低浓度利多卡因对大鼠海马CA1区缺氧神经元持续钠电流的影响

目的观察低浓度利多卡因对大鼠海马CA1区缺氧神经元持续钠电流的影响,探讨其对缺血脑损伤保护作用的机制。方法酶消化法急性分离SD大鼠海马CA1区锥体细胞,随机分为7 组(n=10):缺氧组(C组)、利多卡因1μmol·L-1组(L1组)、3μmol·L-1组(L2组)、6μmol·L-1组(L3组)、10 μmol·L-1组(L4组)、20μmol·L-1组(L5组)、30μmol·L-1组(L6组)。以全细胞膜片钳技术记录各组缺氧前持续钠电流的基础值后,C组以无糖缺氧灌流液、L1-6组以含有不同浓度利多卡因的无糖缺氧灌流液在20 s内快速置换灌流液,建立体外神经元缺氧模型。记录缺氧5 min时各组神经元的持续钠电流。结果与基础值比较,各组神经元在缺氧5 min时持续钠电流均增大(P<0.01)。在缺氧5 min 时,L1-6组持续钠电流均低于C组,L2-6组均低于L1组,L3-6组均低于L2组,L4-6组均低于L3组(P< 0.01)。结论低浓度利多卡因能抑制大鼠海马CA1区神经元缺氧引起的持续钠电流增加,该作用在10 μmol·L-1时达到最大。     

丙泊酚对肺动脉高压大鼠肺动脉的作用及机制

目的观察丙泊酚对肺动脉高压大鼠（pulmonary hypertensive rat,PHR）离体肺动脉环的影响,探讨其机制与ATP敏感性钾通道的关系。方法建立PHR模型。分为丙泊酚组和空白对照组。丙泊酚组：PHR离体肺动脉环以去甲肾上腺素（NE）10μmol／L预收缩血管达最大收缩幅度后,加入丙泊酚10、30、100μmol／L,记录张力变化。空白对照组：加入NE10μmol／L收缩稳定后不给任何药物。给100μmol／L丙泊酚前10min给予格列苯脲5μmol／L,观察肺动脉环张力的变化。结果各浓度丙泊酚组均有舒张PHR肺动脉环的作用,与空白对照组对应时点比较,差异有统计学意义（P〈0．01）。各浓度组之间比较差异有统计学意义（P〈0．01）,浓度越高舒张作用越强。格列苯脲可部分拈抗丙泊酚扩张PHR肺动脉环的作用（P〈0．01）。结论本研究表明丙泊酚对PHR肺动脉有舒张作用,该舒张作用与ATP敏感性钾通道有关。     

异丙酚对内毒素性休克大鼠血管反应性的影响

目的评价异丙酚对内毒素性休克大鼠血管反应性的影响。方法40只雄性SD大鼠随机分为4组(n=10),对照组;休克组:静脉注射内毒素(LPS)15 mg·kg-1;异丙酚组:静脉注射LPS 后1 h,静脉注射异丙酚10 mg·kg-1后10 mg·kg-1·h-1持续静脉泵注4 h;5-甲氧色胺组:静脉注射LPS 后1 h,腹腔注射5-甲氧色胺10 mg·kg-1。注射LPS后6 h,各组大鼠依次静脉注射去氧肾上腺素(PE) 0.5、1、2、2.5 μg·kg-1,记录注药后平均动脉压(MAP)的增幅百分比。注射LPS后6 h,经心内穿刺取血, 测定血浆丙二醛(MDA)及一氧化氮浓度(NO2-/NO3-)。所有在体实验结束后取大鼠胸主动脉环做离体张力实验,建立去氧肾上腺素的剂量-张力反应曲线,并计算相应主动脉环最大收缩张力(Emax)、半数有效浓度(EC50)。结果休克组、异丙酚组、5-甲氧色胺组MAP增幅百分比均低于对照组(P< 0.05),异丙酚、5-甲氧色胺组MAP增幅百分比均高于休克组(P<0.05)。异丙酚组、5-甲氧色胺组血浆MDA及NO2-/NO3-浓度均低于休克组(P<0.05)。在离体实验中,休克大鼠主动脉环对PE反应的Emax及EC50与均低于对照组(P<0.05),但是异丙酚组和5-甲氧色胺组主动脉环对PE的反应均升高(P<0.05)。异丙酚组和5-甲氧色胺组主动脉收缩力均高于休克组,并且主动脉环对PE的Emax增高,EC50降低(P<0.05)。结论异丙酚可能通过减少氧自由基,抑制NO的合成,从而改善内毒素性休克大鼠的血管低反应性。     

舒芬太尼对去甲肾上腺素诱发自发性高血压大鼠离体胸主动脉收缩的影响

目的 探讨舒芬太尼对去甲肾上腺素(NE)诱发自发性高血压大鼠离体胸主动脉收缩的影响.方法 雄性自发性高血压大鼠8只,体重250～300 g,每只大鼠取离体胸主动脉血管环4段,采用随机区组设计,随机分为4组(n=8):生理盐水对照组(NS组)、低浓度舒芬太尼组(7×10-11mol/L,S1组)、中浓度舒芬太尼组(2×10-10 mol/L,S2组)和高浓度舒芬太尼组(1×10-9mol/L,S3组).将血管环悬挂于血管张力测量装置,张力稳定后加入60 mmol/L KCl收缩血管环,记录血管环张力.洗脱KCl后分别加入生理盐水及不同浓度的舒芬太尼各100 μl,20 min后依次加入终浓度为10-8、10-7、10-6、10-5mol/L的NE,使血管充分收缩,记录不同NE终浓度下血管环张力,计算血管环收缩幅度.结果 与NS组比较,S1组、S2组、S3组血管环收缩幅度降低(P<0.05或0.01).与S1组比较,S2组、S3组血管环收缩幅度降低(P<0.01).与S2组比较,S3组血管环收缩幅度降低(P<0.05或0.01).结论 舒芬太尼可抑制NE诱发自发性高血压大鼠离体胸主动脉收缩,且与浓度有关.

Abstract：

Objective To investigate the effect of sufentanil on norepinephrine (NE)-induced contraction of thoracic aorta isolated from rats with spontaneous hypertension (SH) .Methods Eight male rats with SH weighing 250-300 g were used in this study. The rats were decapitated and their thoracic aortas were isolated and cut into rings 2-3 mm in length. The aorta rings were suspended for isometric tension recording. The aortic rings obtained from SH rats were divided into 4 groups ( n = 8 each) : control group and 3 sufentanil groups. The contraction of aortic rings in response to NE in the absence (control) and presence of 3 concentrations of sufentanil 7 × 10-11 ,2 × 10-10 and 1 × 10-9 mol/L was recorded. Results The amplitude of NE-induced contraction of thoracic aorta was significantly greater in 3 sufentanil groups than in control group. Sufentanil significantly inhibited the NE-induced aortic contration in proportion to concentration. Conclusion Sufentanil can inhibit NE-induced contraction of thoracic aorta isolated from rats with SH in a concentration-dependent manner.     

内源性及外源性一氧化氮诱导心肌细胞预适应的延迟保护作用

目的 研究内源性及外源性一氧化氮(NO)是否诱导心肌细胞预适应延迟保护作用及其可能的机制。方法取体外培养的新生大鼠心肌细胞,分为如下各组:(1)阴性对照组(C组);(2)NO供体S-亚硝基-N-乙酰青霉胺(SNAP)500μmol·L-1组;(3)L-精氨酸(L-Arg)1 mmol·L-1组;(4)NOS抑制剂(L-NAME)1 mmol·L-1与L-Arg 1 mmol·L-1共同作用于心肌细胞组(L-NAME L-Arg组);(5)缺氧预适应组(HP组);(6)L-NAME 1 mmol·L-1作用细胞后再行缺氧预适应组(L-NAME HP组);(7)cGMP阻断剂亚甲基蓝(M8)50μmol·L-1加SNAP 500μmol·L-1组;(8)MB 50μmol·L-1加L-Arg 1 mmol·L-1组;(9)MB 50μmol·L-1加HP组;(10)缺氧复氧损伤组(H/R组)。(2)-(9)组细胞在给予干预因素24 h后使细胞经历6 h缺氧及3 h复氧,H/R组不予任何处理直接使其缺氧61h复氧3h。分别检测心肌细胞存活率及乳酸脱氢酶(LDH)活性,以判定心肌细胞损伤程度。结果SNAP处理心肌细胞24 h后使其缺氧复氧损伤减轻,表现为与单纯H/R组细胞比较其LDH活性显著降低,细胞存活率显著提高(P<0.01);缺氧预适应和L-Arg处理细胞24 h后均可显著减轻心肌细胞缺氧复氧损伤(P<0.01),但此作用可被NOS抑制剂L-NAME所拮抗;SNAP、L-Arg和HP减轻缺氧复氧心肌细胞损伤的作用均可被cGMP阻断剂所取消。结论 内     

异丙酚对大鼠缺氧性肺血管收缩反应的影响

目的 观察异丙酚对大鼠缺氧性肺血管收缩(HPV)反应的影响及可能机制。方法 雄性 SD 大鼠，麻醉后取出心肺并制成肺动脉环，给予不同的悬挂初张力，以得到鼠肺动脉环收缩的最适初张力，在此最适初张力下测定肺动脉环的 HPV 反应强度；此后，分别给予不同浓度的异丙酚(1、3、10、30、100μmol/L)测量 HPV 反应强度的变化。测量60mmol/L KCI 引起的肺动脉环收缩强度，并比较异丙酚(10、30μmol/L)预先给药后收缩强度的改变；累计剂量式加入去氧肾上腺素(PE)测量肺动脉环收缩强度，并与异丙酚(10、30μmol/L)预先给药后进行比较。结果 小剂量异丙酚对 HPV 反应无明显影响(P>0.05)，随着剂量的增加对 HPV 的影响加大(P<0.05)。异丙酚呈剂量依赖性抑制肺动脉对 KCl 的收缩反应(P<0.05)。异丙酚抑制肺动脉对 PE 的收缩反应与剂量有关，不仅对 PE 引起的最大收缩反应具有抑制作用，且导致肺动脉对 PE 的敏感性降低。结论 异丙酚剂量依赖性抑制鼠肺动脉环的 HPV 反应，其可能机制是异丙酚对于肺动脉平滑肌细胞内钙的敏感性、内钙释放以及多种钙离子通道的抑制作用。     

硝普钠对高胆固醇血症兔Oddi括约肌运动的影响

目的 观察外源性一氧化氮(NO)供体硝普钠(SNP)对高胆固醇(Ch)血症兔Oddi括约肌(SO)运动的影响及对不同钾离子通道的作用.方法 将24只新西兰大白兔随机分为对照组、4-氨基吡啶(4-AP)实验组及盐酸四乙胺(TEA)实验组,给予高Ch饮食饲喂8周,通过等长张力记录方法,观察SO肌环对钾离子通道阻滞剂4-AP和TEA的收缩反应,并观察比较SNP对各组SO肌环的舒张作用.结果 SO肌环初始收缩平均波幅为(0.144±0.004)g,平均收缩频率为(10.8±1.1)次/min.累积浓度4-AP对SO肌环有收缩作用,收缩频率较对照组减低(P＜0.05),以16 mmol/L为终质量浓度的4-AP组肌环对SNP舒张作用明显低于对照组(P＜0.05).累积浓度TEA也可明显收缩SO肌环,收缩作用较对照组明显增强,收缩频率较对照组减低(P＜0.05).以10 mmoL/L为终质量浓度的TEA组肌环对SNP舒张作用同样低于对照组(P＜0.05).结论 外源性NO供体SNP可能部分通过钾(KV)及大电导钙激活钾通道(BKCa)通道发挥舒张SO肌环的作用.     

依托咪酯对大鼠皮层、海马脑片缺氧复氧损伤的保护作用

目的观察依托眯酯对大鼠皮层、海马脑片缺氧复氧损伤的保护作用及其机制。方法雄性SD大鼠10只,体重90-100 g,制备大脑皮质和海马脑片,随机分为对照组、缺氧复氧组、3 μmol ·L-1依托咪酯组、6μmol·L-1依托咪酯组、15 μmol·L-1依托咪酯组和6 μmol·L-1依托咪酯+γ-氨基丁酸 A(GABAA)受体拮抗剂Picrotoxin 50 μmol·L-1组。各组脑片缺氧10 min复氧120 min时,测定经三苯基氯化四唑氮染色的吸光度(A490),Fluo-3荧光染色后计算细胞内Ca2+浓度。结果缺氧复氧可导致大脑皮层、海马A490降低,细胞内Ca2+浓度升高,不同浓度依托咪酯可减弱缺氧复氧导致的上述改变,以 6 μmol·L-1依托咪酯的效果较好,且此作用可被GABAA受体拮抗剂完全拮抗。结论依托咪酯对大鼠皮层、海马脑片缺氧复氧损伤有一定的保护作用,可能通过GABAA受体介导,并降低Ca2+负荷有关。     

吗啡预先给药对去甲肾上腺素诱导大鼠心肌细胞NF-κB活化的影响

目的观察吗啡预先给药对去甲肾上腺素(NE)诱导大鼠心肌细胞NF-κB活化的影响,探讨吗啡在细胞水平对缺血心肌的保护作用机制。方法出生1～3 d的SD大鼠,分离、培养心肌细胞,将培养4～5 d呈亚融合状态下的细胞随机分为5组(n=4):对照组(C组)、10-6 mol·L-1 NE组(NE1组)、10-7 mol·L-1 NE组(NE2组)、10-8 mol·L-1 NE组(NE3组)、10-5 mol·L-1吗啡 10-8 mol·L-1 NE组(M NE组)。NE1组、NE2组、NE3组细胞培养基内分别加入相应浓度的NE,M NE组在加入NE前30 min加入10-5 mol·L-1吗啡。加入NE后24 h,进行下述指标的测定,采用流式细胞术测定心肌细胞胞浆NF-κB表达水平;采用免疫细胞化学染色技术测定NF-κB、TNF-α表达,采用酶免疫试验测定TNF-α含量,采用反转录PCR技术测定TNF-αmRNA表达。结果与C组相比,NE1组、NE2组、NE3组细胞浆NF-κB水平降低,其中NE3组NF-κB表达水平最低。NE2组、NE3组TNF-α含量及TNF-αmRNA表达升高,NE3组NF-κB、TNF-α表达升高(P<0.05);与NE3组比较,M NE组细胞浆NF-κB水平升高,TNF-α含量及TNF-αmRNA表达降低(P<0.05)。结论10-5 mol·L-1吗啡预先给药可在一定程度上抑制NE诱导大鼠心肌细胞NF-κB的活化,从而减少了TNF-α的释放。     

尼可地尔对冠状动脉内皮细胞功能的影响

目的 探讨尼可地尔对缺氧、复氧的冠状动脉内皮细胞功能的影响.方法 新鲜猪心外膜下冠状动脉前降支中、下1/3部切3段,每段长2 mm.取45段,单纯随机抽样法分5组,每组9段.各组冠状动脉血管环分别处理如下:对照组—未经缺氧、复氧处理,37℃有氧条件下Krebs-Henseleit (KH)液浸泡90 min;A组-37℃、KH液缺氧浸泡30 min后复氧30 min;B组-37℃、KH液缺氧浸泡1h后复氧30 min;C组—-37℃、含尼可地尔(0.1 μmol/L)的KH液缺氧浸泡1h后复氧30 min;D组—37℃、含尼可地尔(0.1μmol/L)及5-羟基癸酸甘油酯(10 μmol/L)的KH液缺氧浸泡1h后复氧30 min.分别检测消炎痛(7 μmol/L)、N-硝基-L-精氨酸(300 μmol/L)及氧合血红蛋白(20 μmol/L)作用下,前列腺素F2α和缓激肽引发的血管收缩、舒张反应.结果 与对照组相比,缓激肽引发的血管环最大舒张反应,A、B、D组均明显降低(P＜0.001),C组变化不明显(P＞0.05);与A组相比,B、D组明显降低(P＜0.001).结论 缺氧、复氧会损害冠状动脉内皮源性超极化因子所介导的内皮依赖性舒张功能,缺氧时间越长,损害作用越大.尼可地尔对其有保护作用,其机制可能与尼可地尔能选择性开放线粒体上的ATP敏感性钾离子通道有关.     

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.