波及后髁的胫骨平台骨折手术入路选择

目的以胫骨平台三柱分型理论为指导,设计波及后髁胫骨平台骨折的手术入路并观察术后疗效。方法自2011-01—2013-09以三柱分型理论为指导对17例波及后髁的胫骨平台骨折设计相应的手术入路进行内固定,单纯后柱骨折以及后柱骨折+内侧柱骨折设计膝关节后方倒L形入路,外侧柱+后柱骨折以及外侧柱+内侧柱+后柱骨折设计膝关节后方倒L形入路+前外侧入路。术后定期摄膝关节X线片观察骨折愈合情况并测量胫骨平台的内翻角及后倾角,以膝关节Rasmussen功能评分对术后疗效进行评估。结果17例术后均获平均13.7(12~17)个月随访。骨折临床愈合时间为3~8个月,平均5.6个月。术后即刻胫骨平台内翻角为(86.27±0.35)°,术后1年为(86.39±0.32)°,差异无统计学意义(t=-0.911,P=0.376);术后即刻胫骨平台后倾角为(9.15±0.34)°,术后1年胫骨平台后倾角为(9.17±0.34)°,差异无统计学意义(t=0.557,P=0.585)。术后1年膝关节功能Rasmussen评分:优9例,良7例,可1例,优良率94.1%。结论胫骨平台三柱分型理论对设计波及后髁的胫骨平台骨折手术入路有指导意义,但该理论在设计胫骨平台后髁合并外侧髁骨折手术入路时可能需要进一步明确骨折亚型。     

膝前正中加后内侧入路联合三柱钢板内固定治疗复杂胫骨平台骨折

目的 ：探讨膝前正中加后内侧入路联合三柱钢板内固定治疗复杂胫骨平台骨折的手术方法及临床疗效。方法：自2010年1月至2012年12月,采用膝前正中加后内侧入路联合三柱钢板内固定治疗复杂胫骨平台骨折28例。男17例,女11例;年龄28~64岁,平均45.3岁;左侧12例,右侧16例。按Schatzker分型：Ⅴ型12例,Ⅵ型16例。三柱分型：均为涉及三柱。受伤至手术时间6~15 d,平均9.4 d。术前主要临床症状为膝关节肿胀、畸形及活动受限,X线及CT检查均提示复杂性胫骨平台骨折胫骨平台三柱均涉及。术后随访骨折愈合时间,术后1年按照美国特种外科医院膝关节评分（HSS评分）评价临床疗效,比较术后即刻及术后1年胫骨平台内翻角、后倾角、股胫角等力学指标的变化。结果：术后切口均甲级愈合,未发现切口感染及皮肤坏死等并发症。28例术后均获随访,时间12~24个月,平均18.1个月。骨折愈合时间5~10个月,平均7.8个月。骨折愈合后患者膝关节肿痛消退,关节功能基本恢复正常。HSS评分：疼痛27.81±2.17,功能19.52±2.05,活动范围15.82±1.73,肌力8.51±1.32,屈曲畸形8.33±1.08,关节稳定性9.36±0.52,总分89.35±3.19;优20例,良5例,中2例,差1例。术后与术后1年胫骨平台内翻角、后倾角、股胫角比较差异均无统计学意义。结论：采用膝前正中加后内侧入路联合三柱钢板内固定治疗复杂胫骨平台骨折可达到解剖复位、坚强固定及早期功能锻炼的目的,是一种行之有效的手术治疗方法。     

联合入路双钢板内固定治疗骨折脱位型胫骨内侧平台骨折

目的 :探讨膝前正中入路联合后内侧倒"L"形入路双接骨板内固定治疗骨折脱位型胫骨内侧平台骨折的临床疗效。方法:自2010年2月至2013年9月收治17例骨折脱位型胫骨内侧平台骨折患者,男11例,女6例;年龄21~65岁,平均42岁。采用前正中入路复位固定内侧平台骨折块,后内侧倒"L"形入路复位及支撑固定后内侧骨块,术后进行临床和影像学随访,采用HSS评分进行评价。结果:所有患者获随访,时间11~25个月,平均18个月。术后即刻和随访终末胫骨平台内翻角(TPA)分别为(87.8±4.2)°和(88.2±4.6)°,差异无统计学意义(P=0.458);术后即刻和随访终末胫骨内侧平台后倾角(PSA)分别为(10.1±3.7)°和(10.3±4.1)°,差异无统计学意义(P=0.512)。膝关节HSS评分86.7±6.1,所有患者无感染、皮肤坏死、内固定松动断裂及骨折复位丢失等并发症。结论:联合入路双钢板固定治疗骨折脱位型胫骨内侧平台骨折,具有显露清楚、复位满意、固定可靠、便于早期功能锻炼等优点,临床效果满意。     

后外侧联合后内侧入路治疗胫骨平台后柱骨折的临床研究

目的观察后外侧联合后内侧入路治疗胫骨平台后柱骨折手术方法及临床疗效。方法对13例胫骨平台后柱骨折采用后外侧联合后内侧入路切开复位内固定术进行治疗。比较术后即刻、12个月的胫骨平台内翻角(TPA)、胫骨平台后倾角(PA)。采用HSS膝关节评分及膝关节活动度(ROM)评价术后疗效。结果本组均获12~20个月随访,骨折全部愈合,术后12个月HSS膝关节评分73~92分,平均(82.4±6.8)分,ROM平均为(121.6±1.2)°。术后即刻与12个月TPA、PA度数差异均无统计学意义(P>0.05)。结论后内侧联合后外侧入路可治疗广泛而复杂的胫骨平台后柱骨折,采用双切口对于后内侧和后外侧骨折复位和固定都较充分,对软组织创伤较小,利于关节功能恢复。     

联合入路手术治疗复杂胫骨平台骨折

目的:探讨后内侧倒"L"形辅助前外侧联合入路手术治疗复杂胫骨平台骨折的早期临床疗效。方法:自2011年3月至2014年6月,采用后内侧倒"L"形辅助前外侧联合入路手术治疗SchatzkerⅣ、Ⅴ、Ⅵ型胫骨平台骨折34例,其中男23例,女11例;年龄18~67岁,平均34.9岁;左侧19例,右侧15例。按Schatzker分型:Ⅳ型11例,Ⅴ型15例,Ⅵ型8例。按三柱分型:双柱骨折23例,三柱骨折11例。记录X线愈合时间、膝关节活动度,测量并记录患者术后即刻、6、12个月胫骨平台内翻角(TPA)及后倾角(PA),术后3、6、12个月采用美国特种外科医院评分系统(HSS)评定膝关节功能。结果:28例患者获得随访,时间8~39个月,平均(21.6±8.7)个月。骨折全部愈合,X线愈合时间12~24周,平均(14.5±3.6)周;膝关节活动度105°~135°,平均(121.5±5.5)°。术后即刻、6、12个月胫骨平台内翻角分别为(84.3±1.8)°,(85.1±1.3)°和(85.6±1.6)°;后倾角分别为(7.8±1.6)°,(7.8±1.3)°和(7.7±2.3)°;术后即刻、6、12个月胫骨平台内翻角及后倾角比较差异均无统计学意义。术后3、6、12个月HSS膝关节功能评分为71.4±1.4,76.7±1.7和81.6±1.2;术后3、6、12个月HSS膝关节功能评分比较差异均无统计学意义。1例早期膝关节僵硬,经积极功能锻炼,术后1年膝关节伸直受限范围6°;1例术后前外侧伤口裂开,经换药后愈合,未发生深部感染;4例天气变化时出现疼痛。末次随访,无膝关节不稳、膝关节外翻、内固定松动及断裂发生。结论:后内侧倒"L"形辅助前外侧联合入路手术治疗复杂胫骨平台骨折,能够充分显露手术区域,直视下精准复位骨折,同时对塌陷平台进行足量植骨,从而恢复了关节面的平整性,固定牢靠,利于早期功能锻炼,并发症少,临床疗效满意。     

联合入路双钢板固定治疗陈旧性Schatzker Ⅳ型胫骨平台骨折

目的:探讨膝前正中联合内后纵行入路双锁定钢板固定治疗陈旧性SchatzkerⅣ型胫骨平台骨折的临床疗效。方法:自2013年7月至2015年7月,采用膝前正中联合内后侧纵行手术入路、重建锁定钢板固定后内侧骨块及解剖锁定钢板固定内前侧骨块治疗15例陈旧性胫骨平台骨折患者,男9例,女6例;年龄21~61岁,平均49.2岁;左侧8例,右侧7例。均为SchatzkerⅣ型。受伤至手术时间21~65 d,平均26.5 d。术前主要症状体征为膝关节肿胀、疼痛、畸形及活动受限,X线及CT检查确定骨折类型。通过X线片比较术后即刻及末次随访胫骨平台内翻角、股胫角及后倾角等形态学变化,采用美国特种外科医院(Hospital for Special Surgery,HSS)膝关节评分评价临床疗效。结果:术后2例发生切口并发症,经处理愈合;1例继发创伤性关节炎。15例患者均获随访,时间13~24个月,平均16.6个月。无感染、下肢深静脉血栓、内固定松动断裂、骨折再移位及关节面塌陷等并发症发生。骨折愈合时间3~8个月,平均6.07个月。胫骨平台内翻角、股胫角及后倾角,术后即刻分别为(86.81±1.67)°、(168.00±3.29)°及(10.20±1.47)°,末次随访分别为(86.47±1.67)°、(168.53±3.03)°及(10.54±1.21)°,差异无统计学意义(P0.05);HSS膝关节评分:疼痛26.33±3.86,功能20.00±1.79,活动度16.00±1.55,肌力8.67±0.94,屈曲畸形8.53±1.67,稳定性9.33±0.94,总分88.86±8.92;优10例,良4例,中1例。结论:膝前正中联合后内侧入路、双锁定钢板固定治疗陈旧性SchatzkerⅣ型胫骨平台骨折,具有显露充分、复位固定可靠及便于膝关节早期功能锻炼等优点,术后近期疗效满意。     

改良前外侧入路锁定钢板内固定治疗孤立性后外侧胫骨平台骨折疗效分析

目的探讨改良前外侧入路锁定钢板内固定治疗孤立性后外侧胫骨平台骨折的临床疗效。方法回顾性分析自2015-01—2018-04采用改良前外侧入路锁定钢板内固定治疗的23例孤立性后外侧胫骨平台骨折。末次随访时采用HSS评分标准评价膝关节功能。结果 23例均获得随访,随访时间平均15.4(12～23)个月。骨折均骨性愈合,骨折愈合时间平均12(10～16)周。术后骨折复位情况根据Rasmussen评分标准评定:优17例,良6例。术后1年随访时均未见明显关节面复位丢失。术后即刻X线片测量胫骨平台内翻角为(87.3±0.5)°,术后1年为(87.7±1.2)°。术后即刻X线片测量胫骨平台后倾角为(7.3±0.7)°,术后1年为(7.5±1.2)°。术后1年随访时膝关节活动度平均125.5°(105°～135°)。末次随访时膝关节功能HSS评分:优12例,良9例,可2例。结论采用改良前外侧入路锁定钢板内固定治疗孤立性后外侧胫骨平台骨折可清晰地显露骨折部位并完成有效固定,较好地维持膝关节稳定性,有利于患者术后早期功能锻炼。     

后内侧入路倒L形切口结合重建钢板治疗胫骨平台后髁骨折

目的:探讨应用后内侧倒"L"形切口结合重建钢板治疗胫骨平台后髁骨折的临床疗效。方法:自2011年2月至2015年2月,采用后内侧倒"L"形切口直视下,重建钢板固定后髁治疗19例胫骨平台骨折患者,其中男14例,女5例;年龄28~71岁,平均45.5岁。受伤至手术时间6~15 d,平均9.2 d。按Schatzker分型:Ⅱ型6例,Ⅳ型2例,Ⅴ型7例,Ⅵ型4例。按三柱理论分型:内侧柱合并后柱骨折2例,外侧柱合并后柱骨折6例,三柱骨折11例。术前主要临床症状为膝关节肿胀、畸形及活动受限,X线及CT检查完善。术后采用美国特种外科医院膝关节HSS评分评价临床疗效。结果:术后1例患者出现内后侧切口皮肤感染,加强换药后愈合良好,无神经血管损伤、下肢深静脉栓塞、内固定断裂失效、骨折再移位等其他并发症发生。19例患者均获随访,时间10~24个月,平均12.5个月。随访患者术后定期复查X线片,骨折均Ⅰ期愈合,骨折愈合时间5~11个月,平均8.2个月。HSS评分总分82.1±7.3;优9例,良7例,中2例,差1例。术后3 d与术后1年骨折愈合后胫骨平台内翻角、后倾角、股胫角比较差异均无统计学意义。结论:采用膝关节后内侧入路倒"L"形切口治疗胫骨平台后髁骨折,显露充分,损伤小,内固定安装方便、有效。重建钢板具有易于塑形、支撑性较强、内植入体积小、费用低廉的优点,配合恰当的术后康复训练,膝关节的结构和功能恢复可以取得满意的临床疗效。     

前外侧加后内侧入路治疗复杂胫骨平台骨折

目的 探讨前外侧加后内侧入路治疗复杂胫骨平台骨折的疗效. 方法 回顾性分析2008年1月至2011年12月收治且获得随访的68例SchatzkerⅤ、Ⅵ型胫骨平台骨折患者资料,男42例,女26例;年龄22～64岁,平均42.3岁;左侧24例,右侧44例.受伤至手术时间为3～15 d,平均7.4d.所有患者胫骨平台骨折均采用前外侧加后内侧入路,外侧采用T型或L型钢板、后内侧采用重建钢板或桡骨远端T型钢板固定治疗.末次随访时按照美国特种外科医院膝关节功能评分法评定疗效. 结果 本组患者手术时间平均为3.13h,术中出血量平均为526.7 mL,住院时间平均为20.4d.68例患者术后获12 ～ 38个月(平均18.8个月)随访.骨折愈合时间为4～8个月,平均6.7个月.68例患者术后即刻胫骨平台内翻角、后倾角、股胫角平均分别为87.3°±1.5°、12.0°±2.5°、170.0°±2.5°,术后1年平均分别为86.8°±1.2°、13.0°±1.8°、171.0°±1.7°,以上项目术后即刻与术后1年比较差异均无统计学意义(P＞0.05).末次随访时按照美国特种外科医院膝关节功能评分法评定疗效:优36例,良24例,中6例,差2例,优良率为88.2％.本组患者无神经及血管损伤、深部感染、内固定物松动或裂断等并发症发生. 结论 采用前外侧加后内侧入路治疗复杂胫骨平台骨折可达到解剖复位、坚强固定及早期进行功能锻炼的目的,效果满意.     

胫骨平台后侧骨折的手术治疗策略及疗效分析

目的探讨胫骨平台后侧骨折的手术治疗方法及疗效。方法自2009年1月~2012年1月共收治53例闭合性新鲜胫骨平台后侧骨折,所有患者入院后常规行X线摄片和64排CT三维重建。根据CT下"三柱理论"分类:其中后外侧柱骨折12例,后内侧柱骨折26例,后内侧及后外侧均有骨折者15例。采用膝关节后侧倒L形入路切开复位、桡骨远端T形普通钢板或锁定钢板固定15例,采用膝关节后内侧纵形入路切开复位、钢板固定26例,采用膝关节后外侧纵形入路切开复位、钢板或螺钉固定12例。术后按AKS评分评价膝关节功能恢复情况。结果 53例术后获12~30个月随访,末次随访时AKS评分平均87(58~95)分,15例采用膝关节后侧倒L形入路者AKS评分平均82(58~90)分,26例采用后内侧纵形入路者AKS评分平均91(70~95)分,12例采用后外侧纵形入路者AKS评分平均85(65~92)分。结论对于不同类型的胫骨平台后侧骨折,术前慎重评估软组织损伤,选用适当的手术入路与内固定方法,可以获得较好的疗效。     

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.