经椎板间完全内镜下L_(2~5)椎间盘摘除术的手术策略

[目的]前瞻性研究经椎板间完全内镜下L2⁵椎间盘摘除术的手术策略、安全性及临床疗效。[方法]2011年4月5椎间盘摘除术的手术策略、安全性及临床疗效。[方法]2011年4月²011年12月,采用经椎板间完全内镜下L22011年12月,采用经椎板间完全内镜下L2⁵椎间盘摘除术治疗61例L25椎间盘摘除术治疗61例L2⁵椎管内非包含型椎间盘突出症,其中4例L2、3,12例L3、4,45例L4、5。将椎管内L25椎管内非包含型椎间盘突出症,其中4例L2、3,12例L3、4,45例L4、5。将椎管内L2⁵椎间盘非包含型突出按照突出物与走行神经根的关系分成腋型(22例)、腹型(27例)及肩型(12例)。对肩型及腹型突出采用肩路,将内镜及工作套管置入走行神经根肩部进行手术;对于腋型突出,如果走行神经根在硬膜囊的发出点位于椎间盘平面或椎间盘平面以上,单纯采用腋路,将内镜及工作套管直接置入走行神经根腋部进行脱出物及椎间盘内松动髓核的摘除;如果走行神经根在硬膜囊上的发出点位于椎间盘平面以下,先采用腋路,摘除腋部脱出或游离椎间盘组织,然后将工作区域移至走行神经根肩部,摘除椎间盘内松动髓核组织。术后第2 d及术后3个月复查腰椎MRI评估突出物切除的彻底性。记录术前,术后3、6、12个月的腰痛视觉模拟评分(visual analogue scales,VAS)、腿痛VAS评分及Oswestry残疾指数(Oswestry disability index,ODI),并比较术前及术后各时间点的统计学差异。评估术后12个月时MacNab腰椎功能评分。[结果]手术均顺利完成,手术时间平均55 min(305椎间盘非包含型突出按照突出物与走行神经根的关系分成腋型(22例)、腹型(27例)及肩型(12例)。对肩型及腹型突出采用肩路,将内镜及工作套管置入走行神经根肩部进行手术;对于腋型突出,如果走行神经根在硬膜囊的发出点位于椎间盘平面或椎间盘平面以上,单纯采用腋路,将内镜及工作套管直接置入走行神经根腋部进行脱出物及椎间盘内松动髓核的摘除;如果走行神经根在硬膜囊上的发出点位于椎间盘平面以下,先采用腋路,摘除腋部脱出或游离椎间盘组织,然后将工作区域移至走行神经根肩部,摘除椎间盘内松动髓核组织。术后第2 d及术后3个月复查腰椎MRI评估突出物切除的彻底性。记录术前,术后3、6、12个月的腰痛视觉模拟评分(visual analogue scales,VAS)、腿痛VAS评分及Oswestry残疾指数(Oswestry disability index,ODI),并比较术前及术后各时间点的统计学差异。评估术后12个月时MacNab腰椎功能评分。[结果]手术均顺利完成,手术时间平均55 min(30⁹0 min)。有1例术后椎间盘突出复发,采用显微内窥镜下椎间盘摘除术翻修,有1例术后走行神经根损伤加重并功能障碍;无感染及其他手术并发症。术后各时间点腰痛VAS、腿痛VAS及ODI评分均较术前明显降低;术后12个月时MacNab评分,33例优,25例良,1例可,2例差。[结论]根据椎间盘突出部位选择腋路或肩路经椎板间完全内镜下腰椎间盘摘除术是治疗L290 min)。有1例术后椎间盘突出复发,采用显微内窥镜下椎间盘摘除术翻修,有1例术后走行神经根损伤加重并功能障碍;无感染及其他手术并发症。术后各时间点腰痛VAS、腿痛VAS及ODI评分均较术前明显降低;术后12个月时MacNab评分,33例优,25例良,1例可,2例差。[结论]根据椎间盘突出部位选择腋路或肩路经椎板间完全内镜下腰椎间盘摘除术是治疗L2⁵椎管内非包含型椎间盘突出症安全、合理、疗效优异的微创脊柱外科手术技术。     

经皮腰椎间孔成形内窥镜下椎间盘切除术治疗腰椎间盘突出症的疗效观察

目的:观察经皮腰椎间孔成形、经椎间孔内窥镜下椎间盘切除术治疗非包含型腰椎间盘突出症的近期疗效.方法:2007年4月～2007年7月收治非包含型腰椎间盘突出症患者26例,其中L3/4 4例,L4/5 12例,L5/S1 10例.应用自制椎间孔成形器械行经皮腰椎间孔扩大成形、经椎间孔内窥镜下椎间盘切除术,分析治疗前及治疗后9个月时腰痛及腿痛视觉模拟评分(VAS)的变化情况,术后9个月时采用MacNab功能评分判断疗效.结果:手术均顺利完成,手术时间45～120min,平均75min;术中出血量20～50ml,平均35ml.2例患者术后1周出现下肢"日光烧灼综合征",均为L5/S1椎间盘突出,经过脉冲电刺激治疗1周后缓解;无其他手术并发症发生.随访9个月,腰痛VAS评分术前6.3±2.5分,术后1d 2.1±1.3分,术后3个月1.8±1.6分,术后9个月1.5±1.1分:腿痛VAS评分术前8.6±2.1分,术后1d 1.1±0.7分,术后3个月0.5±0.6分,术后9个月03±0.1分;术后腰痛和腿痛的VAS评分较术前均明显降低(P<0.01).按照MacNab评分标准,术后9个,月随访时优18例,良8例,优良率为100％.结论:经皮腰椎间孔成形、经椎间孔内窥镜下椎间盘切除术治疗非包含型腰椎间盘突出症患者创伤小、近期疗效好.     

微创经椎板间入路脊柱内窥镜椎间盘摘除术治疗L5S1椎间盘突出症

目的评价微创经椎板间入路脊柱内窥镜治疗L5S1椎间盘突出症的疗效。方法对49例瞄。椎间盘突出症均行经椎板间入路脊柱全内窥镜下微创椎间盘切除术。结果49例获得6-9个月,平均7个月的随访。术后各随访时间的腰痛及腿痛VAS、ODI评分较术前均明显改善,差异有统计学意义（P〈0．05）,而术后各时间点之间比较差异无统计学意义（P〉0．05）。末次随访时疗效评定按腰椎改良MacNab功能标准：优22例,良26例,可1例。结论经椎板间入路脊柱内窥镜治疗腰椎间盘突出症安全、微创、有效。     

经皮内镜椎板间入路髓核摘除术联合纤维环修复治疗L5S1椎间盘突出症

目的比较经皮内镜椎板间入路髓核摘除术联合纤维环修复与单纯行经皮内镜椎板间入路髓核摘除术治疗L5S1椎间盘突出症的临床疗效。方法回顾性分析自2017-02—2018-09采用手术治疗的76例L5S1椎间盘突出症,35例采用经皮内镜椎板间入路髓核摘除术联合纤维环修复术治疗(观察组),41例单纯采用经皮内镜椎板间入路髓核摘除术治疗(对照组),比较2组术后L5S1椎间盘突出症复发情况、术后1、3、12个月疼痛VAS评分与ODI指数,以及术后12个月改良Macnab评分。结果2组均获得完整随访,随访时间12~23个月,平均16.1个月,无脑脊液漏、神经根损伤、椎管内血肿等并发症,术后观察组无复发L5S1椎间盘突出症,对照组6例复发L5S1椎间盘突出症,经对症治疗后治愈,观察组术后复发率较对照组低,差异有统计学意义(P<0.05)。2组手术时间、术中出血量、术后1、3、12个月疼痛VAS评分与ODI指数、术后12个月改良Macnab评分比较差异无统计学意义(P>0.05)。结论经皮内镜椎板间入路髓核摘除术联合纤维环修复治疗L5S1椎间盘突出症能够有效降低术后椎间盘突出症的复发率,获得良好的早期疗效,值得临床推广。     

经椎板间隙内镜下L_5～S_1椎间盘摘除术疗效观察

目的总结经椎板间隙入路内镜下L5~S1椎间盘摘除手术经验并评价其临床效果。方法将32例椎间盘突出患者根据L5~S1椎间盘突出物与S1神经根的位置关系分成腋型(14例)、腹型(11例)及肩型(7例)。均采用经椎板间隙内镜下摘除L5~S1椎间盘。术后第3天、3个月复查腰椎MRI评估椎间盘切除的情况,记录术前及术后3、6、12个月的腰、腿痛视觉模拟评分(VSA)和功能障碍指数(ODI),记录术后12个月的腰椎Mac Nab评分,根据Roberts标准和MRI评价椎间隙高度。结果手术时间30~85(45.3±15.8)min。患者均获随访,时间18~42(25.8±8.4)个月。椎间隙高度分级评分:术前为(2.13±0.56)分,术后末次随访为(2.63±0.61)分,差异有统计学意义(P0.01)。无神经损伤、感染及其他手术并发症。1例术后复发,椎间盘再次突出,通过内镜下再次椎间盘翻修术后随访17个月无复发。术后3、6、12个月腰、腿痛VAS及ODI评分均较术前明显降低(P0.01);术后12个月时Mac Nab评分:优22例,良8例,可1例,差1例。术后随访12个月时S1神经根功能状态:神经根支配区感觉和肌力较术前明显改善(P0.01),而跟腱反射和术前相比恢复不明显(P0.05)。结论经椎板间隙内镜下手术治疗L5~S1椎间盘突出手术安全,时间短,是治疗非包含型椎间盘突出的有效方法。     

经皮椎板间隙入路L5S1椎间盘切除术

目的探讨经皮椎板间隙入路内窥镜激光辅助椎间盘切除术治疗L5S1椎间盘突出症的疗效。方法回顾性研究2002年5月至2003年12月收治的L5S1椎间盘突出症病例168例,全部采用局麻下经皮椎板间隙入路内窥镜激光辅助椎间盘切除术,男92例,女76例;年龄18～73岁,平均42.8岁。依据Yeung分型,中央型22例、旁正中型120例、椎间孔型23例、椎间孔外侧型3例。其中钙化突出椎间盘8例,游离椎间盘19例。骶髂间距平均38.6mm。结果随访5～19个月,平均8.3个月。手术时间30￣90min,平均45min;平均住院时间1.3d。临床结果以MacNab标准评定,优73例(43.5%),良79例(47.0%),可8例(4.8%),差8例(4.8%);优良率90.5%。1例发生术中显微髓核钳断裂,8例术后MRI显示病变椎间盘减压不彻底、症状体征未改善,1例发生椎间盘炎,26例出现术后一过性感觉麻木。无一例发生死亡、硬脊膜破裂及脑脊液漏、血管损伤。结论L5S1的椎间盘突出可以采用经皮椎板间隙入椎管途径的内窥镜激光辅助椎间盘切除术,特别适用于髂嵴较高的患者。     

经椎板间隙扩窗入路内窥镜下手术治疗伴椎板间隙狭窄的L5/S1椎间盘突出症

目的:评价采用常规器械扩窗经椎板间隙入路内窥镜下手术治疗伴椎板间隙狭窄的L5/S1椎间盘突出症的可行性.方法:2011年9月～2012年6月应用常规器械扩窗经椎板间隙入路内窥镜下椎间盘切除术治疗伴椎板间隙狭窄的L5/S1腰椎间盘突出症患者45例,其中男29例,女16例;年龄16～53岁,平均35.7岁.突出类型:肩上型25例,腋下型10例,混合型5例,游离型5例.统计手术时间、术中 出 血量、扩窗咬除骨量及并发症等手术基本情况.术前及术后3d、2周、1个月、3个月、6个月进行腰腿痛视觉模拟评分(VAS).结果:所有病例均顺利完成手术和各时间点VAS评分.手术时间60～125min,平均83.5min;术中出血约10～50ml,平均25ml术中扩窗咬除骨量约3～1g,平均6g.术中无神经根损伤、硬膜囊撕裂.术后3例出现下肢麻木感,1周后均恢复,术后无出血、感染等其他并发症.术后各时间点腰腿痛VAS与术前比较有显著性差异(P＜0.05).结论:采用经椎板间隙入路内窥镜下椎间盘切除术治疗伴椎板间隙狭窄的L5/S1椎间盘突出症时,常规器械扩窗具有较大的安全性,操作步骤简单,不需要复杂昂贵的专门设备.     

腰椎椎间盘突出症经椎板间和经椎间孔入路内镜治疗的比较研究

目的 探讨经皮内镜治疗L5/S1腰椎椎间盘突出症的入路选择。 方法 2011年8月~2012年8月符合入选条件的68例L5/S1腰椎椎间盘突出患者按入院奇偶顺序分成2组,椎板间入路组34例,椎间孔入路组34例。对2种手术入路的手术时间、透视次数、术中患者耐受情况、患者疗效满意度、术后残余症状、并发症及术前术后疼痛视觉模拟量表（visual analogue scale, VAS）评分进行比较。 结果 椎板间入路组有4例术中改为椎间孔入路,椎间孔入路组有7例改为椎板间入路,经椎板间入路和椎间孔入路手术时间分别是（50.2±7.0）min、（61.9±9.6）min（P＜0.05）,术中透视次数分别为5.4±2.3次、10.3±2.5次（P＜0.05）,2种入路治疗后腿痛术后即刻及术后3个月VAS评分与术前相比差异均有统计学意义（P＜0.05）。改良MacNab标准评定2组间差异无统计学意义（P＞0.05）。 结论 经皮内镜下治疗L5/S1腰椎椎间盘突出症经椎板间或经椎间孔入路治疗各有特点,且均能取得优良的临床疗效,但需针对患者的解剖情况、影像定位及临床表型选择适宜的个体化手术入路。     

脊柱内窥镜直接与间接椎板间隙入路的选择

目的探讨脊柱内窥镜直接与间接椎板间隙入路治疗腰椎间盘突出症(LDH)的选择及疗效。方法应用椎板间隙入路治疗L5S1椎间盘突出症12例,其中直接入路4例,间接入路8例。结果术后腰痛和腿痛VAS评分均较术前降低(P<0.01)。按照MacNab标准评定:直接入路组优2例,良1例,可1例;间接入路组优7例,良1例。结论直接入路适用于突出间盘较大并将神经根、硬膜囊推开的患者,间接入路适用于所有类型的椎管内突出的患者。     

后外侧入路椎间孔镜下L_5/S_1椎间盘突出伴高髂嵴髓核摘除术的技术改进

目的探讨经皮椎间孔镜后外侧入路完成L5/S1椎间盘突出伴高髂嵴的髓核摘除术操作技巧。方法 2014年1月～2016年4月,对148例L5/S1椎间盘突出伴高髂嵴,实施经后外侧椎间孔镜椎间盘髓核摘除术,采用导杆再置和偏心环锯等改良方法。结果手术均顺利完成,术后即刻腿痛视觉模拟评分(Visual Analogue Scale,VAS)由术前(7.27±0.73)分降为(1.88±0.28)分,无感染、硬脊膜损伤及神经根损伤等并发症发生。随访12～26个月,平均16.2月。椎间盘突出复发或下肢疼痛加重9例。术后3个月[(1.82±0.32)分]、末次随访[(1.80±0.32)分]腿痛VAS评分较术前均明显降低(P=0.000),术后各时点腿痛VAS差异无统计学意义(P0.05);术后3个月[(12.28±1.62)分]、末次随访[(11.88±1.50)分]Oswestry功能障碍指数(Oswestry Disability Index,ODI)较术前[(31.13±2.45)分]显著降低(P0.05);末次随访改良MacNab标准优、良、可、差分别为118、16、5、9例,优良率90.5%(134/148)。结论 L5/S1椎间盘突出伴高髂嵴患者通过后外侧椎间孔入路行椎间孔镜椎间盘髓核摘除术,在导杆再置和偏心环锯等改良方法的基础上是可行和有效的。     

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.