粗聚焦震波对大鼠骨质疏松性骨折愈合的影响及生物力学评估

目的 观察粗聚焦震波对大鼠骨质疏松性骨折愈合过程中的骨密度、骨微结构及愈合后生物力 学特性的影响。方法66只体重为200~250 g的3月龄雌性SD大鼠卵巢去势制造骨质疏松模型,造模成功后左腿胫骨制造开放性骨折并予克氏针内固定。术后分为对照组和治疗组,治疗组用震波能量 密度0. 26 mJ/mm2,频率60次/分,冲击量为2000次治疗一次。结果治疗后4周和8周行组织学观察显示治疗组与对照组比较骨性骨痂所占比例较大,8周时骨小梁改建基本完成;而Micro CT检验数据结果显示治疗组骨密度（BMD );骨小梁体积（BV )、组织体积（TV )、骨体积分数（BV/TV )、平均骨小梁厚 度（Th. Th)、平均骨小梁数目（Tb.N)均明显高于对照组（P<0. 05),其中治疗8周后的骨密度改变存在 显著差异（-3.6% vs 4. 9%,P<0. 05)。且治疗组最大压缩荷载在治疗后4周（48.1±5.6(治疗组)vs 21. 8±4. 8(对照组））、8周时亦明显高于对照组（57.5±6.1(治疗组）vs28.6 ±5.0(对照组））。结论 粗聚焦震波能够抑制骨折后的骨丢失,增加骨密度,促进骨折愈伤组织的生长,改善骨小梁三维结构及骨组织的力学性能,可用来促进骨质疏松性骨折的愈合并改善骨质量,预防再骨折。     

骨质疏松绵羊模型松质骨及皮质骨的微观结构及力学性能变化的研究

目的观察去势手术对绵羊皮质骨和松质骨的骨密度、骨小梁结构及力学性能的影响。方法20只雌性成年绵羊（4±1.5）随机分为去势4个月组（OVX-4months）（4只）、去势12个月组（OVX-12months）（8只）和假手术（Sham）组（8只）。OVX组行双侧卵巢切除术,假手术组仅显露双侧卵巢,术中测定腰椎骨密度。分别与术后4、12个月处死动物,测定股骨颈、股骨干及股骨髁的骨密度,并行MicroCT分析及生物力学测试。结果去势12个月后（OVX-12months）组腰椎、股骨颈及股骨髁的骨密度较对照组显著降低,而皮质骨骨密度无明显降低。其松质骨的相对骨体积（BV/TV）、骨小梁厚度（Tb.Th）、骨小梁数目（Tb.N）较对照组显著降低,表面积体积比（BS/BV）、骨小梁间隙（Tb.Sp）则较对照显著增高。生物力学测试表明,去势12个月后,腰椎松质骨的最大压缩应力分别较Sham组和OVX-12months组下降82.5%和85.9%,力学强度显著下降,而皮质骨的力学强度无显著变化。结论去势12个月后,绵羊腰椎、股骨部的松质骨BMD及骨小梁空间结构参数明显降低,力学强度也显著下降,可以作为骨质疏松的大动物模型。而皮质骨的骨密度和力学强度下降不明显,需要更长的去势时间。     

朝藿定C联合骨髓间充质干细胞移植对糖皮质激素性骨质疏松小鼠骨密度和骨代谢的影响

目的 探讨朝藿定C联合骨髓间充质干细胞移植对糖皮质激素性骨质疏松小鼠骨密度和骨代谢的影响。方法 75只雄性C57BL/6小鼠分为空白对照组、模型组、朝藿定C组、干细胞移植组、联合组，每组各15只。空白对照组以0.1 mL生理盐水肌肉注射，其余4组以0.1mL地塞米松肌肉注射，2次/周，连续干预8周，以骨密度值确定造模成功。造模成功后7 d分别进行骨髓间充质干细胞移植和朝藿定C灌胃治疗，连续8周。测定骨密度和骨结构参数、血清骨代谢指标水平以及AKT蛋白磷酸化（p-AKT）水平。结果 与空白对照组比较，模型组体质量、骨矿物质含量（BMC）、骨矿物质密度（BMD）、组织矿物质含量（TMC）、组织矿物质密度（TMD）、骨体积分数（BV/TV）、骨小梁数量（Tb.N）、骨小梁厚度（Tb.Th）以及骨源性碱性磷酸酶（BALP）、Ⅰ型前胶原羧基端前肽（PINP）、AKT蛋白磷酸化水平显著降低，骨小梁分离度（Tb.Sp）显著增加，血清骨钙素（OCN）和抗酒石酸酸性磷酸酶（Trap）水平显著升高（P＜0.05）。与模型组比较，朝藿定C组、干细胞移植组和联合组小鼠体质量、BMC、BMD、TMC、TMD、BV/TV、Tb.N、Tb.Th显著增加，BALP、PINP、AKT蛋白磷酸化水平显著升高，Tb.Sp、血清OCN和Trap水平显著降低，且联合组上述指标改善优于其余2组（P＜0.05）。结论 朝藿定C联合骨髓间充质干细胞移植可促进糖皮质激素性骨质疏松小鼠骨形成，增加骨密度，改善骨微结构，其机制可能与提高骨代谢水平和活化PI3K/AKT通路有关。     

降钙素对OA大鼠关节软骨及软骨下骨的保护作用

[目的]研究降钙素(calcitonin,CT)对骨性关节炎(OA)模型大鼠关节软骨和软骨下骨的保护作用.[方法]采用前叉韧带切断(anterior cruciate ligament transection,ACLT)法制备大鼠OA模型,30只12周龄雌性SD大鼠,随机分成3组:假手术组(Sham, n=10)、手术组(ACLT+NS, n=10)和给药组(ACLT+CT, n=10).术后ACLT+CT组皮下注射鲑鱼降钙素10 IU·kg-1·d-1,连续12周;ACLT+NS组则给予等量生理盐水.术后12周处死动物取材,采用Mankin评分系统评分;用双能骨密度仪测量右侧股骨远端1/4骨密度和股骨内外侧髁软骨下骨的骨密度;右侧股骨髁脱钙后切片,行番红"O"染色和MMP-13免疫组化染色;右侧胫骨近端做硬组织切片,测量软骨下松质骨的骨组织形态计量学参数.[结果](1)Sham组和ACLT+CT组关节软骨Mankin评分结果显著低于ACLT+NS组.(2)ACLT+NS组软骨下骨骨密度、骨量(BV/TV,Tb.Th)均显著高于Sham组及ACLT+CT组.(3)ACLT+NS组关节软骨MMP-13表达显著高于Sham组及ACLT+CT.[结论]降钙素10 IU·kg-1·d-1皮下注射12周能够抑制OA大鼠关节软骨的退变,其作用机制可能与下调关节软骨中MMP-13的表达及抑制软骨下骨的增生硬化并改善其微观结构有关.     

实验性股骨颈骨折修复过程的生物力学研究

目的：探索股骨颈骨折引起股骨头坏死塌陷的发病机理。方法：在犬股骨头颈交界处截断股骨颈,术后分5周组（5条）。20周组（5条）及各组的对照组,对其修复过程进行病理学,计量组织学、四环素标记及生物力学的研究。结果：（1）病理学检查：5周组,股骨头内骨小梁坏死,其框架结构不变;20周组,股骨头关节面塌陷,头内纤维组织、软骨痂及骨痂形成。（2）计量组织学分析示20周组的股骨头骨小梁体积及软骨下骨厚度较对照组及5周组低。（3）四环素标记示20周组的荧光带比对照组及5周组宽。5周组的最窄。（4）生物力学测定：20周组的软骨下骨及松质骨的生物力学强度较对照组及5周组低。结论：股骨颈骨折可致股骨头坏死,后者引起修复及血供重建,修复则可导致塌陷,股骨头塌陷与软骨下骨及松质骨的生物力学特性关系密切。     

前交叉韧带切断对卵巢切除大鼠股骨骨折愈合的影响

目的观察前交叉韧带切断(OA动物模型)对双侧卵巢切除大鼠(OVX绝经后骨质疏松模型)股骨骨折愈合的影响。方法12周龄SD大鼠共70只，分成基础对照组(Basal)、假手术组(Sham)、双侧卵巢切除术组(OVX)、卵巢切除 前交叉韧带切断术组(OVX OA)、假手术 骨折组(Sham F)、卵巢切除术 骨折组(OVX F)、卵巢切除 前交叉韧带切断 骨折组(OA OVX F)，每组10只大鼠。所有受试大鼠在处死前第10d天和第4d天分别皮下注射盐酸四环素和钙黄绿素行双荧光标记。基础对照组在实验开始时杀死，其余6组在术后6W杀死，取大鼠右侧股骨标本。然后，分别进行CR摄片、组织形态学染色，以及应用Norland-XR36双能X线骨密度仪(DXA)测量右股骨远段骨密度和中段骨密度，并将股骨远段及骨折段骨痂进行硬组织包埋、切片，作骨组织形态计量学测量。结果①OVX OA组与OVX组比较，股骨远段。BMD和BWTV显著增加；②OVX F组与Sham F组比较，骨痂(股骨中段)BMD和BV／TV显著降低：③OVX OA F组与OVX F组比较，骨痂(股骨中段)BMD利BV／TV无统计学差异。结论①骨质疏松不仅延缓骨折愈合过程，而且降低骨折愈合质量；②在此动物模型中，骨性关节炎延缓股骨骨质疏松的发生，但是，对骨质疏松性骨折的愈合没有确切的促进作用。     

鸡冠花黄酮对骨质疏松大鼠TMAO/NF-κB/NFATc1水平的影响

目的 探讨鸡冠花黄酮提取物对老年骨质疏松大鼠TMAO-NF-κB/NFATc1水平、骨微结构及骨特异性磷酸酶蛋白的作用机制。方法 将16周龄大鼠分为假手术组（Sham组,n=13）、模型组（n=9）、干预组（n=11）及药物对照组（n=11）,除Sham组外其余大鼠均建立OP模型,干预组灌胃鸡冠花黄酮提取物。结果 与Sham组相比,模型组大鼠血清Ca、P、ALP及BAP水平均降低,差异具有统计学意义（P＜0.05）,与模型组相比,干预组大鼠血清Ca、P、ALP及BAP水平升高,差异具有统计学意义（P＜0.05）;Sham组、模型组、干预组及药物对照组的骨密度BMD分别为（58.05±6.11）mg/cm3、（47.50±4.53）mg/cm3、（55.17±5.14）mg/cm3及（54.96±5.40）mg/cm3,组间比较差异具有统计学意义（F=6.983,P＜0.001）;与Sham组相比,模型组大鼠股骨组织中TMAO、NF-κB、NFATc1表达较高（P＜0.05）,与模型组相比,干预组大鼠组织中TMAO、NF-κB、NFATc1表达降低,差异具有统计学意义（P＜0.05）。结论 老年骨质疏松大鼠采用鸡冠花黄酮提取物干预后可显著改善骨微结构,提高骨特异性磷酸酶活性并增加骨密度,机制可能与抑制TMAO、NF-κB、NFATc1表达相关。     

仿生脉冲电磁场对0VX-0P大鼠骨密度与生物力学相关关系的影响

目的骨密度与骨的生物力学性能存在相关性，但某些治疗方法对骨密度及骨折发生率的影响并不一致，表明不同治疗方法可能对骨密度与骨的生物力学性能间的相关关系存在不同的影响。为此，本研究观察了仿生脉冲电磁场对去卵巢骨质疏松大鼠骨密度与生物力学关系的影响，并与雌激素进行了比较。方法6月龄雌性未孕Wistar大鼠160只，按体质量随机抽取分为以下4组：去卵巢组（OVX），去卵巢＋苯甲酸雌二醇组（E），假手术组（Sham），电磁场治疗组（EM）。OVX、EM、E组行双侧卵巢切除术，Sham组行假手术。术后第9W开始治疗：E组苯甲酸雌二醇肌肉注射，0．5mg／kg，1次，2W。EM组大鼠暴露于仿生脉冲电磁场治疗，1h／1次／d，OVX、Sham组不予以任何处理，作为对照组。开始治疗后6W、8W、10W、12W等时间点分别在麻醉下处死实验动物，腰6椎体、右侧股骨应用DEXA测定骨密度，并进行腰6椎体、右侧股骨生物力学指标的测定。结果股骨BMD（bone mineral densityBMD）与最大载荷、腰6椎体BMD与最大载荷之间均存在一种正向的线性关系。在股骨中，OVX较组相关曲线较Sham组相关曲线向右下方平移，E组则平移不明显，EM组则有左上方平移。在腰6椎体中，OVX、E组相关曲线向右下方平移不明显，EM组有左上方平移。结论仿生脉冲电磁场不但具有提高OVX-OP大鼠的BMD，同时改善了骨密度与生物力学性能的相关关系。     

雌激素及雄激素对去睾丸大鼠骨质疏松 形成的干预研究

目的　研究雌、雄激素对去睾丸大鼠腰椎、股骨颈、粗隆部、股骨近端的骨密度及股骨颈骨微结构的变化。方法　选用 39只 3～ 4月龄的Wistar雄性大鼠 ,随机分成假去睾丸组 (Sham)、去睾丸组 (Orch)、去睾丸 +雌激素组 (Orch +E2 )和去睾丸 +雄激素组 (Orch +T) ,同条件下饲养 1 8w。处死前用HologicQDR 2 0 0 0 +DEXA测量大鼠腰椎、股骨颈、粗隆部、股骨近端的骨密度。处死前第 1 4 ,1 3d和第 3 ,2d行骨荧光标记 ,大鼠处死时收集血清行T和E2 放免检测 ,同时取左侧股骨近端行塑料包埋的骨组织切片及组织形态计量学分析。结果　Orch组大鼠 1 8w后腰椎、股骨颈、粗隆部、股骨近端的骨密度均下降 ,与Sham组比较差异有显著性 (P <0 0 1 )。Orch +E2 组大鼠的 4个部位骨密度均最高 ,但与Sham组比较无差异 ,Orch组股骨颈的骨小梁面积百分率和骨小梁数目与Sham组比较均减少 (P<0 0 1 ) ,骨小梁分离度增加 (P <0 0 1 ) ;Orch +E2 和Orch +T组大鼠的各静态参数维持在Sham组水平 ;Orch组的骨荧光标记周长百分率、骨形成率BFR/BS、BFR/BV和BFR/TV均增加 (P <0 0 1 ) ,代表骨吸收的骨小梁面积破骨细胞数和骨小梁周长破骨细胞数均增加 (P <0 0 1 ) ;Orch +E2 和Orch +T组大鼠的各动态参数维持在Sham组水平。结论　     

血清中骨质疏松相关蛋白分子标志物的筛选研究

目的：通过蛋白芯片筛选血清中反映早期绝经后骨质疏松症发生、发展的标志性分子。方法3月龄雌性SD大鼠20只，随机分为卵巢切除（ovariectomized, OVX）组和假手术（sham operation, Sham）组，每组10只，分别进行卵巢去势手术和假手术处理。术后2、4、6、8周对两组大鼠进行活体显微CT扫描，测量股骨远端骨密度及相关松质骨形态计量学动态参数；同时经内眦静脉取血，利用蛋白芯片检测血清中不同蛋白因子的含量。结果显微CT检测结果显示OVX组大鼠骨密度（BMD）、相对骨体积（BV/TV）、骨小梁厚度（Tb.Th）、骨小梁数目（Tb.N）从第4周开始下降，骨小梁分离度（Tb.Sp）开始上升， Sham组未见明显变化；到第8周各指标在OVX组与Sham组之间差异有统计学意义（P＜0.05）。蛋白芯片检测结果显示OVX组中干扰素?γ（IFN?γ）、β神经生长因子（b?NGF）分别从术后4周和6周后开始升高，同Sham组比较均至第8周具有明显差异（P＜0.05）。结论 IFN?γ和b?NGF水平在绝经后骨质疏松早期开始增高，可考虑作为诊断早期绝经后骨质疏松症发生的新型蛋白分子。     

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.