局部注射含氯诺昔康的镇痛药物抑制痛觉致敏作用对全膝关节置换手术后疼痛控制的影响研究

目的探讨术中局部注射含氯诺昔康的镇痛药物配方与传统布比卡因配方对全膝关节置换术（TKA）术后疼痛控制的影响.方法 选择2008年1月～2009年8月在第三军医大学西南医院关节外科中心行TKA术的骨关节炎患者.将符合双盲对比研究的患者随机分为两组,传统布比卡因组（A组）78例,加用氯诺昔康组79例（B组）.所有患者施行标准化围手术期口服药物和神经阻滞PCA持续镇痛,每12小时记录术患者后疼痛评估结果,包括：（1）患者静息和被动活动VAS评分;（2）股四头肌肌力;（3）镇痛泵药品消耗量.结果 157例患者中共有12例被剔除.术后12 h两组间的指标无统计学差异（P〉0.05）;术后12～48 h,A组镇痛泵药物用量与B组有统计学差异（P〈0.05）;术后24～96 h,B组被动活动痛VAS评分与A组有统计学差异（P〈0.05）.两组患者间肌力无统计学差异（P〉0.05）.结论 TKA术区局部镇痛药物配方中NSAIDS药物的使用对术后早期镇痛的效果明显优于传统的布比卡因配方.其镇痛作用延长至术后96 h仍明显优于传统布比卡因配方,可能与消除了痛觉致敏有关.     

多模式镇痛用于膝关节镜下交叉韧带重建术临床分析

目的探讨围术期多模式超前镇痛在膝关节镜手术应用的镇痛效果。方法行膝关节镜下交叉韧带重建术患者60例,随机分为A组与B组,每组30例。两组均采用腰硬联合麻醉,A组为多模式超前镇痛组,在术前30分钟肌注帕瑞昔布钠40 mg,B组患者肌注等量生理盐水。手术后A组患者在B超引导下行单次股神经阻滞(0.2%罗哌卡因25 m1)。B组患者在术后给予硬膜外注射吗啡2 mg。两组均带自控镇痛泵,2 mL/h,每次追加0.5 ml,锁时15分钟。术后12小时A组患者肌肉注射帕瑞昔布钠40 mg,B组患者肌注等量生理盐水。记录术后6小时、12小时、1天和2天的膝关节疼痛视觉模拟评分(visual analogue scale,VAS)、股四头肌肌力、自控镇痛泵按压次数和不良反应发生情况。结果 A组在术后6小时、12小时和1天的VAS评分和自控镇痛泵按压次数均显著低于B组(P0.05),两组术后2天的VAS评分和自控镇痛泵按压次数比较,差异无统计学意义(P0.05),两组术后各时间点股四头肌肌力比较,差异无统计学意义(P0.05)。A组术后发生不良反应例数明显低于B组(P0.05)。结论多模式超前镇痛在膝关节镜下交叉韧带重建术的镇痛效果明显优于传统硬膜外给予吗啡的方法,不良反应发生率低。     

持续收肌管阻滞术后镇痛在全膝关节置换术快速康复中的作用

目的探讨持续收肌管阻滞(CACB)术后镇痛在全膝关节置换术(TKA)快速康复中的作用,以进一步优化TKA术后的快速康复方案。方法将90例行单侧TKA的患者按随机数字表法分为CACB组与持续股神经阻滞(CFNB)组,每组45例。所有患者纳入快速康复模式。CACB组手术结束20 min由麻醉医师行术侧收肌管阻滞并留置导管,CFNB组手术结束20 min行术侧股神经阻滞并留置导管。比较两组住院时间、术后静息和活动疼痛数字评分法(NRS)评分、股四头肌肌力、膝关节活动度、膝关节HSS评分、补救性阿片类药物的消耗、术后并发症。结果住院时间CFNB组为(13. 2±2. 98) d,长于CACB组的(11. 9±2. 59) d(P 0. 05);除术后12 h活动NRS评分CACB组高于CFNB组(P 0. 05),两组术后不同时点静息NRS评分和活动NRS评分差异无统计学意义(P 0. 05); CACB组术后第1、2、3、7天膝关节活动度、膝关节HSS评分均高于CFNB组(P 0. 05),CACB组术后1、2、3 d股四头肌肌力均高于CFNB组(P 0. 05)。结论 CACB术后镇痛在TKA中应用能保留股四头肌肌力,缩短住院时间,更有利于快速康复模式的实施。     

罗哌卡因股神经导管不同给药方式对术后镇痛的影响

目的 探讨罗哌卡因股神经导管不同给药方式用于全膝关节置换术后镇痛的效果.方法 拟行全膝关节置换术患者40例,随机均分为持续给药组(A组,0.20％罗哌卡因)和间断给药组(B组,0.33％罗哌卡因).观察患者术后48 h内VAS评分及拔管后24 h股神经感觉功能和改良Bromage评分.结果 术后24hB组静息和运动时VAS评分均明显低于A组(P＜0.05或P＜0.01).术后48 hB组运动时VAS评分明显低于A组(P＜0.05).B组罗哌卡因用量明显低于A组(P＜0.01).B组芬太尼用量明显低于A组(P＜0.05).所有患者神经功能恢复均未出现延迟.结论 经股神经导管持续或间断给予罗哌卡因均能提供较好的镇痛效果,对股神经功能均没有明显影响;0.33％罗哌卡因间断给药可减少镇痛药用量.     

腘丛神经阻滞联合收肌管阻滞用于全膝关节置换术患者术后镇痛的效果

目的 观察腘丛神经阻滞(PPB)联合收肌管阻滞(ACB)用于全膝关节置换术(TKA)患者术后镇痛的效果。方法 选择初次进行全身麻醉下单侧TKA的患者60例,男15例,女45例,年龄50～80岁,BMI 18～30 kg/m²,ASAⅠ—Ⅲ级。采用随机数字表法将患者分为两组：PPB联合ACB组(P组)和ACB组(A组),每组30例。麻醉诱导前,P组采用0.5%罗哌卡因15 ml行ACB,后采用0.5%罗哌卡因20 ml行PPB,A组单纯采用0.5%罗哌卡因15 ml行ACB。记录术中瑞芬太尼总量和手术时间。记录术后4、8、24、48、72 h静息和活动时VAS疼痛评分,术后1、2、3 d主动屈膝最大角度,术后4、8、24 h患肢运动阻滞情况。记录镇痛泵总按压次数、有效按压次数和补救镇痛情况。记录首次下床活动时间、术后住院时间、患者术后满意度评分以及术后不良事件发生情况。结果与A组比较,P组术后4、8、24、48、72 h静息时VAS疼痛评分明显降低(P<0.05),术后4、8 h时活动时VAS疼痛评分明显降低(P<0.05),术后1、2 d主动屈膝最大角...     

开胸手术后伤口持续输注局麻药和PCIA的镇痛效果

目的比较开胸手术后伤口持续输注局麻药和PCIA的镇痛效果。方法择期开胸非心脏手术患者60例,ASAⅠ或Ⅱ级,随机均分为两组:伤口持续输注局麻药镇痛组(A组)和PCIA组(B组)。A组患者缝皮前在切口皮下处放置镇痛泵导管,继之通过导管快速给予0.5%罗哌卡因5ml,术毕48h内以2ml/h持续输注0.5%罗哌卡因。B组患者手术结束前30min缓慢静注舒芬太尼3μg,术毕接PCA泵以2ml/h(3μg/kg舒芬太尼配置成100ml)持续泵注。分别记录患者术后2、8、12、24、36、48h安静和活动时VAS评分、Ramsay镇静评分、术后需哌替啶镇痛例数、不良反应、住院时间及总体满意率等。结果两组患者术后不同时点安静时和活动时VAS评分差异无统计学意义。与A组比较,术后不同时点A组Ramsay镇静评分明显升高(P0.05)。术后A组无一例患者发生不良反应,明显低于B组嗜睡26例(87%)、头晕11例(37%)(P0.05)、呼吸抑制2例(6%)。A组满意率29例(97%),B组25例(83%),患者术后需哌替啶镇痛A组8例(26.7%),B组7例(23.3%),两组差异均无统计学意义。结论伤口持续输注局麻药镇痛和PCIA具有同样的镇痛效果,但伤口持续输注局麻药镇痛不良反应发生率低。     

连续收肌管阻滞和连续股神经阻滞对膝关节置换术患者术后镇痛和早期功能康复的影响

目的 比较连续收肌管阻滞(adductor canal block,ACB)和连续股神经阻滞(femoral nerve block,FNB)在膝关节置换术(total knee arthroplasty,TKA)患者术后镇痛的效果和对早期功能康复的影响.方法 择期拟行单侧TKA患者60例,采用随机数字表法分为两组(每组30例):连续ACB组(A组)和连续FNB组(F组).术中采用全凭静脉麻醉.两组在麻醉诱导前分别行超声引导下ACB和FNB,并放置神经周围导管.术毕经神经周围导管予0.2％罗哌卡因实施患者自控周围神经阻滞镇痛.记录术后4、8、12、24、48 h静息和运动(膝关节被动屈曲45°)疼痛数字评分(numeric rating scale,NRS)、患肢股四头肌肌力Lovett评分和患肢运动阻滞改良Bromage评分.记录:术后1、2、3、14 d膝关节最大主动/被动活动度,术后14 d美国纽约特种外科医院(hospital for special surgery,HSS)膝关节功能评分,术后第1次下床活动时间和术后膝关节主动屈膝90°时间.记录术后48 h内镇痛泵有效按压次数和补救镇痛率.结果 两组术后静息和运动NRS评分、镇痛泵有效按压次数和补救镇痛率等比较,差异均无统计学意义(P＞0.05).A组术后12 h内患肢股四头肌肌力Lovett评分明显高于F组(P＜0.05)、息肢运动阻滞改良Bromage评分明显低于F组(P＜0.05).A组术后1、2、3d膝关节最大主动活动度明显大于F组(P＜0.05),但膝关节最大被动活动度、术后14 d膝关节最大主动活动度、术后14 d膝关节HSS评分以及术后第1次下床活动时间和术后膝关节主动屈曲90°时间两组间比较差异均无统计学意义(P＞0.05).结论 连续ACB和连续FNB可为TKA患者提供等同的术后镇痛效果,而且对早期功能康复具有相似的效果.     

罗哌卡因复合舒芬太尼或地佐辛连续股神经阻滞在全膝关节置换术后镇痛中的应用

目的观察罗哌卡因与罗哌卡因复合舒芬太尼或地佐辛连续股神经阻滞(FNB)在全膝关节置换术(TKA)术后镇痛中的效果。方法择期行单侧TKA患者60例,采用统一麻醉和手术方案,术后FNB自控镇痛48h,持续剂量2ml/h,总量100ml。随机将患者均分为三组:罗哌卡因组(R组):0.225%罗哌卡因;罗哌卡因复合地佐辛组(D组):0.15%罗哌卡因含地佐辛10 mg;罗哌卡因复合舒芬太尼组(S组):0.15%罗哌卡因含舒芬太尼1μg/kg。记录三组患者术后1、3及7d静息状态下VAS(RVAS)评分、主动功能锻炼时VAS(AVAS)评分和被动功能锻炼时VAS(PVAS)评分;记录其他镇痛药物用量、不良事件发生情况。结果术后1、3、7d三组患者RVAS评分,术后1、7d的AVAS评分和术后1d的PVAS评分明显低于术前(P0.05);术后3d,S组与D组RVAS评分明显高于R组(P0.05)。三组术后恶心呕吐及谵妄发生率差异无统计学意义。结论罗哌卡因复合舒芬太尼或地佐辛用于FNB,可提供良好的TKA术后镇痛效果,且不增加不良反应;但0.15%罗哌卡因复合舒芬太尼或地佐辛不及0.225%罗哌卡因镇痛维持时间长,复合地佐辛这一现象更明显。     

罗哌卡因复合芬太尼用于胸科患者术后硬膜外镇痛

目的 评估罗哌卡因复合不同浓度芬太尼用于胸科手术后硬膜外镇痛(PCEA)效果及不良反应.方法 选取择期胸科食管及贲门手术男性患昔72例,年龄18～65岁,随机分成三组,每组24例.术前T7～8行硬膜外穿刺留置导管,术后接硬膜外镇痛泵.分别用罗哌卡因复合芬太尼1μg/ml(A组)、2μg/ml(B组)或3μg/ml(C组),观察术后2、4、8、12、24、36、48 h的安静/咳嗽疼痛VAS评分、不良反应和追加使用吗啡剂量和PCEA按压情况.结果 术后2、4、8 h,B、C组安静和咳嗽时VAS评分均明显低于A组(P＜0.05);术后16 h,B、C组咳嗽时VAS评分仍低于A组(P＜0.05).B、C组PCEA按压次数显著少于A组(P＜0.01),追加吗啡量也明显低于A组(P＜0.01).结论 0.15%罗哌卡因合用1、2、3μg/ml芬太尼用于PCEA均可获得满意镇痛效果;但推荐以0.15%罗哌卡因合用2μg/ml为首选,镇痛效果好,不良反应低.     

置管持续收肌管阻滞与单次注射收肌管阻滞对人工全膝关节置换术后镇痛及早期康复的影响研究

目的探讨多模式镇痛下置管持续收肌管阻滞(adductor canal block,ACB)与单次注射ACB对人工全膝关节置换术(total knee arthroplasty,TKA)后镇痛及早期康复的影响。方法 2016年10月—2017年2月,将60例因重度退行性骨关节炎拟行初次单膝TKA且符合选择标准的患者纳入研究,随机分为置管持续ACB组(A组)和单次注射ACB组(B组),每组30例。两组患者性别、年龄、体质量指数、民族、美国麻醉医师协会(ASA)分级以及术前膝关节活动度、股四头肌肌力等一般资料比较,差异均无统计学意义(P0.05),具有可比性。记录两组术中使用止血带时间、术后引流量、术后住院时间、盐酸哌替啶使用情况、不良反应事件发生情况。术后行静息及活动时疼痛视觉模拟评分(VAS),采用徒手肌力法评定股四头肌肌力,测量膝关节活动度并记录首次屈膝达90°时间。结果 A组术中使用止血带时间、术后引流量、不良反应发生率与B组比较,差异均无统计学意义(P0.05);但A组术后住院时间较B组明显缩短(P0.05)。术后各时间点A组VAS评分均低于B组,其中术后12 h后静息VAS评分及8 h后活动VAS评分与B组比较,差异均有统计学意义(P0.05)。术后各时间点A组股四头肌肌力均优于B组,其中术后24、48、72 h组间比较差异有统计学意义(P0.05)。A组术后24、48、72 h及出院当天膝关节活动度均显著优于B组(P0.05),患者首次屈膝达90°时间较B组明显缩短(t=–2.951,P=0.016)。术后24 h内使用盐酸哌替啶(50 mg/次)者,A组4例、B组7例;术后24~48 h使用,A组3例、B组7例;术后48~72 h使用,A组1例、B组3例。A组2例发生置管处渗液,无1例发生置管脱落。结论置管持续ACB对TKA术后静息及活动状态下的镇痛效果均优于单次注射ACB,能明显降低阿片类药物使用量,更有利于患者股四头肌肌力恢复,促进早期功能康复。     

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.