Patient-controlled extradural analgesia with bupivacaine, fentanyl, or a mixture of both, after Caesarean section

In this randomized, double-blind study of 60 patients, we have assessed the analgesic efficacy of extradural bupivacaine and extradural fentanyl, either alone or in combination, after Caesarean section. Patients received 0.1% bupivacaine (group B), fentanyl 4 micrograms ml- 1 (group F) or 0.05% bupivacaine combined with fentanyl 2 micrograms ml- 1 (group BF) by patient-controlled extradural analgesia (PCEA). Adding fentanyl to bupivacaine reduced the dose of bupivacaine by up to 68%, improved analgesia at rest and decreased PCEA use. Motor and sensory block were decreased, but there was more pruritus. Overall patient satisfaction was increased. Adding bupivacaine to fentanyl reduced the dose of fentanyl by up to 57% without altering pain scores or PCEA use. Sensory block increased but pruritus did not decrease. Bupivacaine 0.05% produced clinically significant leg weakness in three patients. Overall patient satisfaction was not altered. There was a significant additive analgesic effect between 0.05% bupivacaine and fentanyl but no clinical benefit was demonstrated from using the combination compared with fentanyl alone for this group of postoperative patients.      

Does pre-incisional thoracic extradural block combined with diclofenac reduce postoperative pain after abdominal hysterectomy?

In a double-blind, randomized study, we investigated 40 patients undergoing abdominal hysterectomy; patients received 0.5% plain bupivacaine 20 ml via a low thoracic extradural catheter and a diclofenac suppository (100 mg), either 30 min before incision (group 1) or 30 min after incision (group 2). All patients received a standard general anaesthetic and no opioid was used before or during operation. Postoperative analgesic requirements were measured using a patient- controlled analgesia (PCA) system. Pain was assessed using a visual analogue scale (VAS) and a verbal pain score (VPS) on movement up to 48 h after operation. There was no significant difference in the time to first request for morphine but consumption of morphine was significantly greater in group 1 at all times except 24 h. There were no significant differences in VAS and VPS pain scores, although both scores were consistently higher in group 1. Patient satisfaction with the quality of analgesia, at 24 h, demonstrated no significant difference between the two groups. The combination of extradural block and diclofenac suppository given before operation did not appear to produce a clinically effective pre-emptive analgesic effect.      

VENTILATORY RESPONSE TO CARBON DIOXIDE DURING EXTRADURAL ANAESTHESIA WITH LIGNOCAINE AND FENTANYL

Twenty-seven patients undergoing extracorporeal shock-wave lithotripsyor knee arthroscopy received extradural anaesthesia with 2%lignocaine plus adrenaline 1 in 200000. They were allocatedrandomly to three groups, one receiving no fentanyl (n = 6),the two others receiving fentanyl 50 µg either extradurally(n = 15) or i.v. (n = 6). Three tests of sensitivity to carbondioxide (Read's method) were performed successively on eachpatient: before operation and at 1 and 2 h after the extraduralinjection. Whereas lignocaine and adrenaline alone had no significanteffects on basal ventilation and the ventilatory response tocarbon dioxide, extradural fentanyl caused a slight reductionin resting ventilatory rate and ventilation at 1 and 2 h withno change in resting end-tidal carbon dioxide concentration.In addition, the slope of the ventilatory response to carbondioxide was reduced slightly at 1 h and ventilation at end-tidalnCO₂ of 7.3 kPa was reduced also at 1 and 2 h. Conversely, thesame dose of fentanyl i.v. had lesser and shorter effects onventilation at rest and during carbon dioxide rebreathing. Ourresults show that fentanyl 50 µg given extradurally causedslight ventilatory depression which is probably clinically unimportant.     

Comparison of three different loading doses to establish epidural analgesia in labour

Women requesting epidural analgesia were randomized to receive one of three loading doses. Group 1 received a single dose of bupivacaine 9.375 mg (15 ml of 0.0625%) containing fentanyl 37.5 microg and adrenaline 37.5 microg group 2 received a single dose of bupivacaine 15 mg (15 ml of 0.1%) containing fentanyl 30 microg and adrenaline 30 microg and group 3 received a test dose of bupivacaine 10 mg (4 ml of 0.25% - test) followed 5 min later by bupivacaine 20 mg (8 ml of 0.25% - loading). All groups received an infusion of bupivacaine 0.0625% with fentanyl 0.00025% and adrenaline 0.00025% at 10-12 ml/h started 15 min after the loading dose. Speed of onset of analgesia was the same in all three groups, with the majority of women achieving satisfactory analgesia by 20 min. Motor block was significantly increased in group 3 at 30 min, but by 1 h there was no difference in motor block between the groups.     

Epidural fentanyl markedly improves thoracic epidural analgesia in a low-dose infusion of bupivacaine, adrenaline and fentanyl. A randomized, double-blind crossover study with and without fentanyl

BACKGROUND: The objectives of the present study were to evaluate the effects on postoperative pain intensity, pain relief, and side effects when removing fentanyl from an optimally titrated epidural infusion consisting of bupivacaine, fentanyl and adrenaline. METHODS: A prospective, randomized, double-blind, crossover study was carried out in 20 patients after major upper abdominal surgery requiring a large longitudinal incision. Patients with only mild pain when coughing during thoracic epidural infusion of about 10 ml per hour of bupivacaine 1 mg x ml(-1), fentanyl 2 microg x ml(-1), and adrenaline 2 microg x ml(-1) were included. On the 1st and 2nd postoperative days, each patient was given a double-blind epidural infusion, at the same rate, with or without fentanyl. The effects were observed for 6 h or until pain when coughing became unacceptable in spite of rescue analgesia. Rescue analgesia consisted of up to two patient-controlled epidural bolus injections (4 ml) per hour and intravenous morphine if necessary. RESULTS: Main outcome measures, i.e. pain intensity when coughing and at rest, increased (P<0.001) when fentanyl (19.2+/-5.2 microg x h(-1)) was omitted from the epidural infusion: after 6 h pain intensity when coughing had increased to unacceptable levels in spite of increased consumption of rescue bupivacaine and adrenaline (P<0.001). Within 15-20 min after restarting the triple epidural mixture with fentanyl, pain intensity was again reduced to mild pain when coughing. CONCLUSIONS: A low dose of epidural fentanyl (20 microg x h(-1)) markedly improved the pain-relieving effect of bupivacaine and adrenaline infused epidurally at a thoracic level after major upper abdominal surgery. This dose of fentanyl is much too small to relieve severe dynamic pain when given systemically. Therefore, this study indirectly supports the view that a low-dose thoracic epidural infusion of fentanyl has a spinal analgesic site of action.     

布比卡因分别复合芬太尼、咪唑安定或曲马多用于术后硬膜外自控镇痛的比较

目的：比较布比卡因分别复合芬太尼,咪唑安定,曲马多行术后硬膜外自控镇痛（ＰＣＥＡ）的临床效果。方法：６０例在腰麻加硬膜外麻醉下行择期妇科手术的病人分为四组。Ａ组：０．１２５％布比卡因：Ｂ组：０．１２５％布比卡因＋芬太尼,Ｃ组０．１２５％布比卡因＋咪唑安定,Ｄ组：０．１２５％布比卡因＋曲马多ＰＣＥＡ参数设置,负荷剂量６ｍｌ,单次剂量３ｍｌ,锁定时间３０分钟,持续剂量２ｍｌ／ｈ。术后分别记录２４小时用     

Intrapleural bupivacaine analgesia after thoraco-abdominal incision for oesophagectomy

Intrapleural bupivacaine administration is said to produce good analgesia for the pain induced by a subcostal incision. However, reports of its efficacy after thoracotomy are conflicting. The goal of this study was to compare the analgesia produced by intrapleural administration of bupivacaine after oesophagectomy using a thoraco-abdominal incision with that obtained from intrapleural saline. After informed consent and institutional approval were obtained, 20 patients were randomly assigned to two groups of 10 patients each. Subjects received intrapleurally 10 ml of either 0.25% bupivacaine with 1:200,000 adrenaline or normal saline, every 8 h, beginning on the first post-operative day and lasting for 4 days. Pain was evaluated using a visual-analogue scale 2 h after the first daily treatment at rest and during physiotherapy. Pain scores were significantly lower in the bupivacaine group than in the saline group. Additionally, PaO2 was significantly higher in the bupivacaine group than in the saline group on Day 1 (P less than 0.05). The plasma bupivacaine concentration never reached the level of toxicity. Plasma bupivacaine concentrations on Day 1 after the first intrapleural bupivacaine injection were less than 350 ng ml-1; on Day 4 after the last injection they were less than 1300 ng ml-1. In conclusion, intrapleural administration of bupivacaine produces effective analgesia after oesophagectomy performed with a thoracoabdominal incision. The technique is easy to perform and is safe.     

Does adrenaline improve epidural bupivacaine and fentanyl analgesia after abdominal surgery?

The alpha-adrenergic agonists have been demonstrated to have synergistic effects with opioids and local anesthetics in animal research. The present study was performed to determine whether the addition of adrenaline improves the analgesic effects of an epidural infusion of a combination of fentanyl and bupivacaine after abdominal surgery. We studied 90 ASA 1 or 2 patients scheduled for abdominal surgery under epidural anaesthesia, with or without general anaesthesia. Patients were randomly divided into two groups to receive a postoperative epidural infusion of fentanyl 5 micrograms/ml in bupivacaine 0.2%, with or without adrenaline 5 micrograms/ml, at a rate of 2 ml/h for more than 48 hours. Postoperative pain relief was assessed using visual analog scales (VAS), both at rest and during coughing, at 2, 24, and 48 hours after surgery. The number of rescue analgesics and side-effects such as nausea, vomiting, pruritus, respiratory depression, headache, muscle weakness, and hypotension were recorded. Patients who received adrenaline (n = 40) reported significantly lower mean VAS scores than those who received no adrenaline (n = 37), both at rest at 24 hours postoperatively and during coughing at 24 and 48 hours. The number of additional analgesics and incidence of side-effects did not differ between groups. In conclusion, the results of the present study demonstrate that the addition of adrenaline to a combination of fentanyl and bupivacaine improves the quality of epidural analgesia after abdominal surgery. Under the conditions of the study, we did not detect any disadvantage from the addition of adrenaline.     

The pre-emptive analgesic effect of intra-articular bupivacaine in arthroscopic knee surgery

BACKGROUND: The purpose of this study was to determine whether intra-articular injection of bupivacaine prior to surgery provided better pain control after arthroscopic meniscectomy as compared with post-operative administration of bupivacaine. METHODS: Forty patients of American Society of Anesthesiologists (ASA) class I or II undergoing arthroscopic meniscectomy were assigned in a randomized, double-blinded manner into two groups: Group I received 20 ml of 2.5 mg/ml bupivacaine without epinephrine 30 min before skin incision and 20 ml of saline immediately after skin closure. Group II received identical injections in reverse order. All patients received total intravenous anesthesia. Post-operative pain scores were evaluated at 1, 2, 4, 6, 8, 12 and 24 h at rest and movement of the knee, using a 10-cm visual analog scale (VAS). The time to first analgesic use and 24-h analgesic consumption were recorded. RESULTS: Pain scores were lower in Group I compared with Group II at 1, 2, 4 and 6 h at rest and on movement (P < 0.05). The time to first analgesic use was longer in Group I, but there was no statistically significant difference in 24-h analgesic consumption. CONCLUSION: Intra-articular bupivacaine administered before surgery provided a statistically significant reduction in post-operative pain scores compared with post-operative bupivacaine administration.     

Suprascapular nerve block for ipsilateral shoulder pain after thoracotomy with thoracic epidural analgesia: a double-blind comparison of 0.5% bupivacaine and 0.9% saline.

Despite receiving thoracic epidural analgesia, severe ipsilateral shoulder pain is common in patients after thoracotomy. We recruited 44 patients into a double-blinded randomized placebo-controlled study to investigate whether suprascapular nerve block would treat postthoracotomy shoulder pain effectively. All patients received a standard anesthetic with a midthoracic epidural. Thirty patients who experienced shoulder pain within 2 h of surgery were randomly assigned to receive a suprascapular nerve block with either 10 mL of 0.5% bupivacaine or 10 mL of 0.9% saline. Shoulder pain was assessed before nerve blockade, at 30 min, and then hourly for 6 h after the block using a visual analog scale (VAS) and a 5-point verbal ranking score (VRS). The incidence of shoulder pain before nerve block was 78%. There was no significant decrease in either VAS or VRS in the Bupivacaine group. These results suggest that this pain is unlikely to originate in the shoulder and lead us to question the role of a somatic afferent in referred visceral pain. We conclude that suprascapular nerve block does not treat ipsilateral shoulder pain after thoracotomy in patients with an effective thoracic epidural. IMPLICATIONS: This randomized, double-blinded, placebo-controlled trial showed that suprascapular nerve block does not treat the severe ipsilateral shoulder pain that patients experience after thoracotomy. This has implications for established theories of referred pain and indicates that this pain is unlikely to originate in the shoulder.     

Preemptive analgesia. Clinical evidence of neuroplasticity contributing to postoperative pain.

Recent evidence suggests that surgical incision and other noxious perioperative events may induce prolonged changes in central neural function that later contribute to postoperative pain. The present study tested the hypothesis that patients receiving epidural fentanyl before incision would have less pain and need fewer analgesics post-operatively than patients receiving the same dose of epidural fentanyl after incision. Thirty patients (ASA physical status 2) scheduled for elective thoracic surgery through a posterolateral thoracotomy incision were randomized to one of two groups of equal size and prospectively studied in a double-blind manner. Epidural catheters were placed via the L2-L3 or L3-L4 interspaces preoperatively, and the position was confirmed with lidocaine. Group 1 received epidural fentanyl (4 micrograms/kg, in 20 ml normal saline) before surgical incision, followed by epidural normal saline (20 ml) infused 15 min after incision. Group 2 received epidural normal saline (20 ml) before surgical incision, followed by epidural fentanyl (4 micrograms/kg, in 20 ml normal saline) infused 15 min after incision. No additional analgesics were used before or during the operation. Anesthesia was induced with thiopental (3-5 mg/kg) and maintained with N2O/O2 and isoflurane. Paralysis was achieved with pancuronium (0.1 mg/kg). Postoperative analgesia consisted of patient-controlled intravenous morphine. Visual analogue scale pain scores were significantly less in group 1 (2.6 +/- 0.44) than in group 2 (4.7 +/- 0.58) 6 h after surgery (P less than 0.05), by which time plasma fentanyl concentrations had decreased to subtherapeutic levels (less than 0.15 ng/ml) in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Efficacy of patient-controlled epidural analgesia using a disposable PCA device

We evaluated efficacy of patient-controlled epidural analgesia (PCEA) using a disposable PCA device (3.0 ml type). Twenty-two patients for elective gynecological surgery were randomized into two groups. Patients of the continuous epidural group received epidural fentanyl (15 micrograms.ml-1) with bupivacaine (1.25 mg.ml-1) from a disposable infusion pump (infusion rate: 2.1 ml.hr-1). Patients of the PCEA group received the same anesthetic solution from the same infusion pump serially connected to the disposable PCA device. There were no significant differences in postoperative visual analogue scale (VAS) scores at rest and with movement between the two groups. However, VAS scores significantly decreased from 6.8 +/- 1.6 to 1.0 +/- 1.3 when the PCA device was used for severe pain. This suggests that segmental analgesic effect might be obtained by diffusion of anesthetic solution in the epidural space after 3.0 ml PCEA bolus administration. The incidences of side effects were similar in both groups. Respiratory depression and sedative effects were not observed in both groups. We conclude that PCEA using a disposable PCA device (3.0 ml type) seems to be effective for postoperative pain relief.     

Differential analgesic effects of low-dose epidural morphine and morphine-bupivacaine at rest and during mobilization after major abdominal surgery.

In a double-blind, randomized study, epidural infusions of low-dose morphine (0.2 mg/h) combined with low-dose bupivacaine (10 mg/h) were compared with epidural infusions of low-dose morphine (0.2 mg/h) alone for postoperative analgesia at rest and during mobilization and cough in 24 patients after elective major abdominal surgery. All patients in addition received systemic piroxicam (20 mg daily). No significant differences were observed between the groups at any assessment of pain at rest (P greater than 0.05), whereas pain in the morphine/bupivacaine group was significantly reduced during mobilization from the supine into the sitting position 12 and 30 h after surgical incision and during cough 8, 12, and 30 h after surgical incision (P less than 0.05). We conclude, that low-dose epidural bupivacaine potentiates postoperative low-dose epidural morphine analgesia during mobilization and cough. Evaluation of postoperative analgesic regimens should include assessment of pain during various activities as different analgesics may have differential effects on pain at rest and during mobilization.     

A prospective, double-blind, randomized, placebo-controlled study of dexmedetomidine as an adjunct to epidural analgesia after thoracic surgery

OBJECTIVE: The purpose of this study was to test the hypothesis that after thoracic surgery, the supplementation of a low-dose thoracic epidural (ED) bupivacaine (0.125%) infusion by intravenous (IV) dexmedetomidine decreases analgesic requirement without causing respiratory depression. The primary endpoint was the need for additional ED bupivacaine administered through patient-controlled epidural analgesia (PCEA). Secondary endpoints included the requirement for supplemental opioids and the impact of dexmedetomidine on CO2 retention. DESIGN: A prospective, randomized, double-blinded study. SETTING: A major US tertiary care university hospital. PATIENTS: Twenty-eight patients scheduled to undergo elective thoracotomy for wedge resection, lobectomy, or pneumonectomy. INTERVENTIONS: On intensive care unit arrival, the thoracic ED catheter was loaded with 0.125% bupivacaine to a T4 sensory level and a continuous infusion of 0.125% bupivacaine without opioid was commenced at 4 mL/h. Patients were then randomized into 1 of 2 groups. The dexmedetomidine group received an IV loading dose of dexmedetomidine of 0.5 microg/kg over 20 minutes, followed by continuous IV infusion at 0.4 microg/kg/h. The placebo group received IV saline at the same calculated loading and infusion rates by volume. If necessary, supplemental analgesia (increased ED rate, ED fentanyl, ketorolac [IV]) was provided to ensure a visual analog scale (VAS) score of < or =3. MEASUREMENTS: The analgesic effect was monitored by the VAS, and the requirement for PCEA dosing and additional analgesics was recorded. Heart rate, blood pressure, and blood gases were also monitored. MAIN RESULTS: There was no significant difference in PCEA use and VAS score between the 2 groups, but requirement for supplemental ED fentanyl analgesia was significantly greater in the placebo group (66.1 +/- 95.6 v 5.3 +/- 17.1 microg, p = 0.039). Mean PaCO2 was also significantly greater in the placebo group (40.3 +/- 4.1 v 43.9 +/- 4.3 mmHg, p = 0.04). Patients in the dexmedetomidine group exhibited significantly decreased heart rate (1 patient required and responded to atropine) and blood pressure (4 patients required and readily responded to IV fluid) compared with the placebo group. CONCLUSION: The authors conclude that in postthoracotomy patients, IV dexmedetomidine is a potentially effective analgesic adjunct to thoracic ED bupivacaine infusion and may decrease the requirement for opioids and potential for respiratory depression.     

Pre-incisional administration of ketamine reduced the postoperative pain

This study was designed to examine the postoperative analgesic effect of pre-/post-incisional administration of ketamine. Thirty-nine female patients scheduled for transabdominal hysterectomy were randomly allocated into 3 groups. Patients in group-K1 (n = 13) received intravenous ketamine 100 mg before surgical incision and patients in group-K2 (n = 13) received the same after laparotomy. Group-C (n = 13) did not receive any ketamine. All patients were anesthetized with combined spinal/epidural anesthesia supplemented with sevoflurane 0.5% and nitrous oxide in oxygen. Postoperative pain was controlled by epidural infusion of the mixture of fentanyl (25 mcg.ml-1) and bupivacaine (3.8 mg.ml-1) at 2.1 ml.hr-1. Analgesic effect was assessed by visual analogue scale (VAS) and verbal rating scale (VRS). VAS and VRS in group-K1 were significantly lower compared with those in group-C, while there was no difference between group-K2 and C. The incidence of side effects and additional use of analgesics were similar among the three groups. In conclusion, pre-incisional administration of ketamine reduced the postoperative pain, but post-incisional ketamine was not effective.     

胸段硬膜外复合静脉全麻与全凭静脉麻醉在开胸手术中的比较

目的 比较胸段硬膜外复合静脉全麻与全凭静脉麻醉对开胸手术患者血流动力学、麻醉药维持剂量、术后苏醒、躁动及疼痛的影响.方法 64例择期行剖胸手术患者,ASA Ⅱ级～Ⅲ级,采用完全随机设计的方法分为2组.A组:胸段硬膜外复合静脉全麻组,患者预先用10 ml 0.25%布比卡因和0.1 mg芬太尼硬膜外给药.术中硬膜外0.25%布比卡因和芬太尼10μg/ml,5 ml/h复合丙泊酚维持.B组:全凭静脉麻醉组,丙泊酚-端芬太尼全凭静脉麻醉.观察并记录不同时间点2组心率(HR)、平均动脉压(MAP)、中心静脉压(CVP)、所需麻醉维持药量、术毕清醒及出现疼痛时间.结果 2组患者各观察点血流动力学变化比较,差异无统计学意义;胸段硬膜外复合静脉全麻组麻醉维持不需要静脉镇痛药瑞芬太尼和肌松药阿曲库铵,只需复合充分的丙泊酚镇静,就能满足手术需求;术后苏醒早;拔管时间(11±4)min,相对于全凭静脉麻醉组(23±16)min明显缩短(P<0.05):躁动例数显著减少;术后出现疼痛时间(7.4±2.6)min相对于全凭静脉麻醉组(0.5士0.3)min明显延长(P<0.01).结论 胸段硬膜外复合静脉全麻用于开胸手术快通道麻醉是一种安全、经济、有效并有利于患者术后恢复的麻醉方法.     

Patient-controlled epidural analgesia in labour: varying bolus dose and lockout interval

This double-blind prospective study was designed to determine the best dose variables for patient-controlled epidural analgesia (PCEA) and to compare bolus-only PCEA with continuous infusion epidural analgesia (CIEA) during the first stage of labour. Five groups of parturients self-administered 0.125% bupivacaine with 1:400,000 epinephrine and fentanyl 2.5 μg·ml^?1 using PCA pumps programmed as follows: Group A, 2 ml bolus/10 min lockout interval (LI); Group B, 3 ml bolus/15 min LI; Group C, 4 ml bolus/20 min LI; Group D, 6 ml bolus/30 min LI; Group E, 8 ml·hr^?1 continuous infusion. Hourly assessments included: VAS scores for pain and satisfaction, sensory and motor block, bupivacaine and fentanyl consumption. Blood samples were collected at birth for maternal and fetal fentanyl concentrations. Data from 68 patients showed no differences among groups in pain relief or maternal satisfaction. Most patients received excellent analgesia and those requiring extra epidural supplements were evenly distributed across groups. There was higher consumption of bupivacaine and fentanyl in Group E than in any of the other four groups: bupivacaine mg·hr^?1, mean (SD), 9.4 (2.7) in Group E vs 5.2 (1.7) in Groups A-D inclusive (P<0.0001); fentanyl μg·hr^?1, 19.6 (4.6) in Group E vs 12.6 (7.5) in Groups A-D inclusive (P<0.05). Motor block was minimal, whereas sensory levels were higher at the 3- and 4-hour assessments in Groups D and E than in all other groups (P<0.05). Plasma fentanyl concentrations were <0.5 ng·ml^?1 in all samples and no sequelae from fentanyl were observed, apart from mild pruritus. Bolus-only PCEA is a safe and effective alternative to CIEA during the first stage of labour irrespective of the initial dose variables selected.     

COMPARISON OF BUPIVACAINE AND BUPIVACAINE WITH FENTANYL IN CONTINUOUS EXTRADURAL ANALGESIA DURING LABOUR

In a randomized, double-blind study of 39 mothers in labour,we have compared a loading dose of 0.5% bupivacaine 6.0 ml andfentanyl 100 µg given extradurally, followed by an infusionof 0.08% bupivacaine 15 ml h^–1 plus fentanyl 37.5 µgh^–1, with a loading dose of 0.5% bupivacaine 6.0 ml andsaline 2.0 ml, followed by an extradural infusion of 0.08% bupivacainealone, per hour. Analgesic levels were more consistent and sustainedin mothers who received fentanyl in addition to bupivacaine,and the duration from the time of the loading dose to the firsttop-up was extended considerably in this group. The only significantside effect was a high incidence of mild pruritus in the fentanylgroup. The addition of fentanyl to the extradural loading doseand subsequent infusion of local anaesthetic is a satisfactoryalternative to giving higher doses of local anaesthetic alone.     

Does intrathecal fentanyl produce acute cross-tolerance to i.v. morphine?

We have examined the hypothesis that intrathecal fentanyl at operation can increase postoperative i.v. morphine requirements. We studied 60 patients undergoing Caesarean section. All received intrathecal 0.5% plain bupivacaine 2 ml combined with either fentanyl 0.5 ml (25 micrograms) (group F) (n = 30) or normal saline 0.5 ml (group S) (n = 30). In addition, 10 ml of an extradural solution (fentanyl 1 ml (50 micrograms) combined with 0.5% bupivacaine 9 ml) was administered after delivery. Extradural solution was only given before delivery if the intrathecal injection failed to produce a block above T6 or the patient required further analgesia. Postoperative analgesia was provided with i.v. morphine patient-controlled analgesia. At operation, intrathecal fentanyl reduced the need to administer extradural solution before delivery, increased the anaesthetist's satisfaction with analgesia and reduced nausea, but increased pruritus. Up to 6 h after delivery there was no difference in postoperative morphine requirements or pain scores. Between 6 h and 23 h there was a 63% increase in morphine requirements in group F. We consider the most likely explanation for this finding to be that intrathecal fentanyl induced acute spinal opioid tolerance.      

Patient controlled epidural analgesia during labour: choice of solution

Epidural characteristics, when using different solutions for patient controlled epidural analgesia (PCEA), were compared in a randomised, blinded study in labour. Women in group 1 (n=23) self-administered 0.25% plain bupivacaine, in group 2 (n=23) 0.125% plain bupivacaine plus fentanyl 3 microg/ml and in group 3 (n=20) 0.0625% bupivacaine with adrenaline 1:250,000 plus fentanyl 3 microg/ml. There were no significant differences between groups with respect to the quality of obstetric pain relief or maternal satisfaction, the requirement for supplementary boluses of staff-administered solution or the incidence of side effects. There was more intense motor block after 3 hours of PCEA (odds ratio 3.33 for score 0 versus 1, 2 or 3) and a significantly higher ratio of demands received to demands made (P<0.03) in group 1 compared groups 2 and 3. The rate of bupivacaine utilisation was significantly higher in group 1 compared to groups 2 and 3 and lower in group 3 compared to 1 and 2 (median+interquartile range: 16+11-21 vs 9+6-11 vs 4+3-8 mg/hr, P<0.0002). Although all solutions provided effective pain relief for PCEA during labour, the use of a low-dose bupivacaine-fentanyl combination offers clinical advantages and further evaluation of such solutions is warranted.