椎体成形术与椎体后凸成形术治疗骨质疏松性椎体压缩骨折的效果分析

目的探讨骨质疏松性椎体压缩骨折采用椎体成形术与椎体后凸成形术效果对比。方法选取骨质疏松性椎体压缩骨折患者80例随机分为2组,每组40例,PVP组实施经皮椎体成形术,PKP组实施椎体后凸成形术,比较2组治疗效果。结果 2组患者术后活动能力、VAS评分均优于术前,差异有统计学意义(P0.05)。术后2组间比较,差异无统计学意义(P0.05)。术后PKP组椎体高度恢复优于PVP组(P0.05)。PVP组骨水泥渗漏率高于PKP组,差异均有统计学意义(P0.05)。结论骨质疏松性椎体压缩骨折应用椎体成形术与后凸成形术均可缓解疼痛,促进患者改善生活质量,但椎体后凸成形术伤椎高度恢复效果好,骨水泥渗漏率低。     

骨质疏松性椎体空腔样骨折对椎体后凸成形术疗效的影响

目的 评估骨质疏松性椎体空腔样骨折对椎体后凸成形术疗效的影响.方法 自2004年3月～2009年8月对157例因骨质疏松性单椎体压缩骨折行椎体后凸成形术,以27例伤椎星空腔样改变作为A组,选取27例伤椎无空腔样改变作为B组,两组年龄、性别构成及骨折压缩程度均相近.术后常规拍摄脊柱正侧位X线片及CT,比较两组椎体高度的恢复、后凸畸形的矫正、骨水泥的注入量及渗漏情况.采用疼痛视觉模拟评分(VAS)和Oswestry功能障碍指数评估两组的临床疗效.结果 所有患者均顺利完成手术,两组术后VAS、ODI均得到明显改善,组间比较差异无统计学意义(P＞0.05);A组椎体高度的恢复和后凸畸形的矫正优于B组,差异有统计学意义(P＜0.05);A组骨水泥注入量大于B组,差异有统计学意义(P＜0.05);两组间骨水泥渗漏率分别为11.1％和7.4％,差异无统计学意义(P＞0.05).结论 椎体空腔样骨折与无空腔样骨折相比,术后腰背痛、生活能力的改善及骨水泥渗漏的发生率相近,但是椎体高度的恢复和后凸畸形的矫正更明显.     

高黏度骨水泥椎体成形术与低黏度骨水泥椎体后凸成形术治疗骨质疏松性胸腰椎压缩骨折疗效分析

[目的]比较高黏度骨水泥椎体成形术与低黏度骨水泥椎体后凸成形术治疗骨质疏松椎体压缩骨折的疗效和并发症。[方法]收集本院骨科2011年1月~2014年1月使用高黏度骨水泥椎体成形术和使用低黏度骨水泥椎体后凸成形术治疗的骨质疏松性胸腰椎压缩骨折患者110例,进行回顾性研究。将患者化分为A组(高黏度骨水泥椎体成形术组42例)和B组(低黏度骨水泥椎体后凸成形术组68例)。术前统计两组患者性别比、年龄、VAS评分及骨密度值(-T值)。采用视觉模拟量表(VAS)进行疼痛评分,观察并比较两组患者的住院花费、透视时间、骨水泥用量、术后VAS评分、椎体复位高度、骨水泥静脉渗漏、椎旁渗透率、邻近椎体骨折、其他并发症等发生情况。[结果]术后随访时间为3~36个月。术前患者的年龄、性别、术前VAS评分等基本临床资料在两组间差异无统计学意义(P0.05)。A组手术透视时间、骨水泥用量、住院花费均少于B组(P0.05);A组患者术后24h VAS评分低于B组,差异有统计学意义(P0.05);两组患者术后3 d VAS评分差异无统计学意义(P0.05)。两组患者经俯卧位并手法复位及术后椎体高度均有明显恢复,但两者之间差异无统计学意义(P0.05)。A组发生椎体周围骨水泥静脉丛渗漏3例(7.1%),椎旁骨水泥渗漏7例(16.7%),发生邻近椎体再骨折4例(9.5%),应激性胃溃疡1例(2.4%);急性脑梗塞1例;B组发生椎体周围骨水泥静脉丛渗漏6例(8.8%),椎旁骨水泥渗漏8例(11.7%),其中B组出现1例骨水泥肺栓塞,导致严重后果,应激性胃溃疡2例(2.9%),冠心病急性发作1例,脑脊液漏1例。两组比较差异无统计学意义(P0.05)。两组患者术前、术后24 h VAS评分差异具有统计学意义(P0.01)。[结论]高黏度骨水泥椎体成形术与低黏度骨水泥椎体后凸成形术治疗骨质疏松性胸腰椎压缩骨折具有相似的治疗效果及并发症发生率,但前者在治疗花费及透视时间方面占明显优势。     

骨填充网袋椎体成形术与经皮椎体后凸成形术治疗骨质疏松性椎体压缩骨折的比较

目的 比较骨填充网袋椎体成形术(vesselplasty)与经皮椎体后凸成形术(percutaneous kyphoplasty,PKP)治疗骨质疏松性椎体压缩骨折(osteoporotic vertebral compression fractures,OVCFs)的疗效差异.方法 回顾性研究2015年1月 ～2017年12月收治的138例OVCFs的患者,根据手术方式分为vesselplasty组(30例)和PKP组(108例).记录两组手术时间、骨水泥注射量、骨水泥渗漏率、骨水泥弥散面积率.比较两组VAS评分、伤椎前缘高度、伤椎后凸Cobb角.结果 术后随访12～36个月,平均21.4个月.vesselplasty组的手术时间、骨水泥弥散面积率小于PKP组(P<0.05),两组骨水泥注入量比较无明显统计学差异(P>0.05).vesselplasty组骨水泥渗漏率为6.67％,PKP组为16.67％.两组患者术后1 d VAS评分较术前降低(P<0.05),末次随访时较术后1 d进一步降低(P<0.05).两组患者术后1 d伤椎前缘高度、伤椎后凸Cobb角较术前改善(P<0.05),末次随访时较术后1 d无明显变化(P>0.05).两组各时间点的VAS评分、伤椎前缘高度及伤椎后凸Cobb角比较无明显统计学差异(P>0.05).结论 骨填充网袋椎体成形术治疗骨质疏松性椎体压缩骨折可取得与经皮椎体后凸成形术相似疗效,且骨填充网袋椎体成形术能缩短手术时间、减少骨水泥渗漏.     

椎体成形术与椎体后凸成形术治疗椎体压缩性骨折疗效的Meta分析

[目的]系统评价椎体成形术与椎体后凸成形术治疗椎体压缩性骨折的有效性和安全性。[方法]计算机检索数据库,手工检索骨科相关杂志,纳入关于比较椎体成形术与椎体后凸成形术治疗椎体压缩性骨折的研究并进行Meta分析。[结果]纳入15篇研究共1 082例椎体,其中PVP组563例,PKP组519例,进行Meta分析。结果显示椎体成形术与椎体后凸成形术治疗椎体压缩性骨折相比较,VAS及骨水泥渗漏率无明显统计学差异。椎体后凸成形术对Cobb角的矫正度数大于椎体成形术,差异具有统计学意义。[结论]椎体成形术与椎体后凸成形术治疗椎体压缩性骨折在缓解疼痛和骨水泥渗漏上无明显的区别。在矫正Cobb角度上,椎体后凸成形术较椎体成形术具有显著的优越性。     

弹性弧形骨钻用于椎体成形术的实验研究

目的观察自制弹性弧形骨钻在体外骨质疏松椎体成形术中的手术效果,从而探讨其在椎体成形术中的应用价值。方法采用乙二胺四乙酸二钠盐(EDTA-Na2)浸泡法制备小牛体外骨质疏松椎体,将40个骨质疏松椎体随机分为A、B两组,每组各20个椎体行椎体成形术,A组行常规直钻穿刺,B组采用自制弹性弧形骨钻穿刺,弧形方向朝向穿刺对侧,深度达到椎体中前1/3终止,对两组穿刺骨钻及骨水泥是否达到或越过椎体矢状中线进行统计分析。结果 EDTA-Na2浸泡法脱钙9 d时成功制备出体外骨质疏松椎体,直钻穿刺组钻头达到或越过椎体矢状中线有7个椎体,骨水泥分布达到或越过椎体矢状中线11个;弹性弧形骨钻组穿刺钻头达到或越过椎体矢状中线有18个椎体,骨水泥分布达到或越过椎体矢状中线19个,两组骨钻穿刺效果及骨水泥分布上的差异有统计学意义(P0.05)。A组9个椎体发生骨水泥椎管内渗漏,B组4个椎体发生骨水泥椎管内渗漏,两组间在骨水泥渗漏上差异无统计学意义(P0.05)。结论自制弹性弧形骨钻通过一侧椎弓根穿刺,可以建立一个达到或越过椎体矢状中线的骨性通道,引导骨水泥向穿刺对侧分布,避免了双侧椎弓根穿刺的弊端,其实验效果优于直骨钻。     

骨水泥分布形态对经皮椎体成形术疗效的影响

目的 探讨骨水泥分布形态对经皮椎体成形术(PVP)治疗骨质疏松性椎体压缩骨折(OVCF)疗效的影响。方法 将156例采用PVP治疗的OVCF患者依据骨水泥分布形态不同分为A组(骨水泥分布呈H型，91例)、B组(骨水泥分布呈T型，49例)和C组(骨水泥分布呈O型，16例)。比较3组手术时间、术中出血量、骨水泥注入量、骨水泥渗漏率、邻近椎体骨折发生率、疼痛VAS评分、伤椎后凸Cobb角。结果 患者均获得随访，时间17～36(25.1±7.6)个月。手术时间、术中出血量及骨水泥渗漏率3组比较差异均无统计学意义(P>0.05)。骨水泥注入量A组>B组>C组(P<0.01)。邻近椎体骨折发生率A组0.05)。3组伤椎后凸Cobb角术后1年、2 d与术前比较均明显减小(P<0.05),术后1年与术后2 d比较差异均无统计学意义(P>0.05),组间比较差异均无统计学意义(P>0.05)。结论 3种骨水泥...     

椎体后凸成形术与椎体成形术生物力学比较

目的比较椎体后凸成形术（KP）与椎体成形术（VP）对骨质疏松性椎体压缩骨折（OVCF）椎体力学性能的影响。方法5具尸体取20个胸腰段骨质疏松单椎体标本,按配对设计,分配为球囊扩张椎体后凸成形术组（KP组）和椎体成形术组（VP组）。经轴向加载压缩25%,制成椎体压缩骨折,记录制成骨折时的最大载荷及刚度数据。KP组将椎体压缩骨折标本行球囊扩张椎体后凸成形术;VP组将椎体压缩骨折标本行椎体成形术。然后将骨水泥强化治疗的椎体再次经万能力学试验机轴向加载,记录治疗后最大载荷及刚度数据。结果KP组和VP组骨折治疗后椎体最大载荷均分别明显高于骨折前（P〈0.01）,而椎体刚度差异无统计学意义（P〉0.05）。KP组与VP组间比较治疗后椎体最大载荷差异无统计学意义（P〉0.05）,椎体刚度差异无统计学意义（P〉0.05）。结论KP和VP均可明显增加OVCF椎体的抗压强度和恢复刚度。     

液压输送式椎体成形术与扩张球囊椎体后凸成形术治疗单节段骨质疏松性脊柱骨折的疗效比较

[目的]对比分析评估新型液压输送式椎体成形术与扩张球囊椎体后凸成形两种术式在治疗单节段骨质疏松性脊柱骨折中疗效的差异。[方法]对本院骨科一区2012年5月~2013年9月间符合条件的64例单节段骨质疏松性脊柱骨折患者术前随机分为液压输送式椎体成形(A组,34例)以及扩张球囊椎体成形(B组,30例)两组,分别进行相应的手术术式处理。术后随访1年,通过VAS评分、ODI评分评估患者手术前后症状改善、功能恢复情况;通过骨水泥渗漏与否、椎体高度恢复程度、骨水泥弥散情况等进一步分析比较两种不同椎体成形术式治疗脊柱骨折疗效及预后可能产生的差异。[结果]两组患者术后VAS评分及ODI评分均较术前明显改善,术后1年时椎体高度恢复率A、B两组分别为(27.84±2.12)%和(29.82±5.13)%。A、B两组患者均未出现骨水泥过敏、肺栓塞、椎管渗漏引起神经症状等严重并发症。无症状性骨水泥渗漏发生例数分别为7例和3例(P<0.05)。[结论]液压输送式椎体成形术与扩张球囊式椎体后凸成形术在改善单节段骨质疏松性脊柱骨折症状及功能方面疗效相当。二者骨水泥弥散情况和椎体高度恢复率的比较差异无统计意义,提示液压输送式椎体成形术在有着更简洁的手术过程、更简短的手术时间、更经济的手术花费的同时,在手术疗效以及结构恢复等方面都有着不差于扩张球囊式椎体后凸成形术的效果,而且对术后同椎、邻椎骨折的发生可能有着更好的预后。     

经皮椎体成形术和经皮椎体后凸成形术治疗重度骨质疏松性椎体压缩性骨折疗效分析

目的 观察经皮椎体成形术( Percutaneous vertebroplasty,PVP)和经皮椎体后凸成形术(Percutanous kyphoplasty,PKP)治疗重度骨质疏松性椎体压缩骨折的临床疗效、可行性、安全性.方法回顾性分析2006年1月至2010年12月收治重度骨质疏松性椎体压缩骨折患者并获得随访34例,PVP治疗19例25个椎体,PKP治疗15例20个椎体.观察两组患者间SF-36评分、伤椎高度恢复、骨水泥渗漏及随访期间伤椎高度丢失情况、临近椎体骨折情况.结果 PVP组和PKP组患者在术中骨水泥渗漏率、末次随访时SF-36评分、末次随访时临近椎体骨折发生率间差异无统计学意义(P＞0.05).在椎体复位效果的观察指标上,PKP组术后椎体前缘间、椎体上下终板中心间高度恢复量、术后后凸角度恢复值、末次随访后凸角度恢复值上与PVP组间差异有统计学意义(P＜0.05),同时在末次随访时PKP组伤椎高度丢失量与PVP组差异也有统计学意义(P＜0.05).结论 PVP和PKP治疗重度骨质疏松性椎体压缩性骨折均可显著改善患者症状,PKP具有较好的复位效果,但术后椎体高度丢失明显,在骨水泥渗漏率、相邻椎体骨折发生率指标上相对于PVP未表现出明显优越性.     

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.