前十字韧带断裂继发半月板损害的临床研究

目的研究前十字韧带(anteriorcruciateligament,ACL)断裂对半月板的影响。方法回顾分析1984年12月～1999年12月间收治的419例ACL断裂患者半月板的损伤情况及其与软骨损伤的关系。结果外侧半月板的损伤率随病程增加无显著变化,而内侧半月板的损伤率随病程增加显著增加,由急性期的31.1%增至亚慢性期的48.2%(P<0.01),又增至慢性期的78.8%(P<0.001)。内侧半月板后角损伤率较前角高,差异有显著性意义(P<0.05)。损伤形态以纵裂最常见,随着病程的增加,半月板损伤也越发复杂。内侧半月板损伤患者的内髁软骨损伤的发生率要高于内侧半月板正常者的内髁软骨损伤发生率,但差异无显著性意义(P>0.05);而外侧半月板损伤患者的外髁软骨损伤的发生率却显著高于外侧半月板正常者,差异有非常显著性意义(P<0.01)。结论ACL断裂可伴发和继发半月板的损害,ACL断裂时伴发的多为外侧半月板的损伤,而继发的半月板损害却以内侧为重。内髁软骨损害主要由股胫关节前后向不稳、异常活动增加造成,而与内侧半月板的损伤关系不大。     

前交叉韧带断裂合并不同部位半月板桶柄样损伤的临床研究

目的探讨前交叉韧带(anterior cruciate ligament,ACL)断裂合并半月板桶柄样损伤同期修复的临床疗效,ACL断裂后半月板桶柄样损伤发生部位与病程的关系。方法 2012年1月至2018年12月间,选择19例ACL断裂合并不同部位半月板桶柄样损伤患者,其中男10例,女9例;年龄19～56岁,平均年31.2岁。19例患者均同期进行ACL重建+半月板缝合修复手术,手术前后采用国际膝关节文献委员会(international knee documentation committee,IKDC)评分和Lysholm膝关节功能评分评价。使用Kneene时间划分标准,根据病程将患者分三组:a)急性期组5例;b)亚慢性期组6例;c)慢性期组8例。分析桶柄样损伤位置与受伤存续时间的关系。结果本组19例患者,随访6个月～2年,平均1.5年。内侧桶柄样损伤发生率随受伤存续时间增加而上升,急性期组占60.0%,亚慢性期组占66.7%,慢性期组占75%。外侧桶柄样损伤发生率与受伤存续时间无显著联系。手术前后Lysholm评分、IKDC评分,差异有统计学意义。结论 ACL断裂合并半月板损伤发病率随受伤存续时间延长而明显增加,外侧桶柄样损伤发病率增加与受伤存续时间并无差异,内侧桶柄样损伤的发生率随受伤存续时间增加而升高。同期修复ACL断裂合并半月板桶柄样损伤,使用何种修复技术疗效无差异,有利于功能恢复,半月板愈合率较高,临床疗效满意。     

前交叉韧带退变与髁间窝撞击及内侧半月板撕裂的相关性研究

目的探讨膝骨关节炎(knee osteoarthritis,KOA)患者前交叉韧带(anterior cruciate ligament,ACL)退变与髁间窝撞击、内侧半月板撕裂间的相关性。方法回顾分析2014年7月-2016年2月收治伴ACL退变的KOA患者55例(55膝,退变组)临床资料,另随机选择55例(55膝)ACL正常的KOA患者作为对照(55膝,正常组)。两组患者性别、年龄、体质量指数、侧别比较,差异均无统计学意义(P0.05)。于术前MRI测量髁间窝指数,评价是否存在髁间窝狭窄;关节镜下观察内、外侧半月板撕裂发生情况以及发生部位,有无ACL胫骨止点骨赘形成;计算各部位半月板撕裂及骨赘形成发生率。结果两组内侧半月板前角、体部撕裂发生率,外侧半月板前角、体部、后角及后根部撕裂发生率比较,差异均无统计学意义(P0.05);内侧半月板后角及后根部撕裂发生率、ACL胫骨止点骨赘形成发生率、髁间窝狭窄发生率以及髁间窝指数比较,差异均有统计学意义(P0.05)。两组13例存在ACL胫骨止点骨赘患者中,内侧半月板后根部撕裂发生率为53.8%(7/13);97例无ACL胫骨止点骨赘患者中,其发生率为16.5%(16/97);比较差异有统计学意义(χ~2=9.671,P=0.002)。结论 KOA患者ACL退变与髁间窝撞击以及内侧半月板后角、后根部撕裂密切相关,ACL胫骨止点骨赘形成与内侧半月板后根部撕裂发生率相关。     

前交叉韧带合并不同类型半月板损伤的治疗策略

背景:前交叉韧带合并半月板损伤临床常见,针对不同的损伤类型,采取不同的治疗策略,对术后膝关节功能恢复至关重要。目的目的:研究前交叉韧带合并半月板不同损伤类型的特点,探讨相应的治疗策略。方法方法:选取2005年10月至2013年12月期间收治的前交叉韧带合并半月板损伤患者139例,男98例,女41例;年龄13~71岁,平均31.2岁;左膝62例,右膝77例,病程5 d至1.6年,陈旧性损伤(病程>3周)32例,新鲜性损伤(病程≤3周)107例。患者均有外伤史。临床主要表现为膝关节不稳、疼痛、弹响、绞锁。将术中镜下影像资料进行分析,统计前交叉韧带合并半月板损伤的类型特征及手术方式。结果结果:所有病例均采用关节镜微创手术治疗,前交叉韧带完全断裂113例,部分断裂26例。外侧半月板损伤46例(盘状半月板损伤8例,胫骨髁间棘撕脱2例)占33.1%,内侧半月板损伤65例(46.7%),内外侧半月板同期损伤28例(20.2%)。半月板纵行撕裂42例(桶柄状撕裂24例),水平状撕裂8例,斜行撕裂36例,瓣状撕裂13例,横断性撕裂12例,复合性撕裂28例。前交叉韧带重建139例,半月板部分切除36例,半月板缝合103例。结论结论:陈旧性前交叉韧带合并半月板损伤以外侧半月板多见,急性损伤以内侧半月板损伤为主。内外侧半月板同期损伤多见于陈旧性损伤。陈旧性损伤多数需要半月板部分切除,急性损伤多数可以缝合。前交叉韧带合并半月板损伤应早期手术。     

前交叉韧带断裂合并半月板损伤的关节镜手术治疗

目的探讨关节镜下治疗膝关节前交叉韧带（anterior cruciate ligament,ACL）断裂合并半月板损伤的治疗效果。方法回顾72例ACL断裂合并半月板损伤的临床资料,其中ACL断裂并内侧半月板损伤25例,并外侧半月板损伤37例,并内、外侧半月板损伤9例,双膝均有ACL断裂并半月板损伤1例。行关节镜下单纯半月板切除9例,半月板切除（或缝合）同时ACL重建63例。术前Lysholm评分为42.5±10.5 单纯半月板切除组为45.7±9.6 同时ACL重建组为40.9±12.7。结果术后均获随访,平均3.1年,术后总Lysholm评分为82.2±12.5 单纯半月板切除组为78.6±11.8 同时ACL重建组为85.3±9.0,三者组内手术前后比较,术后均优于术前（P〈0.001） 而同时ACL重建组又优于单纯半月板切除组（P〈0.01）。结论ACL损伤后膝关节发生半月板损伤的可能性增高,一期同时修复可以减少膝关节其它继发损伤的发生。     

关节镜观察前十字韧带断裂继发膝关节软骨损伤的临床研究

目的分析前十字韧带 (anterior cruciate ligament, ACL)断裂继发膝关节软骨损伤的原因及规律 ,探讨早期重建 ACL的意义。方法应用膝关节镜观察继发的膝关节软骨损伤的病理改变、发生部位、损害程度,并对损伤发生率、发生时间、损伤程度与 ACL损伤后病程的关系以及股骨髁软骨损伤与半月板损伤的关系等进行统计学分析与对比研究。结果 ACL陈旧性断裂合并软骨损伤发生率 (75％ )明显高于急性损伤组 (26％ ),差异有非常显著性意义 (P< 0.01);软骨损伤的病理改变不同,但以股骨髁软骨“垄沟”状病损为特征性改变;病程在 1年以内者软骨损伤发生率为 60％, 1年以上者为 79.6％;病程 1年以上者软骨重度损伤发生率 (44.9％ )明显高于 1年以内者 (4.76％ ),差异有非常显著性意义 (P< 0.01);有股骨髁软骨损伤的 43例 (67.2％ ),其中伴有半月板损伤者 55.8％,无半月板损伤者 44.2％。结论 ACL断裂后膝关节软骨损伤发生率明显增高;软骨损伤程度随病程延长而加重;关节软骨损伤以股骨髁软骨负重区受累最重,但与半月板损伤无明显关系,主要因 ACL断裂后膝关节不稳所致。 ACL断裂后应尽早手术重建,恢复膝关节稳定性,改善功能,预防和中止对软骨的损害。     

关节镜下半月板水平撕裂的保全治疗

2008年2月～2009年4月,笔者对11例膝关节半月板水平撕裂患者经关节镜行半月板撕裂部分切除保全术,效果满意. 1 材料与方法 1.1 病例资料本组11例,男9例,女2例,年龄36～62(47±14)岁.左膝1例,右膝10例.均经MRI确诊为关节积液并半月板水平撕裂损伤.膝关节半月板水平撕裂的MRI分级标准[1]:Ⅰ级3例,Ⅱ级8例.内侧半月板损伤8例,外侧半月板损伤3例,均为后角损伤,其中隐性水平撕裂4例.1例合并前交叉韧带(ACL)断裂,2例骨性关节炎.     

膝关节骨关节炎内侧半月板突出的临床意义

目的 探讨膝关节骨关节炎患者内侧半月板突出的病因及影响.方法 选取2011年1月至2012年3月诊断为膝关节退行性骨关节炎并经MRI确认有内侧半月板突出的60例患者为半月板突出组,无突出的60例为对照组.在MRI上测量内侧半月板突出距离、胫股角,分析突出组胫股角与突出距离的相关性,比较两组膝内翻、内侧半月板及胫股关节软骨损伤的发生率,分析内侧半月板突出对半月板损伤、膝内翻对半月板突出的影响.结果 突出组:半月板突出距离平均(8.30±1.79) mm;60例有膝内翻,胫股角平均179.0°±2.2°;内侧半月板损伤发生率:前角50.0％ (30/60),体部93.3％ (56/60),后角93.3％ (56/60);内侧半月板后角根部撕裂14例,发生率23.3％(14/60);胫股内侧关节软骨退变发生率:胫骨内侧平台100％(60/60),股骨内髁100％(60/60);胫股角与内侧半月板突出距离呈负相关.对照组:内侧半月板超出胫骨内侧平台边缘的距离平均(0.57±0.80) mm;4例膝内翻;内侧半月板损伤发生率:前角0,体部16.7％(10/60),后角70.0％ (42/60);无内侧半月板后角根部撕裂;胫股内侧关节软骨退变发生率:胫骨内侧平台26.7％(16/60),股骨内髁30.0％ (18/60).半月板突出组与对照组半月板损伤比值比为6.0、膝内翻例数比值比为15.0.半月板突出组内侧半月板各部位及胫股内侧关节软骨损伤的发生率和严重程度高于对照组.结论 膝内翻可能是内侧半月板突出的原因之一,内侧半月板突出显著增加半月板损伤的发生率,其对膝胫股内侧关节骨关节炎的发生、发展有重要影响.     

非创伤性半月板损伤关节镜下观察分析

目的：总结不同年龄段患者非创伤性半月板损伤的关节镜下特点。方法按照纳入标准：（1）MRI确诊半月板III度损伤,（2）且有半月板损伤症状,（3）无明确急性外伤史和急性症状,（4）保守治疗无效,（5）在手术中确证为半月板损伤。纳入2012年全年全部非创伤性半月板损伤患者,以45岁为界分为两组。术前采集基本信息、症状、体征及Lysholm评分,术中记录半月板损伤的部位、类型、伴发损伤及手术方式。应用SPSS19.0（SPSS公司,美国）统计软件包进行统计分析,统计不同年龄段患者的发病频数,对不同年龄段患者的性别、患侧（左或右）、半月板损伤类型以及伴发损伤情况的比较采用χ2检验。结果共纳入患者201例,发病年龄呈双峰分布（20岁和60岁）。年轻患者外侧半月板损伤发生比例更高（单纯外侧半月板损伤占56.10%）,而中老年患者则相反（单纯内侧半月板损伤占66.90%）。年轻患者内侧半月板损伤以纵行撕裂（27.80%）、鸟嘴样撕裂（38.90%）和水平撕裂（27.80%）为主;而中老年患者则以鸟嘴样撕裂（20.60%）、水平撕裂（27.20%）、根部损伤（19.10%）和复杂损伤（31.60%）为主。在外侧半月板,年轻患者以鸟嘴样撕裂（45.50%）为主,复杂损伤也达22.70%;而中老年患者中70.20%为复杂损伤。年轻患者中前十字韧带损伤（34.15%）、外侧盘状半月板（21.95%）和半月板囊肿（9.76%）的发生率较高,而中老年患者则大多伴存软骨损伤（81.25%）。结论年轻患者非创伤性半月板损伤更多发生在外侧半月板,更多伴发前十字韧带损伤、外侧盘状半月板和半月板囊肿,而中老年患者则更多发生在内侧半月板,更多伴发软骨损伤;且两组患者非创伤性半月板损伤的类型各有不同。     

MRI在ACL合并伤中对半月板损伤诊断评价

目的通过关节镜检查,评价术前MRI检查在前交叉韧带(ACL)合并伤中半月板损伤的诊断符合率。方法选取2014年1月至2020年6月因外伤致ACL损伤,术前阅读MRI检查,评估ACL损伤患者的半月板损伤情况,并术中关节镜检查确诊半月板损伤部位及损伤类型,进一步评价MRI诊断符合率。结果 MRI检查对内侧半月板损伤的诊断率明显高于外侧半月板损伤的诊断符合率,但差异无明显统计学差异(P0.05)。MRI对内侧半月板前角和外侧半月后角的诊断符合率较低。结论在ACL损伤合并半月板损伤中,MRI对内侧半月板前角和外侧半月后角的诊断符合率较低,因此术前应更加仔细阅读MRI,以免漏诊。     

Reduction of Plasma Fibrinogen, Immunoglobulin G, and Immunoglobulin M Concentrations by Immunoadsorption Therapy with Tryptophan and Phenylalanine Adsorbents

Abstract Immunoadsorption (1A) therapy with tryptophan (TR-350) or phenylalanine (PH-350) adsorbents has been used to reduce the concentration of serum antibodies in human lymphocyte antigen (HLA)-immunized patients. Other forms of plasma purification have been reported to reduce the level of fibrinogen, which affects the blood properties. In this study we investigated the effects of IA therapy using both adsorbents on plasma fibrinogen and immunoglobulins G and M in 13 patients (8 patients were treated with TR-350, and 5 patients were treated with PH-350). During each session 1 plasma volume (2.8 ± 0.4 L of plasma) was processed through the immunocolumn and then returned to the patient together with the blood cells. Compared with the pretreatment values, the plasma fibrinogen, IgG, and IgM concentrations were significantly reduced after IA therapy (p < 0.01 for TR-350; p < 0.04 for PH-350). There was a positive correlation between the degree of reduction of plasma proteins and the number of IA treatments given. A nonpara-metric test (Wilcoxon's signed-rank test or the Mann-Whitney test) was used for statistical analysis. We conclude from our study that IA therapy effectively lowers the plasma levels of fibrinogen, IgG, and IgM and thus can be considered a valuable alternative to other blood purification methods.     

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.     

The multiply injured child

Blunt trauma is the principal cause of childhood death in many developed countries. This review outlines the differences between adults and children with respect to resuscitation and treatment of orthopaedic injuries in a child with polytrauma. Recent advances in techniques of fracture stabilization are reported.     

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.     

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.     

Adrenaline markedly improves thoracic epidural analgesia produced by a low-dose infusion of bupivacaine, fentanyl and adrenaline after major surgery: A randomised, double-blind, cross-over study with and without adrenaline

Background: Basic pharmacological research indicates that there are synergistic antinociceptive effects at the spinal cord level between adrenaline, fentanyl and bupivacaine. Our clinical experience with such a mixture in a thoracic epidural infusion after major surgery confirms this. The objectives of the present study were to evaluate the effects on postoperative pain intensity, pain relief and side effects when removing adrenaline from this triple epidural mixture. Methods: A prospective, randomised, double-blind, cross-over study was carried out in 24 patients after major thoracic or abdominal surgery. Patients with only mild pain when coughing during a titrated thoracic epidural infusion of about 10 ml · h^?1 of bupivacaine 1 mg · ml^?1, fentanyl 2 μg · ml^?1, and adrenaline 2 μg · ml^?1 were included. On the 1^st and 2^nd postoperative days each patient was given a double-blind epidural infusion, at the same rate, with or without adrenaline. The effect was observed for 4 h or until pain when coughing became unacceptable in spite of a rescue analgesic procedure. Rescue analgesia consisted of up to two epidural bolus injections per hour and i.v. morphine if necessary. All patients received rectal paracetamol 1 g, every 8 h. Fentanyl serum concentrations were measured with a radioimmunoassay technique at the start and end of each study period. Main outcome measures were extent of sensory blockade and pain intensity at rest and when coughing, evaluated by a visual analogue scale, a verbal categorical rating scale, the Prince Henry Hospital pain score, and an overall quality of pain relief score. Results: The number of hypaesthetic dermatomal segments decreased (P <0.001) and pain intensity at rest and when coughing increased (P <0.001) when adrenaline was omitted from the triple epidural mixture. This change started within the first hour after removing adrenaline. After 3 h pain intensity when coughing had increased to unacceptable levels in spite of rescue analgesia (epidural bolus injections and i.v. morphine). Within 15–20 min after restarting the triple epidural mixture with adrenaline, pain intensity was again reduced to mild pain when coughing. Serum concentration of fentanyl doubled from 0.22 to 0.45 ng · ml^?1 (P <0.01), and there was more sedation during the period without adrenaline. Conclusions: Adrenaline increases sensory block and improves the pain-relieving effect of a mixture of bupivacaine and fentanyl infused epidurally at a thoracic level after major thoracic or abdominal surgery. Serum fentanyl concentrations doubled and sedation increased when adrenaline was removed from the epidural infusion, indicating more rapid vascular absorption and systemic effects of fentanyl.