一期前后联合入路全脊椎切除在颈椎孤立性浆细胞瘤中的应用北大核心CSCD

目的探讨一期经前后联合入路全脊椎切除加重建术治疗颈椎孤立性浆细胞瘤(solitary plasmacytoma,SP)的可行性,以期为临床治疗颈椎SP提供可靠、有效的手术方式。方法回顾分析2000年6月—2015年3月行一期经前后联合入路全脊椎切除的12例颈椎SP患者临床资料。其中男8例,女4例;年龄28~74岁,平均46岁。病程3~15个月,平均8.4个月。发病部位:C_2 2例,C_3 4例,C_4 2例,C_5、C_6 1例且为复发病例,C_73例。根据WBB(Weinstein-Boriani-Biagini)分期,累及椎体且超过一侧4扇区或9扇区8例,同时超过两侧4扇区或9扇区4例;肿瘤侵及A^D层7例,B^D层5例。术前脊髓损伤按Frankel分级,B级1例,C级6例,D级5例。5例椎动脉被侵袭,其中4例单侧累及,1例双侧累及;病变累及单椎节11例,2个椎节骨质破坏1例。患者术后均接受辅助放疗。记录手术时间、术中出血量;采用Frankel分级评价神经功能恢复情况,疼痛视觉模拟评分(VAS)评估疼痛恢复情况。结果手术时间6.8~9.3 h,平均7.2 h;术中出血量1 100~2 600 mL,平均1 600 mL。1例C_5、C_6复发SP患者术后1周出现食道瘘,1例术后出现伤口脂肪液化,均经相应处理后治愈;其余患者均未出现脊髓神经功能损伤加重,无大血管损伤(特别是椎动脉),膈神经、喉上、喉返神经损伤,呼吸衰竭等并发症。12例患者均获随访,随访时间27~98个月,平均58个月。末次随访时神经功能均恢复至Frankel E级;VAS评分由术前(6.7±2.7)分减小至(1.1±0.7)分,差异有统计学意义(t=2.485,P=0.014)。2例患者分别于术后29、37个月复发,均行辅助化疗,其中1例进展为多发性骨髓瘤,术后43个月死于多器官功能衰竭;另1例患者带瘤生存。1例术后4年出现内固定物松动、断裂,予以翻修。其余患者随访期间均未见肿瘤复发或恶变,无内固定物松动、断裂等并发症发生。结论手术切除是治疗颈椎SP的主要手段,一期经前后联合入路全脊椎切除术能明显降低颈椎SP复发率,并能缓解脊髓压迫症状,最大限度改善患者生存质量。进展到多发性骨髓瘤的患者应接受个体化治疗,但预后较差。     

一期前后联合入路全脊椎切除在颈椎孤立性浆细胞瘤中的应用

目的探讨一期经前后联合入路全脊椎切除加重建术治疗颈椎孤立性浆细胞瘤(solitary plasmacytoma,SP)的可行性,以期为临床治疗颈椎SP提供可靠、有效的手术方式。方法回顾分析2000年6月—2015年3月行一期经前后联合入路全脊椎切除的12例颈椎SP患者临床资料。其中男8例,女4例;年龄28~74岁,平均46岁。病程3~15个月,平均8.4个月。发病部位:C_2 2例,C_3 4例,C_4 2例,C_5、C_6 1例且为复发病例,C_73例。根据WBB(Weinstein-Boriani-Biagini)分期,累及椎体且超过一侧4扇区或9扇区8例,同时超过两侧4扇区或9扇区4例;肿瘤侵及A~D层7例,B~D层5例。术前脊髓损伤按Frankel分级,B级1例,C级6例,D级5例。5例椎动脉被侵袭,其中4例单侧累及,1例双侧累及;病变累及单椎节11例,2个椎节骨质破坏1例。患者术后均接受辅助放疗。记录手术时间、术中出血量;采用Frankel分级评价神经功能恢复情况,疼痛视觉模拟评分(VAS)评估疼痛恢复情况。结果手术时间6.8~9.3 h,平均7.2 h;术中出血量1 100~2 600 mL,平均1 600 mL。1例C_5、C_6复发SP患者术后1周出现食道瘘,1例术后出现伤口脂肪液化,均经相应处理后治愈;其余患者均未出现脊髓神经功能损伤加重,无大血管损伤(特别是椎动脉),膈神经、喉上、喉返神经损伤,呼吸衰竭等并发症。12例患者均获随访,随访时间27~98个月,平均58个月。末次随访时神经功能均恢复至Frankel E级;VAS评分由术前(6.7±2.7)分减小至(1.1±0.7)分,差异有统计学意义(t=2.485,P=0.014)。2例患者分别于术后29、37个月复发,均行辅助化疗,其中1例进展为多发性骨髓瘤,术后43个月死于多器官功能衰竭;另1例患者带瘤生存。1例术后4年出现内固定物松动、断裂,予以翻修。其余患者随访期间均未见肿瘤复发或恶变,无内固定物松动、断裂等并发症发生。结论手术切除是治疗颈椎SP的主要手段,一期经前后联合入路全脊椎切除术能明显降低颈椎SP复发率,并能缓解脊髓压迫症状,最大限度改善患者生存质量。进展到多发性骨髓瘤的患者应接受个体化治疗,但预后较差。     

颈后路单开门椎板成形术后发生C5神经根麻痹的原因分析

目的:分析两种颈后路单开门椎板成形术治疗多节段脊髓型颈椎病术后C_5神经根麻痹的发生率和影响因素。方法:对2010年1月至2014年6月因多节段脊髓型颈椎病接受椎管成形术160例患者的临床资料进行回顾性分析,其中80例接受4节段(C_3-C_6)椎管成形术(A组),男44例,女36例,平均年龄(68.4±9.2)岁;80例接受3节段(C_4-C_6)椎管成形术(B组),男48例,女32例,平均年龄(66.8±8.9)岁。术前及末次随访时分别记录颈痛VAS评分,上肢痛VAS评分,JOA评分,MR最小脊髓直径,颈椎的Cobb角及活动度。术后观察C_5神经根麻痹的发生率,及C_5神经根麻痹时三角肌肌力,伴随神经症状,恢复时间。结果:所有患者获随访,时间6~15个月,平均(12.4±3.2)个月。手术前后两组患者的颈痛VAS评分、上肢痛VAS评分、JOA评分、MRI最小脊髓直径、颈椎的Cobb角及活动度差异无统计学意义。A组患者中7例(8.75%)发生C_5神经根麻痹,其中4例出现上肢放射痛,3例出现上肢感觉减退;在末次随访时2例残留轻微的上肢放射痛及感觉减退。B组患者中5例(7.5%)发生C_5神经根麻痹,其中3例出现上肢放射痛,2例出现上肢感觉减退,在末次随访时所有患者上肢放射痛及感觉减退均恢复正常。两组C_5神经根麻痹的患者发生率差异无统计学意义。C_5神经根麻痹时三角肌肌力、伴随神经症状、恢复时间A组分别为(2.3±1.0)N、30例(37.5%)、(11.4±1.0)周,B组分别为(2.8±0.8)N、23例(28.8%)、(8.2±0.8)周,三角肌肌力下降两组差异无统计学意义,伴随神经症状及恢复时间A组比B组差。结论:两种术式相比,患者术后出现C_5神经根麻痹的概率相当,但是C_4-C_6单开门椎管成形术患者C_5神经根麻痹症状较轻,恢复较快。     

Hangman骨折的颈后路CerviFix系统固定治疗

目的探讨颈后路CerviFix系统固定C_(2～3)治疗Hangman骨折的适应证及疗效。方法2002年6月~2004年1月在新鲜的Hangman骨折患者中选择6例C_(2～3)不稳(MRI示C_(2～3)椎间盘形状和信号无明显改变、前纵韧带连续)行颈后路C2椎弓根螺钉、C3侧块螺钉的CerviFix系统固定术。6例患者中LevineEdwardsI型2例,IIa型3例,IIb型1例;脊髓损伤Frankel分级D级1例,E级5例。结果手术均顺利完成,未发生手术并发症,术前脊髓损伤FrankelD级的1例术后恢复至E级,骨折于术后6~12周愈合;颈椎无畸形、活动无明显受限,颈部无明显不适,未出现内固定物松动、断裂方面的并发症;2例于术后1年骨折愈合后取出内固定物并且C_(2～3)仍保持稳定。结论颈后路CerviFix系统固定C_(2～3)选择性治疗部分Hangman骨折,术后可以获得骨折端良好的复位固定和C_(2～3)间稳定性的即刻重建,为骨折愈合和C_(2～3)间韧带修复创造条件,疗效满意。其适应证为C椎间盘和韧带解剖结构完整但不稳定的Hangman骨折。     

人工颈椎间盘置换术治疗C_(3-4)椎间盘突出症的中期疗效研究

目的探讨人工颈椎间盘置换术(artificial cervical disc replacement,ACDR)治疗C_(3-4)椎间盘突出症的中期临床及影像学结果。方法 2010年4月-2014年12月,我院采用ACDR治疗C_(3-4)椎间盘突出症患者9例,含C_(3-4)的双节段椎间盘突出症患者12例;使用Prestige LP人工椎间盘16例,使用Discover人工椎间盘5例;男14例,女7例;年龄35-60岁,平均42.8岁;其中神经根型颈椎病8例,脊髓型7例,混合型6例;术前病程12-60个月,平均27.6个月。分别在术前、术后1周及末次随访时采用生活质量量表(SF-36)、日本矫形外科协会(JOA)脊髓功能评分及颈椎功能障碍指数(NDI)评估临床疗效,在颈椎正侧位X线片上观察假体稳定性并测量C_(3-4)脊柱功能单位(functional spinal unit,FSU)的前凸角,在过伸过屈位X线片上测量C_(3-4)节段屈伸活动度。结果 21例患者术后均获得随访,随访时间6-48个月,平均28.3个月。所有患者术后神经症状均明显改善,SF-36躯体及心理评分、JOA及NDI评分术后1周及末次随访时均明显优于术前(P0.05)。置入的假体均保留了活动度,无假体沉降或移位。C_(3-4)节段FSU的前凸角与术前相比差异无统计学意义(P0.05),术后1周时C_(3-4)节段屈伸活动度较术前明显下降(P0.05),末次随访时恢复到术前水平(P0.05)。术后4例患者出现咽部不适,2例患者出现C_(3-4)节段周围的异位骨化。结论 C_(3-4)节段人工颈椎间盘置换术后中期临床效果良好,维持了手术节段的生理曲度,且人工椎间盘在C_(3-4)节段仍能保持较好的活动度。     

内镜辅助微血管减压术治疗原发性三叉神经痛临床疗效观察

目的观察内镜辅助微血管减压术治疗原发性三叉神经痛疗效。方法方法对50例原发性三叉神经痛患者应用内镜辅助微血管减压术治疗,回顾性分析患者的临床资料。结果本组50例患者经治疗后显效28例(56.00%),有效19例(38.00%),无效3例(6.00%),总有效率94.00%。术后2例感头晕或恶心,1例出现呕吐,2例有面部麻木感,经对症处理后均明显缓解。患者均获随访6个月~2年,未出现小脑半球损伤、出血、听力丧失或死亡病例。结论应用内镜探查辅助微血管减压术治疗原发性三叉神经痛,可减少遗漏责任血管、协助调整隔片位置等,提高手术治疗总有效率,降低术后并发症。     

单开门椎管扩大成形术后颈椎曲度与C_5神经根麻痹的关系

目的探讨单开门椎管扩大成形术后颈椎曲度与C5神经根麻痹发生率的关系。方法对254例颈椎病患者采取3种不同术式治疗:A组(126例)行颈椎单开门椎管成形术;B组(70例)行颈椎单开门椎管成形+未明显改变颈椎曲度的后路内固定术;C组(58例)行颈椎单开门椎管成形+明显改变颈椎曲度的后路内固定术。结果患者均获得随访,时间12~18个月。X线、MRI和CT检查显示:3组患者脊髓均有不同程度的向后漂移,侧块螺钉均没有进入椎间孔和椎管内,椎板没有再关门,椎板合页处没有向内陷入椎管,亦没有明显压迫硬膜脊髓的硬膜外血肿。A组颈椎曲度无改变;B组颈椎曲度无显著性改变;C组颈椎曲度改善明显,曲度增加值为5.3 mm±2.7 mm。18例术后发生C_5神经根麻痹,其中A组2例(1.59%)、B组4例(5.71%)、C组12例(20.69%);A、B两组比较差异无统计学意义(P0.05),A、B组与C组比较差异均有统计学意义(P0.017);脊髓型组5例(3.09%),混合型组13例(14.13%),两组比较差异有统计学意义(P0.05)。18例C_5神经根麻痹患者于术后2~4 d出现颈肩痛或原有颈肩痛加重,其中12例随后迅速出现肌力下降,而感觉减退不明显。18例均给予保守治疗,术后2~3周患者颈肩部麻痛消失;术后4~24周12例肌力下降中11例完全康复,1年后另1例C_5神经支配区肌力恢复至4+级。结论颈椎单开门椎管扩大成形术后可发生C_5神经根麻痹,无内固定时发生率最低,在颈椎生理曲度明显改变时发生率最高;术后混合型较脊髓型更易出现C_5神经根麻痹,其损伤机制可能与脊髓漂移有关。     

前路手术对颈椎椎间盘突出症患者颈椎矢状位参数的影响

目的探讨前路手术对颈椎椎间盘突出症患者颈椎矢状位参数的影响。方法 2011年1月—2016年9月在本院行前路颈椎椎间盘切除融合术(ACDF)及前路颈椎椎体次全切除融合术(ACCF)治疗的颈椎椎间盘突出症患者159例,男79例,女80例;年龄(51.85±9.60)岁。在MRI上测量颈椎矢状位参数,包括C_(2~7) Cobb角、T_1倾斜角(T_1SA)、颈倾角(NTA)和胸廓入口角(TIA),采用配对t检验比较手术前后各参数的差异。根据T_1SA大小分为低T_1SA组(T_1SA≤20°,53例)、中T_1SA组(20°T_1SA≤30°,81例)和高T_1SA组(T_1SA30°,25例),采用χ~2检验比较不同T_1SA组间各个节段退变率的差异。结果术后C_(2~7) Cobb角、T_1SA和NTA的测量结果与术前相比,差异有统计学意义(P0.05),TIA与术前相比,差异无统计学意义。159例病例中病变共累及311个节段,其中C_5/C_6最多,为102个;C_4/C_5次之,为91个。C_3/C_4、C_4/C_5、C_5/C_6和C_6/C_7退变率在不同T_1SA组之间差异有统计学意义(P0.05),随着T_1SA增加,C_3/C_4和C_4/C_5退变率逐渐增加,C_5/C_6和C_6/C_7退变率逐渐降低。结论前路手术可能通过增加颈椎椎间盘突出症患者C_(2~7) Cobb角进而增加T_1SA,从而更有力地维持颈椎生理曲度;随着T_1SA的增加,退变节段有由下往上发展的趋势。     

Zero-P用于三节段颈椎前路融合术的中期疗效

目的通过与传统融合器并钛板融合术比较,探索C_4/C_5/C_6/C_7三节段Zero-P融合治疗颈椎退变性疾病的中期临床疗效与影像学变化。方法纳入2009年7月—2013年5月在本院接受C_4/C_5/C_6/C_7颈椎融合手术的患者共72例。其中A组患者应用Zero-P进行融合,共30例;B组用传统融合器加钛板,共42例。两组患者术前各项参数比较差异无统计学意义。于术后2个月、6个月、1年、2年及近期各时间点进行复查随访,比较两组患者日本骨科学会(JOA)评分、颈椎功能障碍指数(NDI)、颈椎曲度、C_(4~7) Cobb角、吞咽困难发生率、融合率、邻近节段退变(ASD)发生率等的差异。结果所有患者随访2年,随访期间,A组与B组术后JOA评分、NDI、融合率及ASD发生率比较差异均无统计学意义。A组患者术后C_(4~7)Cobb角呈缓慢丢失趋势,在术后2年及末次随访时小于B组(P0.05)。A组患者术后颈椎曲度呈缓慢丢失趋势,在末次随访时低于B组(P0.05)。A组患者吞咽困难发生率于术后2个月时低于B组(P0.05),余随访时间两组差异无统计学意义。结论 Zero-P用于颈椎三节段融合时中期疗效满意、并发症少。其可有效降低术后2个月吞咽困难发生率,但对手术节段Cobb角及颈椎曲度的维持作用较差。     

测量MRI预测颈椎病减压术后发生C5神经根麻痹的研究

目的探讨术前MRI测量与颈椎病减压术后C_5神经根麻痹之间的相关性。方法回顾性分析2012年1月至2016年12月行C_(4～5)水平前路或后路减压术的脊髓型颈椎病90例患者资料,其中男24例,女66例;年龄42～70岁,平均(56.2±16.2)岁。测量每例患者C_(4～5)节段MRI图像,采用双盲法,测量指标包括颈椎中线前后径(anteroposterior diameter,APD)、左侧和右侧的椎间孔直径(foraminal diameter,FD)以及左侧和右侧的脊髓-椎板角(cord-lamina angle,CLA)。基于一个或多个预测因子的多因素Logistic回归分析,预测C_5神经根麻痹发生的可能性。结果13%患者出现了术后C_5神经根麻痹,通过多元Logistic回归分析,与APD、FD及CLA相关的C_5神经根麻痹发生的优势比分别为0.292、0.019、1.507;APD的增加与术后发生C_5神经根麻痹的概率呈负相关;FD的增加与术后发生C_5神经根麻痹的概率呈负相关;CLA的增加与术后发生C_5神经根麻痹的概率呈正相关。结论本研究首次提出了用于预测颈椎病减压术后C_5神经根麻痹的一种简单可行方法,所用的参数分别为APD、FD及CLA,该预测方法有助于手术病例的选择,并根据预测结果建议术者采取相应的干预措施。     

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.