟醚-N2O-O2或静滴国产雷米芬太尼-丙泊酚,间断0·05mg/kg维库溴铵维持机械通气,调整通气量,使PETCO2保持35~45mmHg。术毕停药,记录停药~睁眼、停药~拔除喉罩时间。术中全程BioZICG无创血液动力学监测,记录恢复期各时点心率(HR)、心输出量(CO)、胸液成分(TFC)、心肌加速度指数(ACI)、外周血管阻力(SVR)、MAP、左心作功(LCW)备分析。结果两组恢复期HR、CO、MAP、ACI、LCW均较术期升高,自停药9min后HR、MAP、LCW高于停药前水平(P<0·05)。SE组自停药9min后HR、MAP分别增加16·7%和13·8%。RP组自停药9min后HR、MAP、LCW分别增加16·9%、13·5%、36·7%。在恢复期两组SVR与停药前比较差异无显著意义,但与诱导前比较两组均呈明显上升趋势,SE组与RP组分别增加了26·4%和15·6%。两组停药~睁眼、停药~拔除喉罩时间无差别。结论雷米芬太尼-丙泊酚静脉麻醉对老年冠心病患者全麻恢复期循环功能抑制轻;但因雷米芬太尼作用消除快,痛反应出现早,应于停药前追加适量芬太尼或舒芬太尼等长效镇痛药,或开启镇痛泵,以消除应激带来的心肌氧耗增加。七氟醚-N2O-O2全麻恢复期,后遗镇痛效应续时较短,亦应考虑适当镇痛。     

脊柱手术中应用雷米芬太尼控制性降压的研究

目的对比评价脊柱手术中应用雷米芬太尼或硝酸甘油行控制性降压麻醉的效果。方法30例后路椎间盘(植骨)融合术的病人,年龄18~65岁,随机分为雷米芬太尼组(R组)和硝酸甘油组(N组),每组15例。两组病人麻醉诱导及维持方法相同。R组以雷米芬太尼2μg/kg静注,0·1~0·5μg·kg-1·min-1维持;N组以硝酸甘油2μg/kg静注,0·5~3μg·kg-1·min-1维持,均将MAP降至60~65mmHg,持续60min。观察两组病人术中MAP、CVP、HR变化,失血量及清醒拔管时间的差异。结果降压期间R组的HR显著低于降压前(P<0·05,P<0·01),而N组显著高于降压前(P<0·05)。N组降压5、10、15min时的CVP显著低于降压前(P<0·05),R组与降压前相比差异无显著意义。R组术中失血量明显少于N组(P<0·01)。两组病人清醒拔管时间差异无显著意义。结论雷米芬太尼可有效用于脊柱手术术中控制性降压。与硝酸甘油相比,具有减慢HR、降压平稳、对CVP影响小、失血量少等优点。     

雷米芬太尼用于颅内肿瘤术中控制性降压

目的 探讨雷米芬太尼用于颅内肿瘤术中控制性降压效果.方法 择期50例颅内肿瘤手术患者随机分为雷米芬太尼组(R组)和硝普钠组(N组).手术开始时,R组给予雷米芬太尼0.10～0.20 μg·kg-1·min-1泵注,N组给予硝普钠3～8 μg·kg-1·min-1泵注.监测并记录麻醉诱导前(T0)、麻醉诱导后(T1)、开始降压前(T2)、开始降压后(T3)、停止降压5 min(T4)及停止降压30min(T5)时的MAP、HR、SpO2、PETCO2、CVP及围术期总输液量、输血量、出血量和尿量.结果 与T0时比较,两组T1～T4时MAP明显降低,R组HR明显减慢,T1时N组HR明显减慢,T2～T4时N组HR明显增快(P<0.05).与T1时比较,两组T2～T4时MAP明显降低(P<0.05),N组患者T5时MAP反跳性升高,且明显高于R组(P<0.05).与T1时比较,N组患者T2～T5时HR明显增快,且T2～T4时明显快于R组(P<0.05).R组的输液量、输血量、出血量均较N组明显减少(P<0.05).结论 雷米芬太尼可安全用于颅内肿瘤术中控制性降压.     

雷米芬太尼-硝普钠用于鼻内镜手术控制性降压

目的研究雷米芬太尼或雷米芬太尼-硝普钠用于鼻内镜手术控制性降压的效果及对血浆内分泌激素的影响。方法48例择期全麻下行鼻内镜手术病人，采用硝普钠（N组）、雷米芬太尼（R组）或雷米芬太尼复合微量硝普钠（RN组）控制性降压，维持MAP在60～70mmHg。记录降压前即刻（T0）、降压30min（T1）和停降压待BP自然恢复稳定后（T2）时的MAP、HR，并在以上各时点抽取动脉血测定血浆皮质醇（Cor）、血管紧张素Ⅱ（A-Ⅱ）、白细胞介素-6（IL-6）和血糖（BG）的浓度。结果R组17例（70．8％）单纯用雷米芬太尼可达到降压目的。降压期间，N组HR明显增快（P〈0．05），停降压后出现反跳性高血压；R和RN组HR减慢（P〈0．05），停降压后MAP回复至降压前水平。降压后BG、Cor、A-Ⅱ的浓度和T0时相比，N组明显增高（P〈0．05）；三组IL-6的浓度均明显升高（P〈0，05），N组升高幅度大于R、RN组（P〈0．05）。结论雷米芬太尼用于鼻内镜手术行控制性降压安全可行，有效抑制了机体的应激反应；复合微量硝普钠能减少雷米芬太尼的用量，降压效果可靠。     

雷米芬太尼对妇科腹腔镜术中眼内压的影响

目的 观察雷米芬太尼对妇科腹腔镜术中眼内压变化的影响.方法 40例全凭静脉麻醉下行妇科腹腔镜手术的患者随机均分为两组,对照组(Ⅰ组)和雷米芬太尼组(Ⅱ组).所有患者均采用静脉注射咪达唑仑、异丙酚、维库溴铵、芬太尼麻醉诱导,持续输注异丙酚、间断静脉注射维库溴铵麻醉维持.Ⅱ组加用雷米芬太尼.使用笔式眼压计(Tono Pen XL To-nometer)分别于全麻后5 min(T0)、气腹后5 min(T1)、气腹后15 min(T2)、气腹结束前5 min(T3)、气腹结束后5 min(T4)、气腹结束后15 min(T5)测量眼内压(intraecular pressure,IOP),同时观测各时点平均动脉压(mear material pressure,MAP)、心率(heart rat,HR)、呼出终未CO2分压(end tidal CO2 pressure,PETCO2)、气道压(ariway pressure,PAW)的变化.结果 与Ⅰ组相比,Ⅱ组T1、T2、T3时MAP、IOP降低(P<0.05).两组各时点的HR、PETCO2、PAW的无统计学差异.结论 雷米芬太尼能够缓和妇科腹腔镜术中患者眼内压的升高.     

七氟醚静吸复合麻醉控制性降压用于鼻内窥镜手术的临床观察

目的探讨七氟醚静吸复合麻醉控制性降压用于鼻内窥镜手术的安全性和可行性。方法选择择期鼻内窥镜手术患者40例,ASA Ⅰ或Ⅱ级,无凝血功能障碍,随机均分为控制性降压组(Ⅰ组)和非控制性降压组(Ⅱ组)。两组麻醉诱导均为咪唑安定、丙泊酚、维库溴铵、芬太尼;麻醉维持为七氟醚、芬太尼、丙泊酚、维库溴铵。术中Ⅰ组手术开始后逐渐增加七氟醚浓度至目标血压(MAP70mmHg),并维持在65~75mmHg。比较两组术中出血量?手术时间,术中监测心电图、有创MAP、HR和SpO2,记录时点为手术开始前即刻(T0)?手术20min(T1)、手术结束后10min(T2)。于手术结束后30min行血气分析。结果与T0时比较,Ⅰ组T1时MAP显著下降(P<0.01),T2时回升。T1时Ⅰ组MAP较Ⅱ组显著下降(P<0.01)。两组各时点HR差异无统计学意义。Ⅰ组比Ⅱ组手术出血量明显减少(P<0.01)。Ⅰ组比Ⅱ组手术时间明显缩短(P<0.01)。两组血气分析值均在正常范围,两组均未出现心律失常及心肌缺血征象。结论七氟醚静吸复合麻醉控制性降压用于鼻内窥镜手术能有效减少出血量,缩短手术时间,无明显并发症及不良反应。     

尼卡地平控制性降压对颅内压的影响

目的 观察尼卡地平控制性降压对颅内压(ICP)的影响.方法 选择ASA Ⅰ或Ⅱ级神经外科手术患者20例,年龄19～50岁.行腰椎穿刺术直接测得ICP.尼卡地平起始剂量为0.01%～0.02%的溶液静脉滴注,维持SBP在100 mm Hg以下.记录降压前(T0)、降压10 min(T1)、20min(T2)、30 min(T3)和结束降压后10 min(T4)、20 min(T5)的ICP、rSO2、HR、MAP.结果 T1～T3时MAP显著低于T0(P<0.01).T4时MAP明显回升(P<0.05),T5时回到T0水平.降压期间ICP、rSO2、HR无明显改变.结论 尼卡地平降压起效快,降压平稳,对ICP、脑氧饱和度无明显影响.     

舒芬太尼在老年患者全麻诱导中对血液动力学的影响

目的 研究舒芬太尼在老年患者全麻诱导中对血液动力学的影响。方法 择期全麻下手术治疗的老年患者40例,随机分为两组,每组20例。观察组诱导时加用舒芬太尼,对照组则加用芬太尼。分别记录麻醉前（T0）、插管时（T1）、插管后2min（T2）、5min（T3）、10min（T4）各时点的平均动脉压（MAP）、心率（HR）、心输出量（CO）及心脏指数（CI）。结果 MAP、CO、CI在T2、T3、T4时点观察组较对照组低（P〈0．05）,HR在T3、T4时点观察组较对照组低（P〈0．05）,而观察组的MAP、CO、CI、HR在组内T0与T2、T3、T4时点比差异无显著意义。结论 舒芬太尼在老年患者全麻诱导过程中不但对MAP、CO、CI、HR等血液动力学指标无影响,而且能更好地保持循环系统的稳定。     

鼻内镜手术患者异丙酚复合瑞芬太尼控制性降压的可行性

目的探讨鼻内镜手术患者异丙酚复合瑞芬太尼控制性降压的可行性。方法择期行鼻内镜手术患者30例,ASAⅠ或Ⅱ级,随机分为2组(n=15):对照组(Ⅰ组)和降压组(Ⅱ组)。两组均采用静脉注射咪达唑仑、异丙酚、瑞芬太尼和维库溴铵麻醉诱导,持续输注异丙酚和瑞芬太尼、间断静脉注射维库溴铵麻醉维持。桡动脉穿刺置管监测有创动脉血压(MAP)。Ⅰ组不施行控制性降压,Ⅱ组于手术开始时降压,瑞芬太尼初始速率为0.25μg·kg-1·min-1,每隔2分钟增加0.1μg·kg-1·min-1,直到降至靶目标血压,维持MAP 50～70 mm Hg至手术结束。分别记录控制性降压开始即刻(T0)、30 min(T1)和停止降压20min(T2)的HR、MAP,并于各时点抽桡动脉血行血气分析和乳酸测定。用评分法评定术野的质量。结果与Ⅰ组相比,Ⅱ组手术时间缩短(P<0.05),术野质量提高0.05)。两组均无心血管不良事件发生。结论异丙酚复合瑞芬太尼用于鼻内镜手术患者控制性降压安全、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.     

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.