脊神经后支阻滞在老年人腰椎后路椎间融合术多模式镇痛方案中的应用

目的 探讨联合罗哌卡因脊神经后支阻滞多模式镇痛方案在老年人后路腰椎椎间融合术(PLIF)围手术期镇痛中的应用。方法 行PLIF的老年患者(年龄 ≥ 65岁)60例,随机分为对照组(A组,n=20)、常规多模式镇痛组(B组,n=20)和脊神经后支阻滞多模式镇痛组(C组,n=20),记录3组患者术前6 h及术后6、12、24、48、72 h及1周时疼痛视觉模拟量表(VAS)评分,术后1、3、7 d及出院时的运动阻滞(Bromage)评分;统计不良反应发生率和额外使用镇痛药物的例数。结果 术前6 h,VAS评分B、C组低于A组,差异有统计学意义(P<0.05);术后6、12、24 h,C组低于A、B组,差异有统计学意义(P<0.05);术后48 h,各组间差异无统计学意义(P>0.05);术后72 h及1周,B、C组低于A组,差异有统计学意义(P<0.05)。术后1 d,Bromage评分C组低于A、B组,差异有统计学意义(P<0.05);术后3、7 d及出院时,各组间差异无统计学意义(P>0.05)。B、C组不良反应发生率低于A组,差异有统计学意义(P<0.05);额外使用镇痛药物例数C组 < B组 < A组,各组间差异均有统计学意义(P<0.05)。结论 联合应用罗哌卡因脊神经后支阻滞的多模式镇痛方案能有效缓解老年人PLIF围手术期疼痛,且不影响运动功能。     

髂筋膜间隙阻滞对前外侧小切口入路全髋置换术的影响

目的:比较单纯椎管内麻醉与联合髂筋膜间隙阻滞（fascia iliaca compartment block,FICB）对前外侧小切口（orthopädische chirurgie München,OCM）入路全髋关节置换术（total hip arthroplasty,THA）的影响分析。方法：2019年1月至2020年10月择期行单侧全髋关节置换术患者,分别采用椎管内麻醉复合超声引导下髂筋膜间隙阻滞（A组30例）和单纯椎管内麻醉（B组30例）。两组患者椎管内用药成分相同,术后采用相同静脉镇痛治疗方案。观察比较两组手术时间、术中出血量、臀中肌剥离程度、股骨大转子劈裂情况,术后髋关节疼痛视觉模拟评分（visual analogue scale,VAS）,术前及术后48 h 股四头肌及髋关节外展肌力,术后髋关节功能Harris评分。结果：所有患者获得随访,时间48~62（54.2±4.0）周。A组患者切口长度、手术时间及术中出血量明显低于B组（P<0.05）。A组术后24 h血红蛋白水平明显高于B组（P<0.05）。A组术后48 h髋关节外展肌力明显高于B组（P<0.05）。A组患者臀中肌剥离程度明显低于B组（P<0.05）。A组患者术后8、12、24 h VAS明显低于B组（P<0.05）;A组患者术后2、8周Harris评分明显高于B组（P<0.05）。结论：超声引导下髂筋膜间隙阻滞应用于侧卧位OCM入路THA,能明显缩短手术时间、减少术中出血量、减少术中臀中肌剥离情况等髋关节周围创伤及改善患者术后早期疼痛,有利于OCM入路临床操作及患者术后快速康复。     

超声引导下不同入路肩胛背神经阻滞治疗肩胛间区疼痛

目的 观察超声引导下不同入路肩胛背神经（DSN）阻滞治疗肩胛间区疼痛的效果。方法 针对213例接受DSN阻滞治疗单侧肩胛间区疼痛患者行肌间沟、C5横突后结节（RTFCV）和肩胛骨内侧缘（MES）入路超声扫查,统计DSN识别率;而后将患者随机纳入3组（每组71例）,分别行超声引导下经肌间沟（A组）、RTFCV （B组）及MES （C组）入路DSN阻滞（注射1%利多卡因2 ml）,对比3组超声扫查耗时、神经阻滞有效率及不良反应。结果 经肌间沟、RTFCV及MSE入路超声扫查对A、B、C组DSN的识别率分别为91.08%（194/213）、46.01%（98/213）、26.29%（56/213）,3组总体差异及两两差异均有统计学意义（P均<0.05）。A组超声扫查平均耗时低于C组,B组神经阻滞有效率高于A组和C组（P均<0.05）。A组神经损伤发生率高于B、C组,A、B组超范围阻滞发生率高于C组（P均<0.05）。结论 超声引导下经RTFCV入路行DSN阻滞治疗肩胛间区疼痛较经肌间沟及肩胛骨内侧缘入路更为安全、有效。     

超声引导下选择性神经阻滞在肩关节镜术后镇痛的临床应用

目的 对比研究超声引导下C5神经根联合锁骨上神经阻滞与肌间沟臂丛神经阻滞在肩关节镜手术后镇痛的临床应用价值。方法 采用前瞻性随机对照研究,将我院2017年3月至2018年12月收治的60例进行单侧肩关节镜手术的病人纳入研究。按照随机数字表法分为观察组（超声引导选择性C5神经根联合锁骨上神经阻滞）和对照组（超声引导下肌间沟臂丛神经阻滞）。两组均在超声引导下完成神经阻滞后实施全身麻醉,均采取相同的全身麻醉药物诱导及维持。记录并比较两组病人术后3、6、9、12 h静息疼痛视觉模拟量表（visual analogue scale, VAS）评分,屈肘、屈腕肌力评分,术后30 min膈肌麻痹程度、霍纳综合征的发生率及病人满意度等指标。结果 两组静息VAS评分在各时间点的差异均无统计学意义（P均＞0.05）。与对照组比较,观察组膈肌麻痹程度显著降低（P＜0.05）,屈肘、屈腕肌力显著增高（P＜0.05）,霍纳综合征的发生率显著降低（P＜0.05）,病人满意度显著增高（P＜0.05）。结论 在肩关节镜手术中,肌间沟臂丛神经阻滞和选择性C5神经根联合锁骨上神经阻滞均能有效缓解术后疼痛,但选择性神经阻滞对病人的膈肌麻痹程度、屈肘及屈腕肌力影响小,能显著降低霍纳综合征的发生率,更有利于病人术后功能锻炼,达到早日康复的目的。     

鸡尾酒疗法联合硬膜外单次小剂量吗啡对全膝关节置换术后疼痛控制的研究

目的 研究鸡尾酒疗法联合硬膜外单次小剂量吗啡对全膝关节置换术（total knee arthroplasty, TKA）后疼痛的控制作用。方法 采用随机双盲对照研究,选取2018年2月至2018年9月我院收治的拟行初次单侧TKA的膝骨关节炎病人160例,随机分为4组,每组40例,麻醉方式均采用硬膜外麻醉。A组病人给予鸡尾酒疗法（含激素）联合硬膜外单次小剂量吗啡;B组病人给予鸡尾酒疗法（不含激素）联合硬膜外单次小剂量吗啡;C组病人给予单纯鸡尾酒疗法（含激素）;D组为对照组,给予单纯鸡尾酒疗法（不含激素）。记录4组病人术后2、6、12、24、48、72 h静息状态下及术后24、48、72 h活动状态下的疼痛视觉模拟量表（visual analogue score, VAS）评分,术后48 h、72 h、4 d、5 d的膝关节最大屈曲活动度以及术后不良反应。结果 4组病人术后静息状态下、活动状态下的VAS评分及膝关节活动度总体比较,差异均有统计学意义（F=10.798,P＜0.001;F=6.220,P=0.001;F=6.075,P=0.001）。A、B、C组术后静息状态、运动状态下的VAS评分均显著低于D组,且其膝关节活动度均显著大于D组,差异均有统计学意义（P均＜0.05）。C组病人静息状态下VAS评分的总体均数高于A组,差值为0.52,差异有统计学意义（P=0.005）。结论 鸡尾酒疗法联合硬膜外单次小剂量吗啡在TKA术后显示出更强且更协同的镇痛效果,可更好地改善术后膝关节活动度;在无激素禁忌及不良反应的条件下,建议“鸡尾酒”混合镇痛药中添加糖皮质激素。     

氢吗啡酮复合罗哌卡因髂筋膜间隙联合骶丛神经阻滞在老年全髋关节置换术中的应用

目的 探讨氢吗啡酮复合罗哌卡因髂筋膜间隙联合骶丛神经阻滞在老年病人全髋关节置换术后镇痛的效果及不良反应。方法 选取2019年6月至2020年2月在襄阳市第一人民医院行单侧全髋关节置换术的病人90例,随机分为R组（罗哌卡因+肌注生理盐水组）、H组（罗哌卡因、氢吗啡酮+肌注生理盐水组）和RH组（罗哌卡因+肌注氢吗啡酮组）。三组术前30 min均在超声引导下行髂筋膜间隙联合骶丛神经阻滞,R组在髂筋膜间隙阻滞用药为0.35%罗哌卡因40 mL,骶丛神经阻滞用药为0.4%罗哌卡因20 mL,随后臀大肌肌注生理盐水2 mL;H组在髂筋膜间隙阻滞用药为0.35%罗哌卡因+10 mg/kg氢吗啡酮共40 mL,骶丛神经阻滞用药为0.4%罗哌卡因+10 mg/kg氢吗啡酮共20 mL,随后臀大肌肌注生理盐水2 mL;RH组在髂筋膜间隙阻滞用药为0.35%罗哌卡因40 mL,骶丛神经阻滞用药为0.4%罗哌卡因20 mL,随后臀大肌肌注氢吗啡酮2 mL。待神经阻滞起效后行喉罩全麻。观察记录各组神经阻滞起效及维持时间,术后6、12、24、48 h静息及运动状态下的疼痛视觉模拟量表（visual analogue scale, VAS）评分、术后镇痛药的使用、恢复质量及不良反应发生情况。结果 三组神经阻滞起效时间的差异无统计学意义（P＞0.05）,H组术后神经阻滞维持时间长于R组和RH组（P均＜0.05）。H组术后6、12、24 h VAS评分低于R组和RH组（P均＜0.05）。H组术后首次按压镇痛泵晚于R组和RH组（P均＜0.05）。H组术后首次下床活动时间早于R组和RH组（P均＜0.05）。H组术后舒芬太尼用量、住院天数、恶心呕吐的发生率均少于R组和RH组（P均＜0.05）。结论 氢吗啡酮复合罗哌卡因髂筋膜间隙联合骶丛神经阻滞在老年全髋置换术中可以延长阻滞时间,减少阿片类药物的消耗及术后不良反应的发生率,利于病人术后康复。     

高位胸椎竖脊肌平面阻滞与臂丛上干阻滞在全身麻醉肩关节镜手术中应用的比较

目的 比较高位胸椎竖脊肌平面阻滞（high thoracic erector spinae plane block，HT-ESPB）与臂丛上干阻滞（superior trunk block，STB）在肩关节镜手术围手术期的镇痛效果。方法 纳入择期全身麻醉下行肩关节镜肩袖修补术病人共计60例，采用随机数字法将其分为HT-ESPB组（30例）与STB组（30例）。记录两组术中镇痛药物用量、拔管时间、膈肌阻滞发生率、相关并发症；术后2、6、12、24、48、72 h时静息和活动时的疼痛视觉模拟量表（VAS）评分，术后曲马多镇痛补救情况，病人术后镇痛满意度评分，术后24、48、72 h的15项恢复质量量表（QoR-15）评分以及不良反应发生情况。结果 HT-ESPB组术中舒芬太尼用量高于STB组［（21.5±11.1） μg vs. （15.6±10.3） μg，P=0.037］，术后曲马多用量高于STB组［（36.9±10.2） mg vs. （25.4±9.5） mg，P＜0.001］，膈神经阻滞发生率低于STB组（0 vs. 80%，P＜0.001），术后24 h QoR-15评分显著高于STB组［（76.3±12.2）分 vs. （66.4±11.6）分，P=0.003］；两组病人静息和活动时VAS评分、镇痛满意度评分、并发症发生率差异无统计学意义（P＞0.05）。结论 肩关节镜手术中应用HT-ESPB能达到与STB类似的麻醉和镇痛效果，且膈神经阻滞发生率更低，尽管其镇痛药补救需求更多，仍是STB一种可行的替代方案。     

不同麻醉方式对老年全膝关节置换术早期预后的影响：一项单中心回顾性研究

目的 探讨不同麻醉方式对老年全膝关节置换术后早期预后的影响。方法 回顾性分析2018年10月至2021年9月在我院骨科行单侧全膝关节置换术病人的临床资料,根据麻醉方式分为全身麻醉组（GA组）、复合麻醉组（CA组）、外周神经阻滞组（PNB组）和腰麻组（SA组）,与GA组和CA组比较,PNB组和SA组病人美国麻醉医师协会（ASA）分级,合并症比率更高,差异有统计学意义（P＜0.05）。记录病人的一般资料、手术时间、麻醉时间、术后恢复室（PACU）观察时间和术后住院天数;记录低血压、血管活性药物泵注、术后24 h补救镇痛、舒芬太尼用量、术后炎性指标和48 h内并发症的发生率。结果 与GA组、CA组比较,PNB组和SA组病人低血压、低氧血症、血管活性药物泵注、急性心肌损伤、术后谵妄、术后恶心呕吐（PONV）、补救镇痛、入住ICU的发生率更低,舒芬太尼用量、炎性指标水平更低,术后PACU观察时间和住院时间缩短,差异均有统计学意义（P＜0.05）。与GA组比较,CA组术中舒芬太尼用量、术中低血压、血管活性药物泵注和补救镇痛率显著降低,差异有统计学意义（P＜0.05）。结论 与全身麻醉和复合麻醉相比,外周神经阻滞和腰麻是老年病人全膝关节置换术推荐的麻醉方式,可以改善早期预后。     

腹股沟韧带上髂筋膜阻滞联合经静脉患者自控镇痛在老年髋关节置换术后的应用

目的：比较经静脉患者自控镇痛(patient controlled intravenous analgesia,PCIA)与腹股沟韧带上髂筋膜阻滞联合PCIA在老年髋关节置换术后的应用效果。方法：2019年6月至2021年6月84例老年患者接受髋关节置换术,其中42例以PCIA镇痛作为对照组,男18例,女24例;年龄60~78(70.43±3.67)岁;股骨颈骨折28例,股骨头坏死14例;另42例以腹股沟韧带上髂筋膜阻滞联合PCIA镇痛作为研究组,男20例,女22例;年龄61~76(69.68±3.74)岁;股骨颈骨折25例,股骨头坏死17例。分别于术后2、6、12、24、48 h进行疼痛视觉模拟评分(visual analogue scale,VAS)及Ramesay镇静评分。观察比较两组术后48 h的舒芬太尼总消耗量、PCIA总按压次数、术后首次下地时间、住院时间、不良反应发生率、镇痛满意度等随访结果。结果：两组术后随访9~24(13.85±2.67)个月。两组手术时间和术中出血量比较,差异无统计学意义(P＞0.05)。两组术后2 h的VAS比较,差异无统计学意义(P＞0.05),研究组术后6、12、24、48 h的VAS均低于对照组(P＜0.05)。研究组术后2、6、12 h的Ramesay镇静评分均高于对照组(P＜0.05),两组术后24、48 h的Ramesay评分比较差异无统计学意义(P＞0.05)。研究组术后48 h内舒芬太尼消耗量、PICA按压次数少于对照组(P＜0.05),术后首次下地时间早于对照组(P＜0.05)。研究组镇痛满意度高于对照组(P＜0.05)。两组住院时间、不良反应发生率、随访期间并发症比较差异无统计学意义(P＞0.05)。结论：腹股沟韧带上髂筋膜阻滞联合PCIA在老年髋关节置换术后镇痛和镇静效果显著,可减少舒芬太尼使用量及PCIA总按压次数,有利于患者早期下床活动,提高镇痛满意度。     

胸腰筋膜间平面阻滞对后路腰椎融合术后镇痛效果的影响

目的 探讨超声引导下胸腰筋膜间平面（thoracolumbar interfascial plane, TLIP）阻滞对后路腰椎融合手术病人术后镇痛效果的影响。方法 前瞻性选择2017年4月至2018年5月在我院择期行后路腰椎融合手术病人50例。采用随机数字表法分为两组,每组25例,TLIP阻滞联合静脉自控镇痛（patient controlled intravenous analgesia, PCIA）组（TLIP组）和单纯PCIA组（对照组）。TLIP组,男12例,女13例,年龄为（49.4±7.7）岁;对照组,男10例,女15例,年龄为（49.5±7.1）岁。TLIP组在全麻诱导后行超声引导下双侧TLIP阻滞,每侧注入0.375%罗哌卡因20 ml。两组术后均使用舒芬太尼行PCIA,维持术后24 h内静息疼痛视觉模拟量表（visual analogue scale, VAS）评分≤3分。记录两组病人围手术期阿片类药物用量及补救镇痛例数,术后2、4、6、12、24 h的静息VAS评分和Ramsay镇静评分,术后24 h 内恶心呕吐、头晕、瘙痒和呼吸抑制的发生情况以及TLIP组阻滞相关并发症的发生情况。结果 与对照组比较,TLIP组术中瑞芬太尼用量及术后24 h内PCIA舒芬太尼用量明显减少（P＜0.05）,术后恶心呕吐发生率明显降低（P＜0.05）,两组均未行补救镇痛。两组间各时间点静息VAS评分和Ramsay镇静评分,以及术后头晕、瘙痒和呼吸抑制等发生率的差异均无统计学意义（P均＞0.05）,TLIP组未发生阻滞相关并发症。结论 超声引导下TLIP阻滞可减少后路腰椎融合术病人围术期阿片类药物用量,降低术后恶心呕吐的发生率。     

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.