对颅骨牵引结合后路枕颈融合术治疗枕颈部畸形所致寰枢椎脱位的疗效评价

目的:探讨颅骨牵引结合后路枕颈融合术治疗枕颈部畸形所致寰枢椎脱位的临床疗效。方法:回顾性分析2004年1月~2011年6月收治的28例枕颈部畸形所致寰枢椎脱位患者,男18例,女10例;年龄13~56岁,平均31.1±14.2岁。颅底凹陷(扁平)畸形16例,其中8例伴寰椎枕骨化畸形,6例伴寰枢椎椎弓发育畸形,2例伴上述两种畸形;单纯寰椎枕骨化畸形6例;齿状突发育不良4例;单纯寰枢椎椎弓发育畸形2例。MRI示所有病例脊髓均有不同程度受压,术前JOA评分5~9分,平均7.2±1.4分。术前均行颅骨牵引,牵引重量4~7kg,平均5.2±0.7kg;牵引时间7~14d,平均10.1±2.1d;复查X线片,22例患者脱位部分复位,6例患者脱位完全复位。均行枕颈融合术,术中枢椎尽量置椎弓根螺钉(根据枢椎畸形程度,20例患者枢椎双侧置入椎弓根螺钉,6例单侧置钉,2例未能置钉),余固定节段(固定至畸形椎体下2~3个节段)置侧块螺钉。结果:全部病例手术均安全完成,手术时间3~5h,平均3.5h;术中出血量180~400ml,平均250ml;无脊髓、血管损伤及其他严重并发症。术后第1天JOA评分8~13分,平均10.6±1.5分,较术前明显改善(P<0.05)。术后复查X线片和MRI,21例患者脱位完全复位,7例患者脱位较术前明显改善,脊髓受压完全解除。随访6~48个月,平均20.3±9.7个月,所有病例术后3~6个月(平均4.3±0.9个月)获得骨性融合。末次随访时,JOA评分11~16分,平均14.6±1.7分,较术前及术后第1天均有改善(P<0.05)。随访期间内固定无松动、断裂。结论:颅骨牵引结合后路枕颈融合术治疗部分枕颈部畸形所致寰枢椎脱位近期疗效确切,安全可靠。     

枕骨钉结合枢椎椎弓根螺钉内固定术治疗寰枕融合并寰枢椎脱位

[目的]探讨单纯后路枕骨钉结合枢椎椎弓根螺钉内固定术治疗先天性寰枕融合并寰枢椎脱位的治疗效果。[方法]回顾性分析2008年4月~2013年12月本科收治的34例先天性寰枕融合并寰枢椎脱位患者的临床资料。采用单纯经后路枕骨螺钉和C_2椎弓根内固定,应用提拉撑开复位技术治疗此类畸形,术前及术后3、6个月及末次随访时行颈椎X线、枕颈区3D-CT、MRI检查,所有患者均根据术后影像学检查和日本骨科协会(Japanese Orthopedic Association Scores,JOA)评分评价影像和临床效果。[结果]随访9~38个月,平均16.5个月。患者症状有不同程度改善,无感染、死亡病例。术后影像学检查显示,所有患者复位满意,减压充分,且形成良好骨性融合。比较术前及术后随访时JOA评分和影像数据,结果示术前与术后末次随访时JOA评分及影像数据差异均有统计学意义(P0.05)。[结论]单纯后路枕骨钉结合枢椎椎弓根螺钉内固定提拉撑开复位技术,可以安全有效地治疗寰枕融合并寰枢椎脱位。     

牵引与后路枕颈复位固定治疗寰椎枕骨化并颅底凹陷症

目的评价术前牵引加后路多轴螺钉-棒系统枕颈复位固定治疗寰椎枕骨化合并颅底凹陷症的疗效.方法2004年1月～2006年2月共收治5例寰椎枕骨化合并颅底凹陷症患者,男3例,女2例,平均年龄34.8岁.患者均有明显神经功能损害症状,JOA评分平均9.4分.颈髓延髓角平均109.4°.4例合并难复性寰枢关节脱位.入院后均行颅骨牵引复位2～4周,当寰枢前后脱位复位达50%及齿状突垂直复位达4mm后行多轴螺钉-棒系统枕颈复位固定.术后均给予硬颈托固定3个月.结果齿状突均有较好的复位,术后颈髓延髓角平均增加32.4°,无术中、术后并发症.平均随访16个月,均固定满意并坚固融合,末次随访时所有患者神经功能恢复良好,JOA评分平均15.1分,改善率为75.0%.结论术前牵引加后路多轴螺钉-棒系统枕颈复位固定是治疗寰椎枕骨化合并颅底凹陷症的简单、安全、有效方法.     

寰椎后弓椎板钩联合枢椎椎弓根螺钉固定治疗游离齿状突并可复性寰枢椎脱位

背景：游离齿状突并可复性寰枢椎脱位常需要手术治疗,但目前缺乏操作简单且安全有效的寰枢椎内固定方式。 目的：评估寰椎后弓椎板钩联合枢椎椎弓根螺钉固定植骨融合治疗游离齿状突并可复性寰枢椎脱位的疗效。 方法：回顾性分析2005年7月至2012年6月采用寰椎后弓椎板钩联合枢椎椎弓根螺钉固定自体髂骨植骨融合术治疗游离齿状突并可复性寰枢椎脱位患者l1例。对脱位复位情况、内固定植骨融合率、JOA功能评分、影像学评估及术后并发症等进行分析。 结果：11例术中均未发生椎动脉和脊髓损伤。术后均获得随访,随访时间为12~37个月,平均25个月,均未发生内固定物松动、断裂,术后疼痛和神经症状均得到缓解,术后JOA评分较术前明显改善（P＜0.01）,寰枢椎均融合。 结论：寰椎后弓椎板钩联合枢椎椎弓根螺钉固定植骨融合术治疗游离齿状突并可复性寰枢椎脱位是一种安全有效的方法。     

牵引复位手术治疗颅底凹陷症合并寰枢椎脱位

目的 探讨牵引复位后手术治疗颅底凹陷症合并寰枢椎脱位的治疗方法和临床疗效。方法颅底凹陷症合并寰枢椎脱位患者20例．术前均采用颅骨牵引．其中18例在牵引4～10d后复位,行后路手术减压、枕颈融合术,2例在牵引2周后未能复位．行前路口咽入路松解减压,后路寰椎后弓切除忱颈融合术。术后头颈胸支具固定6～12个月。结果所有患者均获得随访,随访时间12～48个月。平均32个月。20例患者神经功能均恢复良好,术后6～12个月内植骨均融合良好,尤内固定松动、断裂,JOA评分由术前平均8．6分增加到15．6分,14例能恢复正常生活、工作,6例达到生活自理。结论颅底凹陷症合并寰枢椎脱位的治疗,术前有效的牵引复位和手术重建枕颈区的稳定性是治疗的关键。     

经口咽寰枢椎侧块关节复位块状骨支撑植骨治疗颅底凹陷症并寰枢椎脱位

目的:探讨经口咽寰枢椎侧块关节牵开复位、三面皮质块状骨支撑植骨、内固定治疗颅底凹陷症合并寰枢椎脱位的价值.方法:2009年12月～2011年12月我院收治33例合并寰枢椎脱位的颅底凹陷症患者,均有脊髓压迫症状.术前寰齿间隙(ADI)3.8～12.1mm (7.9±3.9mm),齿状突顶部与Chamberlain线的垂直距离(DCL) 3.0～15.6mm (9.3±6.2mm),寰枢椎垂直脱位指数(VAAI)0.35～0.51 (0.46±0.07),颈髓延髓角(CMA)112°～145°(127°±13°),JOA评分7～10分.均采用经口咽寰枢椎侧块关节牵开复位、三面皮质块状髂骨支撑植骨、TARP内固定术治疗.记录手术时间、手术出血量等,观察并发症发生情况.术后随访8～23个月,平均11.5个月,复查影像学评价寰枢椎脱位复位和脊髓压迫改善情况,采用JOA评分改善率对脊髓功能改善情况进行评价,在CT扫描图像上观察螺钉位置及植骨融合情况.结果:手术时间110～185min (145±35min),出血量35～85ml(58±18ml).共置入寰椎侧块螺钉66枚,枢椎逆向椎弓根螺钉41枚,枢椎椎体螺钉25枚.术后钉道扫描显示,寰椎螺钉均位于侧块内,2枚逆向枢椎椎弓根螺钉偏外进入椎动脉孔,导致椎动脉孔闭塞,小脑缺血梗死,其余枢椎螺钉均无偏差.术后发生咽后壁感染1例,将钢板取出后改行后路手术获得愈合.术后CT重建图像显示陷入枕骨大孔的齿状突获得较理想复位,脊髓受压解除,ADI改善为0.2～4.5mm( 2.3±2.1 mm),VAAI改善为0.6～0.84(0.74±0.08),CMA改善为140°～178°(157°±15°),与术前比较均有显著性差异(P＜0.01).植骨块镶嵌在寰枢侧块关节间隙,术后6～11个月均获骨性愈合.术后患者肢体麻木、肌肉无力等症状均较术前有明显改善,术后3个月复查JOA评分恢复至13～16分(15.2±0.9分),末次随访时为13～17分(15.3±0.8分),与术前比较均有显著性差异(P＜0.01).结论:经口咽寰枢椎侧块关节牵开复位三面皮质块状髂骨支撑植骨内固定术是治疗颅颈交界区病变的有效方法,但有一定风险和难度,应在严格掌握手术适应证和严格围手术期处理的条件下合理应用.     

术前牵引后路枕颈复位固定融合治疗颅底凹陷症并可复性寰枢椎脱位

目的:评价术前牵引后路枕颈复位固定融合治疗颅底凹陷症并可复性寰枢椎脱位的疗效.方法:2004年3月～2012年6月共收治12例颅底凹陷症并可复性寰枢椎脱位患者,男9例,女3例,年龄8～63岁,平均37.5±18.7岁.术前单纯表现为颈肩痛3例、头晕1例,余均存在脊髓损伤症状. 术前JOA评分5～12分,平均8.3±2.1分;颈髓延髓角108°～121°,平均108.9°±8.1°入院后均行颅骨牵引7～28d,平均14.7±8.1d.当齿状突满意复位后,维持牵引3～5d,行后路枕颈复位固定并取髂骨植骨融合术,术后颈托外固定3个月. 结果:齿状突均有较好的复位,无术中、术后并发症 . 11例患者获得随访,随访时间8～98个月,平均43.0±19.6个月,固定满意并坚固融合,融合时间为3～6个月,平均4.3个月. 所有患者神经功能恢复良好,末次随访JOA评分为8～17分,平均15.1±1.6分,较术前明显提高,差异有统计学意义(P＜0.05),神经功能改善率为78.2％. 未次随访颈髓延髓角为125°～141°,平均133.3°±9.3°,较术前明显增加,差异有统计学意义(P＜0.05).未次随访时手术疗效按Epstein标准评定,优6例,良4例,可1例 . 结论:术前牵引后路枕颈复位固定融合是治疗颅底凹陷症并可复性寰枢椎脱位的简单、安全、有效方法.     

经口咽前路寰椎侧块置钉固定治疗合并寰枕融合畸形颅底凹陷症的临床疗效

目的:探讨经口咽前路寰椎侧块置钉固定治疗合并寰枕融合畸形颅底凹陷症患者的可行性及临床疗效。方法:回顾性分析2009年3月~2011年10月我院收治的55例合并寰枕融合畸形的颅底凹陷症患者,行颅底和颈椎薄层CT扫描,冠状面和矢状面图像重建,同期我院影像数据库中55例无枕颈畸形患者上颈椎CT资料作为对照。在PACS图像系统上测量寰椎侧块的前高Ha、后高Hp、外侧高度Ho、内侧高度Hi、侧块的矢径A和横径B,观察并测量硬腭后缘投影点到寰椎侧块下缘的高度d等参数。并以寰椎侧块中下1/3的水平线与内中1/3垂线的交点作为侧块螺钉的模拟进钉点,在PACS图像工作站上寻找最合适的钉道方向,测量钉道的外倾角α和上倾角β,螺钉理论钉道长度L等。按照上述设计方案,所有患者接受了经口咽前路寰枢椎脱位松解复位,钢板内固定手术(TARP)。术后CT扫描观察钉道情况,测量螺钉的实际外倾角α2和上倾角β2,螺钉长度L2等,并与影像学测量数据对比。临床疗效采用JOA评分系统对患者术后3个月、6个月及12个月随访时脊髓功能进行评分,测量术前、术后脑干脊髓角评价脊髓压迫改善情况。结果:寰枕融合组寰椎切面的形态与对照组形状相似,测量寰椎侧块的横径为14.5±3.4mm,纵径为19.3±2.6mm,均小于对照组(P<0.05)。侧块前、后、外、内高度均小于对照组,其中后高差别尤为明显(P<0.05)。寰枕融合组的硬腭投影点明显偏下,投影点与侧块下缘的距离均值为4.7±1.7mm,明显小于对照组的17.6±2.4mm(P<0.05)。该组病例手术顺利,共置入寰椎侧块螺钉110枚,其中2枚螺钉偏外指向椎动脉孔,3枚螺钉偏内部分穿破侧块内侧缘,并呈切线进入椎管内,但未引起神经症状,其余均位于侧块内。术后患者肢体麻木、肌肉无力等症状均有明显改善,JOA评分术前8.1±1.6分,术后3个月复查时恢复至15.9±0.9分(P<0.05),末次随访时为16.0±0.8分。脑干脊髓角由术前127°±11°改善至156°±14°(P<0.05)。结论:经口咽前路侧块螺钉技术用于合并寰枕融合的颅底凹陷症是可行的,采用该技术的经口咽前路复位钢板治疗颅底凹陷症可获得良好疗效。     

应用改良Harms钉棒技术治疗寰椎枕骨化的寰枢椎脱位

[目的]探讨采用改良Harms钉棒技术治疗寰椎枕骨化的寰枢椎脱位患者的可行性和价值。[方法]2012年1月~2014年1月,采用改良Harms钉棒技术治疗寰椎枕骨化的寰枢椎脱位患者11例,男7例,女4例;年龄14~60岁,平均为33.4岁。11例患者均存在不同程度的慢性进展性四肢无力和感觉异常。术前均行X线片、CT及MRI检查,术前JOA评分11~14分,平均13.3分。记录手术时间、手术失血量、术中及术后并发症。术后常规行X线片、CT检查以评估复位情况及内固定位置。出院后常规门诊随访。[结果]11例均成功进行了对枕骨化的寰椎及枢椎的钉棒固定融合术。手术时间90~160 min,平均119 min,术中出血量150~300 ml,平均245 ml。术中无椎动脉、静脉丛、神经根、脊髓及硬膜损伤。术后无感染、C2神经功能障碍及枕部皮肤压疮。全部患者均获得随访,随访时间9~28个月,平均19个月。患者均获得骨性融合,无内固定松动、移位及断裂。11例症状均获得不同程度缓解,末次随访JOA评分14~17分,平均15.8分。[结论]应用改良Harms钉棒技术对寰椎枕骨化的寰枢椎脱位患者行寰枢椎钉棒复位、固定及融合是治疗该类患者的一种简单、有效的方法,避免了使用枕颈内固定器械所带来的并发症;与Goel技术相比,操作更简便,并且能够避免术后C2神经功能障碍。     

寰椎提拉螺钉术中复位治疗寰枢椎脱位

目的总结应用寰椎椎弓根提拉螺钉结合枢椎椎弓根螺钉行后路提拉复位固定植骨融合术治疗寰枢椎脱位的疗效。方法 2010年1月—2014年12月本院共收治27例寰枢椎脱位患者,均有不同程度的枕颈部疼痛和活动受限,并伴有神经功能障碍,美国脊髓损伤协会(ASIA)分级:B级2例,C级17例,D级8例;日本骨科学会(JOA)评分4~14分,平均8.3分。MRI示20例患者有不同程度的脊髓受压,其中8例脊髓受压节段髓内出现T2加权像高信号改变。患者均为寰椎前脱位,术前均进行颅骨牵引,17例部分复位,10例不可复位。术前寰齿间距(ADI)4~15 mm,平均10.3 mm;颈髓延髓角(CMA)113.1°~135.7°,平均120.9°。均采用寰椎椎弓根提拉螺钉结合枢椎椎弓根螺钉行后路提拉复位固定植骨融合术,观察患者术后临床症状和神经功能改善情况及寰枢椎复位和植骨融合情况。结果所有患者均顺利完成手术,术中均未发生椎动脉和脊髓损伤。患者随访6~36个月,平均20个月。术后CT及MRI示寰枢椎序列重建满意,齿突区域脑脊液线清晰,脊髓无压迫。术后6个月随访时患者神经功能明显改善,2例B级患者提高至C级;17例C级患者中2例提高至E级,15例提高至D级;8例D级患者均提高至E级。JOA评分10~17分,平均14.6分,平均改善率78.4%。术后ADI 2~4 mm,平均2.6 mm;CMA139.2°~152.4°,平均144.6°。术后6个月随访时所有患者获得骨性融合;随访期间未发现螺钉松动、移位和断裂及寰枢椎再移位、失稳现象。结论寰枢椎脱位会造成寰枢椎不稳及脊髓受压,应用寰椎椎弓根提拉螺钉结合枢椎椎弓根螺钉后路提拉复位技术治疗可获得良好的临床效果。     

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 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.     

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.     

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.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

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.