利多卡因混合不同剂量肾上腺素局部浸润麻醉对全麻下鼻内窥镜手术患者血液动力学的影响

目的 观察利多卡因混合不同剂量肾上腺素局部浸润麻醉对全麻下鼻内窥镜手术患者血液动力学的影响。方法 69例拟在全身麻醉下行鼻内窥镜手术的患者随机分为3组（n=23），采用含不同剂量肾上腺素的1％利多卡因进行鼻粘膜下多点浸润注射。Ⅰ组：含1：20万肾上腺素的1％利多卡因4ml（20μg）；11组：含1：10万肾上腺素的1％利多卡因4ml（40μg）；Ⅲ组：1％利多卡因4ml（不含肾上腺素）。采用阻抗心动图（ICG）测量并记录浸润麻醉开始前（基础值）、浸润麻醉开始后0．75、1．5、2．25、3、3．75、4．5、5．25、6min平均动脉压（MAP）、心率（HR）、心脏排血指数（CI）、外周血管阻力指数（SVRI）和加速度指数（ACI），同时评价术中出血状况。结果与基础值比较，Ⅰ组和Ⅱ组在浸润麻醉开始后1．5min时MAP下降，HR增快（P〈0．01）；从浸润麻醉开始后1．5minSVRI下降，CI、ACI上升，到浸润麻醉开始后6min时仍未恢复（P〈0．05或0．01）。与Ⅱ组比较，Ⅰ组在浸润麻醉开始后2．25、3、3．75minMAP下降，从2．25min起CI下降（P〈0．01或〈0．05）。与Ⅲ组比较，Ⅰ组、Ⅱ组出血较少（P〈0．01）；Ⅰ组和Ⅱ组之间差异无统计学意义。结论 全身麻醉下鼻内窥镜手术中局部浸润麻醉时，局麻药中肾上腺素的吸收会引起明显的血液动力学变化，推荐在鼻内窥镜手术中使用含有5μg/ml肾上腺素的利多卡因。     

β2受体阻断剂ICI118551对大鼠鼻内浸润注射小剂量肾上腺素后血压的影响

目的 观察静脉预先注射特异性β2受体阻断剂ICI 118551对大鼠鼻内浸润注射小剂量肾上腺素后血压的影响.方法 成年雄性SD大鼠32只,随机均分为四组:生理盐水+生理盐水组(S组)和ICI 118551+生理盐水组(I组)先分别静脉注射生理盐水0.2 ml和ICI 118551 0.5mg/kg,20 min后在大鼠鼻内浸润注射生理盐水0.2 ml;生理盐水+肾上腺素组(E组)和ICI 118551+肾上腺素组(IE组)先分别静脉注射生理盐水0.2 ml和ICI 118551 0.5mg/kg,20 min后在大鼠鼻内浸润注射1:100 000肾上腺素0.2 ml.记录浸润注射前(基础值)和注射后1、2、3、4、5、6、7、8、9、10min的MAP和HR.结果 与浸润注射前相比,E组在注射后3 min时MAP出现明显下降,并持续至注射后10min(P＜0.05).IE组在注射后6、7 min时MAP上升.S组和I组MAP无明显变化.四组HR均无明显变化.结论 大鼠鼻内浸润注射小剂量肾上腺素可引发低血压,静脉预先注射β2受体阻断剂ICI 118551可预防此类低血压.     

局部利多卡因凝胶与静脉注射利多卡因在喉罩应用中的比较研究

目的探讨在喉罩使用过程中局部利多卡因凝胶与静脉注射利多卡因对维持血流动力学的稳定性是否有相同效应。方法选择2011年6月～2012年10月择期全麻下腹腔镜胆囊切除术48例,随机分为3组,每组16例。T组（局部给药组）,2％利多卡因凝胶涂抹于喉罩罩杯的双面,同时静脉注射生理盐水10ml;1组（静脉给药组）,普通水溶性润滑剂涂抹于喉罩罩杯的双面,同时2％利多卡因1．5mg／kg生理盐水稀释至10ml静脉注射;C组（对照组）,普通水溶性润滑剂涂抹于喉罩罩杯的双面,同时生理盐水10ml静脉注射。记录喉罩置入前,置入即刻,置入后1、3、5min,以及拔除喉罩前1min,拔除即刻,拔除后1、3、5min的平均动脉压（MAP）、心率（HR）,记录拔除喉罩前后并发症。结果3组置入和拔出喉罩时MAP、HR无明显变化（P〉0．05）。T组和I组MAP在喉罩置入后1min和拔出即刻、1min、3min、5min明显低于C组（P〈0．05）。拔除喉罩后3组均无喉痉挛和吞咽困难发生,咽痛、干呕并发症发生率3组差异无显著性（P〉0．05）。结论局部应用利多卡因凝胶与静脉注射利多卡因在喉罩使用过程中对维持血流动力学的稳定性具有相同效应。     

右美托咪定预注对瓣膜置换术患者麻醉诱导期血流动力学和脑电双频指数的影响

目的观察新型肾上腺素受体激动剂右美托咪定（dexmedetomi（iine,Dex）预注对瓣膜置换术患者麻醉诱导期血流动力学和脑电双频指数（bispectralindex,BIS）值的影响。方法选择择期瓣膜置换术患者30例,采用随机数字表法分为两组：Dex组（D组）和对照组（C组）,每组15例。D组于麻醉诱导前静脉微量泵预注用生理盐水稀释成50ml的Dex（浓度为4mg／L）0．5μg／kg,输注时间为10min,C组以同样方式输注等体积生理盐水。均以依托咪脂、芬太尼、哌库溴铵、咪达唑仑复合诱导麻醉。记录入室后输注Dex前即刻基础值（T1）、输注Dex后5min（T2）、输注Dex后10min麻醉诱导前时刻（T3）、麻醉诱导后1min（T4）、麻醉诱导后3min（T5）、插管前OPN（T6）、插管即刻（T7）、插管后1min（T8）、插管后3min（Tq）、插管后5min（T10）各时点的心率（heartrate,HR）、有创血压值（artefial blood pressure,ABP）[收缩压（systolic blood pressure,SBP）、舒张压（diastolic blood pressure,DBP）、平均动脉压mean artery pressure,MAP）]和BIS变化。结果全麻诱导前,与T1（92．6±2．5）比较,D组BIS在T2（73．2±1．9）、T3（70．1±2．3）时显著下降（P〈0．05或P〈0．01）,C组没有明显变化;全麻诱导期,与T3比较,两组BIS明显下降;气管插管期间,与T6比较,C组在T7时BIS（34．8±2．2）显著增高（P〈0．05或P〈0．01）,而D组BIS无明显变化。与C组比较,D组BIS在T2～T5、T7明显降低（P〈0．05或P〈0．01）。全麻诱导前,与T1比较,D组在T2、T3时ABP略有增高,HR显著降低（P〈0．05或P〈0．01）;全麻诱导期,与T1比较,两组ABP、HR均下降;气管插管期间,与T6比较,D组DBP、MAP、HR在T7、T8略有升高,T9、T10无明显变化（P〉0．05）,C组ABP、HR在B～T10显著增高（P〈0．05或P〈0．01）。与C组比较,D组SBP、MAP在T4-T10和DBP在T3-T10显著增高、HR在T2～T10显著降低（P〈0．05或P〈0．01）。结论静脉预注Dex能明显加深麻醉,BIS降低,减少瓣膜置换术患者气管内插管期心血管反应,血流动力学更加平稳,适合在临床中应用。     

倍他洛克用于气管插管期对BIS，ICP和血流动力学的影响

目的：观察长效选择性β受体阻滞剂—倍他洛克（metoprolol．美托洛尔）对丙泊酚麻醉诱导气管内插管期的BIS、ICP和血流动力学影响。方法：随机选择鼻蝶入路垂体瘤切除术病人100例，ASAⅠ-Ⅱ级，分为倍他洛克组（工组）和对照组（Ⅱ组），每组50例。工组於麻醉诱导期静脉注射倍他洛克60μg／kg；Ⅱ组静脉注射等容量生理盐水。麻醉诱导采用丙泊酚2mg/kg、芬太尼3μg／kg、罗库溴铵1mg／kg，OSS／A评分0级施行气管内插管．术中持续监测平均动脉压（MAP），心率（HR），颅内压（ICP）和脑电双频谱指数（BIS）。结果：倍他洛克组与对照组在气管插管后1min时的BIS分别为39±11和58±8，前者与插管前相比无显着性改变，而后者则较插管前有明显增高并延续至插管后5min（P〈0.05，P〈0.01），且其组间的显着性差异延续至插管后15min（P〈0.01）．倍他洛克组与对照组的MAP和HR在插管后3min和5min，均较插管前明显上升，对照组HR分别为89±11bpm和76±12bpm，MAP分别为122±16mmHg和106±18mmhg，倍他洛克组HR分别为81±12bpm和74±8bpm，MAP分别为111±18mmHg和97±17mmHg。两组相比，对照组的血流动力学显着性上升（P〈0.01），且其组间的显着性差异延续至插管后30min（P〈0.05，P〈0，01）。对照组的ICP於插管后3min上升为14．0±2.3mmHg，舆插管前相比有显着性差异（P〈0．05）；插管后5min，15min和30min的ICP分别为14.9±．0mmHg，15．5±2．6mmHg和14.4±2.7mmHg，显着性高於倍他洛克组（P〈0．05，P〈0．01）．两组插管后的ICP舆麻醉前比较均有显着性升高（P〈0。01）。结论：倍他洛克能减低麻醉诱导气管插管期的血流动力学波动和ICP升高，并抑制DIS反跳．     

急性高容量血液稀释对患者靶控输注异丙酚时镇静深度的影响

目的 观察急性高容量血液稀释（AHH）对患者靶控输注（TCI）异丙酚时镇静深度的影响。方法 择期全麻患者80例，随机分为4组（n=20）：A组、B组、C组气管插管后5min均开始进行急性高容量血液稀释，静脉输注乳酸钠林格氏液8ml／kg，同时30min内静脉输注6％羟乙基淀粉（HES，200／0．5）15ml／kg。B0组为B组的对照组，只静脉输注乳酸钠林格氏液8ml／kg，不进行急性高容量血液稀释。A组、B组、B0组、C组分别以2、4、4、6μg／ml异丙酚效应室靶浓度实施靶控输注至血液稀释结束。监测各组开始血液稀释即刻、5、10、15、20、25、30min时的BIS、AAI、MAP、HR、SpO2及ECG的变化，采集血标本，检测血液稀释前即刻和血液稀释结束时的Hct、Hb。结果 与B0组比较，B组MAP升高，BIS和AAI降低（P〈0．05或P〈0．01），血液稀释结束时Hct、Hb下降（P〈0．01）。随AHH的进行A组和B组MAP逐渐上升，BIS、AAI逐渐下降（P〈0．05或P〈0．01），Bn组和C组的MAP、BIS、AAI无明显变化，4组HR、SpO2差异无统计学意义（P〉0．05）；与血液稀释前即刻比较，A组、B组、C组在血液稀释结束时的Hct、Hb降低（P〈0．01），Bn组无变化（P〉0．05）。结论 患者以异丙酚2、4μg／ml效应室靶浓度靶控输注时，急性高容量血液稀释可加深镇静深度，当效应室靶浓度升为6μg／ml时，对其镇静深度无明显影响。     

不同剂量艾司洛尔复合异丙酚对气管插管时应激反应的影响

目的 了解艾司洛尔预防气管插管引起的血流动力学变化的合理用量。方法 30例病人随机分为3组。A组为对照组,B组为0．5mg.kg^-1艾司洛尔组,C组为1．0mg.kg^-1艾司洛尔组。静注异丙酚和维库溴铵诱导气管内插管。监测插管后1、3、5及10min收缩压（SP）、舒张压（DP）、心率（HR）;并抽取血标本用高压液相色谱仪测血浆中去甲肾上腺素（NE）、肾上腺素（E）和多巴胺（DA）浓度。结果 A组插管后1min时血压、心率显著升高（P＜0．01）或0．05）。B组插管后3、5及10min时血压、心率显著降低（P＜0．01或0．05）;3及5min时去甲肾上腺素与肾上腺素水平显著降低（P＜0．01或0．05）,与B组比较,插管后1和3min时肾上腺素水平显著降低（P＜0．01）。结论 1．0mg.kg^-1艾司洛尔复合异丙酚可缓解插管时的循环反应及儿茶酚胺反应。     

肾上腺素对利多卡因硬膜外麻醉时血流动力学的影响

目的 观察肾上腺素对利多卡因硬膜外麻醉时血流动力学的影响.方法 择期行骨科下肢手术患者40例,ASA Ⅰ或Ⅱ级,随机均分为肾上腺素(E)组和生理盐水(S)组,分别采用2%利多卡因加5 μg/ml肾上腺素或等容生理盐水进行硬膜外麻醉.采用阻抗心动图记录注药前即刻(T0)、注药后5、10、15、20、25、30 min(T1～T6)的MAP、HR、心脏指数(CI)、外周血管阻力指数(SVRI)和加速指数(ACI).结果 与T0时比较,E组在T1～T6时MAP和SVRI降低、CI和ACI升高、HR增快(P<0.05),而S组血流动力学差异无统计学意义.结论 肾上腺素加入利多卡因用于硬膜外麻醉可引起MAP和SVRI下降、CI和ACI升高、HR增快等血流动力学改变.     

预注美托洛尔对全麻术中血流动力学及血清皮质醇、一氧化氮的影响

目的观察预注美托洛尔对患者血流动力学、吸入麻醉药MAC值及血清皮质醇（Cor）,一氧化氮（NO）的影响。方法择期行胃肠道手术的患者24例,ASAⅠ或Ⅱ级,随机分成两组,分别给予美托洛尔0．05mg／kg（M组）及生理盐水（C组）。手术中连续监测MAP、HR、ST段,分别记录基础值（T0）、给药后（T1）、气管插管后即刻（T2）、手术切皮前（T3）、进腹后（T4）、手术结束时（T5）的MAP、HR、ST段的数值及每小时异氟醚的MAC值。分别在T0、T4、T5抽取患者的静脉血约4ml进行Cor、NO的测定。结果M组的HR明显慢于C组（P〈0．01）,MAC值低于C组（P〈0．01）。两组各时点的MAP、ST段、Cor和NO水平差异均无统计学意义。C组L时Cor水平明显高于T0时（P〈0．05）。两组T4、T5时NO均高于T0时（P〈0．05）。结论术前预注β受体阻滞药具有稳定血流动力学、降低异氟醚MAC值的作用。     

右美托咪定对妇科腹腔镜手术全身麻醉气管插管期心血管反应的影响

目的观察右美托咪定预防妇科腹腔镜手术全身麻醉气管插管期心血管应激反应的效果。方法将80例择期妇科腹腔镜手术行全身麻醉气管插管患者随机为两组：右美托咪定治疗组（D组,n=40）和对照治疗组（N组,n=40）。麻醉诱导前10min静脉泵注右美托咪定（1ug／kg）或等容量等速度注射0．9％氯化钠溶液。比较诱导前（T1）、诱导后（气管插管前）（T2）、气管插管后即刻（T3）及插管后1min（T4）、3minfT5）的血流动力学变化。结果在T2时,D组平均动脉压（MAP）为（81.3±5．9）mmHg,心率（HR）为（54．9±2．5）次／min,N组MAP为（71．5±4．7）mmHg,HR为（65-3±3．1）次／分,与T1比较显著降低,差异有统计学意义（P〈0．05）;与N组比较,D组MAP在12、rr4、T5均显著升高,差异有统计学意义（P〈0．05）;D组HR在1、2、T3、T4、T5时则明显降低,差异有统计学意义（P〈0．05）。结论右美托咪定可安全有效地减少妇科腔镜手术患者全身麻醉诱导及气管插管期间的血流动力学波动,减轻心血管应激反应。     

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.     

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.     

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.     

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.