切除椎弓根的楔形截骨术治疗脊柱后凸或侧后凸临床效果观察

[目的]探讨单纯后路切除顶椎椎弓根的楔形截骨技术治疗脊柱后凸或者脊柱侧后凸的临床疗效及其注意事项.[方法]对17例脊柱后凸或侧后凸患者予以后路切除顶椎椎弓根的楔形截骨,畸形严重患者在椎体间置入融合器,术中唤醒试验观察脊髓功能.术后观察患者的外形,拍摄X线片并进行测量,评估脊柱的矫形效果.[结果]10例青少年脊柱侧后凸患者,术前脊柱侧凸主弯冠状面Cobb角平均为75°(62°～95°),术后矫正率为60%(48%～73%),后凸平均Cobb角为83°(74°～92°),术后矫正率为51%(41%～69%),手术前冠状面失衡约21 mm,术后为9 mm.胸腰段后凸7例,术前为45°(32°～75°),术后为5°(0～17°),术后矫正率为89%(74%～100%).无切口感染及假关节发生病例.[结论]采用单纯后路切除顶椎椎弓根的楔形截骨技术治疗脊柱后凸或者脊柱侧后凸临床效果较好,但术前术中应准确评估脊髓功能,注意截骨限度.     

后路松解胸椎间隙联合楔形截骨治疗重度僵硬性脊柱侧后凸

目的 评价经后路胸膜外松解胸椎间隙联合顶椎区楔形截骨结合椎弓根螺钉内固定矫正术治疗重度僵硬性脊柱侧后凸畸形的安全性和早期临床效果.方法 2004年3月至2007年6月,对14例重度僵硬性脊柱侧后凸患者行手术治疗.男6例,女8例;年龄15-31岁,平均22.1岁.其巾特发性7例,先天性6例,神经纤维瘤病l例.术前侧凸Cobb角81°～139°,平均111.2°;后凸57°～165°,平均85.8°.所有患者均行一期经后路胸膜外松解椎间隙联合顶椎区楔形截骨,经椎弓根螺钉内固定矫止及植骨融合术.结果 平均松解椎间隙5.1个,椎体截骨平均2.3个,手术时问7.2～14.1 h,平均9.2 h.术中出血量1500～6100 ml,平均3970 ml.无神经损伤,2例术中胸膜破裂,1例术后并发肠系膜上动脉综合征.所有患者经过7～31个月随访,平均12.7个月,术后侧凸Cobb角15°～71°,平均31.3°,矫正率71.9%;后凸22°～48°,平均34.9°,矫正率59.3%.结论 经后路胸膜外松解胸椎间隙节省了前路经胸的于术时间,创伤小,对心肺干扰小,降低了风险,改善了脊柱柔韧性.顶椎区凸侧三柱楔形截骨,依靠凹侧保留的椎间纤维环、黄韧带及肋椎关节作为稳定铰链,手术较伞脊椎切除术简便、安全.对重度僵硬性弧形脊柱侧后凸用单一的截骨术难以达到三维矫正,后路椎间隙松解联合顶椎区楔形截骨结合椎弓根螺钉内崮定矫正能获得良好的脊柱三维矫正.     

后路截骨联合椎弓根内固定矫形治疗僵硬性脊柱侧后凸畸形

目的探讨经后路截骨联合椎弓根内固定矫形治疗僵硬性脊柱侧后凸畸形疗效。方法对26例僵硬性脊柱侧后凸畸形患者进行后路截骨、椎弓根内固定矫形。8例行后路Ponte截骨,13例行椎弓根截骨术(PSO)联合Ponte截骨,5例行全椎体切除术(VCR)。比较患者术前、术后和末次随访时Cobb角的变化及C7中垂线与骶骨中垂线距离的变化。结果患者均获得随访,时间12~60个月。侧凸Cobb角:术前30°~135°(90.7°±30.6°),术后12°~30°(18°±5.6°),矫正率为82.5%,末次随访13°~32°(20°±5.8°),丢失4.3%;后凸Cobb角:术前20°~60°(40.6°±18.5°),术后10°~26°(16.8°±6.2°),矫正率为85%,末次随访13°~30°(20.5°±7.0°),丢失3.7%;C7中垂线与骶骨中垂线距离:术前3.8~6.5(5.1±1.3)cm,术后0.3~1.3(0.7±0.3)cm,末次随访0.4~1.7(0.8±0.3)cm。所有患者未发生神经损伤等并发症,仅1例患者术后3个月出现内固定松动,经延长固定节段后骨性融合。结论术前充分的评估,选择合适的后路截骨方式,联合椎弓根内固定矫形治疗僵硬性脊柱侧弯,能有效矫正畸形和恢复脊柱冠、矢状面平衡。     

骨桥切断凹侧松解半椎体切除治疗儿童轻中度混合型先天性脊柱侧后凸

目的:探讨骨桥切断、凹侧松解、半椎体切除治疗儿童轻中度混合型先天性脊柱侧后凸的效果。方法:2001年1月~2013年1月对32例椎体分节障碍混合椎体形成障碍的先天性脊柱侧后凸患儿行后路半椎体切除的同时,行凹侧骨桥切断、松解,利用椎弓根钉棒系统矫形。其中男10例,女22例;年龄4~12岁(7.8±4.2岁)。侧凸Cobb角58.3°±12.5°(35°~78°),后凸Cobb角47.6°±15.6°(13°~55°),躯干偏移18.2±5.5mm(11~32mm)。畸形位于T7~L3,顶椎位于胸段11例、胸腰段13例、腰段8例。合并脊髓纵裂3例,神经根囊肿1例,脊髓拴系综合征1例。结果:手术时间230±125min(160~270min),术中出血量590±113ml(310~850ml)。术中2例置钉过程中出现椎弓根骨折,调整固定节段后完成矫形。术后1例出现单侧下肢麻木无力,予甲强龙及脱水剂治疗1周后症状缓解;2例出现脑脊液漏。术后脊柱侧凸Cobb角13.8°±7.1°(5°~28°),矫正率(76.3±9.5)%;脊柱后凸15.1°±3.9°(0~20°),矫正率(68.3±11.2)%;躯干偏移距离3.1±2.3mm(0~11.6mm)。随访18.4±12.6个月(12~60个月),末次随访时侧凸矫正率丢失(3.9±1.6)%,后凸矫正率丢失(2.3±0.9)%,无内固定松动及断裂发生。结论:对儿童轻中度混合型先天性脊柱侧后凸畸形,行后路一期半椎体切除的同时,将凹侧分节障碍的骨桥予以切断、松解,再通过椎弓根钉棒系统矫形,可获得满意的矫形效果。     

经后路胸膜外松解脊椎楔形截骨治疗重度特发性脊柱侧凸

目的:评价经后路胸膜外松解脊椎楔形截骨治疗重度僵硬性特发性脊柱侧凸的安全性和早期临床效果.方法:2004年5月～2007年10月采用经后路胸膜外松解凸侧胸椎间隙、顶椎区楔形截骨、凹侧肋椎关节松解及椎弓根螺钉同定矫正治疗重度僵硬性特发性脊柱侧凸患者19例,男12例,女7例,年龄14～39岁,平均18.9岁.术前侧凸Cobb角890～132°,平均107°;C7中垂线与骶骨中垂线距离3～5.7cm,平均4.1cm;侧凸柔韧性为16.1%～29.6%,平均24.2%;12例合并后凸畸形,后凸Cobb角56°-89°,平均67°.结果:平均松解椎间隙5.2个,楔形截骨平均2.1个椎体.手术时间平均8.9h,术中出血量1200～4700ml,平均3100ml.无脊髓损伤.1例术中发生血气胸,术毕行胸腔闭式引流,2周后痊愈;1例术后第4d并发肠系膜上动脉综合征,采取禁食水、持续胃肠减压、维持水电解质平衡、左侧卧位,术后2周痊愈.术后侧凸Cobb角矫正至12°～59°,平均24.1°,矫正率为77.5%;12例后凸Cobb角22°～460°,平均35.6°,矫正率为46.9%;C7中垂线与骶骨中垂线距离0.3～1.3cm,平均0.7cm.随访8～41个月,平均17.2个月,末次随访时侧凸Cobb角15°～67°,平均27.9.,丢失3.6%;12例后凸Cobb角25°～51°,平均39.4°,丢失5.7%;C7中垂线与骶骨中垂线距离0.4～1.6cm,平均为0.9cm.所有患者植骨愈合良好,内固定无断裂及松动.结论:经后路胸膜外松解、脊椎楔形截骨与胸廓成形及后路脊柱矫形使用同一个手术切口,创伤小,节省了前路经胸的手术时间,对心肺干扰小,降低了手术风险.应用此方法治疗重度特发性脊柱侧凸安全性好,能获得较好的脊柱三维矫正.     

前路半椎体切除截骨后路矫形固定治疗严重先天性脊柱侧凸

目的探讨分期前路半椎体切除截骨后路矫形手术治疗严重先天性脊柱侧凸的临床疗效。方法严重先天性脊柱侧凸14例,男4例,女10例;年龄8～13岁,平均11.2岁。其中形成缺陷2例,分节缺陷6例,混合型6例。半椎体位于T53例,T2、T8、T10、T11、L1、L4各1例。胸弯12例,胸腰弯2例。术前冠状面Cobb角63°～95°,平均72.1°。胸椎后凸减小或前凸8例,胸腰段后凸4例。一期采用前路半椎体切除、多节段椎体间楔形截骨及分节不全松解;二期采用后路椎弓根钉棒系统三维矫形固定。前后路手术均植骨,平均截骨5.5个节段。结果一期前路术后冠状面Cobb角48°～60°,平均51.5°;矫正率19.6%～37.8%,平均28.6%。二期术后冠状面Cobb角5°～45°,平均30.5°;矫正率52.6%～87.5%,平均62.5%。8例存在胸椎后凸减小或前凸的患者均恢复生理性后凸,4例胸腰段后凸患者3例达到矢状面矫正。全部病例随访8～30个月,平均12.1个月。无断钉、断棒及明显的矫正度丢失,植骨融合良好。发生并发症2例,椎弓根钉帽松动1例,T1神经根激惹1例。结论一期前路半椎体切除、多节段椎体间楔形截骨、分节不全松解,二期后路矫形固定及前后路植骨治疗先天性脊柱侧凸能够达到较满意的矫形效果,适合于8～12岁的青春期前患者。     

半椎体切除术与后路松解截骨矫形术治疗小儿先天性脊柱侧凸的疗效比较

目的比较半椎体切除术与后路松解截骨矫形术治疗小儿先天性脊柱侧凸的临床疗效。方法回顾性分析自2015-03—2017-12诊治的96例小儿先天性脊柱侧凸,48例采用后路松解骨矫形术治疗(截骨矫形组),48例采用半椎体切除术治疗(半椎体切除组)。比较2组手术时间、术中出血量、术后脊柱Cobb角及并发症发生率。结果 96例均获得随访,随访时间平均15.6(12～24)个月。与截骨矫形组比较,半椎体切除组手术时间更短,术中出血量更少,并发症发生率更低,术后Cobb角更小,差异有统计学意义(P 0.05)。结论与后路松解骨矫形术比较,半椎体切除术治疗小儿先天性脊柱侧凸疗效更为确切,术后并发症发生更少,具有较高的安全性。     

单纯后路松解原位弯棒技术治疗重度僵硬的脊柱侧凸

目的 探讨单纯后路松解原位弯棒技术对重度僵硬的非角状脊柱侧凸的治疗效果.方法 采用后路松解、原位弯棒技术治疗包括各种病因导致的重度僵硬的非角状脊柱侧凸畸形14例,依据患者的影像学资料、并发症的发生情况等评估临床效果.结果 脊柱侧凸的主弯平均Cobb角为86.3°(70～97°),柔韧性为21.3%(8%～28%),术后...     

后路松解楔形截骨矫治先天性胸腰段半椎体并重度僵硬性脊柱侧后凸畸形

目的:评价经后路松解楔形截骨矫治先天性胸腰段半椎体并重度僵硬性脊柱侧后凸畸形的安全性和临床初步效果,并探讨其融合固定节段的选择。方法:2007年4月～2010年3月收治先天性胸腰段半椎体并重度僵硬性脊柱侧后凸畸形患者11例,男4例,女7例,年龄14～22岁,平均17.1岁;半椎体均为单个完全分节型,T11 3例,T12 4例,L1 1例,L2 3例;术前侧凸Cobb角82°～125°,平均94.4°,侧凸柔韧性为17.4%～28.9%,平均24.8%;后凸Cobb角72°～145°,平均101.1°;C7铅垂线与骶正中线距离1.5～5.5cm,平均2.9cm。均行经后路松解楔形截骨矫形手术,以触及椎(touched vertebrae,TV)(指站立前后位像上被骶正中线触及的最近端椎体)作为融合固定下端椎;1例合并脊髓拴系和脊髓纵裂者,术中一期行骨嵴切除,解除拴系。结果:均顺利完成手术。平均松解3.0个椎间隙。手术时间5.5～10.0h,平均7.7h;术中出血量1000～7000ml,平均3500ml。无脊髓神经损伤。1例术中切除肋骨小头时引起左侧胸膜撕裂,发生血气胸,行胸腔闭式引流,2周后痊愈;1例术后出现螺钉穿破背部皮肤,1枚螺钉钉尾外露,术后3个月取出该枚螺钉。术后侧凸Cobb角7°～54°,平均28.0°,平均矫正率为70.9%;后凸Cobb角20°～36°,平均27.8°,平均矫正率为71.7%;C7铅垂线与骶正中线距离0.1～2.3cm,平均0.6cm,冠状位平衡平均矫正率为78.1%。随访14～35个月,平均23.4个月,末次随访侧凸Cobb角8°～57°,平均29.7°,丢失率为7.3%;后凸Cobb角22°～38°,平均29.9°,丢失率为7.7%;C7铅垂线与骶正中线距离0.2～2.5cm,平均0.7cm;随访X线片证实植骨均融合,内固定物无松动、断裂。选择TV作为远端融合椎(lowest instrumented vertebrae,LIV)比选择稳定椎(stable vertebrae,SV)平均节省了1.09个椎体,未发现失代偿现象。结论:经后路松解楔形截骨矫治先天性胸腰段半椎体并重度僵硬性脊柱侧后凸畸形安全有效,选择TV作为LIV可以减少融合节段。     

双侧肋骨截骨结合后路矫形固定治疗重度僵硬性脊柱侧凸

目的探讨双侧肋骨截骨结合后路广泛松解椎弓根钉矫形治疗重度僵硬性脊柱侧凸的临床疗效。方法自2005年6月~2010年3月采用后路广泛松解结合双侧肋骨截骨(凹侧肋骨截骨抬高,凸侧肋骨切除胸廓成型术)矫治重度僵硬性脊柱侧凸18例。结果每例凹侧肋骨抬高数为3～6根,平均4.5根,凸侧肋骨切除数为3～5根,平均3.5根,肋骨切除长度为5～6 cm。术后主弯Cobb角冠状面为45.3°(38～87°),矫正率平均为54.1%;"剃刀背"畸形7～16°,平均11.2°,双侧背部高度差3.3 cm(1.8～4.3 cm),术后1年肺活量1.3～4.5 L,平均2.5 L,第1秒用力呼气容积FEV1.0 0.8～3.8 L,平均2.0 L。2例出现胸腔积液,2枚胸椎弓根钉误入椎管,未累及硬脊膜。结论后路广泛松解和一期双侧肋骨截骨术可显著改善侧凸的柔韧性,提高矫形效果,对肺功能无不良影响。     

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.     

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.     

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.