Epidural vs. intravenous infusion of alfentanil in the management of postoperative pain following laparotomies*

Background : This study was designed to compare the efficacy of epidural vs. intravenous administration of alfentanil for treatment of postoperative pain. Methods : Twenty patients were randomly allocated to one of the two study groups to receive either an epidural bolus dose (0.75mg) followed by an epidural infusion (0.36mg/h) (EPI group) or an intravenous infusion (0.36mg/h) of alfentanil (IV group) for 24 h. These dose regimens were chosen such that equivalent and subanalgesic plasma concentrations of alfentanil were obtained. PCA-morphine was available to both groups. Morphine consumption, pain scores measured on a Visual Analogue Scale (VAS) and the number of demands were used as variables to evaluate the efficacy of the postoperative analgesic therapy. In addition, plasma concentrations of alfentanil were measured. Results : The mean plasma concentrations of alfentanil were similar and < 20ng/ml in both groups. Total morphine consumption (EPI: 40mg, IV: 43 mg), pain scores (time when the VAS-score>3. 0 : EPI: median 215 min; IV: median 215 min) and number of valid demands (EPI: median 25; IV: median 34) did not differ between the groups. Conclusion : Compared to intravenous infusion of alfentanil epidural infusion resulting in the same plasma concentrations is not more effective in relieving postoperative pain. In view of this observation we were not able to demonstrate a spinal mechanism of alfentanil.     

Role of magnesium sulfate in postoperative pain management for patients undergoing thoracotomy

OBJECTIVE: The purpose of this study was to investigate the effect of magnesium sulfate on pain management for post-thoracotomy patients. DESIGN: A prospective, randomized, controlled clinical study. SETTING: University hospital. PARTICIPANTS: Twenty-four patients undergoing thoracotomy. INTERVENTIONS: After thoracotomy operations, patients were assigned to 2 groups. The control group received intravenous morphine (0.5 mg/h infusion, 0.3 mg patient-controlled anesthesia dose, 15-minute lockout time) via patient-controlled analgesia, and the magnesium group received magnesium sulfate (30-mg/kg bolus, 10 mg/kg/h infusion for 48 hours) plus the same patient-controlled analgesia protocol. MEASUREMENTS AND MAIN RESULTS: Visual analog scale for pain score, sedation score, mean arterial pressure, heart rate, and valid and invalid analgesic demand were recorded. Serum magnesium levels were determined at postanesthesia care unit admission, at 24 hours, and at 48 hours. Side effects were also recorded. There were no significant differences between groups with respect to demographics, sedation score, and pain score. Cumulative mean morphine consumption was found to be higher in the control group compared with the magnesium group at 4, 8, and 48 hours (5.6 +/- 1 mg v 3.2 +/- 0.6 mg [p < 0.0001], 10.2 +/- 1.8 mg v 7.2 +/- 1.6 mg [p = 0.0003), and 40.2 +/- 4.5 mg v 34.8 +/- 6.3 mg [p = 0.02], respectively). CONCLUSION: Postoperative use of magnesium sulfate reduced opioid consumption for pain after thoracotomy operations.     

Effects of gabapentin on postoperative morphine consumption and pain after abdominal hysterectomy: a randomized, double-blind trial

BACKGROUND: Preliminary clinical studies have suggested that gabapentin may produce analgesia and reduce the need for opioids in postoperative patients. The aim of the present study was to investigate the opioid-sparing and analgesic effects of gabapentin administered during the first 24 h after abdominal hysterectomy. METHODS: In a randomized, double-blind study, 80 patients received oral gabapentin 1200 mg or placebo 1 h before surgery, followed by oral gabapentin 600 mg or placebo 8, 16 and 24 h after the initial dose. Patients received patient-controlled analgesia with morphine at doses of 2.5 mg with a lock-out time of 10 min for 24 h postoperatively. Pain was assessed on a visual analogue scale (VAS) at rest and during mobilization, nausea, somnolence and dizziness on a four-point verbal scale, and vomiting as present/not present at 2, 4, 22 and 24 h postoperatively. RESULTS: Thirty-nine patients in the gabapentin group, and 32 patients in the placebo group completed the study. Gabapentin reduced total morphine consumption from median 63 (interquartile range 53-88) mg to 43 (28-60) mg (P < 0.001). We observed a significant inverse association between plasma levels of gabapentin at 2 h postoperatively, and morphine usage from 0 to 2 h, and from 0 to 4 h postoperatively (R2 = 0.30, P = 0.003 and R2 = 0.24 P = 0.008, respectively). No significant differences in pain at rest or during mobilization, or in side-effects, were observed between groups. CONCLUSION: Gabapentin in a total dose of 3000 mg, administered before and during the first 24 h after abdominal hysterectomy, reduced morphine consumption with 32%, without significant effects on pain scores. No significant differences in side-effects were observed between study-groups.     

Does prophylactic intravenous infusion of indomethacin improve the management of postoperative pain in children?

The efficacy of prophylactic intravenous infusion of indomethacin as a postoperative analgesic was studied in 100 children aged one to 16 years. At the end of surgery a bolus dose of indomethacin 0.35 mg.kg-1 followed by an infusion 0.07 mg.kg-1.hr-1 for 24 hr or placebo was given in double-blind manner. The efficacy of the treatment was measured by the need of additional morphine given 0.1 mg.kg-1 intravenously in the Recovery Room and 0.15 mg.kg-1 intramuscularly on the ward according to clinical needs. The other measure of the efficacy was assessment of pain intensity in the Recovery Room and pain relief on the ward. In the Recovery Room the pain scores differed between the groups in advantage of indomethacin only at 30 minutes (p less than 0.05) but the need of morphine was significantly less (p less than 0.01) in the indomethacin group. On the ward the mean doses of morphine given and the nurses' pain relief scores were not different between the study groups. However, in the indomethacin group the total dose of morphine given during 24 hr was lower (p = 0.02) and the children assessed the pain relief to be significantly better (p less than 0.02). Twenty per cent of the children in both groups had transient nausea and vomiting. No skin reactions or other allergic manifestations were observed. Prophylactic indomethacin infusion diminished the need of morphine and resulted in better postoperative analgesia than morphine p.r.n. alone.     

Effect of intra-operative magnesium sulphate on pain relief and patient comfort after major lumbar orthopaedic surgery

The effects of intra-operative magnesium sulphate on pain relief after major lumbar surgery were investigated in 24 patients. Patients were randomly allocated to receive either an infusion of 50 mg x kg(-1) magnesium sulphate or an equivalent volume of saline at induction of anaesthesia. Anaesthesia was induced with propofol and remifentanil. Tracheal intubation was facilitated using rocuronium. Maintenance was achieved with remifentanil and sevoflurane in nitrous oxide/ oxygen. Intra-operative monitoring included standard equipment and neuromuscular transmission. During surgery, neuromuscular block recovery was longer in the magnesium group. Postoperative opioid consumption and pain scores were lower in the magnesium group. The first night's sleep and the global satisfaction scores were better in the magnesium group. The results of the study support magnesium sulphate as a useful adjuvant for postoperative analgesia after major lumbar surgery.     

Intramuscular low-dose ketamine versus pethidine for postoperative pain treatment after thoracic surgery

In a double-blind prospective study the effects of low-dose intramuscular ketamine (1 mg/kg) were compared to pethidine (1 mg/kg) in the treatment of pain after pulmonary surgery. Thirty patients were admitted to the study and postoperatively randomized to either a ketamine or a pethidine group. The analgesic effect was evaluated using a scale ranging from 0 to 10, where 0 denoted no pain and 10 severe pain. We did not find any significant difference between the analgesic effect of ketamine and pethidine; however, the duration of action of ketamine appeared to be slightly longer. Throughout the study PaCO2 was significantly lower in the ketamine group. PaO2 increased through the study in both groups and was significantly higher after 2 h. Heart rates increased significantly only in the pethidine group. Mean arterial pressures remained unchanged and the respiratory frequencies were similar in the two groups. The incidence of adverse reactions was low and not significantly different between the groups. The findings indicate that low-dose intramuscular ketamine is a potent analgesic for postoperative analgesia following thoracic surgery and that it has no respiratory depressive effect.     

Efficacy and safety of patient-controlled opioid analgesia for acute postoperative pain. A quantitative systematic review

BACKGROUND: The usefulness of intravenous patient-controlled analgesia (PCA) with opioids for postoperative analgesia is not well defined. METHODS: We systematically searched (MEDLINE, EMBASE, Cochrane Library, bibliographies, any language, to January 2000) for randomised trials comparing opioid-based PCA with the same opioid given intramuscularly, intravenously, or subcutaneously. Weighted mean differences (WMD) for continuous data, relative risks (RR) and numbers-needed-to-treat (NNT) for dichotomous data were calculated with 95% confidence intervals (CI) using fixed and random effects models. RESULTS: Data from 32 trials were analysed: 22 (1139 patients) were with morphine, five (682) with pethidine, three (184) with piritramide, one (47) with nalbuphine and one (20) with tramadol. In three morphine and one pethidine trial (352 patients), more patients preferred PCA (89.7% vs. 65.8%, RR 1.41 (95%CI 1.11 to 1.80), NNT 4.2). Combined dichotomous data on pain intensity and relief, and the need for rescue analgesics from eight morphine, one pethidine, one piritramide, and one nalbuphine trial (691 patients), were in favour of PCA (RR 1.22 (1.00 to 1.50), NNT 8). In two morphine trials (152), pulmonary complications were more frequently prevented with PCA (100% vs. 93.3%, RR 1.07 (1.01 to 1.14), NNT 15). There was equivalence for cumulative opioid consumption, pain scores, duration of hospital stay, and opioid-related adverse effects. CONCLUSION: These trials provide some evidence that in the postoperative pain setting, PCA with opioids, compared with conventional opioid treatment, improve analgesia and decrease the risk of pulmonary complications, and that patients prefer them.     

Epidural magnesium reduces postoperative analgesic requirement

Background: Magnesium has antinociceptive effects in animal and human modelsof pain. Our hypothesis was that the addition of magnesium topostoperative epidural infusion of fentanyl may decrease theneed for fentanyl. Methods: Fifty patients undergoing hip surgery were enrolled to receiveeither fentanyl (Group F) or fentanyl plus magnesium sulphate(Group FM) for 24 h for epidural analgesia. All patients wereequipped with a patient-controlled epidural analgesia deviceand the initial settings of a demand bolus dose of fentanyl25 µg. In Group FM, patients received 50 mg magnesiumsulphate epidurally as an initial bolus dose followed by a continuousinfusion of 100 mg day^–1. Ventilatory frequency, heartrate, blood pressure, pain assessment using a visual analoguescale (VAS), sedation scores and fentanyl consumption were recordedin the postoperative period. Results: There was no significant difference between groups in the timeto first analgesic requirement. Compared with Group F, patientsin Group FM received smaller doses of epidural fentanyl (P <0.05). The cumulative fentanyl consumption in 24 h was 437 (SD110)µg in Group F and 328 (121) µg in Group FM (P <0.05). Patients in Group F showed a higher VAS score in thefirst hour of the postoperative period (P < 0.05). The groupswere similar with respect to haemodynamic and respiratory variables,sedation, pruritis, and nausea. Conclusion: Co-administration of magnesium for postoperative epidural analgesiaresults in a reduction in fentanyl consumption without any side-effects.     

Does morphine premedication influence the pain and consumption of postoperative analgesics after total knee arthroplasty?

Evidence of pre-emptive analgetic effect of opioid would offer great potential benefit to patients with postoperative pain, a better pain relief with less opioid. The aim of this double blind randomised trial was to study the effect of intramuscular morphine premedication on postoperative pain.
Forty-one patients undergoing total knee arthroplasty were randomly allocated to four groups. Two groups received epidural morphine, 4 mg immediately after operation and 3 mg ten hours later, and two groups the same volume of saline. All patients had access to intravenous PCA-fentanyl. One epidural morphine and one epidural saline group (PreEpiMo and PreMo, respectively) received morphine, 0.14 mg/kg i.m. as premedication. Pain was measured with a visual analogue scale (VAS). Respiration was monitored by means of pulseoximetry, arterial blood gas analysis and rate of breathing.
Morphine premedication reduced postoperative pain in the immediate postoperative period in patients with epidural placebo (PreMo), hut the effect was absent in patients with PreEpiMo. Epidural morphine (EpiMo) provided stable analgesia with reduced need of PCA-fentanyl. Two patients (10%) (one in EpiMo and one in PreEpiMo) developed respiratory depression requiring naloxone treatment. The dosage of epidural morphine used in this study was a likely explanation of this depression. Nausea, vomiting, itching and urinary retention were the most frequent side effects without significant differences between the groups. In conclusion, morphine premedication had a temporary rest effect on the postoperative pain. Epidural morphine provides a better analgesia than intravenous PCA-fentanyl.     

术后急性疼痛与慢性疼痛关系的研究进展

背景 术后急性疼痛管理仍然不尽人意,如何防治急性疼痛转化为慢性疼痛仍然是临床亟待解决的问题. 目的 阐述术后急性疼痛转化为慢性疼痛的研究进展,为术后疼痛管理以减少慢性疼痛的发生提供参考. 内容 就急性疼痛转化为慢性疼痛的可能性等方面作一综述. 趋向 进一步研究术后急性疼痛转化为慢性疼痛的机制,以明确有效的预防急性疼痛慢性化的方法.     

Retrospective evaluation of continuous epidural infusion for postoperative pain in children

BACKGROUND: The safety and efficacy of postoperative epidural analgesia (EDA) in children are not well documented in larger series of patients given routine postoperative care. The aims of this study were to evaluate the efficacy of pain relief, determine the incidence and type of complications during the entire period of epidural pain treatment in children, and assess the factors affecting efficacy METHODS: Children treated postoperatively with an EDA infusion during the period 18 September 1994 to 1 January 1999 were studied. Data regarding the age, gender, efficacy of analgesia, duration of epidural infusion, types of side-effects and complications, reasons for discontinuation, and types and duration of surgery were collected daily by the Acute Pain Treatment Service. The sensory dermatomal level of the surgical incision site was included retrospectively. RESULTS: Five hundred and eighteen epidural infusions were given to 476 children. Pain relief was rated as 'good' at 76% of visits. There were no major complications or sequelae. Thirty-seven per cent of the epidural infusions were prematurely discontinued, and 21% were discontinued because of unsatisfactory analgesia. Factors related to a higher percentage of unsatisfactory function were surgical incision site located above the umbilicus, gastroenterologic surgery, protracted surgery and age. Age and duration of surgery were significantly related to unsatisfactory function. CONCLUSION: This study shows that continuous epidural infusion for postoperative pain was satisfactory in most cases, and that no major side-effects or complications occurred in children nursed on regular wards. The early recognition of unsatisfactory function of an EDA is important for a child's well being.     

Assessment of acute and chronic pain

Acute and chronic pain states are under-recognized and under-treated. The assessment of pain and evaluation of treatment requires repeated measurement of pain intensity using reliable and well-validated scales. Sensory components of pain must also be assessed and in particular, the diagnosis of neuropathic pain should not be missed as this diagnosis may direct treatment and potentially alter long-term outcomes. Several neuropathic screening tools are available to aid the detection and monitoring of neuropathic pain but importantly, a clinical examination is essential to corroborate this diagnosis. The further assessment of chronic pain should involve a thorough assessment of global function and quality of life using reliable and well-validated screening tools. In particular, physical and emotional functioning should be monitored.     

脊髓环氧合酶与术后疼痛

前列腺素（prostaglandins,PGs）是广泛存在于动物和人体内的一组重要的组织激素,在疼痛的产生过程中发挥着重要作用,其中最主要的是前列腺素E2（PGE2）和前列环素（PGI2）。近年来研究发现,PG受体也存在于脊髓背根神经节,这是感觉传人神经轴索进入脊髓以及脊髓感受伤害的起始部位。行为学研究也证实,鞘内注射PGs可以引出伤害性感受反应。环氧合酶（cyclooxygenase,COX）是以花生四烯酸为底物生成前列腺素（prostaglandins,PGs）途径中的限速酶。非甾体抗炎药（NSAIDs）干预伤害性感受的过程在脊髓,可能是通过减少神经系统中前列环素的合成来实现的。术后疼痛是急性疼痛的一种常见形式,各种类型手术的病人术后没有得到有效的镇痛是急性疼痛转为慢性疼痛的主要原因之一,近年来脊髓中COX参与术后疼痛的研究取得了一些进展。     

Caudal analgesia with buprenorphine for postoperative pain relief in children

Caudal buprenorphine was investigated as a postoperative analgesic in a randomized double blind study in thirty children aged 5–12 years undergoing lower abdominal and lower limb surgery. Comparison was made between two groups of patients, one group receiving plain bupivacaine and the other a combination of plain bupivacaine with buprenorphine. Postoperative analgesia was assessed using a linear analogue scale, and by the response to direct questioning of children using an illustration of sequence of faces. Any untoward side effects and the need for additional analgesics were recorded. The degree and duration of analgesia was far superior in the buprenorphine group and there was a highly significant difference in the requirement of postoperative analgesia between the two groups. There were no major adverse side effects and no motor weakness in either groups, however the incidence of nausea and vomiting was higher in the buprenorphine group. It is concluded that a combination of bupivacaine with buprenorphine administered through the caudal epidural space is a safe and reliable means of providing postoperative pain relief in children for up to 24 h.     

Survey of postoperative analgesia following ambulatory surgery

Background: The quality of pain relief during the first 48 hours following ambulatory surgery has been poorly documented. This questionnaire study was performed to evaluate the nature and severity of pain after the patient leaves the hospital. Methods: 1100 patients in the age group 5–88 years who underwent ambulatory surgery during a period of 6months were asked to complete a questionnaire 48 h after the end of the operation. In thecase of children, parents were asked to complete a similar questionnaire. The questions were related to pain experienced during the first 48 h after surgery and to the nature andseverity of postoperative complications. Results: A total of 1035 out of the 1100 patients returned the questionnaire, 94.1%. Overall the majority (65%) of patients had only mild pain at home; however, patients undergoing certain types of surgery had moderate-to-severe pain: inguinal hernia surgery (62% patients), orthopaedic surgery (41%), hand surgery (37%) and varicose vein surgery (36%). In these patients the severity of pain did not decrease during the 2-day study period. About 10% patients had more severe pain than they had anticipated, and 20% had difficulty in sleeping at night due to severe pain. Despite this, over 95% of patients were satisfied with man-agement of postoperative pain. Nausea (20%), tiredness (20%) and vomiting (8%) were the commonest complications reported during the first 48 h. A significant association was found between the administration of a general anaesthetic and the incidence of nausea postoperatively. A large number of patients were alone at home after the operation (28.4%); some (3.8%) had no access to a relative or friend in case of need. Conclusion: Our results show that about 35% of day-surgery patients experience moderate-to-severe pain at home in spite of analgesic medication. About 20% of patients had sleep problems due to severe pain. However, only 5% of patients were dissatisfied. Better analgesic techniques are necessary for patients undergoing certain types of surgery. Patient information and follow-up routines need to be improved.     

术后静脉病人自控镇痛（PCIA）的临床应用与研究

目的：评价连续基础静脉注射（ＣＢＩ）加静脉病人自控镇痛方法（ＰＣＡ）用于术后镇痛的效应。方法：３２０例ＡＳＡⅠ～Ⅱ级病人术后按ＣＢＩ速率分为四组，Ⅰ组：０．５ｍｌ·ｈ－１；Ⅱ组：１．０ｍｌ·ｈ－１；Ⅲ组：１．５ｍｌ·ｈ－１及Ⅳ组：２．０ｍｌ·ｈ－１。ＰＣＡ指标设置：锁定时间５分钟，ＰＣＡ剂量１．０ｍｌ，负荷剂量为３～５ｍｌ，所用药液为每毫升含１０μｇ芬太尼及０．１ｍｇ氟哌利多混合液。观察期为术后２４小时。结果：镇痛所用药物总剂量四组间无明显差异（Ｐ＞０．０５）。Ⅳ组的ＶＡＳ评分及ＰＣＡ使用次数均为０。与Ⅰ组相比，Ⅱ组及Ⅲ组的ＶＡＳ评分、Ｒａｍｓａｙ评分均明显降低（Ｐ＜０．０５），ＰＣＡ使用次数／无效次数的比值显著升高（Ｐ＜０．０５），但Ⅱ组与Ⅲ组相比，以上指标均无显著性差异。病人的血流动力学及呼吸功能保持平稳，未见其它副反应。结论：采用ＣＢＩ加ＰＣＡ方法静脉注射以上混合液用于术后镇痛安全有效，以芬太尼的负荷量、ＣＢＩ量和ＰＣＡ剂量分别设置为３０～５０μｇ、１０～１５μｇ·ｈ－１和１０μｇ，ＰＣＡ锁定时间设为５分钟更为合理。     

Comparison of preoperative with postoperative topical lidocaine spray on pain after tonsillectomy

Seventy-five children aged 4-6 years scheduled for tonsillectomy were randomly allocated to receive either topical tonsillar spray with 10% lidocaine 4 mg kg^-1 3 minutes before surgical incision; identical tonsillar spray after both tonsils had been removed; or no topical spray (control group). There were significant differences in postoperative pain between the lidocaine groups and the control group at 0.5 and one hour after awaking ( P <0.05). Also in the lidocaine groups, consumption of paracetamol on the day of operation was less, and additional postoperative pethidine was not required. There were no significant differences between pre- and postoperative lidocaine groups in pain scores during the observation period but the use of pre-operative lidocaine tended to be associated with a more rapid return to calm wakefulness. Topical lidocaine seemed to have short-acting analgesic activity. The results of this study do not support the theory of pre-emptive analgesia.     

腹部手术后患者静脉输注丁丙诺啡镇痛的可行性

目的 评价腹部手术后患者静脉输注丁丙诺啡镇痛的可行性.方法 采用多中心、随机、开放、平行、阳性药物对照进行研究,择期全身麻醉下行腹部手术患者200例,年龄18～64岁,ASAⅠ级或Ⅱ级,性别不限,体重50～100 kg,随机分为丁丙诺啡组(B组)和芬太尼组(F组),每组100例.2组术后分别静脉输注丁丙诺啡0.3 μg·kg-1·h-1、芬太尼0.3 μg·kg-1·h-1.采用视觉模拟评分法(VAS评分)评价术后6、12、24、36和48 h的疼痛程度,于各时点行镇静评分及Prince-Henry评分,监测心率、呼吸频率(RR)和脉搏血氧饱和度(SpO2),记录不良反应的发生情况.结果 与F组比较,B组各时点VAS评分、镇静评分和Prince-Henry评分差异无统计学意义(P＞0.05),恶心发生率较低(P＜0.05);两组各时点RR和SpO2差异无统计学意义(P＞0.05).结论 静脉输注丁丙喏啡0.3 μg·kg-1·h-1可有效缓解腹部手术后患者疼痛,且不良反应少.