后路椎弓根钉系统三维矫形治疗青少年特发性脊柱侧凸

[目的] 回顾分析三维矫形内固定手术治疗青少年特发性脊柱侧凸(AIS)的临床效果,探讨经后路椎弓根钉系统三维矫形的生物力学及避免脊柱失平衡的对策.[方法] 2005年1月～2007年6月在本院行三维矫形内固定手术的AIS患者31例,男18例,女13例;年龄11～18岁,平均15.2岁.其中Lenke I型8例,LenkeⅡ型4例,LenkeⅢ型8例,LenkeⅣ型2例,Lenke V型5例,Lenke VI型4例.术前冠状面Cobb's角平均54°,顶椎偏距平均5.8 cm,躯干偏移距离平均2.6 cm.根据患者畸形类型和柔韧性选择融合范围.术后及随访时在X线片上测量主弯冠状面的Cobb's角、顶椎偏距、躯干偏移距离.[结果] 术后随访1～3年,平均16个月,冠状面Cobb's角平均残留24°,矫正率为61%;终末随访平均丢失4.0°,丢失率为8%;顶椎偏距平均残留2.5 cm,矫正率为56%,终末随访时平均丢失0.5 cm,丢失率为8.5%;终末随访时躯干偏移距离平均1.0 cm.[结论] 后路椎弓根钉系统矫治青少年特发性脊柱侧凸具有优越的力学基础,因此能有效改善AIS畸形,但术中需始终关注躯体和脊柱的力学平衡.     

选择性椎板关节突截骨联合椎弓根螺钉系统治疗青少年特发性脊柱侧凸

目的:探讨探讨特发性脊柱侧凸畸形矫形术早期疗效及手术体会。方法:对18例特发性脊柱侧凸畸形矫形术的患者采用后路选择性椎板关节突截骨联合椎弓根螺钉系统治疗,随访测量各种影像学指标。结果:术后随访18个月,术后1例出现神经牵拉损伤,和术前冠状面Cobb角平均21°,矫正率为59%,终末丢失率为11%;顶椎偏距平均2.4cm,矫正率为50%,均丢失0.4cm,丢失率为8.3%;躯干偏移距离平均1.5cm。终末随访时躯干偏移距离平均0.2cm。丢失率为7.4%。结论:采用选择性椎板关节突截骨联合椎弓根螺钉系统治疗青少年特发性脊柱侧凸,效果理想,固定牢靠,术后并发症少。     

青少年特发性脊柱侧凸的选择性胸椎融合治疗

目的　探讨青少年特发性脊柱侧凸选择性胸椎融合治疗的适应证。方法　回顾性分析12例行选择性胸椎融合患者术前、术后及随访时的X光像 ,对侧凸类型、侧凸Cobb角、顶椎旋转度、顶椎偏距、侧凸柔韧性、躯干偏移及胸腰段矢状面Cobb角进行测量和分析。患者 12例中男 2例 ,女10例 ,平均年龄 15 1(13～ 18)岁。侧凸均为KingⅡ型 ,其中PUMCⅡb1型 9例 ,Ⅱc3型 3例。所有病例均行选择性胸椎融合 ,平均随访 3 5 (1～ 10 5 )年。结果　手术前后胸弯冠状面Cobb角分别为5 4 0°、19 0° ,平均矫正率 6 2 7% ;腰弯冠状面Cobb角分别为 34 6°、12 5° ,自动矫正率为 6 4 7%。最后随访时 ,胸、腰弯的冠状面Cobb角分别为 18 8°、15 9°;腰弯冠状面Cobb角、顶椎偏距及顶椎旋转度与术后相比无显著变化。术后发生胸腰段后凸 1例 ,最终随访时未见进一步加重。无躯干失平衡现象发生。选择性胸椎融合较后路融合双弯平均减少 3 5个融合节段。结论　对腰弯柔韧性好且度数较小的KingⅡ (PUMCⅡb1和部分Ⅱc3)型特发性脊柱侧凸 ,可安全有效地行选择性胸椎融合     

青少年特发性脊柱侧凸选择性胸弯融合的策略

目的:探讨青少年特发性脊柱侧凸(AIS)手术矫形时胸弯选择性融合的策略.方法:回顾分析手术矫形治疗的46例Lenke 1B和1C型AIS患者,男12例,女34例,手术时年龄12～18岁.平均15.4岁,Risser指数0～Ⅳ级.Lenke 1B型29例,knke 1C型17例.胸弯Cobb角43°～82°平均58°,腰弯Cobb角16°～64°,平均45°.采用单纯后路手术,其中CD技术19例,全椎弓根螺钉同定技术27例.手术融合范同的选择依据腰弯的结构特征,包括弯曲大小、柔韧度、顶椎旋转度以及C7重力垂线偏离骶骨中线的距离等,兼顾双肩和腰部外观以及躯干平衡情况.结果:25例1B型和9例1C型融合单胸弯.其余12例融合双弯.随访12～38个月,平均15个月,术后胸弯Cobb角平均18.9°,矫正率64%,末次随访时角度丢失平均2.2°;术后腰弯Cobb角平均11.8°,矫正率70%,末次随访时角度丢失平均2.7°.术后躯干和双肩平衡满意(躯干侧方移位和双肩高度差均在2cm以内).2例随访时出现明显矫形丢失,均为选择性胸弯融合的病例,1例发生"曲轴现象",1例发生腰弯失代偿.结论:在确定青少年特发性脊柱侧凸手术融合范围时,应充分评价腰弯的结构特征以及外观和平衡等因素,尽量保留腰椎活动度,以取得满意的矫形效果.     

后路凸凹侧双棒同步矫形在青少年特发性脊柱侧凸矫治中的应用

目的 探讨后路凸凹双侧矫形棒同步矫形技术在青少年特发性脊柱侧凸(AIS)外科矫治中的应用价值及疗效.方法 2006年2月至2008年8月采用后路凸凹侧双棒同步矫形技术治疗AIS 48例,其中男性16例,女性32例;年龄11～24岁,平均17.1岁.Lenke分型:Ⅰ型17例、Ⅱ型9例、Ⅲ型14例、Ⅳ型8例.行选择性胸弯融合27例,非选择性融合21例.观测手术前后冠状Cobb角、顶椎偏距、顶椎旋转、躯干偏移、尾端融合椎旋转、倾斜角、椎间角、矢状面平衡变化,评价侧凸矫正效果及脊柱平衡状况.结果 术后随访12～27个月,平均15.1个月.选择性融合患者末次随访胸、腰弯Cobb角平均矫正率分别为(76±11)%、(72±9)%.非选择性融合术患者末次随访胸、腰弯Cobb角平均矫正率分别为(74±15)%、(69±9)%.所有病例尾侧保留脊柱活动节段平均4.4个.1例因术中定位错误发生近端交界性后凸行翻修术.其余病例末次随访无脊柱失代偿,无假关节形成、神经损伤等并发症.结论 应用后路凸凹双侧矫形棒同步矫形治疗AIS,有助于提高矫形效果,重建和维持脊柱平衡,减少尾侧融合节段.     

成人胸腰段或腰段脊柱侧凸合并Chiari畸形和脊髓空洞症的三维矫形及融合策略

[目的]探讨合并Chiari畸形和脊髓空洞症的成人胸腰段或腰段脊柱侧凸的三维矫形及融合策略.[方法]回顾性研究2002年1月～2008年5月本科收治的13例合并Chiari畸形和脊髓空洞症的成人胸腰段或腰段脊柱侧凸,全部采用后路椎弓根螺钉系统三维矫形,并根据侧凸结构性特点选择内固定及融合节段.测量术前、术后、末次随访时冠状面Cobb' s角、侧凸矫正率、骨盆倾斜、顶椎旋转度、顶椎偏距、躯干偏移、矢状面胸椎后凸角和腰椎前凸角.[结果]冠状面Cobb' s角从46.8°减少到9.2°,侧凸矫正率80.7%;骨盆倾斜从9.9°减少到3.2°;顶椎旋转度从1.9°减少到0.3°;顶椎偏距从3.6 cm减少到0.8 cm;躯干偏移从16.8 cm减少到1.6 cm;胸椎后凸角从18.2°增加到23.5°;腰椎前凸角从37.4°增加到41.8°.术后平均随访22.2个月,无明显矫形丢失、躯干失平衡、假关节形成,且未发生原有神经症状加重及新的不可逆性神经功能损害.[结论]后路椎弓根螺钉系统三维矫形及融合术治疗合并Chiari畸形和脊髓空洞症的成人胸腰段或腰段脊柱侧凸效果满意.     

合并胸腰段后凸的青少年特发性脊柱侧凸的临床研究

目的 探讨合并胸腰段后凸的青少年特发性脊柱侧凸(AIS)的临床特点和手术治疗策略. 方法对2001年1月至2007年1月收治的413例AIS患者进行回顾性分析,合并胸腰段后凸者共10例,其中男2例,女8例;年龄12～18岁,平均14.3岁.侧凸类型包括PUMC Ⅱb2型3例,Ⅱc 3型4例,Ⅱd2型1例,Ⅲb型2例.单纯后路内固定术8例,前路松解+后路内固定术2例.术前、术后及随访时摄X线片,对侧凸类型、Cobb角、顶椎旋转度、顶椎偏距、侧凸柔韧性、胸腰段后凸、冠状面及矢状面躯干偏移进行评测和分析.结果 本组患者中双弯8例,三弯2例;胸腰弯/腰弯Cobb角≥45°者7例,柔韧性指数≤70%者6例,顶椎旋转度≥Ⅱ度者9例.所有病例的融合范围均符合PUMC分型原则.手术前后平均胸弯冠状面Cobb角分别为71.7°和37.4°,平均矫正率为47.8%;手术前后平均胸腰弯/腰弯冠状面Cobb角分别为65.0°和27.8°,平均矫正率为57.2%;手术前后平均胸腰段后凸分别为35.5°和4.2°,平均矫正率为88.2%.全部病例随访12～72个月,平均23.1个月;最终随访时无躯干失平衡发生. 结论 合并胸腰段后凸的AIS一般多为双弯或三弯,胸腰弯/腰弯畸形往往比较严重,并有明显的旋转畸形.对合并胸腰段后凸的AIS,应融合胸腰弯/腰弯以防止术后发生失代偿或后凸加重, PUMC分型可以有效识别病变类型并指导融合范围的选择.     

后路间隔置钉治疗Lenke 5型青少年特发性脊柱侧凸

目的 探讨后路矫形侧间隔置钉、支撑侧每隔1或2个节段置钉治疗Lenke 5型青少年特发性脊柱侧凸(AIS)的疗效.方法 回顾性分析2001年6月—2012年12月本院收治的20例Lenke 5型AIS患者的影像学资料.术前、术后1周及末次随访时测量胸椎及腰椎Cobb角、冠状面平衡、矢状面平衡、双肩高度差、顶椎偏移(AVT),近端固定椎(UIV)及远端固定椎(LIV)倾斜角、LIV下终板与其下位椎体上终板间的夹角(∠α)、颈椎前凸角、胸椎后凸角及腰椎前凸角.计算术前胸椎和腰椎侧凸的柔韧度、术后Cobb角的矫正率及双侧平均置钉密度.结果 所有手术顺利完成.所有患者随访3.6～12.6年,平均7.3年.术前胸椎及腰椎平均柔韧度分别为74％和67％.平均固定节段7.6个,平均置钉密度矫形侧为59％、支撑侧为43％.术后1周及末次随访时腰椎和胸椎Cobb角、UIV和LIV倾斜角及腰椎AVT较术前明显减小,差异均有统计学意义(P<0.05).结论 后路矫形侧间隔置钉、支撑侧每隔1或2个节段置钉治疗柔韧度较高的Lenke 5型AIS可获得满意的矢状面及冠状面矫形效果,该方法明显减少了置钉数量、手术时间和术中创伤,同时减轻了患者的经济负担.     

选择性胸椎融合治疗PUMC Ⅱ型青少年特发性脊柱侧凸

目的 评价选择性胸椎融合治疗PUMC Ⅱ型特发性脊柱侧凸(IS)的效果.方法 回顾性分析术后随访时间超过1年且影像学资料完整的PUMC Ⅱ型IS 25例,男2例,女23例;年龄11～18岁,平均14.3岁.术前、术后及随访时摄X线片,对侧凸类型、侧凸Cobb角、顶椎旋转度、顶椎偏距、侧凸柔韧性、胸腰段后凸、躯干偏移进行测量和分析.侧凸类型包括Ⅱb1型20例,ⅡC3型5例.其中前路矫形4例,后路矫形21例.结果 手术前后胸弯冠状面Cobb角分别为48.0°和14.3°,平均矫正率为70.0%;手术前后腰弯冠状面Cobb角分别为32.2°和11.9°,自动矫正率为62.9%,最终随访时无躯干失平衡发生.全部病例随访12～58月,平均17.4个月.结论 参照PUMC分型的融合范围选择原则,采用选择性胸椎融合治PUMC Ⅱ b1型和部分PUMCⅡC3型IS,可以保留更多脊柱活动度,同时冠状面和矢状面矫形效果满意,无术后失代偿.     

后路选择性胸腰弯或腰弯融合治疗Lenke 5C型青少年特发性脊柱侧凸

目的:评价后路选择性胸腰弯或腰弯融合治疗青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)的临床效果。方法:回顾性分析45例行后路选择性胸腰弯(20例)或腰弯(25例)融合的Lenke 5C型AIS病例,男4例,女41例,平均年龄14.9±2.1岁(12~20岁)。所有病例均行后路椎弓根螺钉内固定矫形融合,平均随访36±20个月(24~105个月)。术前、术后及末次随访时均摄站立位全脊柱正侧位X线片,对躯干偏移、融合节段邻近椎间盘开角、远端融合椎的倾斜、冠状面和矢状面Cobb角进行测量分析。测量数据使用SPSS 17.0统计学软件进行分析。结果:术前胸腰弯或腰弯Cobb角平均47.3°±7.2°,术后矫正至6.4°±4.6°,矫正率(84.8±11.6)%,末次随访时为9.1°±5.4°,矫形丢失2.7°±4.6°。胸弯术前25.7°±7.4°,凸侧Bending像Cobb角7.6°±5.8°,柔韧性(72.7±23.0)%,术后矫正至13.2°±6.7°,自动矫正率(48.5±29.4)%,末次随访14.2°±7.6°,矫形丢失1°±6°。躯干偏移:术前21.3±11.5mm,术后19.5±13.3mm,末次随访10.9±8.9mm。术后近端与远端融合椎邻近椎间盘开角较术后明显减小,且在随访过程中无明显加重。远端融合椎倾斜术后及末次随访时均显著改善。末次随访时,交界性后凸1例,躯干失衡3例,胸弯失代偿并行融合延长手术1例。所有病例末次随访时均未见假关节形成。结论:后路选择性胸腰弯或腰弯融合对Lenke 5C型特发性脊柱侧凸可获得满意矫形效果,胸弯可获得良好的自动矫正,有效缩短了融合节段。     

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 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.     

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.     

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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.