非体外循环冠脉搭桥术中心脏移位对血液动力学的影响

目的 观察非体外循环冠脉搭桥术(OPCABG)中暴露术野时心脏位置改变对心血管功能的影响。方法 冠心病多支病变患者47例,年龄50～82岁,术前左室射血分数为0.55±0.14,择期行OPCABG,平均移植血管桥3.2条。采用漂浮导管方法监测血液动力学,分别在麻醉诱导后循环稳定时(T_1)、搬动心脏前(T_2)、吻合前降支时(T_3)、吻合右冠状动脉或后降支时(T_4)、吻合左旋支或对角支时(T_5)、血管吻合完成、心脏恢复自然位置后(T_6)、及手术结束时(T_7)作参数测定。结果 吻合前降支时(T_3),SI和LVSWI有所降低(P<0.01),但CI和SvO_2保持在基础水平。吻合后降支或右冠状动脉、左旋支或对角支时(T4、T5),CI、SI、LVWI、LVSWI、RVWI和RVSWI等明显降低(P<0.01),其中CI较对照值降低18％,LVWI和RVWI降低均为25％,MAP和SvO_2也显著下降(P<0.05～0.01),而HR、RAP、MPAP、PAWP和PVRI则显著增高(P<0.05～0.01)。心脏恢复自然位置后(T_6),CI、LVWI和RVWI恢复到对照值水平。结论 OPCABG术中由于心脏被搬动及移位,可导致明显的心功能损害和血压下降;麻醉手术期间采取可靠的血液动力学监测和有效的心血管功能支持十分必要。     

七氟醚诱导及维持麻醉对心脏瓣膜手术病人血液动力学的影响

目的:研究七氟醚及七氟醚-N_2O吸入诱导及维持麻醉对心脏瓣病人血液动力学的影响。方法:44例患者分两组,组1以七氟醚、组2以七氟醚-N_2O诱导,均以七氟醚-N_2O维持麻醉。采用SwanGanz导管技术监测血液动力学变化。结果:诱导过程病人舒适,入睡平稳,几无呛咳屏气及躁动等不良反应发生。诱导后两组HR、PTRI、PVRI和SVRI无变化,但MAP、CI、LVWI、LVSWI及RVWI明显降低(P<0.05),组1尚伴SI和RVSWI减低(P<0.05)。劈胸骨后,两组RAP、PTRI、PORI、SVRI增高,CI、SI、LVWI、LVSWI、RVWI及RVSWI进一步减低(P<0.05)。CPB开始前,两组LVWI、LVSWI、RVWI及RVSW仍继续下降(P<0.01)。结论:心脏瓣膜病人以1.0 MAC七氟醚或1.2 MAC七氟醚-N_2O诱导是可取的,但以此浓度维持麻醉,对强烈刺激反应的抑制仍嫌不足。     

复方丹参液对失血性休克家兔血流及氧动力学的影响

目的：探讨复方丹参注射液改善失血性休克家兔氧动力学、血流动力学的可行性。方法：20只家兔随机分为丹参组和休克组。观察两组家兔休克前、休克即刻、休克1h、3h、6h、12h心指数（CI）、全身血管阻力指数（SVRI）、肺血管阻力指数（PVRI）混合静脉血氧饱和度（SvO2）、氧输送（DO2）、氧消耗（VO2）、氧摄取率（ERO2）、动脉血乳酸（LA）变化及DO2与VO2的关系。结果：休克组于休克1h时SVRI、PVRI、CI、DO2、SvO2较休克前无明显变化（P〉0.05）,于休克3h与休克前比较CI、DO2、SvO2显著降低,ERO2显著增加,（P〈0.05）,VO2保持不变,DO2与VO2呈非依赖关系。休克6h,当DO2降至397mL（min.m2）时,VO2明显降低,DO2与VO2线性相关,相关系数γ=0.62。丹参组于休克1h和3h时SVRI、PVRI、CI、DO2、SvO2与休克前比较无明显变化（P〉0.05）,于休克6h后,SVRI、PVRI、CI、DO2、SvO2降低,但与休克前比较无明显差异。丹参组休克后,CI、ERO2与休克前无显著改变。DO2、VO2显著升高。丹参组DO2与VO2亦呈线性相关（相关系数r=0.34,P〈0.05。丹参组DO2、VO2关系曲线斜率明显低于休克组,相关系数明显降低。两组血乳酸水平于休克后1h无明显变化,于休克3h均明显升高（P〈0.05）,于休克后6h休克组血乳酸水平持续升高,丹参组较前下降,但高于休克前,于休克12h休克组达（8.70&#177;0.73）mmol/L,丹参组下降至休克前水平。结论：失血性休克家兔出现血流动力学、氧动力学障碍,复方丹参注射液可改善这种状况。     

肝移植术后早期血流动力学及氧代谢的变化

目的 观察原位肝移植术后早期全身血流动力学及氧代谢的变化，并探讨与术后早期预后的相关关系。方法 29例终末期肝病的患者接受了首次原位肝移植术。所有病例均于术中放置Swan-Ganz导管，术后48h内，每8h监测1次心率（HR）、平均动脉压（MAP）、心输出量（CO）、肺动脉压（PAP）、肺动脉楔压（PAWP）、中心静脉压（CVP）、全身血管阻力（SVR）、肺血管阻力（PVR）、左室每搏作功指数（LVSWI）、右室每搏作功指数（RVSWI）及氧供（DO2）、氧耗（VO2）、氧摄取率（O2Ext)、静脉血氧饱和度（SvO2)。对这些数据进行回顾性的分析并比较存活与死亡病例的差异。结果 存活者与死亡者术后均呈现持续高的CO、DO2、VO2及SvO2；低的SVR、O2Ext。术后24h HR开始明显下降，而MAP、CVP则明显增加；LVSWI自术后16h开始增加。存活者术前急性生理慢性健康评分（APACHEⅡ）低于死亡者；HR下降更明显；LVSWI高于死亡者；MPAP低于死亡者。结论 肝移植患者术后早期仍存在一定的高动力循环状态，同时全身氧供和氧耗明显增加，组织摄取氧的能力存在一定障碍；死亡者术前疾病的严重程度明显高于存活者，心脏储备能力差，术后早期存在心功能不全。     

亚甲蓝对感染性休克患者术中氧代谢的影响

目的 探讨亚甲蓝对感染性休克患者术中氧代谢的影响.方法 行急诊手术的感染性休克患者40例,ASA分级Ⅱ或Ⅲ级,年龄38～64岁,体重48～75 kg,随机分为2组(n=20):去甲肾上腺素组(NE组)和亚甲蓝组(MB组).人室后NE组静脉输注去甲肾上腺素0.5～2.0μg·kg-1·min-1至术毕,MB组静脉输注亚甲蓝0.5～1.0 mg·kg-1·h-1至术毕.静脉注射咪达唑仑-依托咪酯-舒芬太尼-维库溴铵麻醉诱导,经口气管插管行机械通气,术中吸入七氟醚,间断静脉注射维库溴铵和舒芬太尼维持麻醉.于麻醉诱导前(T0)、手术开始前(T1)、手术开始后30 min(T2)、60 min(T3)、90 min(T4)及术毕时(T5)记录HR、SvO2、MAP、CVP、每搏量,计算外周血管阻力指数(SVRI)、CI.于上述时点采集桡动脉和颈内静脉血样行血气分析,并测定动脉血乳酸(Lac)浓度,计算氧供指数(DO2I)、氧耗指数(VO2I)和氧摄取率(ERO2).结果 与NE组比较,MB组MAP、HR、CVP、SVRI、DO2I、VO2I和ERO2升高,CI和Lac降低(P＜0.05).与T0时比较,T2～5时MB组MAP、HR、CVP、SVRI、VO2I、DO2I和ERO2升高,CI和Lac降低,NE组CI和Lac降低,SVRI、VO2I和ERO2升高(P＜0.05),DO2I差异无统计学意义(P＞0.05).结论术中应用0.5～1.0 mg·kg-1·h-1亚甲蓝不仅可改善感染性休克患者术中血液动力学,还可改善机体氧代谢.     

非转流下原位肝移植术中患者氧代谢的变化

目的 观察非转流下原位肝移植术中患者氧代谢的变化。方法 21例拟行原位肝移植术的终末期肝病患者,采用静吸复合全身麻醉,无肝期不接受体外转流。麻醉前行双侧桡动脉穿刺置管以备采动脉血和监测动压脉,经右颈内静脉放置Swan-Ganz导管测中心静脉压(CVP)、肺动脉平均压(PAP)、肺毛细血管嵌锲压(PCWP),麻醉诱导后经鼻向胃内置入14F TRIP-NGS导管,监测胃粘膜二氧化碳分压(PgCO2)。分别于全麻诱导后30 min(T0)、门静脉阻断即刻(T1)、门静脉开放后5 min(T2)、门静脉开放后90min(T3)和关腹时(T4)用热稀释法测定心输出量(CO),计算心脏指数(CI)、心搏量指数(SVI)、外周血管总阻力指数(SVRI)、肺血管总阻力指数(PVRI),同时取桡动脉血和肺动脉血作血气分析,记录血液动力学指标、PgCO2,计算氧供(DO2)、氧耗(VO2)、氧供指数(DO2I)、氧耗指数(VO2I)、氧摄取率(ERO2)、胃粘膜内pH值(pHi)、胃粘膜及动脉血二氧化碳分压差(Pg-aCO2)。结果与T0比较,T1-4时心率增快(P<0 01),T1时MAP、CVP、PCWP、PAP、CO、CI和SVI下降,SVRI升高(P<0.05或0.01),T2时PAP、PCWP、CO、CI上升(P<0.05),T3时MAP、SVI下降(P<0.05),T1时DO2、DO2I下降,ERO2增高(P<0.01),T4时VO2、VO2I增加(P<0.05),T1-4时pHi下降(P<0.01),T1和T2时PgCO2、Pg-aCO2增高     

非体外循环冠状动脉搭桥手术的麻醉方法及血液动力学和氧代谢的变化

目的 观察非体外循环冠状动脉搭桥手术的麻醉方法、术中病人血液动力学和氧代谢的变化以及术后病人的早期.非体外循环冠状动脉搭桥手术闰人20例，麻醉用咪唑安定0.1-0.2mg/kg、芬太尼15－30μg/kg及0.5%-2%的吸入麻醉药等，在切皮前、开心包后、心脏操作中、操作完成后10min及术毕观察血液动力学指标及脑氧饱和度，同时采集桡动脉和肺动脉血，测定血气及动脉血乳酸（ABL），计算氧供DO2）、氧耗（VO2）和氧摄取率（ERO2）。术后早期观察术后拔除气管插管、ICU停留及术后住院时间、并发症及死亡等情况。结果 心脏操作中MAP、SV、SI下降，HR、CVP升高，MAP下降以搭回旋支时最明显（P＜0.01），HR升高以搭右冠时最明显（P＜0.01）；心脏操作中DO2降低（P＜0.05），VO2无变化，ERO2升高（P＜0.01）；操作后DO2、ERO2恢复至操作前水平；操作后ABL升高（P＜0.01）。结论 本组麻醉方法使病人完全度过非体外循环搭桥术，在心脏操作期易出现血压、每搏量、心指数下降，伴心率、静脉压升高，但时间短暂无严重后果，氧代谢紊乱及缺氧程度较轻。     

不同阿片类药物对婴幼儿紫绀型先天性心脏病氧供氧耗的影响

目的 比较舒芬太尼和芬太尼对紫绀型心脏病婴幼儿氧代谢的影响.方法 紫绀型先天性心脏病患儿48例,随机均分为舒芬太尼和芬太尼两组,分别采用以舒芬太尼1 μg/kg诱导,2～3μg·kg-1·h-1维持(S组)为主和芬太尼10μg/kg诱导,20～30 μg·kg-1·h-1维持为主(F组)麻醉.分别于术前(T1)、心肺转流(CPB)结束后(T2)、术后4 h(T3)和术后24 h(T4)测定心排血量(CO)、混合静脉氧饱和度(SvO2)、混合静脉氧含量(CvO2),并计算出心排指数(CI)、氧供指数(DO2I)、氧耗指数(VO2I)、氧摄取率(ERO2),测定动脉血乳酸(Lac)含量.结果 与T1时比较,两组T2、T3时VO2 I显著升高(P<0.05),同时T2时DO2I升高、ERO2明显增加(P<0.05或P<0.01).S组VO2UI及ERO2的升高幅度小于F组(P<0.05).F组T3、T4时CI及DO2I明显低于S组(P<0.05).T2、T3时两组Lac均较T1时升高(P<0.01),T3、T4时F组较S组升高明显(P<0.05).两组SvO2均有下降趋势.结论 舒芬太尼复合麻醉可改善紫绀型先天性心脏病患儿术后氧代谢障碍.     

混合静脉血氧饱和度反映非体外循环冠状动脉旁路移植术中CO变化的准确性

目的 评价混合静脉血氧饱和度(S(-v)O2)反映非体外循环冠状动脉旁路移植(OPCABG)术中CO变化的准确性.方法 择期行OPCABG的病人25例,年龄50～75岁,体重55～85 kg,NYHA心功能分级Ⅰ～Ⅲ级.静脉注射咪达唑仑、芬太尼、哌库溴铵和依托咪酯麻醉诱导,气管插管后行机械通气.麻醉诱导后,右颈内静脉置入漂浮导管,监测S(-v)O2和CI.静脉注射芬太尼和哌库溴铵,静脉输注异丙酚,必要时吸入异氟醚维持麻醉.于切皮前、吻合冠状动脉前降支(LAD)、吻合右冠状动脉(RCA)、吻合左冠状动脉回旋支(LCX)和关胸时,记录S(-v)O2、CI和Hb,计算氧耗指数(VO2I)、氧供指数(DO2I)和氧摄取率(ERO2).于体位改变前即刻、头低位时、搬动心脏时和固定心脏后,记录S(-v)O2和CI.结果 各时点VO2I和Hb比较差异无统计学意义(P＞0.05);S(-v)O2、CI和ERO2于吻合RCA时降低,吻合LCX时降至最低,关胸时恢复至切皮前水平(P＜0.05);DO2I于吻合RCA和吻合LCX时降低,关胸时恢复至切皮前水平(P＜0.05).吻合RCA前和吻合LCX前,与体位变化前比较,头低位/头低右侧位时S(-v)O2升高(P＜0.05);与头低位/头低右侧位时比较,搬动心脏时S(-v)O2降低(P＜0.05);与搬动心脏比较,固定心脏后S(-v)O2升高(P＜0.05);各体位时CI差异无统计学意义(P＞0.05).结论 OPCABG术中病人体位、心脏位置瞬间改变和固定心脏时,S(-v)O2可实时、准确地反映CO的变化.     

1,6-二磷酸果糖对心肺转流期间氧代谢的影响

目的研究1,6-二磷酸果糖(FDP)对心肺转流(CPB)手术期间氧代谢的影响。方法随机将24例CPB手术病人均分成研究组(A组)和对照组(B组)。A组于转机前静滴FDP200mg/kg,B组于转机前滴入等量生理盐水,观察麻醉后(T1)、CPB前(T2)、升主动脉开放后10min(T3)、停CPB后10min(T4)、停CPB后60min(T5)的氧供(DO2)、氧耗(VO2)、氧摄取率(ERO2)及动脉血乳酸(ABL)的变化。结果两组T3时DO2明显降低(P<0.05),T3时A组ERO2和B组VO2、ERO2及两组T4、T5时VO2、ERO2明显增加(P<0.05或P<0.01),T3、T4和T5时ABL明显增加(P<0.01);B组T3、T4和T5时VO2、ERO2、ABL明显高于A组(P<0.05)。结论FDP对改善CPB手术期间氧供需平衡障碍有明显作用。     

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.     

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.     

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.