辅用右美托咪定全麻诱导对麻黄碱升压效应的影响

目的观察辅用右美托咪定全麻诱导对麻黄碱升压效应的影响。方法择期行腹腔镜胆囊切除术患者44例,年龄18~65岁,随机分为生理盐水组(N组)和右美托咪定组(D组)。D组麻醉诱导前泵注右美托咪定0.8μg/kg,15min后改为0.4μg·kg-1·h-1维持,同时开始麻醉诱导和气管插管,插管后5min给予麻黄碱0.1 mg/kg。N组诱导前以同样方式泵注生理盐水,余同D组。记录泵注右美托咪定或生理盐水前(T0)、麻醉诱导前(T1)、插管即刻(T2)、插管后2min(T3)、给麻黄碱即刻(T4)及之后2min(T5)、5min(T6)、10min(T7)、15min(T8)的SBP、DBP和HR。结果与T0时比较,T2时N组SBP、DBP明显升高,HR明显增快(P0.05或P0.01),其余时点SBP、DBP均明显降低(P0.05或P0.01),T4、T7和T8时HR明显减慢(P0.05或P0.01);D组在T1~T8时的SBP、T1~T4和T8时的DBP明显降低,T1和T3~T4时的HR均明显减慢(P0.05或P0.01)。与T2时比较,T3、T4时N组SBP、DBP明显降低,HR明显减慢(P0.01);D组仅T4时SBP明显降低(P0.01)。与T4时比较,T5、T6时N组SBP明显升高(P0.05或P0.01);T5~T7时D组SBP、DBP明显升高,HR明显增快(P0.01)。与N组比较,T1~T3时D组HR明显减慢(P0.05或P0.01),T2时D组SBP、DBP明显降低(P0.01),T5~T8时SBP和DBP明显升高(P0.05或P0.01)。结论全麻麻醉诱导时辅用右美托咪定不仅可减轻气管插管反应,而且可增强麻黄碱的升压反应。     

雷米芬太尼复合丙泊酚静脉麻醉的临床应用

目的观察雷米芬太尼复合丙泊酚静脉麻醉的效果。方法全身麻醉下腰椎手术患者60例,随机均分为雷米芬太尼复合丙泊酚静脉麻醉组(Ⅰ组)和静吸复合麻醉组(Ⅱ组)。雷米芬太尼和丙泊酚的负荷量分别为1μg/kg和1mg/kg,雷米芬太尼以0.5μg·kg-1·min-1速率输注。麻醉中通过增减雷米芬太尼0.1μg·kg-1·min-1输注速率调整麻醉深度。丙泊酚按5∶4∶3方案输注,即5mg·kg-1·h-1输注10min,4mg·kg-1·h-1输注10min,20min后3mg·kg-1·h-1恒速输注。观察两组气管插管反应、麻醉效果、苏醒质量。结果两组麻醉效果相同,均可抑制气管插管反应(P<0.01),且Ⅰ组较Ⅱ组明显(P<0.05)。Ⅰ组苏醒质量较Ⅱ组好(P<0.01),不良反应较Ⅱ组高(P<0.01),术中无知晓。结论雷米芬太尼复合丙泊酚用两个注射泵静脉麻醉,采用负荷量加两种以上速率输注全凭静脉麻醉简便易行。     

不同剂量右美托咪定对丙泊酚诱导效应室靶浓度的影响

目的观察不同剂量右美托咪定在全麻患者气管插管时有效性和安全性及对丙泊酚效应室靶浓度(Ce)的影响。方法 60例全麻下行择期上腹部手术患者,随机均分为四组:D1、D2、D3、C组,分别在麻醉诱导前10min静脉泵注右美托咪定0.25μg/kg(D1组)、0.5μg/kg(D2组)和1.0μg/kg(D3组)及10ml生理盐水(C组)。麻醉诱导采用靶控输注丙泊酚,以BIS为靶控目标。丙泊酚初始Ce设为1.5μg/ml,递增梯度为0.5μg/ml,同时泵注瑞芬太尼0.2μg·kg-1·min-1。BIS≤60时推注罗库溴铵0.9mg/kg,BIS≤50并维持5s行气管插管。于输注右美托咪定前(T0)、诱导前(T1)、气管插管前(T2)、气管插管后1min(T3)、3min(T4)、5min(T5)、10min(T6)时记录SBP、DBP、HR、BIS、丙泊酚Ce。结果与T0时比较,T1时D2、D3组HR减慢、D3组SBP、DBP升高(P<0.05);与T1时比较,T2时D1组和C组SBP、DBP下降,HR减慢(P<0.05);与T2时比较,T3～T5时D1组和C组SBP、DBP升高,HR增快,T3时C组BIS升高(P<0.05)。T2～T6时丙泊酚CeD1、D2、D3组明显低于C组(P<0.05)。不同剂量右美托咪定各时点对丙泊酚Ce存在明显负相关关系。结论麻醉诱导前静脉输注不同剂量右美托咪定对丙泊酚诱导效应室浓度存在负相关关系。麻醉诱导前静脉输注右美托咪定0.5μg/kg心血管反应平稳并能显著减少诱导时所需丙泊酚Ce。     

雷米芬太尼对小儿心内直视手术心肺转流前血流动力学的影响

目的 观察不同剂量雷米芬太尼对小儿心内直视手术心肺转流(CPB)前血流动力学的影响.方法 75例拟行先天性心脏病矫治患儿随机均分为四个不同剂量的雷米芬太尼组和芬太尼组(F组).麻醉诱导静注芬太尼10μg/kg、雷米芬太尼2μg/kg;麻醉维持于切皮前10 min分别静脉泵注雷米芬太尼0.5μg·kg-1·min-1(R0.5组)、1.0μg·kg-1·min-1(R1.0组)、1.5μg·kg-1·min-1(R1.5组)、2.0μg·kg-1·min-1(R2.0组)和静注芬太尼10μg/kg(F组).记录麻醉前(T0)、插管后2 min(T1)、切皮后2min(T2)、劈胸骨后2 min(HR)的HR、MAP及各组开胸后到CPB前间羟胺的使用例数情况.结果 五组血流动力学在T0～T3时基本稳定.与F组比较,T3时R0.5、R1.0组FIR明显增快(P<0.05),R2.0组MAP降低(P<0.05).开胸后R2.0组间羟胺使用率(60%)明显高于F组(20%)(P<0.05).结论 输注雷米芬太尼0.5～1.5μg·kg-1·min-1能维持心内直视手术CPB前小儿的血流动力学稳定.     

丙泊酚靶控输注用于重症心脏瓣膜病患者全麻诱导

目的探讨丙泊酚滴定法靶控输注用于重症心脏瓣膜病患者全麻诱导的安全性和有效性。方法重症心脏瓣膜病患者47例,随机分成丙泊酚组(P组,n=24)和依托咪酯组(E组,n=23)。P组以丙泊酚靶控输注,初始血浆靶浓度1.0μg/ml,采用改良警觉/镇静(MOAA/S)评分行镇静评分,每2分钟递增靶浓度0.2μg/ml,至患者MOAA/S评分≤1分时给予芬太尼5μg/kg、维库溴铵0.1mg/kg。E组使用依托咪酯0.25～0.30mg/kg和同剂量的芬太尼、维库溴铵并行气管插管。记录入室(T1)、MOAA/S评分≤1分(T2)、诱导期收缩压最低点(T3)、插管前(T4)、插管完毕(T5)、插管后5min(T6)时的SBP、DBP、HR、CVP;记录血管活性药物的使用情况。结果与T1时比较,P组T2～T6时SBP、DBP明显下降,HR明显减慢(P0.05或P0.01),E组T2～T4、T6时的SBP,T2～T6时的DBP明显下降,T2～T4时HR明显减慢(P0.05或P0.01),T3、T4时两组CVP明显降低(P0.05或P0.01)。与E组比较,P组T5时的SBP,T5、T6时的DBP明显降低,T5、T6时HR明显减慢(P0.05或P0.01)。P组患者在T2时的血浆靶浓度平均值为1.61μg/ml。结论丙泊酚滴定法靶控输注用于重症心脏瓣膜病患者全麻诱导的安全性与依托咪酯相似,并且能更好地抑制气管插管后的应激反应。     

Supreme喉罩与气管插管对老年高血压患者人工膝关节置换术应激反应的影响

目的探讨Supreme喉罩(SLMA)和气管插管对老年高血压患者人工膝关节置换术应激反应的影响。方法选择择期老年高血压人工膝关节置换术患者40例,ASAⅠ~Ⅲ级,采用随机数字表法,将患者均分为喉罩组(LMA组)和气管插管组(TT组)。采用相同的麻醉诱导和维持方法,患者入室后连续无创监测SpO2和ECG变化,连续监测SBP、DBP、HR,分别记录两组麻醉诱导前(T0,基础值)、插管(喉罩)后即刻(T1)、5 min(T2)、15 min(T3)时SBP、DBP、HR及血清皮质醇(Cor)、心钠素(ANP)含量、血浆肾上腺素(E)和去甲肾上腺素(NE)浓度。结果与T0时比较,T1~T3时LMA组患者SBP、DBP明显降低(P0.05或P0.01);T1时TT组SBP、DBP明显升高,T2、T3时明显降低,T1时HR明显增快(P0.05或P0.01)。与LMA组比较,T1~T3时TT组SBP、DBP明显升高,T1、T2时HR明显增快(P0.05或P0.01)。与T0时比较,T1~T3时TT组E、NE浓度和Cor含量明显升高,且明显高于LMA组(P0.05或P0.01);T1~T3时两组ANP含量明显升高,且TT组明显高于LMA组(P0.01)。结论与气管插管比较,SLMA可明显减轻老年高血压患者人工膝关节置换术全麻时的应激反应。     

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.     

末梢血管收缩反应预测气管插管血液动力学变化

目的通过末梢血管收缩反应预测气管插管引起的血液动力学变化,提供个体化气管插管所需的麻醉深度。方法末梢血管收缩反应通过强直电刺激(50 Hz、50 mA持续5 s)诱发的末梢灌注指数(tip perfusion index,TPI)变化进行监测。24例ASAⅠ~Ⅱ级颅脑外科择期手术患者,麻醉诱导:咪唑安定0.06 mg/kg、芬太尼4μg/kg,丙泊酚0.25 mg.kg-1.min-1恒速输注。意识消失后每间隔1分钟电刺激一次,记录每次电刺激前后TPI的减少值(△TPI)和插管前后SBP、DBP和HR的增加值(△SBP、△DBP和△HR)。观察组(n=12),△TPI<10%刺激前值时行气管插管;对照组(n=11),不考虑△TPI的变化而根据操作者的经验决定插管时机。记录诱导前、插管前、插管后即刻、1、2和3 min时BIS、SBP、DBP和HR的值。结果插管即刻,观察组比对照组丙泊酚输注时间长(P<0.01)、用量大(P<0.01);插管后每一时间点,对照组SBP、DBP和HR都比观察组高(P<0.01)。组内比较:对照组插管前后SBP、DBP和HR明显增高(P<0.01);观察组插管前后各指标无明显变化。电刺激诱发的△TPI分别与插管引起的△SBP、△DBP和△HR成正相关(r=0.672、0.434和0.236,P<0.01)。结论电刺激诱发的末梢血管收缩反应性可有效预测气管插管引起的血液动力学变化幅度。     

不同剂量雷米芬太尼对气管插管反应的影响

目的 观察不同剂量雷米芬太尼用于全麻诱导气管插管时的心血管反应,探讨其最佳的全麻诱导剂量.方法 将96例择期行腹部手术的患者随机均分为四组.全麻诱导均采用咪唑安定0.06 mg/kg、依托咪酯0.3 mg/kg、维库溴铵0.1 mg/kg;雷米芬太尼剂量分别为1μ9/kg(R1组)、2μg/kg(R2组)、3μ9/kg(R4组)和4μg/kg(R4组).记录诱导前(T0)、诱导后气管插管前(T1)、气管插管后即刻(T2)、气管插管后1min(T3)、2min(T4)、3min(T5)、5min(T6)和10min(T7)的SBP、DBP、HR的变化.结果 与T0比较,各组T1时SBP、DBP均明显下降(P<0.05或P<0.01),R1组T2、T3时SBP显著升高(P<0.05).与T0比较,各组患者T1时的HR均明显减慢(P<0.01),R1组患者T2、T3时HR显著增快(P<0.05或P<0.01).R2、R3组气管插管期间血压波动幅度均较R1、R4组小(P<0.05).结论 采用2～3μg/kg的雷米芬太尼麻醉诱导可有效抑制气管插管时的心血管反应.     

雷米芬太尼在宫腔镜手术中的应用

目的观察单纯输注雷米芬太尼对宫腔镜手术患者呼吸及循环功能的影响。方法选择拟行宫腔镜手术患者60例,随机均分为雷米芬太尼组(R组)和丙泊酚复合芬太尼组(PF组)。R组静注雷米芬太尼1μg/kg,继而以6μg·kg-1.h-1的速率输注。PF组静注芬太尼1μg/kg、丙泊酚2mg/kg,继而以4mg·kg-1.h-1输注丙泊酚。观察术前基础值(T1),注药后5min(T2)、10min(T3)、15min(T4)以及停药后5min(T5)的循环、呼吸情况,并记录意识消失时间、清醒时间、定向力恢复时间。结果与T1时相比,R组各时点MAP无明显变化,T2~T4时HR明显减慢(P<0.05),分钟通气量(MV)减少(P<0.01),PETCO2升高(P<0.01),但均保持自主呼吸;而PF组T2~T4时MAP明显下降,HR明显减慢(P<0.05),呼吸抑制明显,均需进行控制呼吸或辅助呼吸,其中有25例患者出现呼吸停止。T5时R组的MAP、HR和MV与T1时相比差异无统计学意义,而PF组MAP和MV明显降低(P<0.05),HR明显减慢(P<0.05)。R组术中体动患者明显少于PF组(P<0.05),患者均保持清醒而安静,而PF组患者均意识消失。结论在宫腔镜手术麻醉中,单纯输注雷米芬太尼可使患者保持自主呼吸,意识清醒而安静,并对循环影响轻微。     

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.