剖宫产术患者不同比重罗哌卡因腰麻半数有效剂量的比较

目的 比较剖宫产术患者不同比重罗哌卡因腰麻的半数有效剂量(ED50).方法 择期脊椎-硬膜外联合麻醉下行剖宫产术的单胎足月初产妇40例,年龄20～40岁,采用随机数字表法,将其随机分为2组(n=20):重比重罗哌卡因组(HR组)和轻比重罗哌卡因组(LR组).经L2.3间隙行蛛网膜下腔穿刺,2组第1例患者局麻药的初始剂量均为9mg,HR组和LR组分别给予0.5％重比重和0.5％轻比重罗哌卡因,根据腰麻是否有效按照序贯法确定下一例患者的剂量,剂量间隔为1mg.采用概率单位法计算不同比重罗哌卡因腰麻的ED50及其95％可信区间(CI).结果 0.5％重比重和0.5％轻比重罗哌卡因腰麻的ED50分别为9.34 mg(95％CI 8.34～10.46 mg)和9.64 mg(95％CI 8.90～10.44 mg),二者ED50比较差异无统计学意义(P＞0.05).结论 剖宫产术患者0.5％重比重和0.5％轻比重罗哌卡因腰麻的ED50分别为9.34和9.64 mg,比重因素对罗哌卡因腰麻效果无影响.     

舒芬太尼对老年患者蛛网膜下腔阻滞时罗哌卡因ED_(50)的影响

目的观察舒芬太尼联合罗哌卡因行蛛网膜下腔阻滞用于老年患者手术的效果,探讨舒芬太尼对老年患者蛛网膜下腔阻滞时罗哌卡因ED50的影响。方法择期行下肢或会阴部手术的老年患者48例,ASAⅠ~Ⅲ级,随机分为舒芬太尼组(S组)和对照组(C组)。选择L3~4椎间隙穿刺,S组为舒芬太尼和0.5%罗哌卡因,其中舒芬太尼固定为5.0 μg,C组为0.5%罗哌卡因,根据预实验结果及序贯法原则,S组第1例患者罗哌卡因给药剂量为8.0 mg,C组第1例患者罗哌卡因给药剂量为9.0 mg。此后如前一例患者符合有效标准则后一例患者给药剂量下调1.0 mg,反之则上调1.0 mg。ED50采用Dixon-Massey序贯法计算。结果舒芬太尼联合罗哌卡因用于老年患者腰麻下肢或会阴部手术的ED50为6.40 mg(95%CI:5.98~6.80mg),单纯罗哌卡因的ED50为8.42 mg(95%CI:7.79~9.03 mg)。与给药前比较,C组给药后3、6、15 min后MAP明显降低,且明显低于S组(P0.01),但均在正常范围内。结论老年患者蛛网膜下腔阻滞复合5.0 μg舒芬太尼时,罗哌卡因ED50降低。     

罗哌卡因混合舒芬太尼用于剖宫产术患者腰麻的半数有效剂量

目的 确定剖宫产术患者混合舒芬太尼时罗哌卡因腰麻的半数有效剂量(ED50).方法 择期行剖宫产术患者28例,ASA分级Ⅰ或Ⅱ级,经L2,3间隙行脊椎.硬膜外联合穿刺.蛛网膜下腔注射罗哌卡因混合舒芬太尼5 μg,注射时间30 s.第1例患者罗哌卡因剂量为11 mg,采用序贯法,根据腰麻是否成功确定下一例患者的罗哌卡因剂量,相邻剂量梯度为1 mg.采用序贯法计算罗哌卡因腰麻的ED50(95%可信区间).结果 罗哌卡因腰麻的ED50为7.780 mg(95%可信区间为6.850～8.836 mg).结论 罗哌卡因混合舒芬太尼5 μg用于剖宫产术腰麻的ED50为7.780 mg.

Abstract：

Objective To determine the median effective dose (ED50 ) of ropivacaine for spinal anesthesia when combined with sufentanil in patients undergoing caesarean section. Methods Twenty-eight ASA Ⅰ or Ⅱ parturients, aged 18-40 yr, weighing 50-110 kg, undergoing cesarean section under combined spinal-epidural anesthesia, were enrolled in this study. Combined spinal-epidural anesthesia was performed at L2,3 interspace. The mixture of ropivacaine and 5 fig sufentanil was injected into the subarachnoid space over 30 s. The initial dose of ropivacaine was 11 mg. The dose was increased/decreased by 1 mg in the next patient. The ED50 and 95% confidence interval were calculated by up-and-down method. Results The ED50 of ropivacaine was 7.780 mg (95% confidence interval 6.850-8.836 mg). Conclusion When combined with sufentanil 5 μg, the ED50 of ropivacaine for spinal anesthesia is 7.780 mg in patients undergoing caesarean section.     

0.5％布比卡因混合不同剂量舒芬太尼剖宫产腰麻的ED50与ED95

目的 计算0.5％布比卡因6mg混合不同剂量舒芬太尼剖宫产腰麻的ED50与ED95.方法 选择单胎、足月产妇30例,ASA Ⅰ或Ⅱ级,拟在腰麻下行剖宫产术,按照序贯法进行试验,初始舒芬太尼剂量为1 μg,剂量间隔为0.25 μg.用概率单位回归法计算舒芬太尼的ED50、ED95及其95％可信区间(CI).结果 舒芬太尼的ED5o为0.48 μg,95％CI 0.34～0.59 μg; ED95为0.81 μg,95％CI 0.64～2.21μg.结论 0.5％布比卡因6mg混合舒芬太尼剖宫产腰麻的ED50为0.48 μg,ED95为0.81 μg.     

罗哌卡因复合舒芬太尼用于老年患者腰麻的最低有效剂量

目的 研究罗哌卡因复合舒芬太尼用于老年下腹部或下肢手术患者腰麻的最低有效剂量（MLAD）。方法 择期行下腹部或下肢手术老年患者60例，ASAⅡ或Ⅲ级，年龄65—90岁，随机分为2组（n=30）：R组（单纯罗哌卡因）、RS组（罗哌卡因复合舒芬太尼5μg）。选择L3,4间隙穿刺，各组中第1例蛛网膜下腔注入罗哌卡因7．5mg，其后各患者所用剂量按序贯法调整，剂量变化梯度为0．3mg。观察感觉阻滞起效时间、感觉阻滞最高平面、感觉阻滞持续时间、下肢运动阻滞的Bromage分级、恶心呕吐、低血压等不良反应。根据Dixon-Massey法计算两组罗哌卡因MLAD。结果 两组Bromage分级和不良反应差异无统计学意义（P〉0．05）。与R组比较，RS组感觉阻滞起效时间缩短，持续时间延长，感觉阻滞最高平面升高（P〈0．05），蛛网膜下腔单纯应用罗哌卡因MLAD为6．95mg（95％CI6．43-7．48mg），复合5μg舒芬太尼后罗哌卡因MLAD为4．25mg（95％CI3．44—5．06mg）。结论 罗哌卡因复合5μg舒芬太尼用于老年手术患者腰麻的MLAD为4．25mg（95％CI3．44—5．06mg），与单独使用罗哌卡因相比，不仅MLAD降低，而且感觉阻滞起效时间缩短，持续时间延长，阻滞平面升高。     

罗哌卡因复合舒芬太尼蛛网膜下腔麻醉在剖宫产术中的应用

目的探讨罗哌卡因复合小剂量舒芬太尼蛛网膜下腔注射在剖宫产术中的应用。方法将120例择期行剖宫产术产妇随机均分3组:A组为0.75%罗哌卡因10 mg。B组为0.75%罗哌卡因10 mg复合舒芬太尼3μg。C组为0.75%罗哌卡因10 mg复合舒芬太尼5μg。经L2-3行腰—硬联合麻醉,留置硬膜外导管备用。记录3组产妇麻醉效果,感觉和运动阻滞程度和时间,术中血流动力学变化和不良反应、新生儿apgar评分及硬膜外追加局麻药情况。结果 3组均安全完成手术,最高感觉阻滞平面、运动阻滞程度及恢复时间、新生儿apgar评分差异无统计学意义。麻醉优良率C组>B组>A组,但皮肤瘙痒的例数C组>B组>A组,C、B 2组镇痛时间长于A组(P<0.05),3组产妇生命体征变化差异无统计学意义,均无呼吸抑制发生。硬膜外追加局麻药的例数A组明显高于C、B 2组(P<0.05)。结论罗哌卡因复合舒芬太尼蛛网膜下腔麻醉效果满意,术后镇痛时间长,不良反应少,可安全用于剖宫产术。     

甲磺酸罗哌卡因复合舒芬太尼用于分娩镇痛的研究

目的 观察甲磺酸罗哌卡因复合舒芬太尼用于腰-硬联合分娩镇痛的效果.方法 60例初产妇随机均分为2.38 mg甲磺酸罗哌卡因+1.5 μg舒芬太尼组(J组)和5μg舒芬太尼组(S组).两组均采取蛛网膜下腔注射并留置硬膜外导管镇痛.记录蛛网膜下腔镇痛起效时间、维持时间、注药前、注药后5、10、15、30、60 min的视觉模拟评分(VAS)、下肢运动阻滞情况、产程时间、分娩方式、新生儿Apgar评分及产妇不良反应.结果 两组产妇均获得良好的镇痛效果,注药后VAS平均为1～3分,运动神经阻滞评分均为0～1分.产程时间、分娩方式和Apgar评分组间差异无统计学意义;J组瘙痒发生率少于S组(P＜0.01).结论 2.38 mg甲磺酸罗哌卡因+1.5μg舒芬太尼蛛网膜下腔注射行腰-硬联合分娩镇痛安全有效.     

罗哌卡因复合舒芬太尼蛛网膜下腔阻滞麻醉用于剖宫产术的效果

目的探讨罗哌卡因复合舒芬太尼蛛网膜下腔阻滞麻醉用于剖宫产术的效果。方法随机将蛛网膜下腔阻滞麻醉下择期行剖宫产术的88例产妇分为2组,各44例。对照组应用0.75%罗哌卡因,观察组采用0.75%罗哌卡因复合舒芬太尼。比较2组的麻醉效果。结果观察组达到阻滞平面的时间短于对照组,镇痛维持时间长于对照组,差异有统计学意义(P<0.05)。2组新生儿5 min Apgar评分、心率、平均动脉压,以及不良反应发生率,差异均无统计学意义(P>0.05)。结论 0.75%罗哌卡因复合舒芬太尼行蛛网膜下腔阻滞麻醉用于剖宫产术,麻醉效果良好、术中血流动力学稳定、不良反应少、安全性较高。     

布比卡因复合舒芬太尼腰麻在输尿管镜下气压弹道碎石术中的应用

目的 观察经尿道输尿管镜下气压弹道碎石术中0.75％布比卡因复合舒芬太尼腰麻的效果,并测定布比卡因ED50.方法 择期行经尿道输尿管镜下气压弹道碎石术的患者54例,随机分为两组,B组(n=28)腰麻液为单纯0.75％布比卡因,BS组(n=26)腰麻液为0.75％布比卡因复合舒芬太尼10μg.采用序贯法确定0.75％布比卡因剂量,初始剂量均为1.6 ml(12mg),剂量梯度为0.2 ml(1.5 mg),以麻醉平面是否达T10为剂量增减指标.采用Probit回归分析计算布比卡因ED50及其95％可信区间(CI).结果 B组布比卡因ED50为1.90ml(14.25mg),95％CI 1.54～2.60ml(11.55～19.5 mg),BS组布比卡因ED50为1.70ml(12.75mg),95％CI 1.34～2.18ml(10.05～16.35 mg).BS组反映瘙痒发生率明显高于B组(35％ vs.0％,P＜0.01).结论 经尿道输尿管镜下气压弹道碎石术腰麻时,舒芬太尼10μg能使0.75％布比卡因ED50减少10.5％.     

剖宫产术患者重比重罗哌卡因混合小剂量舒芬太尼腰麻的效果

目的探讨重比重罗哌卡因混合小剂量舒芬太尼用于剖宫产术患者腰麻的效果。方法择期行剖宫产术的单胎和妊娠足月初产妇40例,年龄22～34岁,体重60～73 kg,ASAⅠ级。随机分为2组（n=20）,罗哌卡因组（R组）蛛网膜下腔注射1%罗哌卡因1.5 ml（15 nag）＋生理盐水0.7ml＋ 50%葡萄糖0.3 ml;罗哌卡因＋舒芬太尼组（R＋S组）蛛网膜下腔注射1%罗哌卡因1.5 ml（15 mg）＋舒芬太尼5μg（0.1 ml）＋生理盐水0.6 ml＋50%葡萄糖0.3ml。蛛网膜下腔穿刺成功后,将混合药液注入蛛网膜下腔,速率0.1 ml/s。记录感觉阻滞、运动阻滞情况,术中疼痛程度、腹肌松弛程度和牵拉反应程度,术中低血压、心动过缓、恶心、呕吐及瘙痒等不良反应的发生和处理情况,新生儿体重及出生后1 min和5 min Apgar评分。结果R＋S组蛛网膜下腔注药后感觉阻滞平面达到T10、T6和最高阻滞平面的时间短于R组,且最高阻滞平面升高（P〈0.05或0.01）;蛛网膜下腔注药后2组下肢运动阻滞起效时间和达最大运动阻滞时间差异无统计学意义,2组最大运动阻滞评分均为3分（P〉0.05）。R＋S组感觉阻滞恢复至L3、首次感觉疼痛和开始PCA镇痛的时间比R组长（P〈0.05或0.01）,下肢运动阻滞完全恢复时间组间比较差异无统计学意义（P〉0.05）。R＋S组牵拉反应程度低于R组（P〈0.01）。2组不良反应发生率、麻黄碱和阿托品使用率及新生儿体重、出生后1min和5 min Apgar评分差异无统计学意义（P〉0.05）。结论剖宫产术患者重比重罗哌卡因混合舒芬太尼5μg腰麻感觉阻滞起效时间缩短,阻滞平面上移,持续镇痛作用时间延长。     

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.     

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.     

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.