Ilizarov技术改善骨搬运中轴向偏移的临床研究

目的探讨Ilizarov技术改善骨搬运中轴向偏移的角度、发生率及效果。方法回顾分析2010年1月-2014年12月采用Ilizarov骨搬运技术治疗的14例胫骨骨折患者临床资料。男11例,女3例;年龄18~70岁,平均38.8岁。感染性骨缺损10例,非感染性骨缺损4例。根据Paley等提出的骨缺损分型:B1型(不合并短缩的骨缺损)7例,B3型(合并短缩的骨缺损)7例。受伤至手术时间1~72个月,平均11.9个月。采用外固定支架构型和调整固定骨搬运段半针与全环的距离,改变四边形边角关系,调整骨搬运段与对合端骨段的对合关系及对合端两骨段的力线,使患肢力线达到满意程度,以纠正轴向偏移。结果术后患者均获随访,随访时间9~31个月,平均19.1个月。术后4例患者骨对合端自然愈合,余10例经植骨处理后愈合。术后1周初次复查X线片,发生冠状位成角10例(3~12°,平均4.9°),矢状位成角9例(2~12°,平均3.8°);轴向偏移6例(43%),通过矫正,5例轴向偏移明显纠正,1例因患者依从性差错失调整搬移环半针的最佳时机,末次随访时仍有6°力线偏差。末次随访时冠状位成角5例(2~4°,平均2.6°),矢状位成角6例(2~6°,平均4.1°),轴向偏移1例(7%),均较术后初次复查时显著改善。末次随访时根据Paley等提出的评价标准,骨性结果优12例、良2例,功能结果优12例、良2例。结论 Ilizarov骨搬运技术通过安装骨搬运段外固定支架构型,术后搬运过程中逐渐调整半针与搬移环间的距离,可以改善骨对合端轴向偏移发生。     

成人胫骨缺损新分型与骨搬移治疗策略:附58例报告

背景:胫骨缺损常合并软组织损伤、肢体畸形、不等长等问题。目前的临床分型并不能涵盖一些复杂胫骨缺损情况。目的:从Ilizarov骨搬移技术角度探讨成人非感染性胫骨缺损临床新分型及治疗策略。方法:分析2000年4月至2017年1月应用Ilizarov骨搬移技术治疗的58例成人无感染性胫骨缺损。依据胫骨缺损的长度、部位、是否合并畸形以及相应的Ilizarov骨搬移手段分为5个类型。Ⅰ型:1 cm<中下/上段骨缺损≤6 cm,无明显成角畸形。采用胫骨单节段截骨,向缺损端搬移。Ⅱ型:6 cm<中下/上段骨缺损≤10 cm,无明显成角畸形。采用双节段截骨同步向缺损端骨搬移。Ⅲ型:6 cm<中段骨缺损≤10 cm,无明显成角畸形,胫骨上、下双节段截骨,向心性骨搬移。Ⅳ型:6 cm<上、下两段缺损≤10 cm,中段残留活骨≥6 cm,无明显成角畸形。将胫骨中间残留的一段活骨2处截骨,成为3块骨,中间骨块固定作为两块骨搬移再生的"母骨"支点,上下两段骨块反向分离牵拉,一期修复上下2区骨缺损。Ⅴ型:胫骨缺损>10 cm,合并骨干>7°成角畸形。采用腓骨上下两处截骨,先纵向牵拉使胫骨缺损间隙加大、成角畸形矫正,再横向牵拉将腓骨中间段搬移至胫骨缺损处,使其腓骨胫骨化。观察5个临床分型组骨缺损修复骨愈合、畸形矫正、有无肢体短缩等并发症、汇合端愈合情况等。拆除外固定后随访,采用改良Paley骨不连评价标准进行评价。结果:55例患者获得随访,随访时间24~104个月,平均(32.0±21.4)个月。所有患者均实现骨缺损修复并最终骨性愈合,骨愈合指数35~60d/cm,平均(49.0±6.4)d/cm。1例Ⅳ型,4例Ⅴ型患者术后肢体短缩>2.5 cm(2.7~3.5 cm)。末次随访无>7°局部畸形病例。未发生1例深部感染、血管神经损伤等并发症。17例因汇合端骨愈合迟缓,二次手术取自体髂骨植骨。带外固定架时间5~28个月。治疗效果:优41例、良11例、可3例,优良率94.5%(52/55)。结论:成人胫骨缺损新分型既有利于病情评估亦利于制定合理的治疗方案。针对不同类型制定的个体化骨搬移重建方法,可一期手术修复骨缺损、矫正畸形、延长肢体,临床疗效显著,值得推广。     

微创截骨Ilizarov技术治疗胫骨大段感染性骨缺损

[目的]探讨使用微创截骨Ilizarov骨搬移技术治疗大段胫骨感染性骨缺损患者的临床疗效。[方法]对2010年9月～2017年1月本科使用微创截骨Ilizarov骨搬移技术治疗的30例胫骨大段感染性骨缺损患者进行回顾性分析,评价治疗效果,总结临床经验。[结果]手术时间平均(68.12±18.20) min,术中出血量+术后引流量平均(178.43±46.24) ml。30例患者均获随访,平均随访时间(36.54±7.21)个月。所有患者创面平均(35.74±10.82) d愈合。骨延长长度平均(8.52±2.43) cm,骨搬移时间平均(3.54±1.17)个月,去除外固定时间平均(22.54±4.83)个月。无患者出现严重并发症。Paley骨愈合评定:优25例,良3例,一般2例;功能评定:优23例,良4例,一般3例。[结论]应用微创截骨Ilizarov骨搬移技术治疗胫骨感染性骨缺损效果确切,重建了原有肢体长度,缩短了治疗周期,确保了手术疗效。     

手风琴技术用于骨搬移治疗胫骨骨缺损

目的 :分析Ilizarov技术治疗胫骨大段骨缺损时加用"手风琴技术"的临床治疗效果。方法 :2014年1月至2016年6月采用Ilizarov骨搬移技术治疗胫骨大段骨缺损患者22例,男19例,女3例;年龄23~60岁,平均44.04岁;骨搬移前骨缺损长度5~11 cm,平均7.68 cm;14例交通事故,3例摔伤,4例砸伤,1例高处跌落;左侧6例、右侧16例。分成两组,手风琴组搬移结束后实施手风琴技术11例,对照组搬移结束后外架锁定等待矿化11例。两组患者均获得随访,随访时间18~36个月,平均27.9个月。两组患者性别、年龄、骨缺损的长度比较,差异均无统计学意义(P0.05)。分析愈合时间、愈合指数等指标,并采用Paley等方法评价骨愈合和患肢功能恢复的治疗效果。结果:两组X线评价均达到骨性愈合;手风琴组:骨愈合时间(365±91)d,愈合指数(46.2±3.5)d/cm;对照组:愈合时间(435±108)d,愈合指数(57.8±3.5)d/cm;两组骨愈合时间比较,差异无统计学意义(t=1.648:P=0.115);两组骨愈合指数比较,差异有统计学意义(t=7.754,P=0.000)。末次随访时依据Paley评价标准评价疗效:实验组优9例,良2例;对照组优8例,良3例;两组比较差异无统计学意义(Z=-0.479,P=0.619)。并发症:钉道感染:手风琴组9例,对照组10例;局部牵拉痛:手风琴组2例,对照组1例;轴向偏移10°:手风琴组4例,对照组3例;骨缺损汇合端对位差:手风琴组3例;对照组2例;两组并发症比较差异无统计学意义(P0.05)。结论 :Ilizarov骨搬移技术治疗胫骨骨缺损时加用"手风琴技术"操作后可缩短治疗时间和矿化时间,提高愈合指数。     

Ilizarov外固定架骨搬移技术联合皮瓣、VSD技术治疗胫骨长段骨缺损及骨外露的疗效分析

[目的]探讨和总结Ilizarov外固定架骨搬移技术联合皮瓣、VSD技术治疗胫骨长段骨缺损及骨外露的手术方法及其疗效。[方法]本科2011年10月~2013年12月应用Ilizarov环形外固定架联合皮瓣、VSD技术治疗胫骨长段骨缺损及骨外露患者16例;小腿软组织缺损范围(4.0~6.0)cm×(3.0~4.5)cm,胫骨骨缺损长度4.5~8.0 cm,平均6 cm。先清创取出死骨块、VSD技术覆盖创面控制感染,再用Ilizarov骨搬移技术使骨缺损修复,骨折愈合。参照Paley评价标准进行功能评价,并分析其骨折愈合时间、带外固定架时间、术后患肢功能恢复情况。[结果]所有病例均获得随访,随访时间9~24个月,平均10.5个月。其中11例应用皮瓣转移覆盖创面修复,3例通过游离皮片移植创面愈合,2例经换药愈合,软组织修复良好。使用VSD 3~6期,平均4.8期;带外固定架时间6~18个月,平均10.3个月;骨段搬移延长4.5~8.0 cm,平均6 cm;骨折愈合时间6~15个月,平均9.8个月。根据Paley骨折愈合与功能分级评价骨搬移结果及功能,优9例,良5例,可2例。[结论]Ilizarov外固定架骨搬移技术联合皮瓣、VSD技术治疗胫骨长段骨缺损及骨外露具有操作简便、疗效肯定、并发症发生率低、可随时调整纠正畸形等优点,值得推广。     

Ilizarov骨搬移技术在胫骨骨折术后骨感染骨缺损中的应用

目的探讨Ilizarov骨搬移技术治疗胫骨骨折术后骨感染骨缺损的临床疗效。方法回顾性分析自2010-06—2013-06应用Ilizarov骨搬移技术治疗27例胫骨骨折术后骨感染。结果 27例术后均获得平均28(16~50)个月随访。骨搬移长度平均7.9(5~12)cm,搬移时间平均78(55~160)d,骨搬移停止至拆除外固定架时间平均180(95~220)d。出现针道感染2例,停止搬移,静点抗生素、对症处理后感染控制;出现牵张成骨区成骨不全1例,植骨后愈合;拆除外架后发生牵张成骨区骨折1例,经内固定后骨愈合;骨搬移停止后,对15例断端进行去除嵌压组织、新鲜化处理后断端骨性愈合,9例无需进一步手术,通过断端加压后骨愈合,3例加压固定3个月后无明显愈合表现,按照骨不连处理方案,应用手风琴技术处理后顺利愈合。结论应用Ilizarov骨搬移技术治疗胫骨骨折术后骨感染骨缺损可以取得满意的疗效,骨搬移过程中的环形固定器有利于畸形矫正,但患者对单边固定器有更好的耐受性。严谨的术前设计、精细的术中操作、耐心细致的术后随访是治疗成功的必要保证。     

混合与环形外固定架治疗胫骨骨缺损的轴向偏移比较

目的比较混合外固定架与环形外固定架骨搬移治疗胫骨骨缺损的轴向偏移。方法回顾观察2013年5月至2019年8月本院骨搬移治疗的48例胫骨骨缺损患者资料,25例采用混合外固定架治疗(混合组),23例采用环形外固定架治疗(环形组)。混合组男18例,女7例;年龄28～73岁,平均(48.64±10.55)岁;平均病程(19.44±16.41)个月;清创后平均骨缺损长度(7.48±2.39)cm。环形组男18例,女5例;年龄25～66岁,平均(47.22±9.24)岁;平均病程(18.52±10.04)个月;清创后平均骨缺损长度(7.78±2.31)cm。比较两组患者术后、骨残端临会合时(两骨残端间距0.5cm左右时)的轴向成角和轴向偏移发生率,以及外固定指数、骨愈合时间、针道松动发生率、骨性结果和功能结果等。结果 48例患者均获得随访,随访时间16～32个月,平均随访(23.21±4.43)个月。术后混合组和环形组均无轴向偏移,轴向成角差异无统计学意义(P0.05);临会合时混合组轴向偏移和轴向成角均低于环形组(P0.05)。环形组针道松动发生率高于混合组,两组外固定指数、骨愈合时间、骨性结果、功能结果和针道感染率差异无统计学意义(P0.05)。结论相较于环形外固定架而言,混合外固定架能更好地预防胫骨骨搬移过程中轴向偏移的发生。     

骨-软组织复合搬移技术治疗伴有皮肤缺损的胫骨骨缺损

[目的]评价骨-软组织复合搬移技术治疗伴有皮肤缺损的胫骨骨缺损的可行性及临床效果。[方法]2011年10月~2014年7月对7例伴有皮肤缺损的胫骨骨缺损患者行骨-软组织复合搬移治疗。男5例,女2例,年龄25~54岁,平均35.2岁。彻底清创,截除病骨,干骺端截骨,安装Ilizarov外固定架行骨-软组织复合搬移治疗伴有皮肤缺损的胫骨骨缺损。定期随访,软组织靠拢后,予以清创缝合。随访X线片示两缺损端对合后,根据骨愈合及矿化情况,逐步简化Ilizarov外固定架,达到骨性愈合后,拆除外固定架。统计并发症、骨愈合情况,踝、膝关节功能。[结果]所有患者均获随访,时间6~33个月,平均24个月。所有患者均未出现外支架取出后再次骨折,患膝、踝关节功能良好。1例出现钉道感染,经清创换药及抗生素治疗后感染控制;1例出现外固定架术后软组织阻挡,行软组织松解术后阻挡解除。Paley骨愈合评分标准评定优5例,良2例。[结论]骨-软组织复合搬移技术是治疗伴有皮肤缺损的胫骨骨缺损的有效方法,具有创伤小、操作简单、易于推广等优点。     

应用Ilizarov骨搬移术治疗合并软组织缺损的胫骨长段骨缺损

目的探讨应用Ilizarov骨搬移术治疗胫骨长段骨缺损合并软组织缺损的临床疗效。方法回顾性分析我科2015年1月至2019年12月采用Ilizarov骨搬移术治疗33例胫骨长段骨缺损合并皮肤软组织缺损患者,其中男23例,女10例;年龄17～70岁,平均(41.2±3.3)岁。患者均为GustiloⅢ型开放性骨折。清创后骨缺损长度5～18 cm,平均(7.0±3.0)cm。皮肤软组织缺损范围12～198 cm~2,平均(36.0±22.0)cm~2。受伤至骨搬移手术治疗时间5～46 d,平均(12.3±7.5)d。手术均采用环形外固定支架,术后规律骨搬移,创面给予定期湿敷换药处理。结果 33例患者均获随访,随访时间13～42个月,平均(16.0±3.6)个月。患者骨缺损全部通过骨搬移修复,骨愈合时间为9～20个月,平均(10.2±4.6)个月。患者皮肤软组织缺损均自行愈合,愈合时间1～3个月,平均(1.3±0.9)个月。治疗期间患者均未出现血管、神经损伤,术后无骨感染、再骨折等并发症。其中16例对合端软组织塌陷影响骨折愈合,行断端清理、植骨术后骨折顺利愈合;5例对合端接触后连续3个月复查无明显骨痂生长,行松质骨植骨,术后骨折顺利愈合;8例钉道出现不同程度感染,经局部换药后好转;3例牵拉后出现马蹄足畸形,2例发生膝关节屈曲畸形,经二次手术矫形均获得满意效果。33例患者根据Ilizarov方法研究与应用学会(Association for the Study and Application of the Method of Ilizarov, ASAMI)评价标准评价,骨愈合:优31例,良2例,优良率100%;功能:优25例,良6例,可2例,优良率93.9%。结论 Ilizarov骨搬移术是治疗合并软组织缺损的胫骨长段骨缺损的有效方法。     

Ilizarov骨搬移技术修复胫骨创伤性骨髓炎大段骨缺损

目的探讨应用Ilizarov骨搬移技术治疗胫骨创伤性骨髓炎大段骨缺损的临床疗效。方法回顾性分析2010年6月至2014年9月在我科收治15例胫骨创伤性骨髓炎患者,其中男11例,女4例;年龄17~60岁,平均39.3岁。交通事故伤9例,重物压砸伤4例,高处坠落伤2例。根据Cierny-Mader解剖学分型:Ⅲ型6例,Ⅳ型9例。采用病灶骨段切除、Ilizarov骨搬移技术治疗,并记录骨段延长长度、外固定架时间、骨愈合及功能评价结果。结果 15例患者均获随访,随访时间18~40个月,末次随访时,骨缺损均得以重建。骨缺损长度6~13 cm,平均8.6 cm。外固定架固定时间为8.4~16.5个月,平均11.2个月。术后无一例出现深部感染、骨不连或关节僵直。根据改良ASAMI评定标准评定骨性结果:优12例,良1例,中1例,差1例,优良率为87.3%;功能结果:优10例,良2例,中3例,差0例,优良率为80.0%。结论应用Ilizarov骨搬移技术是治疗胫骨创伤性骨髓炎大段骨缺损的有效方法。     

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.     

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.