生物反馈对低位直肠癌术后排便动力学的影响

目的:探讨生物反馈对低位直肠癌经肛内外括约肌间切除术后排便动力学的影响。方法:选择行低位直肠癌经肛内外括约肌间切除术后的患者100例,随机分为2组,对照组给以常规治疗,试验组在对照组基础上进行生物反馈治疗,观察记录两组患者术后排便动力学的变化。结果:治疗后,试验组肛管静息压[(50.66±5.61)mm Hg(1 mm Hg=0.133 k Pa)]、肛管收缩压[(110.80±6.14)mm Hg],明显高于对照组的(43.98±4.36)mm Hg、(102.14±3.48)mm Hg试验组肛管最大收缩时间[(39.46±7.15)s]比对照组[(35.14±3.28)s]长;试验组结肠末端静息压[(3.74±1.52)mm Hg]高于对照组的(3.32±1.26)mm Hg,差异有统计学意义(P0.05),试验组初始感觉容量阈值、初始排便容量阈值、最大耐受容量等均明显高于对照组,差异均有统计学意义(P0.05);试验组结肠末端肛管收缩反射阳性、结肠末端肛管收缩抑制反射阳性明显高于对照组,差异均有统计学意义(P0.05),试验组球囊排出试验时间比对照组长,差异有统计学意义(P0.05);试验组每天排便次数少于对照组,控便时间比对照组长,差异有统计学意义(P0.05)。结论:生物反馈治疗能明显改善低位直肠癌经肛内外括约肌间切除术后各项排便动力学指标。     

直肠肿瘤经括约肌间切除术后内括约肌缺失程度对大便失禁的影响

目的 探讨超低位直肠肿瘤经括约肌间切除术( intersphincteric resection,ISR)后内括约肌不同缺失程度对大便失禁的影响.方法 选取71例直肠肿瘤患者分别行低位前切除术、部分ISR、次全ISR、完全ISR,依次作为A组(内括约肌完整组)、B组(内括约肌缺失1/3组),C组(内括约肌缺失2/3组),D组(内括约肌完全缺失组),采用肛门直肠测压和Vaizey评分系统跟踪随访4组患者术后1年内大便失禁程度的动态变化,并用重复测量方差和多元方差分析对数据进行分析.结果 术后4组肛管高压区长度均有不同程度缩短,随着术后时间推移高压区长度略有延长,但至术后12个月4组之间差异仍有统计学意义(F=41.873,P=0.000).4组肛管最大静息压均明显下降,至术后12个月时有不同程度恢复:A组恢复至接近术前水平;B、C组皆升至约术前2/3水平,两组差异无统计学意义(P=0.30);D组升至术前的1/3水平.术后10d时4组患者均出现Vaizey评分上升,此后B、C两组下降趋势相同,术后12个月时两组差异无统计学意义(P =0.158),并接近于A组;D组至术后12个月为13.7±3.2.多元回归分析显示,术后12个月,肛管最大静息压、肛管高压区长度与大便失禁的主观评分Vaizey评分呈负相关(t=-4.802,P=0.000;t=-2.011,P=0.048).结论 超低位直肠肿瘤患者术后12个月内大便失禁严重程度Vaizey评分与肛管最大静息压、肛管高压区长度相关.术后一年时绝大多数超低位直肠肿瘤切除患者可获得比较满意的控便功能.     

新辅助放化疗对直肠/肛管癌患者行经内外括约肌间切除术后近远期疗效的影响

目的 探讨新辅助放化疗对直肠/肛管癌患者行经内外括约肌间切除术（ISR）后近远期疗效的影响.方法 直肠/肛管癌患者115例,根据患者术前是否行长周期（8周）新辅助放化疗分组,术前行长周期（8周）新辅助放化疗的患者定义为A组,术前未行长周期（8周）新辅助放化疗的患者定义为B组.两组均行经内外括约肌间切除术（ISR）.结果 从术后并发症发生率来看,A组肛周感染率明显高于B组（7.5％vs 0％）（P＜0.05）.从患者术后肛门功能恢复情况来看,两组术后2、3年肛门功能均较术后1年明显改善（P＜0.05）.两组间比较,A组术后1、2、3年肛门功能均较B组差（P＜0.05）.从远期效果来看,两组局部复发率及生存率差异无统计学意义（P＞0.05）.结论 新辅助化疗联合ISR治疗超低位直肠/肛管癌较单纯ISR,没有延缓患者术后近期恢复,且能够获得相似的生存率及局部复发率,但是,新辅助化疗增加了ISR手术患者术后肛周感染发生率,同时,对患者术后肛门功能造成一定的影响,但仍在患者可接受范围之内.     

瑞芬太尼术毕时不同应用模式对颅脑手术患者苏醒期的影响

目的 评价神经外科手术患者全麻苏醒期应用不同模式瑞芬太尼对患者拔管期呛咳反应的影响.方法 ASAⅠ或Ⅱ级择期行颅脑手术的患者60例,均在快速诱导下进行气管插管,术中以微量泵持续输注丙泊酚、瑞芬太尼维持麻醉,术毕按瑞芬太尼的给药方式采用完全随机法分为3组(每组20例):A组缝皮结束时停止输注瑞芬太尼;B组缝皮结束时停止输注瑞芬太尼,包扎头部时再静脉单次注射瑞芬太尼1 μg/kg,C组缝皮结束后继续微泵输注瑞芬太尼0.05 μg· kg-1· min-1至拔管后.记录拔管前、拔管即刻、拔管后1、3 min的心率(heart rate,HR)、平均动脉压(mean arterial pressure,MAP)、血氧饱和度(oxygen saturation,SpO2),记录手术时间、苏醒时间(丙泊酚停止输注至睁眼时间)、拔管时间(缝皮结束至拔管)、丙泊酚与瑞芬太尼的总用量、呛咳程度、拔管后意识状态等.结果 拔管即刻HR:A组(101±7)次/min,B组(90±8)次min,C组(78±9)次min;拔管后1 min的HR:A组(98±9)次min,B组(83±6)次/min,C组(80±5)次/min;拔管后3min的HR:A组(93±5)次/min,B组(82±7)次/min,C组(82±5)次/min;B组、C组在拔管后3个时点的HR低于A组,差异有统计学意义(P＜0.05).拔管即刻MAP:A组(97±11) mm Hg(1 mm Hg =0.133 kPa),B组(87±9)mm Hg,C组(77±7) mmHg;拔管后1 min的MAP:A组(92±8) mm Hg,B组(84±8) mm Hg,C组(75±6) mm Hg;拔管后3 min的MAP:A组(85±6) mm Hg,B组(80±5) mm Hg,C组(76±6) mm Hg;B组在拔管即刻、拔管后1 min的MAP低于A组,差异有统计学意义(P＜0.05),C组在拔管后3个时点的MAP均低于A组,差异有统计学意义(P＜0.05).C组拔管后3个时点的HR、MAP与拔管前比较差异无统计学意义(P＞0.05).A、B、C3组苏醒时间、拔管时间、拔管后OAA/S评分差异无统计学意义(P＞0.05);拔管期A组均出现呛咳,8例轻度、12例中度,B组13例无呛咳、7例轻度呛咳,C组16例无呛咳、4例轻度呛咳,与A组比较,B组、C组呛咳的发生率及程度均降低(P＜0.05).结论 手术结束时继续持续输注0.05 μg·kg-1·min-1的瑞芬太尼或单次静脉注射瑞芬太尼1μg/kg可提高患者的耐管性,减少呛咳反应,抑制拔管期间HR、MAP的过度变化,且不影响患者苏醒时间.     

低位直肠癌患者内括约肌切除术后肛门功能的评估

目的 探讨低位直肠癌内括约肌切除保肛手术对肛门功能的影响.方法 随访2005-2007年间27例低位直肠腺癌患者,手术前经MRI和腔内超声检查明确肿瘤为T0～T2期,距肛缘均＜5 cm(3～5 cm),行经腹和肛门内括约肌切除,结肠肛管直接吻合术.于手术前1周,手术后2周、3、6和9个月时应用肛门测压法对肛门功能进行评估.统计数据采用student t检验和X2检验进行比较.结果 27例患者术后3个月时肛门平均静息压(44±6)mm Hg降至(19±3)mm Hg、最大静息压(60±8)mm Hg降至(33±4)mm Hg、缩榨压(180±19)mm Hg降至(131±16)mmHg和最大耐受容量(165±20)ml降至(55±8)ml,均较术前显著降低(P＜0.05),直肠抑制反射均消失;手术后6个月平均静息压、最大静息压、缩榨压和最大耐受容量明显增加,6例可以引出直肠抑制反射;术后9个月平均静息压、最大静息压和缩榨压分别为:(41±5)mm Hg、(57±8)mm Hg和(173±19)mm Hg,均接近正常水平(P＞0.05),最大耐受容量增加至(110±16)ml,但仍较术前低(P=0.0153),11例直肠抑制反射阳性.结论 直肠内括约肌切除术后短期患者肛门功能明显受损,随手术后时间的延长,肛门功能可以完全恢复或接近手术前水平.     

右美托咪定联合异丙酚对等效剂量芬太尼和舒芬太尼诱发呛咳的影响

目的 探讨右美托咪定(dexmedetomidine,DEX)联合异丙酚对等效剂量芬太尼和舒芬太尼诱发呛咳的影响.方法 200例拟行全麻气管插管的择期手术患者,美国麻醉医师协会(ASA)分级Ⅰ或Ⅱ级,年龄18岁～65岁,随机数字表法随机分为4组(每组50例):对照组(C1组、C2组)全麻诱导前静脉输注生理盐水0.15 ml/kg+脂肪乳0.1ml/kg;DEX联合异丙酚组(DP1组、DP2组)全麻诱导前静脉输注DEX 0.6 μg/kg+异丙酚1 mg/kg.1 min后,C1组、DP1组静脉5s注射芬太尼4μg/kg,C2组、DP2组静脉5s注射舒芬太尼0.5 μg/kg.记录注射芬太尼或舒芬太尼后1min内呛咳的发生情况和强度.之后继续全麻诱导及气管插管.记录各组静脉给药前(To)、气管插管前(T1)、气管插管后(T2)的收缩压(SBP)、舒张压(DBP)和心率(HR). 结果C1组、DP1组、C2组及DP2组呛咳发生率分别为:40％、0、24％、0.与C1组和C2组比较,DP1组、DP2组呛咳发生率明显降低(P＜0.01),但呛咳程度差异无统计学意义(P＞0.05).T1时,与C1组SBP[(94±13)mm Hg(1 mm Hg=0.133 kPa)]、DBP[(56±9) mm Hg]和C2组SBP[(92±14) mm Hg]、DBP[(55±10) mm Hg]比较,DP1组SBP[(114±13) mm Hg]、DBP[(70±10) mm Hg]和DP2组SBP[(116±15) mm Hg]、DBP[(72±10)mm Hg]升高(P＜0.01);T1、T2时,与C1组HR[(68±11)次/min和(80±15)次/min]和C2组HR[(71±18)次/min和(84±17)次min]比较,DP1组HR[(62±11)次/min和(65±10)次/min]、DP2组HR[(61±8)次/min和(65±9) 次/min]降低(P＜0.01);与T1时C1组SBP[(94±13) mm Hg]、DBP[(56±9)mm Hg]和C2组SBP[(92±14) mm Hg]、DBP[(55±10) mm Hg]比较,T2时C1组SBP[(122±22) mm Hg]、DBP[(76±16) mm Hg]和C2组SBP[(117±20) mm Hg]、DBP[(76±14) mm Hg]升高(P＜0.01). 结论静脉注射DEX 0.6 μg/kg联合异丙酚1 mg/kg可完全抑制等效剂量芬太尼和舒芬太尼诱发呛咳的发生,并可使患者全麻诱导气管插管期血流动力学更趋稳定.     

允许性高碳酸血症在胸腔镜治疗新生儿先天性食管闭锁手术中的应用

目的 探讨允许性高碳酸血症(permissive hypercapnia,PHC)在胸腔镜治疗新生儿先天性食管闭锁手术中的应用效果。方法 选择行胸腔镜下先天性食管闭锁(congenital esophageal atresia,CEA)I期吻合术的新生儿30例,男17例,女13例,出生1~5d,体重1.42~3.28kg,ASAⅡ或Ⅲ级。随机分为PHC组(P组)和对照组(C组),每组15例。两组新生儿均采用气管内插管静-吸复合全麻,FiO2100%,新鲜气流量2L/min。P组VT6ml/kg,C组VT_10ml/kg。根据气道压及血气分析结果,通过调节呼吸机RR和PEEP参数,维持P组PaCO_2为60~80mm Hg,C组PaCO_2为35~45mm Hg。记录气胸建立前(T0)、气胸建立后15min(T_1)、30min(T_2)、60min(T3)和气胸解除后15min(T4)的动脉血气分析。记录术后2h内气胸发生情况及术毕至撤离呼吸机时间。结果T_1时,P组P_(ET)CO_2明显高于C组[(73.93±3.53)mm Hg vs.(41.53±1.59)mm Hg,P0.05],动脉血pH值明显低于C组(7.25±0.02vs.7.38±0.03,P0.05),PaCO_2明显高于C组[(74.80±2.45)mm Hg vs.(41.93±1.39)mm Hg,P0.05];T2时,P组P_(ET)CO_2明显高于C组[(73.46±3.04)mm Hg vs.(41.30±1.29)mm Hg,P0.05],动脉血pH值明显低于C组(7.24±0.01vs.7.37±0.03,P0.05),PaCO_2明显高于C组[(75.33±2.19)mm Hg vs.(42.01±1.31)mm Hg,P0.05];T3时,P组P_(ET)CO_2明显高于C组[(74.13±2.85)mm Hg vs.(41.67±1.35)mm Hg,P0.05],动脉血pH值明显低于C组(7.25±0.01vs.7.38±0.02,P0.05),PaCO_2明显高于C组[(75.20±2.08)mm Hg vs.(42.13±1.19)mm Hg,P0.05]。P组气胸发生率明显低于C组(6.7%vs.40.0%,P0.05)。P组与C组术毕至撤离呼吸机时间差异无统计学意义[(3.6±0.6)d vs.(3.5±0.6)d]。结论 允许性高碳酸血症(PaCO_260~80mm Hg)可以安全应用于胸腔镜治疗新生儿先天性食管闭锁手术,同时可以明显降低气胸的发生率。     

羟考酮与舒芬太尼用于无痛人工流产术的镇痛效果比较

目的 研究羟考酮注射液复合丙泊酚在无痛人工流产术中应用的有效性与安全性. 方法 采用随机数字表法将60例行无痛人工流产术患者分为3组(每组20例):丙泊酚与羟考酮组(A组),丙泊酚与舒芬太尼组(B组),丙泊酚与安慰剂组(C组).记录3组麻醉诱导前(T1)、扩张官颈时(T2)、苏醒即刻时(T3)的MAP、HR、Sp02,围手术期的副作用,T3、苏醒后30 min(T4)、苏醒后3.5 h(T5)的VAS评分,3组患者应用阿托品与间羟胺的次数与离院时间,并进行比较. 结果 3组患者一般资料及手术时间差异无统计学意义(P＞0.05).A组、B组的丙泊酚用量[(130±22)、(141±27) mg]与苏醒时间[(1.2±0.8)、(1.3±1.1) min]比C组[(164±40) mg和(2.6.±1.6)min]明显减少(P＜0.01).A组T2时的MAP与HR[(77±10) mmHg(1 mmHg=0.133 kPa)和(67±8)次/min]比T1时[(88±8) mmHg和(78±12)次nin]明显降低(P＜0.01).C组T2时的HR[(80±15)次/min]比T1时[(74±7)次/min]增加(P＜0.05).体动发生次数A组、B组比C组明显减少(P＜0.01),头晕发生次数A组、B组比C组明显增加(P＜0.01),且A组少于B组(P＜0.05).A组T3、T4、T5时的VAS评分明显低于C组(P＜0.01),B组T3、T4时的VAS评分明显低于C组(P＜0.01).A组T3、T5时的VAS评分低于B组(P＜0.05),尤其T5时更低(P＜0.01).3组之间的用药次数比较,差异无统计学意义(P＞0.05).C组的离院时间比A组、B组长(P＜0.05). 结论 丙泊酚联合羟考酮比丙泊酚联合舒芬太尼或单用丙泊酚在无痛人工流产术中具有更好的镇痛效果、更少的副作用,可安全、有效地用于无痛人工流产术.     

吻合器痔上黏膜环切术与外剥内扎术治疗Ⅲ度混合痔后肛管直肠压力的对比研究

目的比较吻合器痔上黏膜环切术(PPH)与外剥内扎术(MMH)治疗Ⅲ度混合痔后的肛管直肠压力。方法前瞻性收集2014年3月至2015年3月期间在新疆医科大学第一附属医院肛肠外科住院治疗的112例Ⅲ度混合痔患者,根据患者意愿予以PPH(n=60)或MMH(n=52)治疗。术后6个月对所有病例进行直肠肛门测压,测压指标包括直肠肛门抑制反射情况、直肠静息压、肛管静息压、肛管最大收缩压和术后肛管高压带长度,并进行组间比较。结果术后6个月时,PPH组患者的直肠肛门抑制反射阳性率〔88.3%(53/60)比61.5%(32/52)〕、肛管静息压〔(56.42±2.25)mm Hg比(46.31±2.58)mm Hg〕及肛管高压带长度〔(3.35±0.12)cm比(2.29±0.23)cm〕均高于MMH组(P0.05),但PPH组和MMH组患者的直肠静息压〔(5.51±1.26)mm Hg比(5.39±1.85)mm Hg〕和肛管最大收缩压〔(156.64±9.78)mm Hg比(155.32±8.53)mm Hg〕比较差异均无统计学意义(P0.05)。结论 PPH和MMH均为治疗Ⅲ度混合痔的有效术式,但PPH在肛门生理功能保护方面更值得肯定。     

止痛如神汤加减方联合康复新液灌肠治疗气滞血瘀型混合痔术后肛门疼痛的临床效果

目的 观察止痛如神汤加减方联合康复新液灌肠治疗气滞血瘀型混合痔术后肛门疼痛的临床效果。方法:选择2021年1月—2022年12月在崇州市人民医院收治的100例混合痔患者,按照随机数字表法分为A组、B组、C组三组。A组30例,予常规西医治疗;B组35例,在A组基础上予康复新液灌肠治疗;C组35例,在B组基础上予止痛如神汤加减方治疗。三组术后1、7 d均评价创面水肿、创面肉芽组织生长情况,通过数字疼痛评分法(NRS)评价肛门疼痛情况,记录三组患者肛门水肿消退时间、创面分泌物消失时间、创面愈合时间,检测三组肿瘤坏死因子α(TNF-α)、表皮生长因子(EGF)、β-内啡肽(β-EP)、白细胞介素-22(IL-22)、纤维连接蛋白(FN)、血管内皮生长因子(VEGF)水平,术前、术后1个月测量患者直肠肛管抑制反射阈值、肛管静息压、肛管高压带长度。结果:C组创面水肿、NRS评分较A组、B组低(P＜0.05),创面肉芽组织生长评分较A组、B组高(P＜0.05);C组创面分泌物消失时间、肛门水肿消退时间、创面愈合时间较A组、B组短(P＜0.05);C组直肠肛管抑制反射阈值、肛管静息压较A组、B组高(P＜0.05),C组肛管高压带长度较A组、B组短(P＜0.05);C组TNF-α、IL-22水平较A组、B组低(P＜0.05),C组β-EP、EGF、FN、VEGF水平较A组、B组高(P＜0.05)。结论:止痛如神汤加减方联合康复新液灌肠可抑制炎症因子水平,调节疼痛介质及EGF、FN、VEGF指标,缓解肛门疼痛,促进创面愈合,提升肛门功能。     

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.     

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.     

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.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

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.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.     

Intravenous endotoxin does not increase tissue extravasation of albumin in rats

Background : It is unclear whether activation of the inducible nitric oxide synthase (iNOS) increases or decreases the extravasation of plasma.
Methods : Chloralose anaesthetised male Wistar rats received E. coli lipopolysacharide (LPS), 3 mg kg^-1 i.v., or the corresponding volume of saline, 3 or 5 h before the end of the experiment. Mean arterial pressure (MAP) and heart rate (HR) were recorded. Tissue clearance of radio-labelled albumin, during the last 2 h of each experiment, was determined by a double-isotope method. In separate animals, the serum concentration of nitrite and nitrate was determined, 5 h after LPS or the solvent.
Main Results : LPS initially decreased MAP and lastingly increased HR. In the 3-h LPS animals (n=8), tissue plasma clearance was lower in the heart and calf muscle and increased only in diaphragm, compared to corresponding control animals (n=8). In the 5-h LPS rats, clearance was lowered (n=8) in the entire gastrointestinal tract and in testes, compared to controls (n=8). The serum nitrite/nitrate concentration was higher in animals given LPS (n=6) than in controls (n=6).
Conclusion : After LPS, tissue clearance of albumin was not increased in any major tissue, in spite of increased serum levels of NO end products. Apparently, after activation of iNOS, the augmented release of NO is not necessarily associated with increased albumin extravasation.