无痛胃镜检查时丙泊酚对羟考酮有效剂量的影响

目的采用保守回归法评价无痛胃镜检查时不同丙泊酚浓度对羟考酮半数有效剂量(ED_(50))的影响。方法无痛胃镜检查患者65例,男35例,女30例,年龄18～60岁,BMI 20～24 kg/m~2,ASAⅠ或Ⅱ级,采用随机数字表法将患者随机分为两组。A组和B组丙泊酚TCI血浆浓度分别为5μg/ml和3μg/ml,首例患者羟考酮初始剂量分别为0.07 mg/kg和0.1 mg/kg。根据前一例患者无痛胃镜置入结果决定次例患者羟考酮剂量。前一例患者体动或呛咳反应阳性,则下一例患者羟考酮剂量增加0.01 mg/kg,反之减少0.01 mg/kg。采用保守回归法计算羟考酮的ED_(50)及其95%可信区间(95%CI),重复样本法计算ED_(95)及其95%CI。记录入镜时吞咽、呛咳、体动发生情况;记录麻醉后低血压和低血氧情况;记录术后恶心、呕吐等不良反应情况。结果 A组羟考酮ED_(50)为0.074 mg/kg(95%CI 0.063～0.086 mg/kg),ED_(95)为0.100 mg/kg(95%CI 0.087～0.194 mg/kg)。B组羟考酮ED_(50)为0.086 mg/kg(95%CI 0.061～0.098 mg/kg),ED_(95)为0.118 mg/kg(95%CI 0.103～0.308 mg/kg)。A组低血压发生率明显高于B组(P0.05)。两组恶心和呕吐发生率差异无统计学意义。结论丙泊酚TCI血浆浓度5.0μg/ml和3.0μg/ml时,羟考酮的ED_(95)分别为0.100 mg/kg和0.118 mg/kg。     

不同剂量羟考酮复合依托咪酯用于老年患者无痛胃镜检查的效果

目的观察不同剂量羟考酮复合依托咪酯用于老年患者无痛胃镜检查的效果。方法选择2017年2—11月全麻下行无痛胃镜检查的老年患者120例,男62例,女58例,年龄65～79岁,体重46～68 kg,ASAⅠ—Ⅲ级,随机分为四组,每组30例:羟考酮1组(O1组)、羟考酮2组(O2组)、羟考酮3组(O3组)及对照组(C组)。O1、O2、O3组分别静脉注射羟考酮0.025、0.05、0.075 mg/kg,C组静脉注射等容量生理盐水,2 min后四组静脉注射依托咪酯0.2 mg/kg。术中出现呛咳或体动反应时,静脉追加依托咪酯0.1 mg/kg。记录胃镜检测时间;追加依托咪酯的情况;记录呛咳、体动、呼吸抑制、头晕、恶心呕吐、肌震颤等不良反应的发生情况。结果 O1、O2和O3组追加依托咪酯例数明显少于C组(P0.05);O2和O3组追加依托咪酯例数明显少于O1组(P0.05)。O1、O2和O3组呛咳、体动、恶心呕吐和肌震颤发生率明显低于C组(P0.05);O2和O3组呛咳、体动、恶心呕吐和肌震颤发生率明显低于O1组(P0.05)。O3组呼吸抑制和头晕发生率明显高于C、O1和O2组(P0.05)。结论羟考酮0.025、0.05、0.075 mg/kg复合依托咪酯用于老年患者无痛胃镜检查,其中羟考酮0.05 mg/kg更为安全有效。     

依托咪酯联合瑞芬太尼用于老年患者胃镜检查时依托咪酯的半数有效剂量

目的测定依托咪酯联合瑞芬太尼用于老年患者胃镜检查依托咪酯的ED50和ED95。方法选择行胃镜检查的老年患者23例,男13例,女10例,年龄65~78岁,体重45~76kg,ASAⅠ~Ⅲ级。预先缓慢静脉注射瑞芬太尼0.3μg/kg,然后注射依托咪酯0.20 mg/kg,待睫毛反射消失后行胃镜检查。依托咪酯的剂量采用改良序贯法确定,起始剂量为0.20 mg/kg,胃镜检查患者反应阳性标准:在整个检查过程中出现躁动、皱眉、吞咽、呛咳等。相邻间隔剂量为0.05 mg/kg,当出现七个交叉点终止研究。应用概率回归分析法计算依托咪酯复合瑞芬太尼老年患者胃镜检查的依托咪酯ED50和ED95及95%CI。结果依托咪酯ED50为0.17mg/kg,95%CI为0.14~0.21mg/kg,ED95为0.23mg/kg,95%CI为0.20~0.42mg/kg。结论依托咪酯联合瑞芬太尼用于老年患者无痛胃镜ED50、ED95分别为0.17mg/kg和0.23mg/kg。     

丙泊酚靶控输注时羟考酮抑制气管插管反应的半数有效剂量

目的测定丙泊酚靶控输注时羟考酮抑制气管插管反应的半数有效剂量(ED_(50))。方法择期全麻下手术的患者,性别不限,年龄18~65岁,BMI 18.5~24.9kg/m~2,ASAⅠ或Ⅱ级,MallampatiⅠ或Ⅱ级。静脉顺序注射羟考酮、靶控输注丙泊酚血浆浓度4μg/ml,BIS60时,静注罗库溴铵0.9mg/kg后行气管插管机械通气。采用改良Dixon序贯法进行试验,羟考酮起始剂量0.2mg/kg。若气管插管反应阳性,则下一例增加剂量;反之,则降低剂量,相邻剂量比值为1∶1.1。气管插管反应阳性的标准:插管后2min内MAPmax或HRmax较基础值≥20%。采用加权概率法计算羟考酮抑制气管插管反应的ED_(50)、ED_(95)及其相应的95%可信区间(CI)。结果共有27例患者完成正式研究。羟考酮抑制气管插管反应的ED_(50)为0.204 mg/kg,(95%CI 0.175~0.249 mg/kg),ED_(95)为0.342mg/kg(95%CI 0.287~0.409mg/kg)。结论血浆靶控输注丙泊酚4μg/ml时,羟考酮抑制气管插管反应的ED_(50)为0.204mg/kg,ED_(95)为0.342mg/kg。     

羟考酮抑制中老年患者全身麻醉诱导期依托咪酯所致肌阵挛的半数有效量

目的 观察羟考酮抑制中老年患者全身麻醉诱导期依托咪酯所致肌阵挛的药效学. 方法 择期全身麻醉下手术患者62例,ASA分级Ⅰ、Ⅱ级.分为两组:中年组(45～54岁)30例,老年组(65～74岁)32例.麻醉诱导:患者面罩吸氧(8 L/min)5 min后,采用改良序贯法30 s内静脉注射羟考酮.2 min后30 s内静脉注射依托咪酯0.3 mg/kg,持续观察2 min,评估肌阵挛发生情况及其程度.然后静脉注射顺式阿曲库铵2 mg/kg和芬太尼3μg/kg,5min内完成气管插管行机械通气.麻醉分别以靶控输注(target controlled infusion,TCI)丙白酚(3.0 mg/L)、瑞芬太尼(2.5～3.0 μg/L)维持.采用Probit回归方法分析各组羟考酮的ED50及其95％CI,并记录手术时间、术后拔管时间及恶心、呕吐等副作用. 结果 羟考酮抑制中老年患者全身麻醉诱导期依托咪酯所致肌阵挛的ED.分别为0.077 mg/kg和0.062 mg/kg,95％CI分别为0.045～0.122 mg/kg和0.043～0.101 mg/kg;中年组羟考酮剂量明显高于老年组患者(P＜0.05).两组患者副作用发生率比较,差异无统计学意义(D0.05). 结论 羟考酮抑制中老年患者全身麻醉诱导期依托咪酯所致肌阵挛的ED50分别为0.077 mg/kg与0.062mg/kg;95％CI分别为0.045～0.122 mg/kg与0.043～0.101 mg/kg.     

不同剂量右美托咪定对依托咪酯致患者意识消失ED95的影响

目的探讨不同剂量右美托咪定对依托咪酯致患者意识消失ED_(95)的影响。方法择期行全麻手术患者120例,男69例,女51例,年龄20～60岁,体重58～79 kg,ASAⅠ或Ⅱ级。按照随机数字表法将患者分为三组:依托咪酯组(E组)、依托咪酯复合右美托咪定0.5μg/kg组(ED1组)和依托咪酯复合右美托咪定1.0μg/kg组(ED2组)。E组按照偏性掷币(BCD)序贯法给予依托咪酯,首剂量为0.04 mg/kg,相邻剂量差0.04 mg/kg。ED1组和ED2组先给予负荷剂量的右美托咪定0.5μg/kg和1.0μg/kg,给药时间为10 min,之后按照BCD序贯法给予依托咪酯。应用保序回归及合并相邻者算法计算依托咪酯致患者意识消失的ED_(95)及其95%可信区间(CI)。观察患者不良反应发生情况。结果 E组依托咪酯ED_(95)及其95%CI为0.222(0.197～0.255)mg/kg,ED1组为0.158(0.121～0.186)mg/kg,ED2组为0.138(0.112～0.168)mg/kg。ED1组和ED2组ED_(95)明显低于E组(P0.05)。ED2组心动过缓的发生率明显高于E组和ED1组(P0.05)。结论预注右美托咪定0.5μg/kg和1.0μg/kg可明显降低依托咪酯致患者意识消失的ED_(95),但右美托咪定1.0μg/kg有增加心动过缓的风险。     

依托咪酯乳剂用于老年患者喉罩放置

目的探讨老年患者喉罩放置时依托咪酯乳剂的合适剂量。方法行择期喉罩全麻下手术的老年患者(年龄>65岁)75例,随机均分为五组:静注芬太尼1μg/kg后,分别静注依托咪酯乳剂0.2 mg/kg(Ⅰ组)、0.25 mg/kg(Ⅱ组)、0.3 mg/kg(Ⅲ组)、0.35 mg/kg(Ⅳ组)、0.4 mg/kg(Ⅴ组),固定由1名麻醉医师放置喉罩。放置喉罩时,患者出现吞咽、呛咳、屏气、喉痉挛等任何气道反应或肢体运动,均认为喉罩置入阳性反应。结果联合应用芬太尼1μg/kg,依托咪酯的50%有效剂量(ED50)为0.24 mg/kg(95%的可信区间为0.21~0.26 mg/kg),95%有效剂量(ED95)为0.35mg/kg(95%的可信区间为0.31~0.44 mg/kg)。结论依托咪酯乳剂0.35 mg/kg复合芬太尼1μg/kg静脉麻醉诱导用于老年患者喉罩放置,血流动力学稳定,不良反应少见。     

瑞马唑仑联合地佐辛用于老年患者无痛胃镜检查的半数有效量和95%有效量

目的观察瑞马唑仑复合地佐辛用于老年患者无痛胃镜检查的半数有效量(median effective dose,ED_(50))和95%有效量(95%effective dose,ED_(95))。方法选取2020年12月在扬州大学附属医院日间手术中心行无痛胃镜检查的老年患者31例,年龄65~86岁,体重45~87 kg,ASA分级Ⅰ~Ⅲ级。监测患者生命体征,静脉给予20μg/kg地佐辛,10 min后给予瑞马唑仑,待患者意识消失后立即行胃镜检查,观察受试患者对胃镜检查的反应情况。设定瑞马唑仑0.20 mg/kg为初始剂量,采用改良序贯法确定瑞马唑仑的剂量。采用概率单位Probit回归分析法计算瑞马唑仑ED_(50)、ED_(95)及其95%CI。结果与用药前相比,患者使用瑞马唑仑后出现一过性MAP、心率和SpO2的降低。复合地佐辛时,瑞马唑仑用于老年患者无痛胃镜检查的ED_(50)为0.184(0.062~0.275)mg/kg、ED_(95)为0.354(0.268~1.677)mg/kg。结论瑞马唑仑复合地佐辛用于老年患者无痛胃镜检查的ED_(50)为0.184 mg/kg、ED_(95)为0.354 mg/kg。     

瑞马唑仑复合瑞芬太尼用于无痛胃镜检查的半数有效剂量

目的测定瑞马唑仑复合瑞芬太尼用于无痛胃镜检查时的半数有效剂量(ED_(50))及95%有效剂量(ED_(95))。方法本研究共纳入患者73例,分为三组:第一组纳入患者性别不限(n=22),第二组仅纳入男性患者(n=29),第三组仅纳入女性患者(n=22)。根据Dixon改良序贯法,所有患者缓慢静注瑞芬太尼0.5μg/kg,随后注射瑞马唑仑0.2 mg/kg,待睫毛反射消失后行胃镜检查。若在进镜时及检查过程中出现呛咳、吞咽、皱眉、体动影响检查操作等反应为阳性反应,下一例患者增加0.05 mg/kg,否则降低0.05 mg/kg,以阳性反应转为阴性反应为交叉点,当出现七个交叉点时终止研究。采用概率单位Probit回归分析法计算第一组瑞马唑仑的ED_(50)和ED_(95)及其95%CI,并分别测定第二组、第三组瑞马唑仑的ED_(50)及其95%CI。结果第一组瑞马唑仑ED_(50)为0.19 mg/kg(95%CI 0.155～0.229 mg/kg),ED_(95)为0.31 mg/kg(95%CI 0.248～0.492 mg/kg)。第二组瑞马唑仑ED_(50)为0.161 mg/kg (95%CI0.135～0.192 mg/kg),第三组瑞马唑仑ED_(50)为0.194 mg/kg (95%CI0.159～0.235 mg/kg)。结论瑞马唑仑复合瑞芬太尼用于无痛胃镜检查的ED_(50)、ED_(95)分别为0.19 mg/kg和0.31 mg/kg,且男性患者瑞马唑仑ED_(50)低于女性患者。     

羟考酮抑制老年患者腹腔镜下胆囊切除术瑞芬太尼静脉复合麻醉苏醒期疼痛的半数有效量

目的 探讨羟考酮抑制老年患者腹腔镜下胆囊切除术瑞芬太尼静脉复合麻醉苏醒期疼痛的药效学. 方法 选择拟在全身麻醉下行腹腔镜胆囊切除术患者32例,年龄65～74岁,ASA分级Ⅰ、Ⅱ级.麻醉诱导:依托咪酯0.3 mg/kg,瑞芬太尼采用Minto模型靶控输注(target controlled infusion,TCI),效应室浓度为3.0μg/L.待BIS值在40～45后,静脉注射顺式阿曲库铵0.2 mg/kg,5 min内完成气管插管行机械通气.术中除瑞芬太尼外,不再追加任何镇痛药物,麻醉维持分别TCI丙泊酚(3.0 μg/L)、瑞芬太尼(2.5～3.0 μg/L).手术结束时停用丙泊酚、瑞芬太尼.手术结束前5 min采用改良序贯法静脉注射羟考酮.拔管后30 min测定患者术后VAS评分,VAS评分≥4分为术后急性疼痛.计算羟考酮ED50及其95％可信区间(confidence interval,CI),并记录手术时间、术后拔管时间及恶心、呕吐等副作用. 结果 羟考酮抑制老年患者腹腔镜下胆囊切除术瑞芬太尼静脉复合麻醉苏醒期疼痛的EDs及其95％CI分别为0.126 mg/kg和0.093～0.181 mg/kg.32例患者术后有1例发生恶心、呕吐,无其他副作用发生. 结论 羟考酮(0.126 mg/kg)可以抑制半数老年患者腹腔镜下胆囊切除术瑞芬太尼静脉复合麻醉苏醒期的疼痛.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.