Quadrant通道下减压经皮椎弓根螺钉固定治疗腰椎管狭窄症

[目的]探讨MAST Quadrant通道结合Sextant行椎管减压、椎间盘切除、椎间植骨融合、经皮椎弓根螺钉复位固定治疗腰椎管狭窄症的效果.[方法]对符合行腰椎后路椎间融合术手术指征的55例患者随机分为微创组(MAST Quadrant通道下微创腰椎融合术28例)和开放组(传统技术行后路腰椎融合术27例),比较两组手术时间、术中出血量、住院时间、术后服止痛药时间、ODI评分、JOA评分等方面的差异.[结果]手术时间:微创组160～195 (170.25±11.72) min,开放组145～180 (164.32±12.59) min (P＜0.05);术中出血量:微创组200～310(245.30±35.60) ml,开放组600 ～920 (654.09±62.38) ml (P＜0.05);术后住院时间:微创组6～10 (7.4±1.78)d,开放组12～16 (14.31±2.85)d(P＜0.05);术后服止痛药时间:微创组7～14 (10.05±7.56)d,开放组12～25 (17.41±6.90) d(P＜0.05).55例术后切口均Ⅰ期愈合,患者均获得随访,时间6～24 (16.3±5.70)个月.末次随访时ODI评分:微创组4～16 (10.13±2.85)分,开放组10 ～20 (14.85±2.89)分(P ＜0.05);JOA评分:微创组21～28 (24.65±2.78)分,开放组16～28 (21.389±3.57)分(P＜0.05);VAS评分:微创组2～6(2.5±0.4)分,开放组5～8(3.1±0.7)分(P＜0.05).术后6个月X线片示54例患者椎间骨性融合,1例骨性椎间融合尚不完全,未见椎弓根螺钉松动、断裂或移位.[结论]在严格掌握手术适应证的情况下,经MAST Quad-rant通道结合Sextant经皮椎弓根螺钉系统行腰椎融合术是一种安全有效的微创方法.     

椎间盘镜下减压椎间融合结合经皮椎弓根螺钉固定的疗效观察

[目的]探讨椎间盘镜下后路腰椎管减压、椎间植骨融合结合经皮椎弓根螺钉固定治疗腰椎退变性疾病的早期疗效及临床体会.[方法]2008年2月～2010年12月椎间盘镜下行后路腰椎管减压、椎间植骨加融合器置入、经皮椎弓根螺钉固定治疗25例患者,男11例,女14例,平均53.3岁.腰椎不稳11例,Ⅰ度腰椎滑脱10例,椎间盘突出症术后复发4例.单阶段双侧固定12例,单阶段单侧固定9例,双阶段双侧固定4例.随访观察治疗效果.[结果]手术时间平均170min.术中失血量平均195ml.术后住院时间平均12d.手术切口均一期愈合.随访10 ～34个月,平均21.7个月.ODI评分术前为(46.55±10.12)分,术后1个月及末次随访时分别为(22.15±8.36)分和(13.24±5.31)分,与术前比较均有显著性差异(P＜0.01).VAS评分术前为(7.15±1.11)分,术后1个月及末次随访时分别为(3.52±1.31)分和(1.45±0.81)分,与术前比较均有显著性差异(P＜0.01).[结论]椎间盘镜下减压、椎间融合结合经皮椎弓根螺钉固定治疗腰椎退变性疾病具有手术切口小、腰骶肌肉剥离范围小、出血少、术后恢复快等优点,可获得良好的近期临床效果,是一种安全有效的微创手术方法.     

微创Quadrant通道下椎间融合术治疗复发性腰椎间盘突出症的初步疗效

【摘要】〓目的〓评价腰椎后路微创Quadrant 通道下椎间融合术治疗复发性腰椎间盘突出症的初步临床疗效。方法〓2010年1月~2012年12月,我科收治25例复发性腰椎间盘突出症患者,采用后路原切口双侧肌间隙入路(Wiltse入路),经微创Quadrant 通道下行椎间融合术。应用Oswestry功能障碍指数(ODI)及疼痛视觉类比评分(VAS)对患者再次手术前、手术后进行临床疗效评价,腰椎薄层CT扫描及三维重建评估椎体间融合。结果〓25例患者均获得随访,随访的时间为12~36个月,平均19.2个月。术前VAS平均评分为8.26±1.4分,术后末次随访VAS平均评分为2.47±0.65分,与术前比较差异有统计学意义(P<0.05)。ODI评分术前平均40.32±3.14分,术后末次随访平均为6.67±2.54分,与术前比较差异有统计学意义(P<0.05)。末次随访椎体间植骨均融合,无椎弓根螺钉断裂和融合器移位。结论〓微创Quadrant通道下椎间融合术治疗复发性腰椎间盘突出症安全有效。     

腰椎结核后路微创内固定软组织保护叶片的设计与应用

[目的]设计一种腰椎结核后路手术软组织保护叶片,并评估其在辅助完成腰椎结核后路微创内固定应用价值。[方法]2013年12月~2015年3月采用自制软组织保护叶片辅助经皮置入椎弓根螺钉固定治疗19例腰椎结核患者,男11例,女8例;年龄20~68岁,平均(48.5±2.4)岁;损伤节段L_(1~5)。记录手术时间并分析后凸Cobb角、VAS评分的恢复情况,并观察并发症发生情况。[结果]手术时间平均(85±12)min。术后所有患者随访7~18个月,平均11个月。Cobb角由术前平均(23.7±4.6)°,减少至术后6个月平均(5.4±2.1)°,与术前相比差异有统计学意义(P0.05)。VAS评分由术前平均(7.8±1.1)分,减少至术后6个月平均(1.7±0.2)分,差异有统计学意义(P0.05);所有病例后路切口愈合良好,6个月CT检查均见植骨融合。[结论]自行研制的软组织保护叶片辅助腰椎结核后路椎弓根螺钉微创置入,切口小、创伤小、简便实用。     

经皮自旋转撑开椎弓根钉内固定系统治疗胸腰椎骨折

目的探讨自行研制的经皮自旋转撑开椎弓根螺钉内固定系统(RTS)治疗单纯胸腰椎新鲜骨折的临床疗效。方法分析应用经皮微创自动旋转撑开椎弓根钉内固定系统(RTS)治疗单纯胸腰椎新鲜骨折30例。结果 30例获随访3~12个月。术前骨折椎体前缘压缩程度为(52.5±4.6)%,后凸Cobb角为(23.4±3.8)°,术后骨折椎体前缘压缩程度为(5.8±3.3)%,后凸Cobb角为(5.2±2.4)°,两者与术前相比较,差异有统计学意义(P0.05)。术后半年无内固定松动、断裂发生,骨折的椎体高度恢复后维持良好。术后半年手术节段的腰背痛VAS评分0~2分,平均0.5分。结论 RTS系统治疗单纯胸腰椎新鲜骨折能够达到微创、安全且满意的治疗效果。     

Quadrant通道结合经皮椎弓根螺钉固定治疗腰椎间盘突出症

目的探讨应用Quadrant通道结合经皮椎弓根螺钉固定技术治疗腰椎间盘突出症的临床疗效。方法 2011-10-2014-02,将符合纳入标准的96例患者随机分为两组,微创组:48例,采用Quadrant通道结合经皮椎弓根螺钉固定技术;传统手术组:48例,行后路切开椎弓根钉固定融合术。术后及随访时复查腰椎X线及CT,评估植入螺钉的位置及融合率,统计手术时间、术中出血量、切口总长度,术后肌酸激酶变化,以及下地活动时间、住院时间、临床疗效、并发症等方面,并进行比较分析。结果所有患者随访10~22月,平均(15±2)个月,两组植入螺钉的位置及融合率、手术时间、总切口长度、术后1年VAS、ODI评分方面比较,差异无统计学意义(P0.05);但术中出血量,术后肌酸激酶变化、下地活动时间、住院时间及术后第3天VAS评分方面比较,微创组优于传统手术组,两组差异有统计学意义(P0.05)。两组病例均未出现脑脊液漏、神经损伤等并发症。结论应用Quadrant通道结合经皮椎弓根螺钉固定技术治疗腰椎间盘突出症,较传统融合方法具有创伤小、出血少、组织损伤轻、术后恢复快等优点。     

改良内窥镜下行后路腰椎间融合和经皮椎弓根螺钉固定治疗腰椎退变性疾患

目的探讨改良内窥镜下后路腰椎管减压、椎间融合和经皮椎弓根螺钉固定治疗腰椎退变性疾病的可行性和有效性.方法2006年2月～2007年3月应用自制直径2.6cm工作通道在METRx内窥镜下行后路腰椎管减压、椎间植骨加融合器置入、经皮椎弓根螺钉固定治疗12例患者,男7例,女5例,年龄38～72岁,平均51.2岁.腰椎管狭窄症5例,Ⅰ度腰椎滑脱症4例,腰椎间盘突出症术后复发3例.随访观察治疗效果.结果手术时间150～260 min,平均175min.术中失血量50～300 ml,平均150ml.术后住院时间7～16 d,平均12d.1例发生硬膜外血肿,行内窥镜下翻修手术.手术切口均一期愈合.随访3～15个月,平均6.3个月.ODI评分术前为46.32±10.14分,术后1个月及末次随访时分别为21.75±8.59分和11.06±5.27分,与术前比较均有显著性差异(P＜0.01).VAS评分术前为7.12±1.06分,术后1个月及末次随访时分别为3.45±1.28分和1.29±0.77分,与术前比较均有显著性差异(P＜0.01).末次随访时采用改良Macnab标准评价临床效果,本组优5例,良6例,可1例.结论改良内窥镜下后路腰椎管减压、椎间融合和经皮椎弓根螺钉固定治疗腰椎退变性疾病可获得良好的近期临床效果,是一种安全有效的微创手术方法.     

显微镜辅助微创经椎间孔腰椎椎间融合术治疗单节段腰椎滑脱症

目的 探讨显微镜辅助经Quadrant通道结合经皮椎弓根钉固定行微创小切口经椎间孔腰椎椎间融合术（MIS-TLIF)治疗单节段腰椎退行性滑脱症的疗效。方法 回顾性分析2018年4月至2021年3月行椎体间融合术治疗单节段腰椎退行性滑脱症患者的临床资料,其中采用开放经椎间孔腰椎椎间融合术(TLIF)治疗患者41例(开放组),经Wiltse入路Quadrant通道直视下TLIF治疗患者25例(微创组),显微镜下减压并采用经皮椎弓根钉TLIF治疗患者38例(显微组)。记录3组患者手术时间、术中出血量、X线透视次数、引流量、术后2天和7天切口周围疼痛视觉模拟评分（VAS）、并发症情况,术后CT检查评估椎弓根钉置钉准确率,记录术前及术后6个月、24个月日本骨科协会（JOA）评分和Oswestry功能障碍指数（ODI）,末次随访时采用改良MacNab标准评价临床疗效。结果 所有手术均顺利完成。显微组术中出血量、引流量、术后2天和7天切口周围疼痛VAS评分均小于微创组和开放组（P<0.05）,椎弓根钉置钉准确率高于微创组和开放组（P<0.05）,但术中X线透视次数高于微创组和开放组（P&...     

Quadrant通道下微创腰椎后路融合术治疗单节段腰椎退行性疾病

目的探讨Quadrant通道下微创腰椎后路融合术治疗单节段腰椎退行性疾病的临床效果。方法回顾性分析2014年11月至2016年3月南京医科大学附属苏州医院收治的12例单节段腰椎退行性疾病的临床资料,所有患者均在Quadrant通道下经多裂肌与最长肌间隙行微创腰椎后路融合手术。其中腰椎后路椎体间融合10例、腰椎后外侧融合2例。记录手术时间、术中出血量、术后引流量、术后血红蛋白水平,以及术前、末次随访时疼痛视觉模拟量表(VAS)评分和Oswestry功能障碍指数(ODI)。结果手术时间120~260 min,平均手术时间180 min;术中出血量50~800 mL,平均术中出血量375 mL;术后引流量8~321 mL,平均引流量128mL;术后血红蛋白水平93~138 g/L,平均血红蛋白水平113 g/L。所有患者无脑脊液漏、神经根损伤、感染及术后顽固性腰背痛发生。随访5~21个月(平均16个月),术前、术后末次随访VAS评分和ODI分别为(6.4±1.0)、(2.0±0.7)分和(18±4)、(46±10)分,手术前后比较,差异均有统计学意义(P0.05)。结论 Quadrant通道下经多裂肌与最长肌间隙入路行腰椎后路融合手术治疗单节段腰椎退行性疾病具有出血少、对后方韧带破坏小、脊柱稳定性好、功能恢复快等优点,符合微创理念,值得临床推广应用。     

通道下单侧椎体间减压融合内固定结合对侧经皮椎弓根螺钉内固定治疗腰椎退变性疾病

目的探讨采用Quadrant通道下单侧椎体间减压融合内固定结合对侧经皮椎弓根螺钉内固定治疗腰椎退变性疾病的方法及疗效。方法 2009年9月至2012年12月,采用Quadrant通道下单侧PLIF技术结合对侧经皮椎弓根螺钉内固定微创治疗腰椎退变性疾病共20例,男8例,女12例;年龄45~66岁,平均57.5岁。病程1~8年,平均36.5个月。腰椎间盘突出症11例,复发性腰椎间盘突出症4例,腰椎间盘突出合并1°退变性滑脱症3例,腰椎间盘突出合并腰椎不稳症2例。术前患者腰痛视觉模拟疼痛评分(visual analogue scale,VAS)为(6.5±1.1)分。结果患者手术时间(150±20)min,术中出血量(340±90)mL,术后住院时间为(11.0±3.5)d。术后切口均Ⅰ期愈合。患者均获随访,随访时间6~20个月,平均15.2个月。末次随访时VAS评分为(1.4±2.2)分,与术前比较差异有统计学意义(P0.05)。X线片示术后6个月椎体间达骨性融合,未见椎弓根螺钉内固定系统松动、断裂或移位。末次随访时临床疗效按改良Macnab标准评定,获优18例,良2例。结论对于单节段病变,且只需要单侧操作即可完成减压和椎间融合者,Quadrant通道下单侧椎体间融合内固定结合对侧经皮椎弓根螺钉内固定是一种可供临床选择的微创手术方式。     

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.     

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.