经皮球囊扩张后凸成形术治疗老年椎体压缩骨折的随访研究

[目的]探讨经皮球囊扩张后凸成形术治疗老年骨质疏松性椎体压缩骨折的手术效果和患者术后的生活质量.[方法]采用经皮球囊扩张后凸成形术治疗老年椎体压缩骨折病例105例.测量术前、术后3d、术后3个月和随访结束时的椎体高度;术前、术后3d、术后3个月和随访结束时对患者腰痛行VAS评分,术前、术后3个月和随访结束时对患者进行ODI评分.[结果]91例患者获随访,随访时间13 ～ 50个月,平均33.2个月.患者术前椎体平均高度为(1.45 ±0.28) cm,术后3d复查X线片测量的椎体平均高度为(1.75 ±0.23) cm,术后3个月时椎体平均高度(1.75±0.23) cm,随访结束时患者椎体平均高度为(1.74±0.24) cm.术前VAS评分为(7.53±0.68),术后3d为(2.69 ±0.49),术后3个月为(1.02±0.33),随访结束时为(1.01±0.39).术前ODI评分为(77.85 ±3.53),术后3个月为(28.67 ±5.85),随访结束时为(21.33±3.47).术前、术后的椎体高度,VAS评分,ODI评分差别有统计学意义(P＜0.01).[结论]经皮球囊扩张后凸成形术治疗老年骨质疏松性椎体压缩骨折能部分恢复椎体高度,针对压缩骨折带来的腰痛有良好的治疗效果,明显改善了患者的生活质量.     

椎体成形术治疗骨质疏松性椎体压缩性骨折

目的:探讨经皮椎体成形术治疗骨质疏松性椎体压缩骨折的临床疗效.方法:对42例骨质疏松性椎体压缩性骨折患者采用经皮椎体后凸成形术(PKP)治疗,通过比较手术前后及术后8个月随访时(即末次随访)疼痛程度(VAS评分)、日常活动能力、止痛药使用情况及椎体前缘高度的变化,以评价手术效果.结果:所有患者手术均获得成功,术后患者疼痛明显缓解,术前VAS评分(8.52±1.13),术后为(2.48±1.04),末次随访时为(2.73±1.08);止痛药使用评分术前为(2.86±0.82),术后为(0.63±0.21）,末次随访时为(0.51±0.22);活动能力评分术前为(2.74±0.68),术后为(1.05±0.34),末次随访时为(1.12±0.27);椎体前缘高度术前为(13.98±4.62),术后为(22.56±4.34),末次随访时为(22.03±4.93).随访六个月无并发症发生.各指标术后及末次随访时与术前比较有显著性差异(P＜0.05),而末次随访时与术后第二天比较无量著性差异(P＞0.05).结论:经皮椎体成形术治疗骨质疏松性椎体压缩骨折,能够迅速缓解疼痛,改善生活质量;增加骨强度,避免椎体继续压缩,是安全有效的微创技术.     

单侧椎弓根穿刺椎体后凸成形术治疗骨质疏松性椎体压缩骨折

目的评价单侧椎弓根穿刺椎体后凸成形术治疗骨质疏松性椎体压缩骨折的临床效果.方法2005年5月～2007年7月应用SKY骨扩张器系统行单侧椎弓根穿刺椎体后凸成形术治疗30例骨质疏松性椎体压缩骨折患者,男10例,女20例;年龄58～86岁,平均70.2岁.患者均有腰背部疼痛,共34个椎体骨折,其中单椎体26例,两个椎体4例,骨折部位T8～L3.随访观察患者的疼痛、日常功能以及影像学改变情况.结果有2例共2个椎体出现骨水泥渗漏,但均未出现临床症状,无其他并发症发生.术后患者腰痛均明显缓解,随访7～28个月,平均12个月,术前VAS评分8.48±0.50分,术后1周时为2.50±0.54分,末次随访时为2.85±0.34分;Oswestry评分术前为58.00±1.93分,术后为31.00±1.88分,末次随访时为35.00±1.51分;椎体前缘高度术前平均为14.70±1.27mm,术后1周时为24.40±0.90mm,末次随访时为21.50±0.37mm;伤椎后凸角度术前平均为30.50°±1.24°,术后1周时为11.00°±1.07°,末次随访时为13.50°±0.49°.各指标术后及末次随访时与术前比较有显著性差异(P＜0.01或P＜0.05),而末次随访时与术后1周时比较无显著性差异(P＞0.05).患者均在术后1个月内恢复受伤前的生活.结论单侧椎弓根穿刺SKY骨扩张器系统椎体后凸成形术可有效恢复骨质疏松性骨折椎体的高度,迅速缓解疼痛,改善患者的生活质量.     

球囊单侧扩张椎体后凸成形术治疗老年骨质疏松性椎体压缩骨折

目的探讨球囊单侧扩张椎体后凸成形术治疗老年骨质疏松性椎体压缩骨折的疗效和安全性.方法2004年12月～2006年12月采用球囊单侧扩张椎体后凸成形术治疗30例骨质疏松性椎体压缩骨折患者,共44个伤椎,其中男13例19个伤椎,女17例25个伤椎;年龄66～83岁,平均72岁;骨折部位为T7～L5椎体,术前CT显示椎体后壁均完整.结果30例患者均手术顺利,3例3个椎体前缘有少许未引起临床症状的骨水泥渗漏,其余椎体X线片上均未见明显骨水泥渗漏.所有患者术后48h内疼痛明显减轻或消失并可下床活动,住院4～12 d.随访6～24个月,平均14个月,术前平均疼痛视觉模拟评分(VAS)为8.6±0.2分,术后为2.0±0.3分,末次随访时为2.1±0.2分,术后评分显著低于术前(P＜0.01);Oswestry功能评分由术前43.1±1.1分降低到术后20.3±1.2分和末次随访21.1±1.2分(P＜0.01);伤椎前、中柱的平均高度由术前15.1±1.8mm增加到术后24.3±2.1 mm和末次随访24.4±1.8 mm,手术前后差异有显著性(P＜0.05).脊柱后凸Cobb角由术前平均21.2°±4.3°减小到术后10.1°±3.2°和末次随访10.2°±3.3°(P＜0.05).结论球囊单侧扩张椎体后凸成形术可有效恢复骨质疏松性椎体压缩骨折椎体的高度,缓解疼痛,改善患者的脊柱功能及减少骨水泥渗漏,临床疗效满意.     

手法复位在骨质疏松性椎体压缩骨折经皮椎体后凸成形术中的应用

[目的]评价手法复位在骨质疏松性椎体压缩骨折经皮椎体后凸成形术中的临床应用.[方法] 2009年1月～2012年6月行经皮椎体后凸成形术的骨质疏松性椎体压缩骨折患者65例随机分为治疗组和对照组,分析比较两组骨水泥外漏发生率及术后2d、术后3个月、末次随访时疼痛恢复情况、椎体高度和脊柱后凸角(Cobb角)的变化.[结果]所有患者均获得6 ～21个月随访,平均11.3个月.于术后2 d、术后3个月及末次随访时进行测量,治疗组VAS评分较术前分别降低(4.32±1.01)、(4.97±0.70)、(5.45±1.95),椎体高度分别增加(6±1.12) mm、(6+1.12) mm、(5.97±1.13) mm,后凸cobb角分别减小(12.48+2.06)°、(12.35±1.96)°、(12.29±1.90)°,有6个椎体发生骨水泥外漏,对照组VAS评分较术前分别降低(4.74±1.24)、(5.21±1.01)、(5.38±0.89),椎体高度分别增加(3.18±0.87) mm、(3.18±0.87) mm、(3.15±O.86) mm,后凸Cobb角分别减小(5.85±1.81)°、(5.59±1.73)°、(5.29±1.45)°,有8个椎体发生骨水泥外漏.术后2d、术后3个月及末次随访时治疗组椎体高度恢复及脊柱后凸畸形矫正均明显优于对照组(P＜0.01),VAS评分变化及骨水泥泄漏率差异无统计学意义(P＞0.05).[结论]手法复位应用于骨质疏松性椎体压缩骨折经皮椎体后凸成形术是安全有效的,可以更好的恢复椎体高度和纠正脊柱后凸畸形,不增加骨水泥泄露的发生率,也不影响术后疼痛的改善.     

椎体成形术与椎体后凸成形术治疗骨质疏松性椎体压缩骨折的临床疗效比较

目的 比较椎体成形术与椎体后凸成形术治疗骨质疏松性椎体压缩骨折的临床疗效、安全性及效价比.方法 对75例骨质疏松性椎体压缩骨折,根据手术方法 不同分为PVP组和PKP组,其中PVP组30例,PKP组45例.记录两组患者的手术操作时间、住院期间费用及骨水泥渗漏情况,比较两组患者术前、术后和随访时的椎体高度、VAS评分以及Cobb角变化.结果 所有患者均顺利完成手术,随访12～36个月,平均18.5个月.PVP组单节椎体手术时间平均为24.4±6.6 min,PKP组单节椎体手术时间平均为31.0±7.3 min(P＜0.01);PVP组患者住院期间所花费用平均为28,793.30±8,023.02元,PKP组患者住院期间所花费用平均为56,291.19±10,471.48元(P＜0.01);PVP 组患者疼痛缓解率为93.3%,PKP 组为91.1%;PKP组椎体前缘高度术前为1.87±0.34 cm,术后为2.24±0.44 cm,椎体中部高度术前为1.43±0.61 cm,术后为1.92±0.39 cm,Cobb角术前为19.34±8.10°,术后为13.00±3.56°,均有显著改善(P＜0.01);PVP组椎体高度及Cobb角无明显变化(P＞0.05);PVP组发生16例骨水泥渗漏,渗漏率为16.2%,PKP组发生11例骨水泥渗漏,渗漏率为7.1%,两组发生渗漏的患者均无明显临床症状.结论 PVP及PKP均为治疗骨质疏松性椎体压缩骨折的有效手段,能显著改善患者临床症状,提高患者生活质量;PKP的安全性高于PVP;PVP的效价比更高,更适合我国国情.     

经皮椎体后凸成形术治疗老年骨质疏松性椎体压缩性骨折

目的 探讨经皮椎体后凸成形术(PKP)治疗老年骨质疏松性椎体压缩性骨折的临床疗效.方法 30例老年骨质疏松性椎体压缩骨折患者在C臂机引导下行PKP治疗,通过疼痛视觉模拟评分法(VAS),测量Cobb角及术前、术后和末次随访椎体高度等评价疗效.结果 所有手术均顺利完成,疼痛明显缓解,椎体高度无明显丢失,未出现严重骨水泥渗漏,无严重并发症发生;VAS由术前的7.7±1.0下降至术后的2.3±0.7,末次随访的2.4±0.6;Cobb角由术前的(29±5.4)°矫正到术后的(21±3.5)°,末次随访时的(22±3.6)°;椎体高度由术前的(12.9±2.6)mm到术后的(21.5±1.8)mm,末次随访时的(21.3±1.7)mm.术后与术前、末次随访与术前差异均有统计学意义(P<0.05),术后与末次随访差异无统计学意义(P＞0.05).结论 经皮椎体后凸成形术创伤小,安全性高,能有效缓解疼痛,矫正后凸畸形,是一种治疗老年骨质疏松性椎体压缩骨折安全有效的方法.     

编织囊袋椎体后凸成形术治疗骨质疏松性胸椎压缩骨折的临床研究

目的评估编织囊袋椎体后凸成形术(CFKP)治疗骨质疏松性胸椎体压缩骨折的临床效果。方法 2014年12月至2016年3月,应用编织囊袋椎体后凸成形术治疗骨质疏松性胸椎体压缩骨折21例,共25个椎体。术前、术后24 h内及末次随访时评估VAS及ODI;测量术前、术后及末次随访的椎体后凸cobb角度变化。结果术后随访6~33个月(平均15.3个月),术前VAS评分7.6±1.2、ODI评分87.4±11.5、cobb角21±4.6、术后24 h VAS评分2.4±0.6、ODI评分43.8±9.6、cobb角5.8±0.6;末次随访VAS评分2.1±0.4、ODI评分42.6±10.1、cobb角6.4±0.7;末次随访时的VAS、ODI评分、cobb角分别与术前比较明显改善,差异均有统计学意义(P0.05);而术后24 h的VAS、ODI评分、cobb角与末次随访比较,差异均无统计学意义。结论编织囊袋椎体后凸成形术治疗骨质疏松性胸椎压缩骨折临床效果满意,可以减少骨水泥渗漏。     

椎体后凸成形术治疗高龄骨质疏松性椎体压缩骨折

目的探讨单一球囊扩张经皮椎体后凸成形术治疗80岁以上老年骨质疏松性椎体压缩骨折的疗效及安全性。方法回顾分析高龄（80岁及其以上）老年骨质疏松性椎体压缩骨折患者15例,男性3例,女性12例,平均年龄（82.2±1.9）岁。共45个椎体,均为骨质疏松性脊柱压缩骨折,压缩骨折椎体后壁均完整。全部在C型臂X线机引导下行单侧入路、单一球囊椎体后凸成形术。结果患者平均能在术后第2天下床行走,未发现严重手术并发症。椎体前缘、中部及后缘平均高度分别由术前的（2.17±0.82）cm、（1.75±0.66）cm、（2.95±0.43）cm增至术后的（2.40±0.73）cm、（2.11±0.51）cm、（3.00±0.45）cm,椎体前缘、中部高度差异有显著统计学意义（P〈0.01）;术后48 h患者胸腰背痛均有缓解,术前、术后48 hVAS评分比较差异有显著统计学意义（P〈0.01）。结论应用椎体后凸成形术治疗高龄骨质疏松性椎体压缩骨折,能够安全、有效地改善骨折椎体高度,明显缓解疼痛,早期下床活动。     

“蛋壳”技术在经皮球囊扩张后凸成形术治疗严重骨质疏松性椎体压缩骨折中的应用

目的 探讨蛋壳技术在经皮球囊扩张后凸成形术治疗老年严重骨质疏松性椎体压缩骨折的可行性和疗效.方法 分析从2009年6月-2013年12月,采用蛋壳技术在经皮球囊扩张后凸成形术治疗老年人严重胸腰椎骨质疏松性压缩骨折43例46个椎体.局麻/全麻下经后路单侧椎弓根穿刺置入病椎,球囊缓慢扩张椎体,小剂量(0.5～1.0 mL)骨水泥注入撑开的空腔,再次插入球囊并撑开椎体高度,使之形成一薄的骨水泥蛋壳,撤出球囊,再次注入骨水泥填充.观察患者的视觉疼痛模拟评分(VAS)、活动能力评分、椎体高度测量及Cobb's角测量.结果 所有手术都顺利完成,无严重手术并发症.VAS评分由术前的(7.9±0.8)分下降至术后的(3.5±0.8)分(P＜0.05),活动能力评分由术前的(3.5±0.6)分改善到术后的(1.3±0.4)分(P＜0.05),椎体高度由术前的(13.5±2.0) mm增加到术后的(31.2±1.5) mm(P＜0.05),Cobb's角由术前的(31.8°±6.9°)矫正到术后的(18.2°±5.8°)(P＜0.05),差异均有统计学意义.所有患者门诊随访1～5个月,平均3.8个月,未出现椎体压缩、新发和相邻节段的骨折,临床表现明显改善.结论 蛋壳技术在经皮球囊扩张椎体后凸成形术中的应用是治疗老年严重骨质疏松性椎体压缩骨折的一种快速有效方法,具有可行性.     

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.