异氟醚-芬太尼静吸复合全麻下妇科腹腔镜手术对脑能量代谢及氧供需平衡的影响

目的观测异氟醚-芬太尼静吸复合全麻下妇科腹腔镜(GL)手术过程中脑能量代谢及氧供需平衡的变化。方法15例行GL手术病人,观察麻醉前、气腹前、气腹后10、20和60 min时的动脉血二氧化碳分压(PaCO2)、颈内静脉球部血氧分压(PjvO2)、血氧饱和度(SjvO2)、血氧含量(CjvO2)、脑动-静脉血氧含量差(Ca-jvDO2)和动、静脉血糖(GluA、GluV)、乳酸(LacA、LacV)及差值(GluA-V、LacA-V)的变化。结果(1)与麻醉前比较,气腹前SjvO2、CjvO2和Ca-jvDO2变化差异无显著意义,气腹后各时间段较气腹前的SjvO2和PjvO2显著升高(P<0.05),而Ca-jvDO2显著降低(P<0.05);(2)与气腹前比较,麻醉前LacA、LacV和LacA-V均有明显降低(P<0.05),气腹后LacA和LacV显著升高(P<0.05);(3)气腹前GluA、GluV和GluA-V与麻醉前比较差异无显著意义,气腹后GluA和GluV极显著升高(P<0.01),而GluA-V有减小趋势,气腹后60 min明显低于其他时间段(P<0.01)。结论异氟醚-芬太尼静吸复合全麻对脑氧供需平衡无明显影响,而在头低足高截石位下行GL手术时对于病人的脑氧供需平衡和能量代谢影响显著。     

后腹腔镜手术CO2气腹对脑氧供需平衡的影响

目的探讨后腹腔镜CO2气腹对脑氧供需平衡的影响. 方法选择后腹腔镜下肾及肾上腺肿瘤切除术20例,ASAⅠ～Ⅱ级,分别于气腹前,气腹后10、30、60 min和关气腹后30 min,抽取颈静脉球血和桡动脉血进行血气分析,比较不同时点动脉血PH(aPH )、颈静脉球PH(jvPH)、动脉血二氧化碳分压(PaCO2)、动脉血糖(aGS)、动脉血乳酸(aLac)、颈内静脉血氧分压(PjvO2)、颈内静脉血氧饱和度(SjvO2)、颅内动静脉氧含量差(AjvDO2)、颈内静脉血二氧化碳分压(PjvCO2)、血糖(jvGS)和乳酸(jvLac)的变化. 结果与气腹前比较,气腹后各时间点aPH、jvPH显著降低(P＜0.05);PaCO2、PjvCO2气腹后各时间点与气腹前相比显著升高(P＜0.05);AjvDO2气腹后各时点与气腹前相比显著下降(P＜0.05);jvLac气腹后各时间点与气腹前相比有降低趋势,但无统计学差异(P＞0.05);aGS、 jvGS气腹前后无显著变化(P＞0.05). 结论后腹腔镜手术期间,脑血流量显著增加,未发现脑无氧代谢增加的证据.     

不同麻醉对腹腔镜胆囊切除术患者二氧化碳气腹时脑氧合的影响

目的 观察不同麻醉对腹腔镜胆囊切除术患者二氧化碳气腹时脑氧合的影响。方法 腹腔镜胆囊切除术患者60例，ASAⅠ级或Ⅱ级，随机分为3组（n=20）：异氟醚组（Ⅰ组）、硬膜外复合异氟醚组（Ⅱ组）和硬膜外复合异丙酚组（Ⅲ组）。分别于气腹前即刻、气腹10、30min取桡动脉血和颈内静脉球部静脉血行血气分析，记录动脉血氧分压（PaO2）、动脉血二氧化碳分压（PaCO2）、动脉血氧饱和度（SaO2）、血红蛋白（Hb）浓度、颈内静脉血氧分压（PjvO2）和颈内静脉血氧饱和度（SjvO2）。根据Fick公式分别计算脑动脉和颈内静脉血氧含量及脑动静脉血氧含量差（Da-jvO2）。结果 与气腹前即刻比较，Ⅰ组、Ⅱ组气腹10、30min时SjvO2升高、Da-jvO2降低（P〈0．01）;与Ⅲ组比较，气腹10、30min时Ⅰ组、Ⅱ组SjvO2升高、Da-jvO2降低（P〈0.05）;与Ⅱ组比较，气腹10、30 min时Ⅰ组SjvO2升高、Da-jvO2降低（P〈0．05）。结论 硬膜外复合异丙酚静脉麻醉可改善术中脑组织的氧合，是腹腔镜手术患者较适宜的麻醉方法。     

低水平呼气末正压通气对全身麻醉腹腔镜胃癌根治术患者脑血流动力学的影响

目的 观察呼气末正压通气对全身麻醉腹腔镜胃癌根治术患者脑血流动力学的影响.方法 择期行全身麻醉腹腔镜胃癌根治术的患者80例,美国麻醉医师协会(ASA)分级Ⅰ～Ⅱ级,采用随机数字表法分为A、B组,每组40例.A组通气参数:潮气量(VT)8ml/kg,呼吸频率(RR) 12次/分,呼气末正压(PEEP)5 cmH2O(1 cmH2O=0.098 kPa).B组通气参数:VT 8 ml/kg,RR 12次/分.于气腹前(T0)、气腹后30 min(T1)、气腹后1 h(T2)、气腹后2h(T3)时记录大脑中动脉平均血流速度(Vm)、平均动脉压(MAP)、心率(HR)、经皮测血氧饱和度(SpO2)、呼气末二氧化碳分压(PetCO2)变化,分别抽取各时点桡动脉血、颈内静脉球部血进行血气分析,记录动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)、动脉血氧饱和度(SaO2)、血红蛋白(Hb)浓度;颈内静脉血氧分压(PjvO2)和颈内静脉血氧饱和度(SjvO2),根据Fick公式分别计算脑动脉和颈内静脉血氧含量(CjvO2)及其差值(Da-jvO2).结果 与气腹前比较,两组气腹后Vm、SjvO2、PaCO2在各时间点明显升高(P＜0.05).但是A组Vm、SjvO2、PaCO2的上升趋势较B组更为缓和,A组PaCO2在T1、T2分别为(35.5±2.7)、(40.7±3.5)mmHg,明显低于B组的(39.9±3.1)、(49.4±4.7)mmHg(P＜0.05),而Vm在T3为(68.9±8.1)cm/s,明显低于B组的(87.9 ±9.6) cm/s(P ＜0.05).与气腹前比较,气腹后2h两组Da-jvO2明显下降(P＜0.05),组间比较,A组下降幅度明显大于B组(P＜0.05).结论 低水平呼气末正压通气对全身麻醉腹腔镜胃癌根治术患者手术期间能有效降低术中的高二氧化碳血症,维持患者脑血流动力学的稳定,从而改善脑的过度灌注状态,改善患者的脑血流量和脑氧供需平衡.     

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。     

改良抬胸Trendelenburg位对腹腔镜结直肠癌根治术老年患者脑氧代谢和早期术后认知功能的影响

目的 观察改良抬胸位对腹腔镜结直肠癌根治术老年患者的脑氧代谢和早期术后认知功能的影响.方法 择期拟行腹腔镜结直肠癌根治术患者80例,年龄60～82岁,体重44～69 kg,ASA分级Ⅰ、Ⅱ级,性别不限,按随机数字表法分为2组(每组40例):M组加用定制体位垫使患者呈改良抬胸Trendelenburg体位(简称T位),T组采用T位.于常规全身麻醉插管后平卧位5 min(T1),气腹改良抬胸T位/T位即刻(T2)、30 min(T3)、60 min(T4)和90 min(T5),气腹放气平卧位15 min(T6),分别采集桡动脉和颈静脉球血样,记录血气分析、血糖、乳酸值及MAP等,计算脑动静脉氧含量差(arteriovenous O2 content difference,Ca-jv DO2)及脑葡萄糖摄取(arteriovenous O2 glucose difference,Da-jvglu)等;并于麻醉前,麻醉结束后2、6、24、48、72 h时,采用简易智能量表(mini-mental state exam,MMSE)进行认知功能评分.结果 与T1时比较,两组患者动脉血二氧化碳分压(arterial partial pressure carbon dioxide,PaCO2)在T3-6时均显著升高,MAP在T2时显著降低,两组患者在T3～5时颈静脉球血氧分压(jugular venous partial pressure oxygen,PjvO2)显著升高,T4-5时颈静脉球血氧饱合度(jugular venous oxygen saturation,SjvO2)显著升高(P＜0.05);M组MAP在T4-6时显著升高,T组在T3-6时显著升高(P＜0.05);T组在T6时SjvO2[(75±9)％]显著升高,T5时Caa-jvDO2[(5.2±1.5)％]显著下降,而颈静脉球血乳酸(jugular venous lactate,Lacjv)[(2.0±0.5) mmol/L]显著上升(P＜0.05).与T组比较,M组MAP在T4-6时上升较慢,Ca-jvDO2[(5.9±1.6)％]在T5时无明显下降,Da-jvglu气腹前后差异无统计学意义(P＞0.05),SjvO2 [(75±9)％]和Lacjv[(1.5±0.5) mmol/L]无显著上升,而PaCO2[(34±3) mmHg(1 mmHg=0.133 kPa)]在T6时显著降低(P＜0.05).与T组比较,M组麻醉结束后6、24 h时MMSE评分明显较高;与麻醉前比较,麻醉结束后2h两组MMSE评分显著降低(P＜0.05).结论 改良抬胸T位缓解了气腹后期脑氧供需失衡,麻醉结束后24 h内认知功能下降的发生率明显降低,有利于较长时间手术的安全.     

高渗氯化钠羟乙基淀粉40注射液对中重度创伤性脑损伤手术患者的脑保护作用

目的探讨高渗氯化钠羟乙基淀粉40注射液(HSH40)对中重度创伤性脑损伤(TBI)手术患者的脑保护作用。方法选择脑外伤手术患者60例,格拉斯哥昏迷评分(glasgow coma scale,GCS)8~10分,随机均分为:HSH40组和甘露醇组,打开硬脑膜前30 min分别输注HSH405ml/kg和甘露醇5ml/kg。记录液体输注前(T0)、输注结束后30 min(T1)、60 min(T2)、120 min(T3)的PaO2、SaO2、动脉血红蛋白含量(Hba)、颈内静脉球氧分压(PjvO2)、颈内静脉球氧饱和度(SjvO2)、颈内静脉球血红蛋白含量(Hbv)。根据Fick公式计算动脉血氧含量(CaO2)、颈内静脉血氧含量(CjvO2)、脑动脉-颈内静脉球氧含量差(Ca-jvDO2),并计算脑氧摄取率(CERO2);于手术前(a1)、液体输注结束后即刻(a2)、术后2h(a3)、1d(a4)抽取外周静脉血,检测神经损伤标志物S100β蛋白含量。采用GOS量表和Barthel指数评定患者神经功能预后。结果与T0时比较,T2、T3时两组SjvO2明显升高、T1~T3时两组Ca-jvDO2和HSH40组CERO2明显降低(P0.05)。与甘露醇组比较,T2、T3时HSH40组SjvO2明显升高(P0.05);T1~T3时Ca-jvDO2和CERO2明显降低(P0.05)。a3时甘露醇组和a4时两组S100β蛋白含量明显高于a1时(P0.01),且a3时HSH40组S100β蛋白含量明显低于甘露醇组(P0.05),HSH40组Barthel指数评定完全自理和轻度缺陷患者18例(60%),明显高于甘露醇组12例(40%)(P0.05)。中、重度缺陷患者12例(40%),明显低于甘露醇组18例(60%)(P0.05)。结论 HSH40注射液和甘露醇均可减少创伤性脑损伤手术患者的脑组织耗氧和S100β蛋白含量,改善GOS评分及Barthel指数,两者均有脑保护作用,且前者保护作用更为显著。     

腹腔镜胆囊切除术中二氧化碳气腹对脑血流的影响

目的 观察腹腔镜期间二氧化碳气腹对患者脑血流的影响。方法 选择行腹腔镜胆囊切除术患者３０例,ＡＳＡⅠ～Ⅱ级、于气腹前、气腹后１０、３０ｍｉｎ分别采取桡动脉血管颈内静脉血,测定ＰａＯ２、ＰａＣＯ２、ＳａＯ３、颈内静脉血氧分压（ＰｉｖＯ２）和血氧和度（ＳｕｖＯ２）等值。结果与气腹前比较,气腹后１０ｍｉｎ、３０ｍｉｎ的ＳｕｖＯ２、颈内静脉血氧含量（ＣｕｖＯ２）和ＰａＣＯ２无显著性增加（Ｐ〈０．０１）,脑     

地氟醚维持麻醉对S_(jv)O_2和CSFP的影响

目的 :研究地氟醚维持麻醉时PaCO2 对SjvO2 和CSFP的影响。方法 :43例脑肿瘤病人用地氟醚维持麻醉 ,术中持续监测颅内压和动脉压。当人为改变PETCO2 时 ,取颈内静脉血和同步采集动脉血作血气分析和测定两者乳酸含量。结果 :地氟醚浓度 <1MAC时 ,ICP随PaCO2 变化而变化 ,SjvO2 与PaCO2 呈显著正相关 ,低PaCO2 可能增加脑静脉血乳酸含量。地氟醚 >1MAC时 ,SjvO2 与PaCO2 相关性差 ,静脉乳酸含量变化小。正常CPP条件下进行过度通气时 ,SjvO2 值仅与地氟醚浓度呈显著正相关。结论 :神经外科病人用地氟醚维持麻醉时 ,浓度为≤ 1MAC维持脑静脉血氧饱和度对二氧化碳反应性 ,可能具有剂量依赖性脑血管扩张效应。     

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.