急性等容血液稀释联合低中心静脉压对肝癌手术脑氧代谢的影响

目的观察急性等容血液稀释(ANH)联合低中心静脉压(LCVP)在肝癌手术中对患者脑氧代谢的影响。方法拟行肝癌手术患者40例,随机均分为两组。ANH+LCVP组全麻后先进行ANH,然后进行LCVP控制,在肝脏实质完全离断前CVP控制在0～5cmH2O,肝实质切除止血彻底后将CVP恢复至7～8cmH2O;常规治疗组手术中CVP维持在7～8cmH2O。分别于入室后(T0)、采血后5min(T1)、肝癌切除后5min(T2)、恢复容量后5min(T3)抽取动脉、颈内静脉球部的血作血气分析,检测动脉、颈内静脉血氧饱和度(SaO2、SjvO2)、动脉、颈内静脉血氧分压(PaO2、PjvO2)、Hb和Hct,并计算动脉、颈内静脉球部血氧含量(CaO2、CjvO2)、脑氧摄取率(CERO2)、动脉、颈内静脉球部血氧含量差(Da-jvO2)和乳酸差(VADL)。结果与T0时比较,T2、T3时两组Hb、Hct值明显降低(P<0.05),T1～T3时ANH+LCVP组SjvO2明显升高(P<0.05),CERO2、Da-jvO2明显降低(P<0.05),T2、T3时常规治疗组CERO2、Da-jvO2明显降低(P<0.05)。与T2时比较,T3时ANH+LCVP组Hb、Hct值明显升高(P<0.05),常规治疗组明显下降(P<0.05)。与常规治疗组比较,ANH+LCVP组T1、T2时Hb、Hct值明显降低、而T3时明显升高(P<0.05),T1～T3时SjvO2、T3时Da-jvO2明显升高(P<0.05);而T1时Da-jvO2明显降低(P<0.05)。结论急性等容血液稀释联合低中心静脉压技术可以安全应用于肝癌手术中,对脑氧代谢无明显不良影响。     

硬膜外复合全身麻醉下急性高容量血液稀释对手术病人脑代谢的影响

目的 探讨硬膜外复合全身麻醉下急性高容量血液稀释对手术病人脑代谢的影响。方法 选择ASAⅠ或Ⅱ级择期手术病人14例，采用硬膜外阻滞复合全身麻醉，诱导后行右侧颈内静脉球部置管，呼气末异氟醚浓度稳定在1．2％时，经硬膜外导管注入1．33％利多卡因＋0．167％地卡因10ml后开始血液稀释，静脉输入6％羟乙基淀粉20ml／kg，速率50ml／min，分别于稀释前即刻（T0）、稀释后15min（T1）、120min（T2）采取桡动脉和颈内静脉球血，分别进行血气分析、乳酸、血糖、红细胞比容及血红蛋白（Hb）测定，计算动脉一颈内静脉球血血氧含量差[D（a-jv）O2]、脑氧摄取率（CERO2）、脑葡萄糖摄取率（CMRGlu）、动脉一颈内静脉球血乳酸浓度差。结果 与T0比较，T1时颈内静脉球部血氧饱和度（SjvO2）上升，D（a-jv）O2、CERO2下降，T2时D（a—jv）O2下降，T1.2Hb降低（P〈0．05），其余各指标差异无统计学意义。结论 硬膜外复合全身麻醉下急性高容量血液稀释可增加脑氧供应，维持脑氧和能量代谢的稳定。     

不同程度急性等容量血液稀释对家兔血清S-100B蛋白浓度和脑氧代谢的影响

目的 探讨常温下不同程度急性等容量血液稀释(ANH)对家兔血清S-100B蛋白浓度和脑氧代谢的影响.方法 健康成年家兔32只,体重2～2.5 kg,随机分为4组(n=8),对照组(Ⅰ组)不行血液稀释;其余3组血液稀释的目标红细胞压积(Hot)分别为24%(Ⅱ组)、18%(Ⅲ组)、12%(Ⅳ组).麻醉下气管插管后行机械通气,维持体温37℃左右.左颈动脉和左颈内静脉穿刺并置管,用于监测血压、采血和血气分析.右颈内静脉穿刺并置管,用于监测中心静脉压.股动脉放血,同时Ⅱ组～Ⅳ组股静脉经30 min输注等量6%羟乙基淀粉200/0.5行ANH至目标Hct.于动脉、静脉穿刺并置管稳定20 min(To)、ANH后2、4、8 h(T1～T3)时,记录血液动力学指标;分别采集左颈动脉和左颈内静脉血样各0.1 ml,行血气分析,计算脑氧摄取率(CERO2);颈动脉取血样,采用ELISA法测定血清S-100B蛋白浓度.ANH后8 h时处死动物,取右侧脑组织,称湿重和干重,计算脑含水量.结果 与T0时比较,Ⅲ组T3时、Ⅳ组T1～T3时CERO2和血清S-100B蛋白浓度升高(P<0.05);Ⅰ组和Ⅱ组各时点CERO2和血清S-100B蛋白浓度比较差异无统计学意义(P>0.05);与Ⅰ组和Ⅱ组比较,Ⅲ组T3时、Ⅳ组T1～T3时CERO2和血清S-100B蛋白浓度升高(P<0.05);与Ⅲ组比较,Ⅳ组T1～T3时CERO2和血清S-100B蛋白浓度升高(P<0.05).各组问脑含水量比较差异无统计学意义(P>0.05).结论 常温下ANH目标Hct为24%时,对家兔脑氧代谢无影响;目标Hct≤18%时,发生脑氧代谢失衡和脑损伤.     

不同程度血液稀释对家兔脑氧代谢的影响

目的 观察不同程度急性等容性血液稀释对常温下家兔脑氧代谢的影响.方法 32只成年家兔,随机均分为A、B、C、D四组,A、B、C三组的目标Hct分别为24%、18%、12%;D组为对照组,不行血液稀释.以20%乌拉坦行静脉麻醉后机械通气,并维持体温在37℃.监测血液稀释前后的动、静脉血气,并根据Fick's公式计算出脑氧代谢率(CERO2).结果 A组各时点CERO2与D组比较差异无统计学意义,B组CERO2在血液稀释后8 h较基础值增高,而C组CERO2在血液稀释后2、4、8 h均较基础值增高.结论 血液稀释目标Hct为24%时.对常温、有创条件下家兔脑氧代谢并无影响;日标Hct为18%时,在血液稀释后8 h可以出现CERO2增高,且血液pH值明显降低;血液稀释至Hct为12%时则不能满足脑氧代谢需求.     

急性高容量血液稀释联合瑞芬太尼控制性降压对颅内动脉瘤术患者血流动力学和脑氧代谢的影响

目的 观察颅内动脉瘤夹闭术患者在急性高容量血液稀释(AHH)联合瑞芬太尼控制性降压(CH)后血流动力学和脑氧代谢的变化,评价其可行性.方法 选择颅内动脉瘤夹闭术患者40例,随机均分为硝酸甘油组(A组)和瑞芬太尼组(B组).手术开始时以15～20 ml·kg-1·h-1的速率输入4％琥珀酰明胶,使Hct稀释为25％～32％.在剪开硬脑膜后行CH,A组泵入硝酸甘油1～5 μg·kg-1 ·min-1;B组泵入瑞芬太尼12～30 μg·kg-1·h-1,使MAP维持在60～65 mm Hg,动脉瘤夹闭后10 min停止CH.记录两组患者AHH前(T0)、AHH后(T1)、降压前(T2)、降压后30 min(T3)、动脉瘤夹闭后5 min(T4)的MAP、HR、Hb和Hct,分别于T2～T4时采集颈内静脉球部血和桡动脉血作血气分析,检测动、静脉血氧饱和度(SaO2、SjvO2)、动、静脉血氧分压(PaO2、PjvO2)、Hb和Hct,计算动脉氧含量(CaO2)、颈内静脉氧含量(CjvO2)、动脉颈内静脉球部血氧差(Da-jvO2)、颈内静脉球部动脉乳酸差(VADL)和脑氧摄取率(CERO2).结果 与T0时比较,T1～T4时两组Hb和Hct均显著降低(P＜0.01).与T2时比较,T3、T4时两组MAP明显降低,A组HR明显增快,B组的HR明显减慢(P＜0.01);T3、T4时B组SjvO2和CjvO2明显高于T2时和A组,Da-jvO2和CERQ明显低于T2时和A组(P＜0.01).结论 AHH联合瑞芬太尼CH用于颅内动脉瘤夹闭术中,不但维持血流动力学的相对稳定,而且明显降低脑氧代谢率,较AHH联合硝酸甘油CH更具优越性.     

单肺通气期间七氟醚或丙泊酚对脑氧代谢的影响

目的观察单肺通气期间七氟醚或丙泊酚联合靶控持续输注瑞芬太尼对脑氧代谢的影响。方法选择行肺叶切除术患者30例,随机分为七氟醚组（S组）或丙泊酚组（P组）,每组各15例。麻醉诱导后,分别持续吸入七氟醚1%-2.5%或静脉持续泵入丙泊酚4-8 mg/（kg.h）。于双肺通气15 min（T1）,单肺通气15 min（T2）,单肺通气30 min（T3）,恢复双肺通气之后15min（T4）时点记录HR、MAP及BIS值,同时采集桡动脉、颈内静脉球血行血气分析,测定颈静脉球氧饱和度（SjvO2）,并计算脑动静氧含量差（AjvDO2）及COER值。结果两组在T2、T3时点的PaO2值较T1时点明显降低（P〈0.05）;S组各时点的SjvO2值、AjvDO2值、COER值与P组相应时点比较,无统计学差异（P〉0.05）。结论单肺通气过程中七氟醚与丙泊酚联合瑞芬太尼均能够达到满意麻醉效果,并保持脑氧供需平衡。     

右美托咪定对小儿先天性心脏病体外循坏术中脑氧代谢及近远期认知功能的影响

目的 探讨右美托咪定(dexmedetomidine,Dex)对小儿先天性心脏病(congenital heart disease,CHD)CPB术中脑氧代谢及近远期认知功能的影响. 方法 择期行CPB手术的CHD患儿84例,采用随机数字表法分为观察组和对照组(每组42例).观察组麻醉诱导后予以吸入2.5％七氟醚及Dex 0.4 μg· kg-1·h-1术中维持麻醉,对照组麻醉诱导后予以吸入2.5％七氟醚维持麻醉,分别在患儿CPB开始前(T1)、升主动脉开放时(T2)、CPB结束10 min(T3)、术后6 h(T4)4个时间点分别采集3 ml的桡动脉及静脉球部血样进行血气分析,计算颈内静脉血氧饱和度(jugular venous oxygen saturation,SjvO2)、动脉-颈内静脉血氧含量差值(arterial venous oxygen content difference,Da-jvO2)以及脑氧摄取率水平(cerebral extraction of oxygen,CERO2),并在术前、术后3d、术后3个月、术后1年行简易智力状况调查(mini-mental state examination,MMSE)评分. 结果 两组患儿T2时SjvO2高于T1时,而Da-jvO2、CER02低于T1时,差异有统计学意义(P＜0.05);T2时观察组SjvO2高于对照组,而Da-jvO2、CER02低于对照组,差异有统计学意义(P＜0.05),而T3、T4时两组患儿SjvO2、Da-jvO2、CERO2的差异无统计学意义(P＞0.05).两组患儿术前MMSE评分差异无统计学意义(P＞0.05);观察组术后4d和术后3个月的MMSE评分[(26.5±1.5)、(27.6±1.6)分]显著高于对照组[(24.3±1.3)、(25.8±1.5)分],差异有统计学意义(P＜0.05);两组术后1年的MMSE评分差异无统计学意义(P＞0.05). 结论 小儿CHD CPB术中应用Dex具有一定的脑保护作用,能改善脑氧代谢以及术后短期认知功能.     

胃减容术3种机械通气对患者氧合情况的比较

目的：探讨病态肥胖患者行腹腔镜胃减容术时，3种机械通气参数对患者氧合情况的影响。方法：选择行腹腔镜胃减容术的病态肥胖24例，按手术时间顺序分为3组，每组8例。A组：潮气量12ml／kg，呼吸频率10次／min；B组：潮气量20ml／kg，呼吸频率10次／min；C组：潮气量12ml／kg，呼吸频率20次／min。分别于气腹前（T1）、气腹后（T2）抽取动脉血测量pH、PO2、PCO2、Plat（平台压）、Peak（峰压）、AaDO2（肺泡-动脉氧分压差）。结果：气腹后B组Plat（33．2±1．8）cmH2O、Peak（36．3±1．6）cmH2O显著高于A组Plat（29．5±3．9）cmH2O（q=3．053，P〈0．05）、Peak（33．0±2．9）cmH2O（q：2．823，P〈0．05）和C组Plat（28．0±4，1）cmH2O（q：4．290，P〈0．05）、Peak（31．8±2．8）cmH2O（q：4．704，P〈0．05）。其他观察指标无统计学差异。结论：病态肥胖患者在腹腔镜下施行胃减容术时，加大潮气量20ml／kg或加快呼吸频率20次／min不能改善患者的氧合情况。     

过度通气对糖尿病病人脑氧供需平衡的影响

目的研究过度通气对手术中糖尿病病人脑氧供需平衡的影响。方法择期全麻下行腹部手术病人30例,2型糖尿病组15例(DM组),非糖尿病组15例(对照组,C组),所有病人术中均随机分别进行三种不同模式机械通气：正常通气量通气[模式I,动脉血二氧化碳分压(PaCO2)维持在35～40mmHg]、轻度过度通气(模式Ⅱ,PaCO2维持在30～35mmHg)、中度过度通气(模式Ⅲ,PaCO2维持在25～30mmHg),检测两组病人在三种不同通气模式下动脉血氧饱和度(SaO2)、动脉血氧分压(PaO2)、动脉血乳酸盐浓度(ABL)、颈内静脉血氧饱和度(SjvO2)、颈内静脉血氧分压(PjvO2)和颈内静脉血乳酸盐浓度(JVBL),并计算病人在不同通气模式下动脉血氧含量(CaO2)、颈内静脉血氧含量(CjvO2)、氧摄取率(CERO2)和颈内静脉与桡动脉血乳酸差(DL A-v)。结果两组病人CjvO2和SjvO2在以模式Ⅲ通气时均明显低于以模式Ⅰ通气,CERO2在模式Ⅲ通气时明显高于以模式Ⅰ通气。DM组病人JVBL和DI A—v在模式Ⅲ通气时均明显高于以模式Ⅰ通气。中度过度通气时,DM组病人DL A-v高于C组。结论中度过度通气可影响2型糖尿病病人脑氧供需平衡,导致大脑组织乏氧代谢增加。     

盐酸戊乙奎醚对多器官功能障碍综合征病人脑氧供需平衡的影响

目的观察盐酸戊乙奎醚对多器官功能障碍综合征(MODS)病人脑氧供需平衡的影响。方法选择50例发病前无肝脑功能障碍由外科疾病并发MODS的病人,按数字随机法分为观察组(T组,n=35):除综合治疗外,另予盐酸戊乙奎醚2 mg,q12 h,肌注,首量加倍;对照组(C组,n=15):除未使用盐酸戊乙奎醚外,其余治疗方案同T组。监测MODS期间病人动脉血氧含量(CaO2)、颈内静脉血氧饱和度(SjvO2)、氧含量(CjvO2)及动脉和颈内静脉血乳酸盐含量(ABL和JVBL),并计算脑氧摄取率(CERO2),桡动脉颈内静脉血乳酸盐差值(DLA-V)。结果与30 min时比较,C组CjvO2、SjvO2、ABL、JVBL、DLA-V进行性增高,CERO2进行性降低(P<0.05,P<0.01)。与C组比较,T组肌注盐酸戊乙奎醚后48、72 h时CjvO2、SjvO2、ABL、JVBL、DLA-V显著降低,CERO2显著增高(P<0.05,P<0.01)。结论MODS状态下,存在以组织缺氧为主的脑氧供需失衡;盐酸戊乙奎醚可明显改善脑组织缺氧,从而纠正脑氧供需失衡。     

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.