不同意识状态对脑电双频指数和听觉诱发电位指数与异丙酚效应室浓度关系的影响

目的观察不同意识状态对脑电双频指数（BIS）和听觉诱发电位指数（AEPI）与异丙酚效应室浓度关系的影响。方法择期行腹腔镜胆囊手术病人20例，ASAⅠ或Ⅱ级，靶控输注异丙酚麻醉诱导，初始效应室靶浓度1．0μg／ml，以1．0μg／ml递增，至5μg／ml时，静脉注射罗库溴铵0．06mg／kg行气管插管，气管插管后以效应室靶浓度3μg／ml维持麻醉，切皮前调为6μg／ml。术中维持血液动力学平稳，术毕停止靶控输注异丙酚。记录麻醉诱导期和苏醒期效应室靶浓度平衡后BIS、AEPI；意识消失前1min、后1min、睁眼前1min、后1min时BIS和AEPI。结果麻醉诱导期BIS和AEPI与异丙酚效应室浓度均呈负相关，意识消失前BIS和AEPI与异丙酚效应室浓度呈负相关；意识消失后BIS与异丙酚效应室靶浓度呈负相关。异丙酚效应室浓度0、1、2μg／ml比较，异丙酚效应室浓度3、4、5、6μg／ml时AEPI降低，随着异丙酚效应室浓度的升高BIS逐渐下降（P〈0．05），睁眼后1min AEPI高于睁眼前1min（P〈0．05）。结论BIS与异丙酚效应室浓度的相关性不受意识状态的影响，AEPI监测无意识状态到意识恢复的变化比BIS灵敏。     

靶控输注异丙酚意识消失时血浆和效应室浓度的EC50与脑电双频谱指数的关系多中心大样本临床研究

目的 研究择期手术患者靶控输注（TCI）异丙酚意识消失时血浆、效应室靶浓度的50%患者意识消失时的药物浓度（EC50）与脑电双频谱指数（BIS）的关系。方法 5家医疗中心405例择期手术患者（国人）,ASAⅠ或Ⅱ级。靶控输注异丙酚,以血浆靶浓度1．2μg/ml为起点,到达预期血浆靶浓度后每30秒递增0．3μg/ml,直至患者意识消失。采用概率单位回归分析计算患者意识消失时异丙酚血浆靶浓度、效应室靶浓度的EC05、EC50和EC95及其所对应的BIS。结果 择期手术患者TCI异丙酚意识消失时异丙酚血浆靶浓度EC05、EC50和EC95分别是2．9μg/ml、3．8μg/ml和4．8μg/ml,效应室靶浓度EC05、EC50和EC95分别是1．3μg/ml、2．2μg/ml和3．2μg/ml,50%患者意识消失的BIS是58,5%和95%患者意识消失的BIS分别是77和40。结论 择期手术患者TCI异丙酚意识消失时血浆靶浓度和效应室靶浓度EC50及95%置信区间分别是3．8μg/ml（3．8～3．9μg/ml）和2．2μg/ml（2．2～2．3μg/ml）, 50%患者意识消失的BIS用95%置信区间是58（58～59）。     

不同血浆靶浓度瑞芬太尼对患者异丙酚镇静效应的影响

目的 探讨不同血浆靶浓度瑞芬太尼对患者异丙酚镇静效应的影响.方法 择期拟行腹腔镜胆囊切除术患者80例,性别不限,ASA分级Ⅰ或Ⅱ级,年龄18～60岁,随机分为4组,每组20例.麻醉诱导:Ⅱ～Ⅳ组靶控输注瑞芬太尼,血浆靶浓度分别设为2、4、8 ng/ml,Ⅰ～Ⅳ组均靶控输注异丙酚,初始血浆靶浓度为2μg/ml,随后每间隔1min增加0.5μg/ml,直至BIS值下降至50.患者意识消失时记录BIS值和异丙酚血浆靶浓度,BIS值降至50时记录异丙酚血浆靶浓度及异丙酚总用量.结果 与Ⅰ组比较,Ⅲ组和Ⅳ组患者意识消失时BIS值升高,异丙酚血浆靶浓度降低,BIS值降至50时异丙酚总用量和异丙酚血浆靶浓度降低(P＜0.05).结论 复合异丙酚麻醉时,瑞芬太尼适宜血浆靶浓度为4 ng/ml.     

异丙酚靶控输注用于硬膜外麻醉病人清醒镇静的可行性

目的探讨异丙酚靶控输注用于硬膜外麻醉病人清醒镇静的可行性及所需靶控血药浓度.方法50例在硬膜外麻醉下行下腹部及下肢手术病人,以血浆室为靶控目标,予以异丙酚TCI清醒镇静.靶控血药浓度最初设定为0.5μg/ml,在与效应室异丙酚浓度达平衡后3min以0.1μg/ml递增,直至OAA/S评分降至3分,并抽取病人各时点静脉血3mi,采用高效液相色谱分析法测定异丙酚血药浓度,确定不同OAA/S评分时对应靶控血药浓度及其与BIS相关性,评估靶控输注系统的性能.结果预期误差的中位数MDPE=-23.1%,预期误差绝对值的中位数MDAPE=27.6%6,清醒镇静深度(OAA/S评分3分)时所需的异丙酚靶控血药浓度为(1.74±0.13)μg/ml.BIS与TCI血药浓度具有良好的相关性(r=-0.80,P＜0.05).结论异丙酚靶控输注用于硬膜外麻醉病人清醒镇静具有可控性良好,病人镇静深度适宜,血液动力学影响小,适用于临床推广.     

复合异丙酚时不同靶浓度瑞芬太尼对神经外科手术患者脑电双频谱指数的影响

目的 探讨复合异丙酚时不同效应室靶浓度瑞芬太尼对神经外科手术患者脑电双频谱指数(BIS)的影响.方法 择期拟行额颞部开颅手术患者15例,年龄18～64岁,体重50～85 kg,ASA Ⅰ或Ⅱ级.先靶控输注异丙酚,效应室靶浓度为3μg/ml,效应室浓度达预设浓度后靶控输注瑞芬太尼,效应室靶浓度分别为2、3、4、5、6、7、8 ng/ml,效应室浓度依次达预设浓度时记录血压(BP)、平均动脉压(MAP)、心率(HR)和BIS.瑞芬太尼效应室浓度达5 ng/ml时行气管插管和机械通气,于气管插管前即刻和气管插管后即刻记录BP、MAP、HR和BIS.结果 与基础值比较,异丙酚效应室浓度3μG/ml 和瑞芬太尼不同效应室浓度时BIS降低(P<0.05或0.01);与异丙酚效应室浓度3μg/ml时比较,瑞芬太尼效应室浓度≥6 nG/Ml时BIS降低(P<0.05或0.01).结论 复合异丙酚时靶控输注瑞芬太尼效应室浓度≥6 ng/ml时可降低神经外科手术患者的BIS.     

日间与夜间靶控输注异丙酚镇静效果的比较

目的 通过比较日间与夜间靶控输注异丙酚的镇静效果,探讨近日节律对异丙酚镇静效果的影响.方法 局部或臂丛神经阻滞下行急诊手部小手术的男性患者65例,ASA分级Ⅰ或Ⅱ级,年龄18～55岁,BMI 18.5～ 24.9 kg/m2,根据患者手术时间分为日间组(07:01至19:00)和夜间组(19:01至07:00).行臂丛或局部神经阻滞,确认麻醉效果完善后开始靶控输注异丙酚,靶控输注过程采用阶梯给药方式,设定4个目标效应室靶控浓度,依次为0.8、1.2、2.0和4.0 μg/ml.当异丙酚效应室浓度达到预设值后,维持5 min,记录该浓度下的BIS值.靶控输注过程中每分钟进行1次警觉镇静评分(OAA/S评分),并记录OAA/S评分为2分(患者意识消失)时的BIS值和异丙酚效应室浓度.结果 共有58例患者完成研究,其中日间组28例,夜间组30例.与日间组比较,夜间组BIS基础状态、异丙酚效应室浓度1.2和2.0 μg/ml时BIS值降低(P＜0.05),异丙酚效应室浓度0.8和4.0 μg/ml时BIS值差异无统计学意义(P＞0.05),OAA/S 2分时异丙酚效应室浓度降低(P＜0.05)而BIS值差异无统计学意义(P＞0.05).结论 近日节律可影响患者异丙酚的镇静效果,表现为夜间镇静效果强于日间.     

Narcotrend在麻醉深度监测上的优劣:与BIS对比的临床研究

目的 评价Narcotrend(NT)监测麻醉深度比脑电双频谱指数(BIS)的优劣情况.方法 择期手术病人80例,性别不限,年龄19～60岁,ASA分级Ⅰ或Ⅱ级,靶控输注异丙酚,达到初始血浆靶浓度2.1 μg/ml后,每30 s增加0.3 μg/ml,直至病人意识消失；然后将效应室靶浓度增加0.5μg/ml 维持麻醉,30 s后静脉注射罗库溴铵0.8 mg/kg,3 min后行气管插管,于靶控输注异丙酚前(基础状态)、意识消失时、静脉注射罗库溴铵前即刻和给药后2 min、气管插管前即刻和气管插管时、插管后1和3 min时分别测定BIS值、NT值、MAP和HR.结果 与基础值比较,意识消失时BIS值与NT值明显降低(P＜0.01)；与罗库溴铵给药前比较,给药后2 min时BIS值和MT值均明显降低(P＜0.05):与气管捕管前比较,气管插管时、插管后1和3 min时HR和MAP明显升高,而NT值和BIS值差异无统计学意义(P＞0.05).结论 NT可准确监测靶控输注异丙酚的镇静效应,肌电活动可对其产生明量影响,监测镇痛效应的准确性较差；与BIS相比其优劣程度无明显差异.     

右美托咪啶对靶控输注异丙酚意识消失时BIS值的影响

目的 评价右美托咪啶对靶控输注异丙酚意识消失时脑电双频谱指数(BIS)值的影响.方法 择期行普外科手术患者120例,性别不限,年龄25～50岁,体重41～68 kg,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将患者随机分为3组(n=40):异丙酚组(P组)、右美托咪啶0.5μg/kg+异丙酚(D1P组)和右美托咪啶1.0μg/kg+异丙酚(D2P组).每组再分为5个亚组(n=8):异丙酚效应室靶控浓度0、1、2、3和4 mg/L组(P0～4组).P0～4组靶控输注异丙酚,效应室靶浓度分别为0、1、2、3和4 mg/L;D1 P0～4组静脉输注右美托咪啶0.5 μg/kg,输注速率0.05μg·kg-1·min-1,输注结束后5min时靶控输注异丙酚,效应室靶浓度分别为0、1、2、3和4 mg/L;D2 P0～4组静脉输注右美托咪啶1.0μg/kg,输注速率0.1 μg· kg-1 ·min-1,输注结束后5min时靶控输注异丙酚,效应室靶浓度分别为0、1、2、3和4mg/L.异丙酚靶控输注3 min时记录OAA/S评分和BIS值,OAA/S评分≤2分判定为意识消失.采用Probit法计算半数患者意识消失时异丙酚的效应室靶浓度(EC50)和半数患者意识消失时的BIS值(BIS50)及其95％可信区间,采用Smith法计算BIS值对意识消失的预测概率.结果 与P组比较,D1P组和D2P组EC50降低,BIS50升高(P＜0.05或0.01),预测概率差异无统计学意义(P＞0.05);D1P组和D2P组EC50、BIS50和预测概率比较差异无统计学意义(P＞0.05).结论 右美托咪啶复合靶控输注异丙酚时BIS 值可准确预测患者的意识水平,而意识消失时的BIS值增加.     

等容量血液稀释对犬异丙酚药代动力学的影响

目的观察等容量血液稀释对犬异丙酚药代动力学的影响。方法13只雄性犬随机分为对照组(n=7)与等容量血液稀释组(n=6)。静脉注射地西泮0.5 mg/kg、氯胺酮5mg/kg麻醉后, 股静脉与股动脉穿刺,乳酸钠林格氏液5—7 ml·kg-1·h-1持续静脉滴注。麻醉后0.5 h等容量血液稀释组由股动脉放血,同时经股静脉1:1快速输入6%羟乙基淀粉,直至红细胞压积达25%。两组持续恒速静脉输注异丙酚10mg·kg-1·h-130 min,分别于输注2、5、10、15、20、30、31、32、35、40、50、70、90、120、150、180、240、300min采动脉血,测定异丙酚血浆浓度并计算药代动力学参数。一周后两组均根据各自药代动力学参数靶控输注异丙酚60 min,分别于靶控输注5、15、30、45、60 min测定两组异丙酚血浆浓度、游离浓度、脑脊液浓度及脑组织含量。结果与对照组比较,恒速给药时等容量血液稀释组异丙酚血浆浓度降低,中央室分布容积、稳态分布容积与全身清除率均升高(P<0.05或0.01);靶控输注时两组异丙酚血浆浓度与血浆靶浓度一致,但等容量血液稀释组异丙酚游离药物浓度、脑脊液浓度、脑组织含量及脑/血浆分配系数升高(P<0.05),脑/血浆分配系数与游离药物百分比[异丙酚游离浓度/(异丙酚游离浓度 异丙酚血浆浓度)]呈正相关(r=0.87,P<0.05)。结论等容血液稀释提高了异丙酚中央室分布容积、稳态分布容积和全身清除率,降低了分布项系数和浓度-时间曲线下面积,中枢药物浓度升高,可能导致药效增强。     

老年人丙泊酚效应室靶控浓度与脑电双频指数变化的关系

目的探讨老年人靶控输注(TCI)丙泊酚时不同效应室靶控浓度与脑电双频指数(BIS)变化的关系,以及镇静和麻醉时效应室靶控浓度的适宜设置值。方法18例老年病人静脉TCI丙泊酚,血浆靶控浓度的设定从0·5μg/ml开始,当效应室靶控浓度上升到血浆靶控浓度水平时,将血浆靶控浓度调高0·5μg/ml,使丙泊酚血浆靶控浓度阶梯式上升,直到效应室靶控浓度达到3·5μg/ml。记录每个效应室靶控浓度水平时的MAP、HR、RR、SpO2、BIS值和Ramsay镇静评级,同时测定丙泊酚血药浓度。结果丙泊酚效应室靶控浓度与实测血药浓度呈高度直线相关(r=0·9982,P<0·01),预测误差中位数(MDPE)=5%,预测误差绝对值的中位数(MDAPE)=12·7%,摇摆率(Wobble)=12·0%。效应室靶控浓度与BIS值呈高度直线负相关(r=-0·9985,P<0·01),回归方程:BIS值=92·94-17·77×效应室靶控浓度值(R2=0·9771,P<0·01)。当效应室靶控浓度达到0·5μg/ml时,50%的病人镇静评级达到3级。效应室靶控浓度达到3·5μg/ml时,MAP的降幅达到基础值的34%,自主呼吸率稍有降低,吸氧条件下SpO2保持在95%以上。结论丙泊酚效应室靶控浓度与BIS值呈负相关,可以用其评估镇静深度。对于老年病人,丙泊酚效应室靶控浓度在0·5~1·0μg/ml时已获得临床镇静效果,2·0~2·5μg/ml时达到全麻诱导的要求。     

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.