丙泊酚镇静下氟马西尼对脑电双频指数的影响

目的 研究丙泊酚镇静时氟马西尼对患者脑电双频指数(BIS)的影响.方法 择期行妇科子宫肌瘤剥出术或全子宫切除术患者40例,ASA Ⅰ或Ⅱ级,随机均分为两组.实施椎管内麻醉,术中采用丙泊酚镇静,维持患者BIS值在65±3.分别在关腹时静注氟马西尼0.01 mg/kg(F组)和生理盐水0.1 ml/kg(C组).观察给药前、给药后2、4、6、8、10、15、20 min时的BIS值.结果 给药后6～20 min F组BIS值显著高于C组(P<0.05).结论 丙泊酚镇静时氟马西尼可提高患者的BIS值,加快患者苏醒.     

经皮穴位电刺激对咪达唑仑镇静作用的影响

目的:探讨经皮穴位电刺激对咪达唑仑镇静作用的影响。方法:选择在我院择期椎管内麻醉行骨科下肢手术患者80例,随机分为两组:经皮穴位电刺激组和对照组,每组均40例。经皮穴位电刺激组在完成椎管内麻醉后开始给予经皮穴位电刺激,刺激参数频率2/100 Hz,波宽0.2~0.6 ms,调节刺激电流至患者可耐受的最大强度,穴位选择双侧合谷穴、内关穴,20 min后靶控输注咪达唑仑。对照组患者在相应穴位贴电极片,并连接刺激器,不予电刺激。对患者进行警觉/镇静(OAA/S)评分,依据脑电双频指数(BIS)调整咪达唑仑靶控输注浓度。观察并记录OAA/S评分首次为3分时的目标靶浓度(Ce)、BIS、咪达唑仑用量、平均动脉压(MAP)、血氧饱和度(SpO2)、心率(HR)及氟马西尼使用和不良反应发生情况。结果:经皮穴位电刺激组在OAA/S评分首次为3分时咪达唑仑效应室靶浓度较对照组低[(60.3±8.0)ng/mL vs.(66.8±8.5)ng/mL],经皮穴位电刺激组的咪达唑仑用量少于对照组[(4.9±0.6)mg vs.(5.3±0.5)mg],差异均有统计学意义(P<0.05);经皮穴位电刺激组术后应用氟马西尼12例,低于对照组的28例,差异有统计学意义(P<0.05);2组间BIS、SpO2、MAP、HR差异无统计学意义。结论:经皮穴位电刺激能够增强咪达唑仑的镇静作用,减少咪达唑仑用量。     

不同年龄患者清醒镇静时靶控输注咪达唑仑的效应室浓度和BIS水平

目的 探讨不同年龄患者靶控输注(TCI)咪达唑仑清醒镇静时效应室浓度(Ce)和脑电双频谱指数(BIS)水平.方法 择期椎管内麻醉下行下肢或下腹部手术患者60例,ASA Ⅰ或Ⅱ级,按年龄分为2组(n=30):青年组(Ⅰ组),年龄20～40岁;老年组(Ⅱ组),年龄≥65岁.麻醉平面均控制在T8以下.TCI咪达唑仑,以Ce为目标靶浓度,初始靶浓度为40 ng/ml,然后以10 ng/ml的浓度梯度递增,每一靶浓度维持15 min.术中每5分钟进行遗忘测试及警觉/镇静(OAA/S)评分1次(患者对正常语调呼名反应快为5分;对轻推或摇动无反应为1分),OAA/S评分达1分时停药.于咪达唑仑给药前即刻和达不同OAA/S评分时记录MAP、HR和SpO2;于OAA/S评分前即刻记录Ce和BIS.术后24h让患者挑出术中不同OAA/S评分时所看到的图片,记录遗忘发生情况.结果 2组OAA/S评分与Ce呈负相关,与BIS呈正相关,OAA/S评分与Ce的相关性低于BIS(P＜0.05);当OAA/S评分≤4时,Ⅱ组Ce低于Ⅰ组,而BIS高于Ⅰ组(P＜0.05);2组Ce、BIS的预测概率比较差异无统计学意义(P＞0.05).结论 BIS和Ce在评价不同年龄患者咪达唑仑的镇静深度及预测意识消失方面均有重要价值.当遗忘率达100%,青年组Ce为(74.3±21.5)ng/ml,BIS为61.6±7.9;老年组Ce为(58.3±12.5)ng/ml,BIS为82.3±4.2.     

七氟醚和依托咪酯镇静催眠效应的相互作用

目的 评价七氟醚和依托咪酯镇静催眠效应的相互作用.方法 择期全麻手术患者24例,ASA Ⅰ或Ⅱ级,年龄18～59岁,体重指数17～27 kg/m2.试验Ⅰ 12例患者靶控输注依托咪酯,效应室靶浓度依次为0.05、0.1、0.2、0.3、0.4、0.5 μg/ml.效应室浓度依次达到预设浓度2 min时,记录反应熵(RE)、状态熵(SE)和警觉/镇静(OAA/S)评分,然后停止输注依托咪酯.随机分为3组(n=4),A1组、B1组、C1组吸入七氟醚,呼气末浓度分别为0.5%、1%、2%.七氟醚呼气末浓度达预定浓度的95%或以上时,靶控输注依托咪酯,效应室靶浓度依次为0.2、0.3、0.4、0.5 μg/ml.效应室浓度依次达到预设浓度2 min时,记录RE、SE和OAA/S评分.试验Ⅱ 12例患者吸入七氟醚,呼气末浓度依次为0.5%、1%、2%、3%、4%、5%.依次达到预定呼气末浓度时,记录RE、SE和OAA/S评分,然后停止吸人七氟醚,吸氧洗脱七氟醚.随机分为3组(n=4),A2组、B2组、C2组靶控输注依托咪酯,效应室靶浓度分别为0.05、0.1、0.2 μg/ml.效应室浓度达到预设浓度2 min时,吸入七氟醚,呼气末浓度依次为0.5%、1%、2%、3%、4%、5%.依次达到预定呼气末浓度时,记录RE、SE和OAA/S评分.采用反应曲面法评价RE、SE和OAA/S评分,判断七氟醚和依托咪酯镇静催眠效应的相互作用.结果 RE和SE的相互作用指数的拟合值及其95%可信区间分别为0.32(-0.07～0.71)、0.25(-0.12～0.63)(P>0.05).OAA/S评分的相互作用指数的拟合值及其95%可信区间为2.25(0.58～3.93)(P<0.05).结论 以脑电熵指数反映镇静催眠效应时七氟醚和依托咪酯为相加作用;以OAA/S评分反映镇静催眠效应时七氟醚和依托咪酯为协同作用.     

近日节律对靶控输注依托咪酯镇静效应的影响

目的通过上午、下午靶控输注(TCI)依托咪酯麻醉诱导时依托咪酯血浆靶浓度测定,探讨近日节律对TCI依托咪酯镇静效应的影响。方法选择术前未用药患者60例,ASAⅠ或Ⅱ级,随机分为上午组(8:00~10:00,A组,30例)和下午组(14:00~16:00,P组,30例)TCI依托咪酯进行全麻诱导。以血浆靶浓度150 ng/ml为起点,达到预期的血浆靶浓度5 min后,每次增加50 ng/ml,直到患者意识消失(睫毛反射消失及OAA/S评分≤3分,且BIS≤50)。记录BIS为50和意识消失时的依托咪酯血浆靶浓度。结果 BIS达50和意识消失时,两组患者HR、MAP、SpO2、BIS差异均无统计学意义。与P组比较,BIS达50和意识消失时,A组依托咪酯血浆靶浓度明显升高(P0.05)。结论近日节律对依托咪酯的镇静作用有影响,下午组TCI依托咪酯患者BIS达50和意识消失时所需血浆靶控浓度较低。     

麻醉状态下氟马西尼对患者脑电双频指数的影响

目的 评估七氟醚麻醉下氟马西尼对患者麻醉深度及脑电双频指数(BIS)的影响.方法 20例ASA Ⅰ或Ⅱ级患者择期全麻下行妇科腹腔镜手术.当麻醉初期BIS(47±3)时静注氟马西尼0.01 mg/kg,记录给药(氟马西尼)前及给药后2、4、6、8、10、15、20 min 7个时点的SBP、DBP、MAP、HR、SpO_2及BIS值.结果 各时点的SBP、DBP、MAP、HR、SpO_2及BIS值差异均无统计学意义.结论 氟马西尼对七氟醚麻醉下患者的镇静程度无明显拮抗作用.     

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。     

氟马西尼对全麻肝叶切除术患者促醒作用及恢复期脑电双频指数、认知功能的影响观察

目的观察氟马西尼对全麻肝叶切除术患者促醒作用及恢复期脑电双频指数(BIS)、认知功能的影响。方法选取50例全麻肝叶切除术患者,根据是否使用氟马西尼分为氟马西尼组(n=25)和非氟马西尼组(n=25),两组均采取瑞芬太尼复合丙泊酚靶控输注(TCI)全麻,术中维持BIS在40~60之间。术毕入麻醉苏醒室即刻,氟马西尼组给予氟马西尼静脉推注,非氟马西尼组给予等体积生理盐水静脉推注。记录两组术后复苏时间指标及入苏醒室后不同时间点BIS值变化,并分别于术前1 d及术后1 d、3 d、5 d采用简易智能精神检查量表(MMSE)评价患者认知功能。结果氟马西尼组较非氟马西尼组术后自主呼吸恢复时间、指令下睁眼时间、指令下握拳时间、拔管时间及回忆起出生日期时间均明显缩短(P0.05)。氟马西尼组BIS值从进入麻醉苏醒室后4 min开始明显增高(P0.05),非氟马西尼组BIS值从进入麻醉苏醒室后6 min开始明显增高(P0.05)。氟马西尼组进入麻醉苏醒室4 min、6 min、8 min、10 min、12 min、14 min、16 min的BIS值均明显高于非氟马西尼组(P0.05)。在术后1 d、3 d、5 d等时间上,氟马西尼组MMSE评分均明显高于非氟马西尼组,差异有统计学意义(P0.05)。结论氟马西尼可促进全麻肝叶切除术患者术后苏醒,改善患者认知功能。     

苯二氮(艹卓)受体在小鼠不同静脉麻醉药遗忘效应中的作用

目的 评价苯二氮(艹卓)受体在小鼠异丙酚、依托咪酯和氯胺酮遗忘效应中的作用.方法 昆明小鼠288只,雌雄各半,体重18～23 g,采用随机数字表法,将其随机分为9组(n=32):生理盐水+生理盐水组(NN组)、生理盐水+脂肪乳组(NF组)、氟马西尼+生理盐水组(FN组)、生理盐水+异丙酚组(NP组)、氟马西尼+异丙酚组(FP组)、生理盐水+依托咪酯组(NE组)、氟马西尼+依托咪酯组(FE组)、生理盐水+氯胺酮组(NK组)和氟马西尼+氯胺酮组(FK组).NN组、NF组、NP组、NE组和NK组于训练前10 min时腹腔注射生理盐水10 ml/kg,于训练前5 min时分别腹腔注射生理盐水10 ml/kg、脂肪乳10 nl/kg、异丙酚25 mg/kg、依托咪酯3 mg/kg和氯胺酮20 mg/kg;FN组、FP组、FE组和FK组于训练前10 min时腹腔注射氟马西尼1 mg/kg,于训练前5 min时分别腹腔注射生理盐水10ml/kg、异丙酚25 mg/kg、依托咪酯3 mg/kg和氯胺酮20 mg/kg.分别采用避暗实验、跳台实验和Morris水迷宫实验测试认知功能.结果 与NN组比较,NF组和FN组认知功能各指标比较差异无统计学意义(P＞0.05),NP组跳台实验潜伏期缩短,NE组跳台实验潜伏期缩短,错误次数增多,NK组跳台实验潜伏期缩短,水迷宫实验潜伏期延长(P＜0.05);与NP组比较,FP组避暗实验潜伏期延长,水迷宫实验潜伏期缩短(p＜0.05);与NE组比较,FE组避暗实验潜伏期延长,避暗实验和跳台实验错误次数减少(P＜0.05);与NK组比较,FK组跳台实验潜伏期延长,水迷宫实验潜伏期缩短(P＜0.05).结论 小鼠异丙酚、依托咪酯和氯胺酮的遗忘效应与激活苯二氮(艹卓)受体有关.     

右旋美托咪啶的镇静效应及其对全麻镇静深度的影响

目的研究右旋美托咪啶(Dex)的镇静效应及其对全麻患者麻醉深度的影响。方法择期手术的患者60例(ASAⅠ～Ⅱ级),根据不同用药时期情况均分为镇静组和麻醉组,镇静组30例又分为Dex组(D1组)和对照组(C1组):D1组静脉泵注Dex负荷剂量0.4μg/kg(5min注完),然后以0.4μg·kg-1·h-1维持静注30min;C1组以同样方式输注生理盐水。记录不同时点的脑电双频指数(BIS)、MAP、HR,并对患者进行OAA/S、Ramesay镇静评分。麻醉组30例全麻患者也随机分为D2和C2组:D2组术中静脉Dex0.4μg/kg5min注完;C2组输注生理盐水。术中以丙泊酚靶控输注(TCI)和雷米芬太尼静脉维持麻醉,调节丙泊酚血浆靶控浓度(Ct),使BIS维持在50±3。结果D1组Dex负荷剂量输注后以及维持期间BIS比基础值降低17.0%～30.9%(P<0.05),镇静效应明显,OAA/S和Ramsay镇静评分明显降低(P<0.05);D2组患者麻醉前BIS为92±1,给予Dex后BIS由51±2降至42±16,C2组则仍为51±3。D2组丙泊酚的用量比C2组减少8%～14%(P<0.05)。结论Dex对清醒患者产生明显镇静效应,并能加深全麻患者的麻醉深度,减少丙泊酚TCI的用量。     

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.