生长抑素对膀胱引流式犬胰腺移植 Oddi括约肌及外分泌功能的影响

目的研究人工合成的生长抑素类似物思他宁对膀胱引流式犬胰腺移植后移植物Oddi括约肌(SO)和外分泌功能的影响.方法正常犬和膀胱引流式胰腺移植后犬应用思他宁前后进行SO测压,检测移植后犬应用思他宁前后尿中胰蛋白酶原激活肽(TAP)和淀粉酶水平.结果正常犬SO有规律收缩,基础压为(18.5±2.8)mmHg,收缩频率为(9.7±1.5)次/min,收缩幅度为 (47.1±5.5)mmHg,动力指数为(235.6±56.1).应用思他宁后SO 基础压、收缩频率、收缩幅度和 动力指数分别显著降低为(11.5±4.3)mmHg,(3.8±0.8 )次/min,(22.7±5.3)mmHg和(76.9±16.4),与用药前相比,P均<0.01.移植物SO基础压和收缩频率分别升高为(27.8±2.8)mmHg和(13.1±1.9)次/min,收缩幅度缩小为(8.3±1.8)mmHg,动力指数无明显变化.移植犬应用思他宁后,SO基础压和动力指数分别升高为(35.2±4.2)mmHg和(418.7±81.5),与用药前相比,P均<0.01.收缩频率和幅度无明显变化(P>0.05).用思他宁后尿淀粉酶和TAP水平分别显著降低为( 5 000±350) IU/L和(15.6±3.7) nom/L,与用药前相比,P<0.01.结论生理情况下,思他宁可抑制犬SO运动,胰腺移植后,思他宁对移植物SO起直接激动作用,思他宁还可以降低膀胱引流式犬胰腺移植后尿中的胰蛋白酶原激活肽和尿淀粉酶水平,从而有助于防治移植物胰腺炎.     

膀胱引流式胰腺移植后Oddi括约肌运动变化的实验研究

目的　研究膀胱引流式胰腺移植后移植物Oddi括约肌功能的变化以及对移植物功能的影响。方法　应用三腔测压管对正常犬、膀胱引流式胰腺移植后犬和离体的犬Oddi括约肌进行测压 ,并检测移植后犬Oddi括约肌的抗反流能力 ,同时监测移植物内外分泌功能。结果　正常犬Oddi括约肌在 ( 18 5± 2 8)mmHg( 1mmHg =0 133kPa)基础压水平上有规律收缩 ,收缩频率为 ( 9 7±1 5 )次 /min ,收缩幅度为 ( 4 7 1± 5 5 )mmHg ,动力指数为 2 36± 5 6。移植后犬胰腺内外分泌功能良好 ,移植物Oddi括约肌失去了正常的收缩规律 ,基础压升高至 ( 2 7 8± 2 8)mmHg ,收缩频率增快至( 13 1± 1 9)次 /min ,但收缩幅度明显缩小至 ( 8 3± 1 8)mmHg ,动力指数无明显变化。胆管残端内压力不随膀胱内压升高而发生变化。结论　膀胱引流式犬胰腺移植后 ,移植物Oddi括约肌丧失了正常的收缩规律 ,基础压升高 ,收缩频率增快 ,但收缩幅度明显缩小 ,仍然具有一定的抗反流能力     

胆囊收缩素对自体胰腺移植犬Oddi括约肌功能的影响

目的研究胆囊收缩素对胰腺移植后移植物Oddi括约肌功能的影响。方法对正常犬和膀胱引流式胰腺移植后犬应用胆囊收缩素前后进行Oddi括约肌测压。结果与正常犬相比 ,应用胆囊收缩素后Oddi括约肌的基础压、收缩频率、收缩幅度和动力指数显著降低 ,分别为 (1 8 5±2 8)mmHg与 (1 0 2± 2 2 )mmHg(P <0 0 1 )、(9 7± 1 5 )次 /min与 (5 0± 1 2 )次 /min (P <0 0 1 )、(4 7± 6 )mmHg与 (1 9± 5 )mmHg(P <0 0 1 )、(2 36± 5 6 )与 (5 0± 1 7) (P <0 0 1 )。移植物Od di括约肌基础压和收缩频率分别升高为 (2 7 8± 2 8)mmHg和 (1 3 1± 1 9)次 /min ,收缩幅度降低为(8± 2 )mmHg。移植犬应用胆囊收缩素后 ,基础压、收缩频率和动力指数分别升高为 (35 5± 5 1 )mmHg ,(1 8 9± 1 9)次 /min和 (5 1 5± 4 2 ) ,与用药前相比 ,P均 <0 0 1。 结论胆囊收缩素可抑制正常犬的Oddi括约肌运动 ,但对移植胰腺的Oddi括约肌起激动作用     

乌司他丁影响膀胱引流式犬胰腺移植Oddi括约肌功能的研究

目的:研究乌司他丁(US)对膀胱引流式犬胰腺移植后移植物Oddi括约肌(SO)功能的影响。方法:正常犬和膀胱引流式胰腺移植后犬在应用US 10万U和30万U前后测定SO的动力学指标。结果:US对正常犬SO基础压和收缩幅度无明显影响(P>0.05),但可降低其收缩频率和动力指数(P<0.01);在10万U和30万U剂量间,动力指数有统计学差异(P<0.01),收缩频率则无统计学差异(P>0.05);移植后应用US可全面降低SO基础压、收缩频率、收缩幅度和动力指数(P<0.01),且在10万U与30万U剂量间差异均有显著性 (P<0.05)。结论:US可抑制犬SO运动, 并呈剂量依赖性;尤其胰腺移植后,抑制作用更显著,可以有效地降低基础压,改善胰液引流,从而有助于防治移植物胰腺炎的发生。     

一氧化氮与胆囊收缩素对犬Oddi括约肌的作用

目的 探讨一氧化氮和胆囊收缩素(CCK)在犬Oddi括约肌运动调节中的作用.方法 测定正常状态及注射CCK、硝普钠、一氧化氮合酶(NOS)抑制剂N-硝基-L-精氨酸甲酯(L-NAME)时,犬Oddi括约肌的基础压、时相收缩频率、时相收缩幅度;免疫组织化学染色法检测犬Oddi括约肌上NOS阳性神经元的表达情况.计量资料的比较采用t检验.结果 注射0、20 ng/kg CCK后,犬Oddi括约肌基础压、时相收缩频率、时相收缩幅度分别为(27±10)mm Hg(1 mm Hg=0.133 kPa)、(10±3)次/min、(32±8)mm Hg和(61±14)mm Hg、(64±21)次/min、(44±15)mm Hg;注射100 ng/kg CCK后产生最大抑制作用和最大兴奋作用时,犬Oddi括约肌基础压、时相收缩频率、时相收缩幅度分别为(77 +31)mm Hg、(69±18)次/min、(79±14)mm Hg和(140±21)mm Hg、(129±25)次/min、( 173±63)mm Hg.胆总管滴注硝普钠后,犬Oddi括约肌基础压、时相收缩幅度均下降(t =3.706,5.183,P＜0.05).而注射L-NAME后,犬Oddi括约肌基础压、时相收缩幅度均升高(t=5.859,3.588,P＜0.05).结论 20 ng/kg生理剂量的CCK可舒张犬Oddi括约肌,大剂量CCK可兴奋犬Oddi括约肌;一氧化氮对犬Oddi括约肌发挥舒张效应,此效应可能在CCK的抑制通路中发挥重要作用.     

肝胆管结石患者胆总管切开取石术后Oddi括约肌肌电的研究

目的 研究肝胆管结石患者胆总管切开取石术后Oddi括约肌(SO)肌电的特点,旨在寻找临床研究、检测SO功能的新方法.方法 对2010年1月至10月在第三军医大学西南医院复诊的33例行胆总管切开取石术的肝胆管结石患者经T管窦道胆道镜辅助行SO压力与肌电检测,根据SO测压结果将33例患者分为低压力组、正常压力组及高压力组,比较各组患者SO峰电位丛(SOSB)幅值、频率和持续时间.结果 低压力组、正常压力组、高压力组患者分别有14、13、6例,平均SO基础压力分别为(3.1±1.2)、(18.5 ±7.6)、(39.8 ±4.8)mm Hg(1 mm Hg=0.133 kPa).低压力组、正常压力组、高压力组患者SOSB幅值、频率、持续时间分别为(41±27)、(150±71)、(301±109)μV,(5.8 ±1.6)、(6.9 ±1.4)、(7.8 ±1.2)次/min,(2.7±0.6)、(3.4±0.7)、(4.2±0.7)s,各组比较,差异有统计学意义(F=50.751,4.293,13.159,P<0.05).结论 SO肌电检测可以从电生理的层面反映SO的功能,有望成为临床研究、检测SO功能的新方法.

Abstract：

Objective To observe the characteristics of electromyography of sphincter of Oddi (SO) in patients with cholelithiasis after common bile duct exploration,and investigate new methods for detecting the motility of SO.Methods The basal pressure of SO(SOBP)and electromyography of SO were detected in 33 patients with cholelithiasis who were reexamined at the Southwest Hospital from January to October,2010.All patients were divided into low SOBP group,normal SOBP group and high SOBP group.The amplitude,frequency and duration of SO spike burst(SOSB)of the three groups were compared.Results The numbers of patients in the low SOBP group,normal SOBP group and high SOBP group were 14,13 and 6,respectively.The mean SOBP of the low SOBP group,normal SOBP group and high SOBP group were(3.1±1.2),(18.5±7.6),(39.8±4.8)mm Hg (1 mm Hg=0.133 kPa).The amplitude,frequency and duration of SOSB were(41±27)μV,(5.8±1.6) times/minutes and(2.7±0.6)s in the low SOBP group,and(150±71)μV,(6.9±1.4)times/minutes and (3.4±0.7)s in the normal SOBP group,and(301±109)μV,(7.8±1.2)times/minutes and(4.2±0.7)s in the high SOBP group,respectively,with significant difference among the three groups(F=50.751,4.293,13.159,P<0.05).Conclusion The results of electromyography of SO could reflect the function of SO,and it is possible to be a prospective method in the clinical research of SO.     

房间隔缺损患者围手术期血浆脑钠肽(BNP)与平均肺动脉压(mPAP)的关系

目的观察心外科三种不同方法治疗房间隔缺损,手术前后血浆脑钠肽(brain natriuretic peptide,BNP)变化,分析其与心功能变化的关系。方法选择2015年1月至2017年6月在我院治疗的房间隔缺损28例,其中体外循环下房间隔缺损补片修补8例,经右胸小切口封堵12例,经颈静脉封堵8例。平均年龄(17.9±12.2)岁,平均体质量(44.6±24.8)kg。分别于封堵当天术前及术后24 h、术后3个月抽血检测BNP浓度。术前、术后24 h和术后3个月经胸心脏超声检查肺动脉压变化。结果补片修补组术前、术后24 h和术后3个月的mPAP分别为(36.2±6.1)mm Hg,(35.8±5.3)mm Hg和(28.8±4.2)mm Hg,血浆BNP浓度分别为(175.2±58.3)pg/ml,(556.5±191.6)pg/ml和(169.0±43.4)pg/ml;经胸封堵组mPAP分别为(23.8±4.8)mm Hg,(22.3±3.9)mm Hg和(22.6±4.5)mm Hg,血浆BNP浓度检测分别为(138.5±63.2)pg/ml,(404.6±188.5)pg/ml和(113.0±41.4)pg/ml;经颈静脉封堵组mPAP分别为(21.3±5.2)mm Hg,(18.8±3.6)mm Hg和(17.9±2.7)mm Hg,血浆BNP浓度检测分别为(102.5±78.5)pg/ml,(392.8±263.1)pg/ml,(78.6±35.4)pg/ml。从总体上讲,手术后各组mPAP逐渐下降,BNP短暂升高后明显下降(P0.05);BNP与mPAP之间有相关性(P0.05)。结论在采用3种不同方法进行治疗的房间隔缺损患者中,mPAP与BNP之间存在明显的相关性。选择合适的手术方法,对心功能及mPAP的恢复具有明显的临床意义。     

血红素加氧酶2和CO在去势大鼠阴茎海绵体中的表达

目的:检测去势大鼠阴茎海绵体中血红素加氧酶2(HO-2)/CO的表达,初步探讨勃起功能障碍(ED)的发病机制。方法:雄性SD大鼠72只均分为对照组、假手术组、去势组和去势锌原卟啉(Zn PP,HO阻断剂)组,检测基础条件和阿扑吗啡(APO)刺激后的海绵体内压(ICP)和勃起率;激光共聚焦显微镜检测大鼠勃起不同时期阴茎海绵体组织中HO-2蛋白的表达,分光光度计测定CO在大鼠勃起不同时期的含量。结果:基础条件和APO刺激后ICP和勃起率,去势组[(11.68±0.69)mm Hg,(54.81±3.86)mm Hg,33.3%]和去势Zn PP组[(11.20±0.71)mm Hg,(41.17±5.41)mm Hg,22.2%],与对照组[(22.83±2.66)mm Hg,(66.92±7.77)mm Hg,100%]和假手术组[(23.35±2.22)mm Hg,(70.43±7.22)mm Hg,100%]比较显著下降(P均0.01),且APO刺激后去势Zn PP组ICP较去势组明显降低(P0.01)。APO刺激后,勃起前和勃起中阴茎海绵体HO-2蛋白表达,去势组(445.4±23.7,847.4±35.0)和去势Zn PP组(390.1±29.7,526.0±52.5)较对照组(512.7±57.4,1 145.2±89.8)和假手术组(583.7±8.0,1 016.3±79.8)显著下降(P0.05或P0.01),且勃起中去势Zn PP组HO-2蛋白表达较去势组明显降低(P0.01);勃起后各组之间的HO-2蛋白表达变化差异无显著性。勃起前、中和后阴茎海绵体CO含量,去势组[(20.59±1.01)×10-7nmol/L,(32.53±1.26)×10-7nmol/L,(18.71±1.22)×10-7nmol/L]和去势Zn PP组[(12.52±1.05)×10-7nmol/L,(21.90±1.02)×10-7nmol/L,(16.56±0.55)×10-7nmol/L]较对照组[(26.76±1.41)×10-7nmol/L,(48.25±1.01)×10-7nmol/L,(27.10±1.58)×10-7nmol/L]和假手术组[(25.41±2.09)×10-7nmol/L,(47.90±1.22)×10-7nmol/L,(25.67±1.20)×10-7nmol/L]显著下降(P0.05或P0.01),且勃起中去势Zn PP组CO含量较去势组明显下降(P0.01)。结论:HO-2和CO表达下降与去势大鼠ED的发生有关。     

生长抑素对Oddi's括约肌功能的影响

目的: 研究生长抑素类似物施他宁对奥狄括约肌(sphincter of Oddi,SO)功能状态的影响.方法: 通过T管窦道经胆道镜途径顺行插入测压管至SO,低压水灌注系统压力传感器与微机相连记录压力曲线,分析软件进行压力曲线分析.结果: 对SO基础压的作用与用药前差异显著(P<0.01);对SO收缩幅度的影响无显著性意义;对SO收缩间期的影响与用药前比较差异显著(P<0.05);对SO收缩频率的影响与用药前比较差异显著(P<0.05).施他宁倍量输入后10 min SO收缩频率与用药前已无差异,与5 μg/min用药10 min比较差异显著(P<0.05).结论: 施他宁显著降低SO基础压,延长收缩间期且具有剂量依赖性.对收缩频率的影响:低剂量时增加,高剂量时抑制;对收缩幅度的作用:高剂量时收缩幅度下降但无显著性意义.     

骨隧道内植入不同长度自体肌腱重建前交叉韧带生物力学研究

目的 利用犬自体屈肌腱重建前交叉韧带(anterior cruciate ligament,ACL),比较骨隧道内植入不同长度肌腱后,移植物总体最大抗拉强度和刚度的变化,探讨移植肌腱的最佳长度.方法 成年雄性比格犬60只,体重13～16 kg.其中3只双膝正常屈肌腱行拉力测试,作为正常对照组.3只双膝正常股骨-ACL-胫骨复合体行拉力测试,拉断后用10 mm自体屈肌腱重建ACL后即刻再行拉力测试,作为自体对照组.54只双膝制备肌腱重建的动物模型,作为实验组;根据肌腱在骨隧道内植入长度的不同分为6组,分别为5、9、13、17、21、25 mm组,每组9只18膝.术后45、90及180 d测量移植物的刚度和最大抗拉强度的变化.结果 正常对照组正常屈肌腱的刚度为(59.89±4.28)N/min,最大抗拉强度为(564.15±36.18)N.自体对照组正常ACL刚度为(74.34±6.99)N/mm,最大抗拉强度为(684.75±48.10)N,断裂点均在关节内;重建后刚度为(31.35±1.97)N,最大抗拉强度为(301.92±15.04)N,断裂点均在骨隧道内编织线处.术后45 d各实验组移植肌腱均从骨隧道中拉出;90 d时24膝移植肌腱从骨隧道中拉出,12膝移植肌腱断裂点位于关节内,其中17 mm组3膝,21 mm组5膝,25 mm组4膝;180 d时各实验组移植肌腱均在关节内被拉断.各观察时间点,17、21、25 mm组的最大抗拉强度和刚度均明显强于5、9、13 mm组(P<0.05).结论 利用犬自体肌腱重建ACL时,骨隧道内植入长度为17 mm的肌腱即可达最佳效果.     

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.