改良Pemberton髋臼成形治疗发育性髋关节脱位术后髋臼发育变化的动态观察

目的: 探讨改良Pemberton髋臼成形, 观察其对髋臼发育变化的影响, 尤其是对髋臼指数发育的影响。方法: 手术方式采用术前不牵引, 一期行髋关节联合术式(切开复位 粗隆下旋转截骨 改良Pemberton髋臼成形)矫正全部畸形, 其中髋臼的处理是在Pemberton的基础上进行术式改良。结果: 1年内随访髋臼发育变化, 并进行动态描述, 股骨头覆盖良好, 髋臼指数明显改善, 由术前(44±5)°减少至(17±4)°。结论: 采用联合术式治疗DDH,其中对浅而大的髋臼采用改良Pemberton髋臼成形术处理, 能够使脱位变形的髋臼形态结构基本接近, 股骨头的覆盖、髋臼指数的改变、CE角的测量都达到满意的程度。这表明本术式使髋臼指数得到充分纠正, 加大了对股骨头的包容, 改善了髋臼受力结构, 术后髋臼发育基本接近正常。     

改良髋臼周围截骨术治疗髋臼发育不良的初步报告

目的　介绍一种新型的髋臼周围截骨术 ,并报告其短期的放射线和临床观察结果。方法　本组髋臼发育不良 9例 9髋 ,全部为女性 ,年龄 1 5～ 4 8岁 ,平均 36 5岁 ,骨性关节炎Ⅰ级 3例 ,Ⅱ级 5例 ,Ⅲ级 1例采用一种新型髋臼周围截骨术治疗。结果　改良髋臼周围截骨术后随访 3～ 6个月 ,平均 4个月。平均手术时间为 2h 5 0min ,术中失血量平均为 70 0ml。Harris髋评分 :术前 73分 ,最后随访为 85分。术前 5例Trendelenburg征阳性 ,术后为 0例。平均CE角 :术前 6 3°,术后为 34 5°。平均Sharp角 :术前 4 8 6°,术后为 36 9°。髋臼指数角 :术前 2 5 9°,术后 8 7°。平均髋臼 -头 (A -T)指数 :术前 6 1 2 % ,术后为 88 0 %。平均股骨头垂直指数 :术前 1 0 9,术后 0 83。水平指数 :术前 1 6 6 ,术后 1 5 7。结论　改良髋臼周围截骨术是一种可在直视下操作的相对容易掌握的手术 ,通过术中的截骨旋转 ,达到髋臼对股骨头的充分覆盖 ,髋臼应力均衡分布 ,防止或延迟骨性关节炎的发生和发展     

植骨重建在节段型髋臼缺损的全髋关节置换中的应用

目的　评价髋臼植骨重建在节段型髋臼缺损的全髋关节置换术 (total hip arthroplasty,THA)中的应用和效果。　方法　回顾分析 1991年～ 2 0 0 0年 ,采用自体骨移植重建髋臼治疗髋臼节段型缺损的 THA 39例 ,男 2 5例 ,女 14例。年龄 34～ 6 2岁 ,平均 4 5 .2岁。缺损为髋臼发育不良 2 1例 ,股骨颈骨折股骨头坏死、髋脱位 14例 ,髋臼骨折骨关节炎 4例。将切除股骨头或髂骨按缺损情况制成楔形置入缺损处 ,采用骨水泥 (12例 )或非骨水泥 (2 7例 )假体。术前Harris评分 18～ 5 0分 ,平均 38.1分。　结果　 2 4髋获随访 2～ 10年 (平均 6 .7年 )。术后肢体长度平均增加 2 .4 cm。植骨愈合良好 ,随访中未见假体松动。术后 1年和最后随访时平均 Harris评分分别为 92 .1和 86 .3分 ,与术前 Harris评分比较有统计学意义 (P<0 .0 5 )。术后 1年和最后随访时优良率分别为 91.7%和 83.3%。　结论　采用自体骨重建存在节段型缺损的髋臼 ,对术后髋关节功能的稳定性具有重要意义。     

Bernese手术治疗先天性髋臼发育不良

目的 :介绍Bernese截骨术治疗先天性髋臼发育不良。方法 :1998年 4月～ 2 0 0 1年 12月 ,共有 2 9例 ( 30髋 )髋臼发育不良患者接受Bernese截骨术治疗。患者年龄 14～ 35岁 ,术前按Merled’Aubigne评分标准积分 6～ 15分 ,平均 13分 ,X线片示CE角 -5～ 2 0° ,平均 -0 .1° ,sharp角 42～ 6 0° ,平均 5 0° ,股骨头覆盖指数 10 %～ 6 0 % ,平均47.2 %。结果 :Merled’Aubigne评分从术前平均 13( 6～ 15 )分提高到术后平均 17( 12 .5～ 18)分 ,术后CE角平均 40°( 2 8～ 5 0°) ,sharp角平均 36°( 2 5～ 38°) ,股骨头覆盖指数 90 % ( 81%～ 10 0 % ) ,术后关节活动范围较术前在各方向上均有减少 ,术后并发症包括下肢深静脉血栓形成 1例 ,股外侧皮神经损伤 2例 ,髋关节半脱位加重 1例 ,浅表液化 2例。结论 :Bernese术具有其它截骨术不可比拟的优势 ,是目前治疗青少年及成年髋臼发育不良的最佳选择。     

改良Salter截骨术治疗先天性髋关节脱位的临床疗效分析

[目的]探讨改良Salter手术及改良贝氏石膏治疗先天性髋关节脱位的疗效.[方法]对26例年龄2～6岁的先天性髋关节脱位患儿应用改良Salter截骨手术进行治疗,术后均采用改良贝氏石膏固定,不固定髋关节.采用X线评定标准和Mackay 临床评定标准进行评估.[结果]所有病例随访时间2～9年,平均7.2年.疗效优24例,良1例,并发股骨头坏死及髋关节半脱位l例.X线片测量:髋臼指数术前为40.05°±5.6°,术后为13.28°±5.06°;CE角术前为-0.12°±8.01°,术后为40.12°±5.58°;髋臼覆盖股骨头的百分比:术前组为45.05%±14.07%,术后为106.06%±11.55%.上述各项指标经两两配对t检验,P＜0.05,各组差异有极显著性意义,效果满意,优良率达93%.[结论]改良Salter手术对2～6岁的先天性髋关节脱位患儿疗效显著,结合改良贝氏石膏固定,患儿能早期活动髋关节,可获得良好的功能.     

先天性髋脱位复位前后AI变化的临床分析

本文通过 1 0 0例 (2 0 0髋 )正常儿童 ,1 0 2例 (1 4 8髋 )先天性髋脱位手法复位前后髋臼指数变化的随访观察。认为 5岁为髋臼发育的高峰期 ,髋脱位复位后髋臼发育的速度 1年内最快 ,3年内不要作出再建髋臼的决定。 3岁内通过手法复位、蛙式石膏固定—蛙式支架固定 ,绝大部分髋臼可以正常发育 ;大于此年龄并有明显髋臼发育不良者常需作髋臼重建术。强调股骨头缺血坏死是导致髋脱位复位后髋臼发育不良的重要因素 ,应尽量避免。     

髋臼合并同侧股骨颈骨折的手术治疗与预后

目的 探讨髋臼合并同侧股骨颈骨折的手术方法与预后.方法 1990年10月至2008年1月共收治7例髋臼合并同侧股骨颈骨折患者,其中男5例,女2例;年龄22～55岁(平均38.6岁).髋臼骨折按Letournel分类:后壁骨折2例,后柱伴后壁骨折1例,横行伴后壁骨折2例,双柱骨折2例.股骨颈骨折按Garden分型:Ⅲ型2例,Ⅳ型5例.其中X线片和CT片示股骨颈骨折合并股骨头游离脱位于髋臼后上方者5例,仅显示股骨颈骨折而无脱位者2例.结果切开复位内固定术后X线片示5例移位髋臼骨折患者获解剖复位,2例获满意复位.股骨颈骨折均获满意复位和固定.7例患者术后获1～18年(平均8.6年)随访,X线片示5例合并股骨头脱位者日后均出现股骨头缺血性坏死,坏死率高达100%(5/5),髋关节功能恢复均为差,于内固定术后2～4年改行全髋关节置换术.而2例股骨头未脱位者至今X线片上仍未显示任何股骨头坏死迹象,也无创伤后关节炎表现,髋关节功能恢复均为优.结论 髋臼合并同侧股骨颈骨折患者,如同时合并股骨头脱位,因股骨头坏死率高,应首选全髋关节置换术治疗.如未合并股骨头脱位,可以考虑首选切开复位内固定.     

髋臼加强环在严重髋臼骨缺损人工髋关节置换中的应用

目的 总结髋臼加强环在严重髋臼骨缺损的人工髋关节翻修术及初次置换术中的应用及疗效. 方法 2000年11月-2005年7月,采用髋臼加强环联合自体或异体骨移植治疗14例15髋伴严重髋臼骨缺损的人工髋关节置换患者.男7例7髋,女7例8髋;年龄34～72岁,平均55岁.行翻修术9例9髋,距初次置换时间3～22年,平均8.9年;初次置换术5例6髋,双髋类风湿关节炎、髋臼发育不良继发骨性关节炎、髋关节感染清创股骨头切除术后、髋臼陈旧骨折不愈合伴股骨头中心脱位、髋臼陈旧骨折不愈合各1例.病程2～25年,平均11.6年.髋臼骨缺损根据AAOS分型:Ⅱ型7髋,Ⅲ型6髋,Ⅳ型2髋.术前Harris评分(59.1±15.4)分. 结果 术后切口均Ⅰ期愈合.1例于麻醉恢复后出现坐骨神经刺激症状,神经营养药物治疗5个月症状缓解.14例患者均获随访,随访时间33～90个月,平均51.3个月.末次随访时Harris评分为(81.9±10.4)分,与术前比较差异有统计学意义(P<0.01).X线片示加强环聚乙烯移位均<5 mm,旋转角度均<5°,髋臼侧及螺钉周围无进行性放射透亮带. 结论 髋臼加强环有助于重建严重骨缺损的髋臼,改善患者髋关节功能,为臼杯植于理想生物力学位置提供早期稳定.     

髋臼周围加股骨近端减压截骨术治疗儿童中晚期Perthes病

目的介绍一种治疗Perthes病新术式-髋臼周围加股骨近端减压截骨.方法1997年8月～2000年8月,21例中晚期儿童接受此术式治疗,共21髋,随访时间24～36个月,X线分期,Ⅲ期17例,Ⅳ期4例,均合并有半脱位和扁平髋畸形.结果术前髋臼指数平均22.45°,骺核高度5.46mm,CE角6.38°,术后髋臼指数6.67°,骺核高度6.56mm,CE角19.95°.功能评价优19例,良2例.结论新术式优于原始术式,并同时解决了压力、肢短、头臼覆盖及预防远期骨性关节炎的目的.另外,强调合理和准确的适应证选择是治疗中晚期Perthes病和降低病残率的关键.     

3D打印技术辅助髋臼成形术治疗脑瘫儿童髋关节脱位

目的:探讨通过3D打印技术明确髋臼发育不良类型选择最合适的髋臼成形术治疗脑瘫儿童髋关节脱位的适应证和临床疗效。方法:自2019年7月至2019年12月,采用3D打印技术辅助髋臼成形术治疗7例脑瘫儿童髋关节脱位,其中男3例,女4例;年龄3~8岁;左侧3例,右侧2例,双侧2例;2例髋关节半脱位,5例髋关节脱位。患儿术前均行骨盆-双股骨全长CT扫描。通过3D打印重建技术,判断髋臼发育不良类型:前侧2髋,前外2髋,外上1髋,后侧2髋,后外1髋,无发育不良1髋(未做髋臼成形术)。对8髋分别进行Pemberton,Dega和San Diego手术模拟,寻找最合适的手术方式并手术。比较术前和末次随访外移比例(migration percentage,MP),髋臼指数(acetabular index,AI),中心边缘角(center-edge angle,CEA),Shenton线和粗大运动功能分级(gross motor function classification system,GMFCS)的变化,并记录其并发症情况。结果:术后患者伤口愈合良好,无并发症发生。7例患者获随访,时间18~24个月。8髋Ⅰ期行软组织松解+股骨近端内翻去旋转短缩截骨+髋关节复位+髋臼成形术;1髋Ⅰ期行软组织松解+股骨近端内翻去旋转短缩截骨+髋关节复位术。MP由术前的58%~100%降至末次随访时的0~17.9%。AI由术前的25.0°~47.6°降至末次随访时的11.1°~25.3°。CEA由术前的0°改善至末次随访时的21.1°~48.5°。Shenton''线均由中断变为连续。其中5例GMFCS分级下降1级,2例无变化。结论:脑瘫儿童髋关节脱位中髋臼发育不良的类型多样,髋臼成形术适用范围也有差异,借助3D打印技术计算机模拟手术可选择最合适的手术方式并判断治疗效果,对脑瘫儿童髋关节脱位做到个体化、精准化治疗。     

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.