创伤性腰椎滑脱症的临床特征及手术治疗近期疗效北大核心CSCD

目的探讨创伤性腰椎滑脱症的临床特征及经后路手术治疗的近期疗效。方法回顾分析2008年1月-2012年6月收治的11例创伤性腰椎滑脱症患者临床资料。男6例,女5例;年龄13～60岁,中位年龄38岁。致伤原因:重物砸伤4例,高处坠落伤4例,交通事故伤3例。受伤至手术时间3 d～13年,中位时间20 d。术前神经功能Frankel分级为:E级2例,D级4例,C级3例,B级2例。X线片示L4滑脱3例,L58例。根据Meyerding分度:Ⅰ度4例,Ⅱ度4例,Ⅲ度2例,Ⅳ度1例。手术固定节段:L4、52例,L5、S17例,L4～S12例。行椎间及后外侧360°植骨融合8例,仅行后外侧植骨3例。术后随访行腰椎正侧位X线片及CT三维重建评价滑脱复位及植骨融合情况,通过疼痛视觉模拟评分(VAS)及Oswestry功能障碍指数(ODI)进行疗效评价。结果术后患者切口均Ⅰ期愈合。11例术后均获随访,随访时间6～40个月,中位时间12个月。无内固定物拔出、断裂等情况发生。CT三维重建显示患者植骨均融合,融合率100%,融合时间3～6个月,平均4.5个月。末次随访时腰椎X线片示滑脱Meyerding分度为0度10例,Ⅰ度1例,与术前比较差异有统计学意义(Z=—2.979,P=0.003)。末次随访时神经功能Frankel分级为E级6例,D级3例,C级2例,较术前显著改善(Z=—2.271,P=0.014)。术后1周及末次随访时VAS、ODI评分均较术前显著改善(P<0.05);术后1周和末次随访间比较差异无统计学意义(P>0.05)。结论急诊腰椎X线片发现多发横突骨折,结合患者受伤机制应高度怀疑创伤性腰椎滑脱症,尽早行经后路椎管减压、植骨融合内固定手术有助于创伤性腰椎滑脱症患者神经功能恢复,获得满意近期疗效。     

后路复位技术治疗急性重度创伤性腰椎滑脱症的疗效分析

目的总结后路复位技术治疗急性重度腰椎滑脱症的复位技巧及疗效。方法回顾性分析自2010年6月至2018年12月郑州市骨科医院脊柱外科采用后路复位技术治疗的急性重度创伤性腰椎滑脱症12例患者资料。男7例, 女5例;年龄(25.7±1.8)岁;L4滑脱4例, L5滑脱8例;滑脱程度根据Meyerding分级:Ⅲ度7例, Ⅳ度4例, Ⅴ度1例;术前神经功能按照美国脊髓损伤协会(ASIA)分级:B级6例, C级4例, D级2例。12例患者均行后路椎弓根螺钉复位内固定和椎间植骨融合术。记录患者的手术时间、术中失血量及并发症的发生情况。手术前、后通过疼痛视觉模拟评分(VAS)和Oswestry功能障碍指数(ODI)评估临床疗效, ASIA分级评价神经功能。X线、CT平扫及重建观察内固定及植骨愈合情况。结果所有患者术后随访(18.5±2.1)个月。手术时间为(165.7±42.3)min, 出血量为(497.7±75.3)mL。术后2周及末次随访时VAS评分[(2.7±0.3)、(1.8±0.2)分]、ODI(18.2%±2.3%、14.5%±2.6%)均较术前[(8.5±0.6)分、72.3%±12...     

青少年脊柱侧凸合并腰椎滑脱的术式选择

目的 :探讨青少年脊柱侧凸合并腰椎滑脱患者手术治疗方式的选择,观察脊柱侧凸及滑脱程度的转归。方法:对2002年5月~2011年1月收治的有完整影像学资料的9例青少年脊柱侧凸合并腰椎滑脱的患者进行回顾性分析。年龄10~18岁,平均14.4±2.7岁。功能性脊柱侧凸3例,特发性脊柱侧凸6例;发育性腰椎滑脱3例,峡部裂性腰椎滑脱6例。滑脱节段均为L5/S1,Ⅰ度滑脱4例,Ⅱ度滑脱2例,Ⅲ度滑脱2例,Ⅳ度滑脱1例。3例(1、3、4号)功能性侧凸患儿均行腰椎滑脱后路复位内固定植骨融合术。1例(2号)特发性脊柱胸腰双弯患儿侧凸Cobb角未达到手术干预标准,行单一腰椎滑脱后路复位内固定植骨融合术;2例(5、6号)无滑脱症状的特发性脊柱侧凸患儿行脊柱侧凸后路矫形内固定植骨融合术;3例(7~9号)伴腰椎滑脱症状者同时行后路滑脱复位与脊柱侧凸矫形联合手术。测量患者术前、术后、末次随访时的Cobb角及滑脱相关参数。结果:仅行单一腰椎滑脱后路复位内固定植骨融合术的4例患儿末次随访时的侧凸主弯Cobb角改善率分别为58.1%、11.5%、57.9%、36.7%,滑脱百分比改善率分别为61.3%、76.9%、59.7%、27.3%;2例仅行脊柱侧凸后路矫形内固定植骨融合术患儿的侧凸主弯Cobb角改善率分别为81.8%及68.6%,滑脱百分比改善率分别为71.8%及25.0%;3例同时行腰椎滑脱后路复位和脊柱侧凸矫形内固定植骨融合术患儿末次随访时Cobb角改善率分别为86.2%、75.6%、72.9%,滑脱百分比改善率分别为31.8%、50.0%、67.7%。7例患儿术前有不同程度的腰痛症状,1~4号患儿ODI评分为26.0(21.0~31.0)分,7~9号为23.0(15.0~29.0)分,末次随访时分别为7.0(5.0~10.0)分和6.0(5.0~8.0)分。9例患儿在术后及随访过程中均未出现并发症。结论:对青少年脊柱侧凸合并腰椎滑脱患儿应根据侧凸类型及腰椎滑脱程度选择手术方式,侧凸Cobb角大于40°伴腰椎滑脱所致腰痛症状时,应同时行脊柱侧凸矫形术和腰椎滑脱复位术;若仅满足腰椎滑脱复位内固定或者仅满足脊柱侧凸矫形的手术干预要求,可考虑行单一后路行腰椎滑脱复位内固定术或单一后路脊柱侧凸矫形手术。     

单枚或双枚cage椎间融合联合椎弓根螺钉固定治疗峡部裂性腰椎滑脱症疗效的比较

目的:比较单枚cage或双枚cage椎间融合联合椎弓根螺钉固定治疗峡部裂性腰椎滑脱症的疗效。方法:对2000年3月至2008年8月手术治疗的172例峡部裂性腰椎滑脱症患者的临床资料进行回顾性分析,172例患者均采用后路椎弓根螺钉固定椎间融合术。其中使用单枚cage融合89例(单枚组),男56例,女33例;年龄18~63岁,平均(41.60±8.20)岁;L_4滑脱25例,L_5滑脱64例;MeyerdingⅠ度滑脱32例,Ⅱ度46例,Ⅲ度11例。双枚cage融合83例(双枚组),男49例,女34例;年龄20~65岁,平均(43.30±6.39)岁;L_4滑脱21例,L_5滑脱62例;MeyerdingⅠ度滑脱25例,Ⅱ度45例,Ⅲ度13例。比较两种手术方式的手术时间、术中出血量、术后引流量、植骨融合率、椎间隙高度以及临床症状改善情况。结果:所有患者顺利完成手术并获得随访,随访时间18~83个月,平均4年3个月。单枚组平均手术时间、术中出血量、术后引流量均少于双枚组(P0.05)。术后2周两组椎间隙高度均较术前明显增高,末次随访时两组差异无统计学意义。术后16个月,X线片示两组患者椎体间植骨均骨性融合。末次随访时两组患者JOA、ODI、VAS评分差异均无统计学意义,无椎弓根螺钉松动、断裂情况发生。结论 :单枚cage椎间融合联合椎弓根螺钉固定治疗峡部裂性腰椎滑脱症与双枚cage椎间融合临床效果相同,且具有手术时间短、出血量少等优点,是一种安全有效的手术方式。     

后路椎间融合术治疗连续两节段双侧峡部裂型腰椎滑脱症的疗效观察

目的探讨后路椎间融合术治疗连续两节段双侧峡部裂型腰椎滑脱症的疗效。方法 2008年2月-2013年12月,采用后路减压、椎间融合术治疗17例连续两节段双侧峡部裂型腰椎滑脱症患者。男12例,女5例;年龄48~69岁,平均55.4岁。病程11个月~17年,中位病程22个月。滑脱程度按照Meyerding分度:Ⅰ度30个节段,Ⅱ度3个节段,Ⅲ度1个节段;涉及节段:L_(4、5)14例,L_(3、4)3例。术前疼痛视觉模拟评分(VAS)为(8.6±3.2)分。结果术中2例硬脊膜撕裂出现脑脊液漏;其余患者切口均Ⅰ期愈合,无其他手术相关并发症发生。患者均获随访,随访时间1~6年,平均3.4年。末次随访时,VAS评分为(1.1±0.4)分,与术前比较差异有统计学意义(t=7.652,P=0.008)。术后1周X线片检查示,滑脱椎体均获得不同程度复位,完全复位率为85%(29/34)。术后6~12个月达椎间融合,平均7.4个月;椎间融合按Lenke标准评价:A级13例,B级4例。随访期间均无内固定物松动、断裂;椎间高度维持良好,滑脱椎体复位无丢失。结论后路椎间融合术治疗连续两节段双侧峡部裂型腰椎滑脱症可取得较好疗效,术中准确植钉、有效减压、先撑开后复位、合理使用提拉螺钉、椎间融合是手术成功关键。     

ISOBAR TTL动态固定联合峡部植骨治疗腰椎峡部裂的临床疗效

目的评价ISOBAR TTL动态固定联合峡部植骨治疗腰椎峡部裂的临床效果。方法 2009年9月—2014年3月,采用ISOBAR TTL动态固定联合峡部植骨治疗单纯腰椎峡部裂或伴MeyerdingⅠ度滑脱患者26例。其中男14例,女12例;年龄19~47岁,平均31岁。病程9~60个月,平均16个月。术前均行腰椎正侧位X线片、CT三维重建及MRI明确峡部裂部位,峡部裂位于L4 9例,L5 17例。其中单纯腰椎峡部裂10例,伴MeyerdingⅠ度滑脱者16例。分别于术前及术后1周、3个月、6个月、末次随访时行疼痛视觉模拟评分(VAS)、Oswestry功能障碍指数(ODI)评分评价临床疗效;根据术后6个月CT三维重建结果评价峡部植骨融合情况;术前及末次随访时采用加州大学洛杉矶分校(UCLA)系统评价邻近节段退变情况。结果术后切口均Ⅰ期愈合,无感染、脑脊液漏、取髂骨区疼痛不适等手术并发症发生。26例患者术后均获随访,随访时间2~5年,平均36.5个月。随访期间未出现椎体继发性滑脱及内固定物松动、断裂现象。术后各时间点VAS及ODI评分均较术前显著改善,且术后3、6个月及末次随访时评分优于术后1周,差异均有统计学意义(P0.05);术后3、6个月及末次随访间比较差异均无统计学意义(P0.05)。术后6个月,CT三维重建结果提示23例(88.5%)峡部断端骨性融合;3例未融合患者中,1例术后1年达骨性融合,2例末次随访时仍未融合,但症状较术前明显缓解。末次随访时根据UCLA系统评价为Ⅰ级20例,Ⅱ级6例,与术前相同,未发现邻近节段退变情况。结论采用ISOBAR TTL动态固定联合峡部植骨治疗单纯腰椎峡部裂或伴MeyerdingⅠ度滑脱安全有效,峡部植骨融合率满意,并可能延缓腰椎融合术后邻近节段的退变。     

后路环形融合术治疗腰椎滑脱的疗效观察

目的回顾性分析经后路环形植骨融合术治疗单节段腰椎滑脱症的临床疗效。方法自2008年7月至2011年7月收治36例单节段腰椎滑脱症患者,均行环形植骨融合术,通过影像学评价患者术前、术后及末次随访的滑脱率、复位率和椎间隙高度变化,通过日本骨科协会(Japanese orthopaedic association,JOA)评分、视觉模拟评分(visual analogue scale,VAS)评分、Oswestry功能障碍指数(oswestry disability index,ODI)评分评价患者术前、术后及末次随访时的症状及功能变化。结果术后、末次随访的滑脱率、复位率、椎间隙高度均较术前有明显改善(P0.05)。末次随访时JOA评分的优良率为94.4%。腿痛VAS评分术前为(6.82±1.33)分、术后(2.11±1.05)分、末次随访为(2.70±1.62)分;腰痛VAS评分为(8.25±1.84)分、术后为(3.85±1.08)分、末次随访为(3.52±1.61)分。ODI指数术前为(68.6±14.7)、术后为(13.7±1.6)、末次随访为(14.0±1.8)。末次随访时骨性融合率为97.2%。结论经后路环形植骨融合术治疗单节段腰椎滑脱,能够明显改善临床症状和功能,具有较高的融合率。     

分期后路短节段固定前路病灶清除植骨融合治疗儿童下腰椎结核

目的:探讨一期后路钉钩棒短节段内固定、二期前路病灶清除植骨融合术治疗儿童下腰椎结核的手术方法及疗效。方法:2004年5月～2008年2月共收治儿童下腰椎结核患者9例,其中男5例,女4例,年龄5～11岁,平均7.8岁。术前腰椎局部前凸角-18°～4°,平均-8.6°±7.4°。均无明显的腰椎后凸畸形。病变累及一个椎体1例,累及2个椎体7例,累及3个椎体1例。术前神经功能Frankel分级:B级1例,C级3例,D级5例。均采用一期行后路短节段内固定,二期行前路病灶清除植骨融合手术治疗。观察比较术前、术后及末次随访时患者局部前凸角,评估植骨融合情况及神经功能恢复情况。结果:所有病例均获随访,随访时间30～53个月,平均41.0±7.8个月。术后腰椎局部前凸角5°～11°,平均8.8°±1.7°,较术前明显改善(P<0.05)。末次随访时腰椎局部前凸角为5°～10°,平均7.3°±1.7°,较术后无明显角度丢失(P>0.05)。1例末次随访时神经功能Frankel分级仍为D级,余患者神经功能均恢复至正常。随访期间无内固定松动及断裂,植骨获得满意融合,无结核复发。结论:对于无明显后凸畸形的儿童下腰椎结核患者,一期后路钉钩棒系统短节段内固定、二期前路病灶清除植骨融合术,是一种安全有效的治疗方法。     

一期后路病灶清除、打压植骨及单节段固定治疗单节段腰椎结核

目的评价单纯采用一期后路病灶清除、打压植骨及单节段固定治疗单节段腰椎结核的安全性、可行性及有效性。方法回顾性分析自2010-09—2015-09采用一期后路病灶清除、打压植骨及单节段固定治疗的18例单节段腰椎结核,手术前后规范抗结核药物治疗。结果 18例均获得4~64(38.5±6.4)个月随访。术后4.5~8.9(5.1±3.6)个月所有患者均获得骨性融合。术前Cobb角为(19.5±5.4)°,术后矫正至(4.2±2.5)°,末次随访时为(6.1±1.5)°,矫正丢失(1.5±0.8)°。术前ODI指数为(38.5±3.6)%,末次随访时为(9.8±2.3)%,改善率为71.3%。术后脊髓神经功能ASIA分级:1例B级恢复至D级,2例C级、4例D级恢复至E级。结论在规范抗结核药物治疗下,采用一期后路病灶清除、打压植骨及病椎内单节段固定治疗单节段腰椎结核术后后凸畸形得到较好矫正,末次随访时脊柱保持稳定,矫正度无明显丢失。     

椎弓根螺钉系统加后路椎间融合术治疗腰椎滑脱症疗效分析

目的分析椎弓根螺钉系统加后路椎间植骨融合术治疗腰椎滑脱症的疗效。方法 2005年1月-2009年1月,采用椎弓根螺钉系统加后路椎间植骨融合术治疗腰椎滑脱症患者26例。其中男11例,女15例;年龄36～73岁,平均56.8岁。病程7个月～11年。滑脱部位:L33例,L412例,L511例。根据Meyerding滑脱程度分类标准:Ⅲ度滑脱20例,Ⅲ～Ⅳ度滑脱5例,Ⅳ度滑脱1例。根据X线片观察术前及术后即刻、2周、3个月腰椎滑脱率(Taillard指数)、Boxall指数、滑脱角、腰椎生理前凸角及椎间隙高度变化,采用SUK标准判断植骨融合情况;采用日本骨科协会(JOA)下腰痛评分标准评价临床疗效。结果术后切口均Ⅰ期愈合。26例均获随访,随访时间10～51个月,平均25.8个月。术后即刻、2周及3个月,Taillard指数、Boxall指数、滑脱角、腰椎生理前凸角及椎间隙高度与术前比较,差异均有统计学意义(P0.05);术后3个月各测量指标与术后即刻、2周比较,差异均无统计学意义(P0.05)。患者术后3～8个月植骨均融合,平均3.5个月,融合率100%。根据JOA评分标准,获优17例,良7例,可1例,差1例,优良率达92.3%。术后发生内固定断裂及下肢神经根放射性疼痛或麻木各1例,经处理后治愈。结论应用椎弓根螺钉系统加后路腰椎间植骨融合术治疗腰椎滑脱症能提供理想复位和坚强内固定,是治疗腰椎滑脱症的一种较好方法 。     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.