骶骨整块切除骨盆环重建治疗骶骨骨巨细胞瘤的疗效观察

目的:探讨骶骨整块切除及骨盆环重建治疗骶骨骨巨细胞瘤的方法与疗效.方法:2003年1月～2006年1月加州大学洛杉矶分校Santa Monica骨科医院脊柱外科中心收治骶骨骨巨细胞瘤患者8例,男5例,女3例,手术时年龄30～72岁,平均46岁.术前腰骶部CT扫描和MRI检查证实肿瘤均累及S1,采用一期前后路联合手术,术中结扎髂内动脉、髂腰动脉和骶正中动脉,显微镜下将肿瘤组织连同整块骶骨完整切除,用骨盆环假体重建腰骶髂关节稳定性.术后采用Toronto Extremity Salvage Score (TESS)评分系统对患者的功能恢复情况进行评价.结果:术中失血量800～2500ml,平均1200ml,手术时间490～720min,平均600min.病理学诊断:骨巨细胞瘤ⅡB期5例,Ⅲ期3例.术后卧床6～14d,平均10d,无1例患者术后并发切口感染.出院时患者均能不借助拐杖行走,恢复了日常生活自理能力.所有患者随访28～64个月,平均43个月,TESS评分由术前平均56.38分提高到73.25分.1例患者(Ⅲ期)术后18个月发生肺转移,接受肺叶切除,同时行放疗,随访至40个月时仍然存活;其余7例患者至末次随访时均存活,没有发现局部复发.结论:骶骨肿瘤累及S1时可行骶骨全切以提高肿瘤切除的彻底性,改善预后;采用骨盆环假体重建稳定性术后可早期活动.     

髂腰肌撞击——全髋关节置换术后并发症的诊治

目的分析全髋关节置换术后髂腰肌撞击假体引起疼痛原因及治疗措施。方法19例人工全髋关节置换术因髂腰肌撞击髋臼假体引起髋部疼痛患者，5例采用保守治疗无效后行髂腰肌肌腱切断术，12例行髂腰肌肌腱切断术，2例髋臼假体翻修。结果术后所有患者疼痛均明显减轻，Harris评分术前47～70（59±5．3）分，术后达83-95（92±1．7）分。双髋对比屈髋力量17例无明显下降，2例部分下降但并不影响髋关节功能。结论人工全髋关节置换术后因髂腰肌撞击髋臼假体引起髋部疼痛的患者，保守治疗常常效果不佳，而髂腰肌肌腱切断术效果较好。     

髂腰固定术治疗U型骶骨骨折的疗效分析

目的:评价应用髂腰固定术治疗U型骶骨骨折的手术疗效。方法:回顾分析2014年1月至2019年12月采用髂腰固定术治疗14例U型骶骨骨折,其中男10例,女4例;年龄24~48(35.4±6.5)岁。术后对获得随访的患者分别进行骨愈合、神经功能、临床功能评价及并发症分析。结果:所有患者术后获随访,时间16~36(26.0±5.9)个月,骨愈合完全负重时间9~16 (12.4±2.0)周。术后发生1例手术切口感染,1例髂骨钉穿出至髂骨外,无压疮、内固定物松动或断裂等并发症发生。根据Gihbons神经功能评分,由术前的(2.9±0.9)分恢复至术后的(2.1±1.1)分,差异有统计学意义(t=6.9,P=0.00)。术后骶骨畸形角度由术前(41.4±11.2)°改善为末次随访时(28.3±7.5)°,差异有统计学意义(t=4.70,P=0.00)。根据Majeed临床功能评价标准,术后末次随访疼痛(23.21±3.17)分,站立(25.57±3.94)分,坐(7.71±1.54)分,性生活(2.64±0.92)分,工作能力(16.14±2.41)分,总分(75.30±8.10)分,疗效优2例,良10例,可2例。结论:髂腰固定术是治疗U型骶骨骨折的一种有效方法,具有内固定坚强、功能恢复满意等优点。     

全骶骨切除术后重建方法的发展及现状

目的回顾全骶骨切除术后重建方法的发展历程,为寻找更好的全骶骨切除重建方法提供参考。方法查阅国内外全骶骨切除术后重建的案例报道和生物力学及有限元研究文献,对重建方法的发展过程及现状进行总结。结果全骶骨切除术后重建方式经过近30年的发展,在重建理念和固定技术上都取得了较大进展。重建方式可概括为3种策略:腰髂、后环和前柱。腰髂指腰椎与双侧髂骨之间的连接,后环指双侧髂骨之间的连接,前柱指邻近腰椎椎体和骨盆的连接。腰髂重建经历了从钩棒到椎弓根钉和髂骨钉棒的技术进步;后环和前柱重建可以提高重建系统的稳定性。结论为了达到力学稳定,腰髂、后环和前柱的联合重建是全骶骨切除术后重建的发展方向,如何实现生物固定提高重建结构远期稳定性,是亟待解决的问题。     

骶管减压及髂腰固定治疗Denis Ⅲ型骶骨骨折患者的临床疗效以及影响因素分析

背景:骶骨骨折是骨盆骨折中的重要类型,DenisⅢ型骶骨骨折常合并神经损伤等并发症,采用骶管减压及髂腰固定术治疗的疗效及其影响因素目前尚未确定。目的:评估骶管减压及髂腰固定术治疗DenisⅢ型骶骨骨折的疗效并分析其影响因素。方法:分析2011年9月至2016年9月行骶管减压及髂腰固定术治疗的65例和接受保守治疗的9例DenisⅢ型骶骨骨折患者随访1年的病例资料,分别采用Gibbons、Majeed评分标准评估患者治疗前和治疗1年后的神经损伤和骨折情况。采用配对t检验比较手术组患者治疗前、治疗1年后的Gibbons评分及Majeed评分。采用成组t检验比较手术组与保守组治疗1年后Gibbons、Majeed评分改善程度。采用COX风险回归模型分析治疗疗效的影响因素。结果:手术组患者治疗前Gibbons评分高于治疗1年后,差异有统计学意义(t=35.553,P=0.000);治疗前Majeed评分低于治疗1年后,差异有统计学意义(t=37.114,P=0.000)。手术组患者Gibbons和Majeed评分改善程度均高于保守组,差异有统计学意义(t=-9.048,P=0.000;t=-10.256,P=0.000)。性别、年龄、受伤原因、减压方式对手术疗效的影响不明显,骨折类型(RR=2.190)、马尾损伤程度(RR=2.575)、Roy-Camille分型(RR=2.548)、手术时间(RR=1.359)、骨折后凸角(RR=2.739)、是否置入骶骨螺钉(RR=1.698)、L5-S1单侧小关节损伤程度(RR=1.223)是影响手术疗效的独立影响因素,且均为危险因素。结论:DenisⅢ型骶骨骨折患者实行骶管减压及髂腰固定术治疗的疗效肯定,骨折类型、马尾损伤程度、RoyCamille分型、手术时间、骨折后凸角、是否置入骶骨螺钉、L5-S1单侧小关节损伤程度是影响手术疗效的独立危险因素。     

全骶骨切除术后重建方法的发展及现状北大核心CSCD

目的回顾全骶骨切除术后重建方法的发展历程,为寻找更好的全骶骨切除重建方法提供参考。方法查阅国内外全骶骨切除术后重建的案例报道和生物力学及有限元研究文献,对重建方法的发展过程及现状进行总结。结果全骶骨切除术后重建方式经过近30年的发展,在重建理念和固定技术上都取得了较大进展。重建方式可概括为3种策略:腰髂、后环和前柱。腰髂指腰椎与双侧髂骨之间的连接,后环指双侧髂骨之间的连接,前柱指邻近腰椎椎体和骨盆的连接。腰髂重建经历了从钩棒到椎弓根钉和髂骨钉棒的技术进步;后环和前柱重建可以提高重建系统的稳定性。结论为了达到力学稳定,腰髂、后环和前柱的联合重建是全骶骨切除术后重建的发展方向,如何实现生物固定提高重建结构远期稳定性,是亟待解决的问题。     

髂腰重建术治疗不稳定性骶骨骨折并神经损伤的临床疗效

目的探讨髂腰重建术治疗不稳定性骶骨骨折并神经损伤的临床疗效。方法选取2008年1月~2013年6月我院收治的不稳定性骶骨骨折合并神经损伤患者12例,其中男性9例,女性3例,年龄22~50岁,平均年龄为(33.6±0.2)岁;Denis分型:Ⅱ区6例,Ⅲ区4例,Ⅱ区合并Ⅲ区2例;患者均有明显的骶神经根损伤症状。Gibbons神经损伤评分:8例3分,4例4分。所有患者均行后路骶管减压、神经松解、髂腰固定重建、后外侧植骨融合术,采用X线片或CT观察骨折复位及愈合情况,应用Majeed功能评分评价患者临床功能恢复情况,应用Gibbons标准评分评定患者神经功能改善情况,并观察并发症情况。结果本组手术时间130~200 min,平均时间(159.3±0.9)min,术中出血量750~1 200 ml,平均(854.5±2.1)ml。所有患者随访8~16个月,平均(12.9±0.8)个月。术后6个月骨折均骨性愈合,无骨折移位、残留骨盆畸形、假关节形成及深部感染等并发症;9例患者神经功能完全恢复;2例明显改善,但遗留不同程度的足下垂和下肢感觉障碍;1例下肢功能及膀胱、直肠功能均无明显改善。Majeed评分评定:优8例,良2例,可1例,差1例,优良率为83.3%;Gibbons评分由术前平均(3.4±0.2)分恢复至末次随访时的(1.4±0.5)分。结论髂腰重建术可恢复腰-骶-髂的解剖关系,重建腰骶复合体的稳定性,对治疗不稳定性骶骨骨折并神经损伤疗效确切。     

全胸腔镜与传统开胸肺癌根治术的比较

目的比较全胸腔镜手术(complete video-assisted thoracoscopic surgery,c-VATS)与传统开胸肺癌切除术的疗效,探讨全胸腔镜肺癌切除术的效果。方法 2010年1月~2012年8月我科行全胸腔镜肺癌切除术(胸腔镜组)31例,选择同期传统开胸肺癌切除术38例作对照研究,比较2组患者手术时间、术中出血量、胸腔引流时间、术后引流量、淋巴结清扫数量、术后住院时间、围术期C-反应蛋白(C reactive protein,CRP)、疼痛评分、肩关节活动功能评分及术后随访情况。结果 2组手术时间、术后住院时间无明显差异(P0.05)。胸腔镜组引流时间较开胸组明显缩短[(3.7±0.9)d vs.(4.9±0.8)d,t=-5.859,P=0.000];术中出血量明显少于开胸组[(178.4±54.5)ml vs.(297.4±73.5)ml,t=-7.487,P=0.000];术后引流量明显少于开胸组[(417.0±218.9)ml vs.(520.3±235.0)ml,t=-2.295,P=0.023];胸腔镜组清扫淋巴结(16.3±9.2)枚,明显多于开胸组(12.0±6.7)枚(t=2.244,P=0.028)。2组患者围术期CRP术后12、72 h比较均无明显差异(P0.05)。2组术后1 d疼痛评分差异无统计学意义[(7.1±0.8)分vs.(7.3±1.0)分,t=0.902,P=0.370],但术后3、7、30 d疼痛评分有明显差异[(5.2±1.1)分vs.(5.8±1.3)分,t=-2.041,P=0.045;(3.7±0.8)分vs.(6.2±1.1),t=-10.572,P=0.000;(1.7±0.9)分vs.(2.6±0.8)分,t=-4.394,P=0.000]。胸腔镜组患者日常活动评分术后7、30 d均明显优于开胸组[(23.2±3.4)分vs.(20.1±2.7)分,t=4.223,P=0.000;(27.3±3.1)分vs.(24.8±2.9)分,t=3.453,P=0.000]。胸腔镜组生存率明显高于开胸组(log-rank检验,χ~2=4.042,P=0.044)。结论全胸腔镜肺癌切除术围术期对患者影响小,具有安全、淋巴结清扫彻底和微创的优点,并能改善预后。     

髂骨钉棒固定治疗单侧不稳定性DenisⅠ、Ⅱ区骶骨骨折

目的探讨后路髂骨钉棒固定治疗单侧不稳定性DenisⅠ、Ⅱ区骶骨骨折的临床疗效。方法回顾性分析2016年3月至2018年10月治疗50例单侧不稳定性DenisⅠ、Ⅱ区骶骨骨折患者资料。根据置钉及固定方式分为髂骨钉棒固定组(简称髂骨钉棒组)和机器人辅助骶髂螺钉置入组(简称骶髂螺钉组),其中髂骨钉棒组20例,男13例,女7例,年龄(41.10±14.07)岁(范围,22~76岁);骶骨骨折Denis分型,Ⅰ型5例,Ⅱ型15例;均合并骨盆前环损伤,骨盆Tile分型,B1型2例,B2型12例,C1型6例;3例合并骶神经损伤,Gibbons分级Ⅱ级。骶髂螺钉组30例,男18例,女12例;年龄(44.70±13.35)岁(范围,16~78岁);骶骨骨折Denis分型,Ⅰ型6例,Ⅱ型24例;均合并骨盆前环损伤,骨盆Tile分型,B1型2例,B2型20例,C1型8例;4例合并骶神经损伤,Gibbons分级,3例Ⅱ级,1例Ⅲ级。两组患者年龄、手术时间、术中出血量、透视次数、Majeed评分比较采用独立样本t检验;骨折复位质量比较采用卡方检验;骶神经损伤恢复Gibbons分级比较采用秩和检验。结果两组患者均获得随访,随访时间22.8个月(范围,12~40个月)。髂骨钉棒组手术时间(41.40±7.30)min;术中出血(105.00±61.94)ml;术中透视(19.10±7.33)次;根据Mears和Velyvis影像学评价标准,9例解剖复位,10例复位满意,1例复位不满意;Majeed评分(84.25±8.29)分;术前3例GibbonsⅡ级骶神经损伤,术后2例恢复为Ⅰ级。骶髂螺钉组手术时间(18.27±5.89)min;术中出血(33.00±17.54)ml;术中透视(14.93±4.49)次;术后15例解剖复位,13例复位满意,2例复位不满意;Majeed评分(86.43±7.43)分;术前3例GibbonsⅡ级骶神经损伤,其中2例术后恢复为Ⅰ级,术前1例Ⅲ级损伤,术后恢复为Ⅱ级。与骶髂螺钉组比较,髂骨钉棒组手术时间长(t=-12.36,P<0.001)、出血量多(t=-6.04,P<0.001)、透视次数多(t=-2.50,P=0.016),以上各指标比较差异均有统计学意义。术后髂骨钉棒组与骶髂螺钉组在骨折复位质量(χ^2=0.23,P=0.89)、Majeed评分(t=0.97,P=0.34)、Gibbons分级(Z=-0.224,P=0.82)比较,差异均无统计学意义。术后髂骨钉棒组1例发生单侧伤口表浅感染,1例诉钉尾部不适;骶髂螺钉组1例发生S1神经损伤。结论对于单侧不稳定性DenisⅠ、Ⅱ区骶骨骨折且不适合使用骶髂螺钉固定者,采用后路髂骨钉棒固定操作简单,术后疗效满意,与使用机器人辅助骶髂螺钉固定相似。     

骶骨肿瘤切除后重建的临床进展

骶骨肿瘤相对少见,辅助治疗效果不确切.全骶骨肿瘤切除是治疗的主要手段,但全骶骨肿瘤切除常常导致骨盆环不稳,因此,术后如何重建腰骶稳定性是手术治疗骶骨肿瘤成功的关键所在.目前文献已报道多种重建方式,包括三角框架重建装置,髂骨棒和髂骨螺钉,改良Galveston,假体置换等.作者就骶骨肿瘤切除术后重建方式及术后评价进行综述.     

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.