Analgesia with sevoflurane during labour: i. Determination of the optimum concentration

Background. Sevoflurane has favourable physical qualities forinhaled analgesia during labour pain. The aim of this preliminarystudy was to identify its optimum concentration. Methods. In this open-labelled escalating-dose study, 22 parturientsin labour self-administered sevoflurane at 10 contractions usingan Oxford Miniature Vaporiser. The inspired concentration wasincreased by 0.2% after each contraction from 0% to 1.4% ordecreased if sedation occurred. Visual analogue scores (0–100mm) for pain intensity, pain relief, sedation, mood and copingwere measured after each contraction. Results. The median (IQR [range]) pain relief and sedation scoresincreased from 44 (43–56 [4–93]) mm and 55 (43–56[0–98]) mm at 0.2% sevoflurane, to 74 (72–78 [50–80])mm and 71 (71–73 [33–97]) mm at 1.2% sevoflurane,respectively. Pain relief scores did not show any significantincrease above 0.8% whilst sedation continued to increase, withexcessive sedation occurring at 1.2% sevoflurane. No significantchanges in other scores were measured. Conclusions. We concluded that the optimal sevoflurane concentrationin labour was 0.8%. This concentration allows a safety marginand balances the risk of sedation with the benefit of pain reliefin labour.      

Measuring the quality of continuous epidural block for abdominal surgery

Background. In view of the wide variation in pain experiencebetween patients, a clinical standard—the time from theend of surgery to the first experience of pain—was appliedto 1359 consecutive patients in order to investigate whetherthe initial quality of epidural block has an effect on the overallquality of postoperative pain relief. Methods. Clinical data were recorded in 58 118 out of 72 412h in 1359 patients, and transferred to a database. Data collectedincluded pain scores on a four-point verbal rating scale; nauseaand vomiting; motor block; sedation scores; systolic blood pressure<100 and <90 mm Hg; ventilatory frequency <10 and <8bpm; and hourly epidural infusion rate. Results. As the time to first experience of pain increased fromnil to >24 hours, the time from the first to last experienceof pain shortened from 34 (19–50) h to 3 (1–12)h (p<0.001) and the proportion of patients receiving an epiduralbolus decreased from 53 to 8% (p<0.001). Increases in theinitial pain free time increased the proportion of patientswith systolic BP<100 mmHg from 59 to 77%, (p<0.001) andincreased the proportion of patients with respiratory rate <10bpm from 13 to 26%, (p<0.001). Conclusion. Extending pain relief for more than 12 h beyondthe end of abdominal surgery significantly improves the overallquality of postoperative pain relief, but is associated withan increase in side-effects. ¹Present address: John Radcliffe Hospital, Oxford, UK. ²Present address: Royal Hospital for Sick Children, Edinburgh,UK     

Respiratory and haemodynamic effects of acute postoperative pain management: evidence from published data

Background. This study examines the evidence from publisheddata concerning the adverse respiratory and haemodynamic effectsof three analgesic techniques after major surgery; i.m. analgesia,patient-controlled analgesia (PCA), and epidural analgesia. Methods. A MEDLINE search of the literature was conducted forpublications concerned with the management of postoperativepain. Information relating to variables indicative of respiratorydepression and of hypotension was extracted from these studies.Over 800 original papers and reviews were identified. Of thesepapers, 212 fulfilled the inclusion criteria but only 165 providedusable data on adverse effects. Pooled data obtained from thesestudies, which represent the experience of a total of nearly20 000 patients, form the basis of this study. Results. There was considerable variability between studiesin the criteria used for defining respiratory depression andhypotension. The overall mean (95% CI) incidence of respiratorydepression of the three analgesic techniques was: 0.3 (0.1–1.3)%using requirement for naloxone as an indicator; 1.1 (0.7–1.7)%using hypoventilation as an indicator; 3.3 (1.4–7.6)%using hypercarbia as an indicator; and 17.0 (10.2–26.9)%using oxygen desaturation as an indicator. For i.m. analgesia,the mean (95% CI) reported incidence of respiratory depressionvaried between 0.8 (0.2–2.5) and 37.0 (22.6–45.9)%using hypoventilation and oxygen desaturation, respectively,as indicators. For PCA, the mean (95% CI) reported incidenceof respiratory depression varied between 1.2 (0.7–1.9)and 11.5 (5.6–22.0)%, using hypoventilation and oxygendesaturation, respectively, as indicators. For epidural analgesia,the mean (95% CI) reported incidence of respiratory depressionvaried between 1.1 (0.6–1.9) and 15.1 (5.6–34.8)%,using hypoventilation and oxygen desaturation, respectively,as indicators. The mean (95% CI) reported incidence of hypotensionfor i.m. analgesia was 3.8 (1.9–7.5)%, for PCA 0.4 (0.1–1.9)%,and for epidural analgesia 5.6 (3.0–10.2)%. Whereas theincidence of respiratory depression decreased over the period1980–99, the incidence of hypotension did not. Conclusions. Assuming a mixture of analgesic techniques, AcutePain Services should expect an incidence of respiratory depression,as defined by a low ventilatory frequency, of less than 1%,and an incidence of hypotension related to analgesic techniqueof less than 5%.     

Epidural analgesia compared with peripheral nerve blockade after major knee surgery: a systematic review and meta-analysis of randomized trials

The relative analgesic efficacy and side-effect profile of peripheral nerve blockade (PNB) techniques compared with lumbar epidural analgesia for major knee surgery is unclear. We undertook a systematic review and meta-analysis of all randomized trials comparing epidural analgesia with PNB for major knee surgery. Eight studies were identified that had enrolled a total of 510 patients of whom 464 (91%) had undergone total knee joint replacement. All were small trials and none was blinded (Jadad score 1-3). PNB technique was variable: in addition to a femoral catheter (n=5), femoral single shot (n=2), or lumbar plexus catheter (n=1) techniques, sciatic blockade was performed in three trials. There was no significant difference in pain scores between epidural and PNB at 0-12 or 12-24 h, WMD 0.22 (95% CI: -0.36, 0.81), 0.05 (-1.01, 0.91), respectively, and no clinically significant difference at 24-48 h, WMD -0.35 (-0.64, -0.02). There was also no difference in morphine consumption (mg) at 0-24 h, WMD -6.25 (-18.35, 5.86). Hypotension occurred more frequently among patients who received epidurals [OR 0.19 (0.08, 0.45)], but there was no difference in the incidence of nausea and vomiting. Two studies reported a higher incidence of urinary retention in the epidural group. Patient satisfaction was higher with PNB in two of three studies which measured this, although rehabilitation indices were similar. PNB with a femoral nerve block provides postoperative analgesia which is comparable with that obtained with an epidural technique but with an improved side-effect profile and is less likely to cause a severe neuraxial complication.     

Postoperative analgesia by epidural methylprednisolone after posterolateral thoracotomy

The aim of this study was to evaluate the potential analgesiceffect of epidural methylprednisolone (MP) after posterolateralthoracotomy (PLT). Adult male patients undergoing PLT for lungsurgery were included in a prospective, randomized, double blindstudy. Peroperative analgesia (bupivacaine plus sufentanil)was given by a thoracic epidural catheter associated with generalanaesthesia. After surgery, patients received either MP 1 mgkg^–1 followed by a continuous epidural infusion of MP1.5 mg kg^–1 during 48 h (MP group) or 0.9% saline as abolus injection and continuous epidural infusion (P group).Additional morphine analgesia was administered by i.v. patient-controlledanalgesia. Pain was assessed at rest and with mobilization every4 h after operation during 48 h with a visual analogue scale(VAS). The primary end-point was the total morphine requirementsduring the 48 first postoperative hour. Twenty-four patientswere allocated to MP (n=12) and P (n=12) groups. Characteristicsof the two groups were similar. There were no differences betweengroups for morphine requirements (median and interquartile range)during the 48 h: 59 mg (40–78) in MP group vs 65 mg (59–93)in P group. There were no differences between groups for morphinerequirements every 4 h during the 48 h and VAS for pain at restand evoked pain. No side effects were reported. It was concludedin this small study that these results did not support the useof epidural steroids for postoperative analgesia after PLT. Br J Anaesth 2001; 87: 635–8     

Optimal concentration of epidural fentanyl in bupivacaine 0.1% after thoracotomy

Background. The aim of this prospective, double-blind, randomizedcontrolled trial was to investigate the analgesic and adverseeffects of three commonly used concentrations of thoracic epiduralfentanyl with bupivacaine in patients undergoing thoracotomyfor lung resection. Methods. We studied 99 patients who were randomized to receivefentanyl 2 µg ml^–1 (group 2), fentanyl 5 µgml^–1 (group 5) and fentanyl 10 µg ml^–1 (group10) in bupivacaine 0.1% via a thoracic epidural. Postoperatively,pain on coughing was assessed using a visual analogue scale(VAS) and an observer verbal rating score (OVRS) at 2, 8, 16and 24 h. At the same times, sedation, pruritus and nausea wereassessed. Results. Of 29, 28 and 32 patients who completed the study ingroups 2, 5 and 10 respectively, there was no significant differencein baseline characteristics between the three groups. The numberof patients with episodes of unsatisfactory pain, i.e. VAS scores>30 mm and OVRS >1, at each of the four assessments postoperativelywas significantly (P<0.01) higher in group 2 than in groups5 and 10. In group 10, 16 patients had sedation scores >1compared with 10 each in groups 2 and 5. In addition, 19 patientsin group 10 experienced pruritus compared with 12 each, in groups2 and 5. These differences were not significant. Nausea wasnot significantly different between the three groups. Conclusion. We conclude that thoracic epidural fentanyl 5 µgml^–1 with bupivacaine 0.1% provides the optimum balancebetween pain relief and side effects following thoracotomy. Br J Anaesth 2004: 92: 670–4     

Single-injection thoracic paravertebral block for postoperative pain treatment after thoracoscopic surgery

Background. Thoracoscopic surgery can be associated with considerablepostoperative pain. While the benefits of paravertebral blockon pain after thoracotomy have been demonstrated, no investigationson the effects of paravertebral block on pain after thoracoscopyhave been conducted. We tested the hypothesis that a single-injectionthoracic paravertebral block, performed preoperatively, reducespain scores after thoracoscopic surgery. Methods. Of 45 patients recruited, 40 completed the study. Theywere randomly allocated to two groups: the paravertebral groupreceived i.v. patient-controlled analgesia (PCA) with morphineplus single-injection thoracic paravertebral block with bupivacaine0.375% and adrenaline 1:200 000 0.4 ml kg^–1 (n=20). Thecontrol group was treated with a back puncture without injectionand morphine PCA (n=20). Results. The main outcomes recorded during 48 h after surgerywere pain scores using the visual analogue scale (VAS, 0–100).Secondary outcomes were cumulative morphine consumption andpeak expiratory flow rate (PEFR). Half an hour and 24 h aftersurgery, median (25th–75th percentiles) VAS on coughingin the paravertebral group was 31.0 (20.0–55.0) and 30.5(17.5–40.0) respectively and in the control group it was70.0 (30.0–100.0) and 50.0 (25.0–75.0) respectively.The difference between the groups over the whole observationperiod was statistically significant (P<0.05). Twenty-fourand 48 h after surgery, median (25th–75th percentiles)cumulative morphine consumption (mg) was 49.0 (38.3–87.0)and 69.3 (38.8–118.5) respectively in the paravertebralgroup and 51.2 (36.0–84.1) and 78.1 (38.4–93.1)in the control group (statistically not significant). No differenceswere found in PEFR or the incidence of any side-effects betweengroups. Conclusion. We conclude that single-shot preoperative paravertebralblock improves post-operative pain treatment after thoracoscopicsurgery in a clinically significant fashion.      

Intermittent vs continuous administration of epidural ropivacaine with fentanyl for analgesia during labour

Background. Many years ago regular intermittent bolus administrationof epidural local anaesthetic solution was recognized to producemore effective analgesia than continuous infusion, but onlyrecently has the development of suitable pumps allowed the formertechnique's wider evaluation. Methods. In this randomized, double-blind trial, 40 primigravidpatients had a lumbar epidural catheter inserted, and plainropivacaine 0.2% 15–20 ml was titrated until analgesiaand bilateral sensory block to T10 were produced (time zero).Patients were then given either an infusion of ropivacaine 2mg ml^–1 with fentanyl 2 µg ml^–1 at 10 ml h^–1,or hourly boluses of 10 ml of the same solution. Pain, sensoryblock and motor block were measured frequently. If requested,additional 10 ml boluses of the study mixture were given foranalgesia. Results. There were no differences between the two groups inpatient characteristics, obstetric/neonatal outcome, or in sensoryor motor block. A total of 12 (60%) patients in the continuousgroup required one or more additional boluses compared with4 (20%) patients in the intermittent group (95% CI 9.6–61.7%,P=0.02). Therefore the intermittent group received a lower totaldrug dose than the infusion group (P=0.02). Duration of uninterruptedanalgesia (time to first rescue bolus) was longer in the intermittentgroup (P<0.02). Conclusions. The intermittent group required fewer supplementaryinjections and less drug to maintain similar pain scores, sensoryand motor block compared with the continuous group. This representsa more efficacious mode of analgesia. Declaration of interest. P.D.W.F., C.S.M. and J.B.W. receivedsalaries from AstraZeneca while working as research fellowsat Ninewells Hospital, Dundee, UK.     

Ultrasonographic guidance for sciatic and femoral nerve blocks in children

Background: Recent studies have shown that ultrasound guidance for paediatricregional anaesthesia can improve the quality of upper extremityand neuraxial blocks. We therefore investigated whether ultrasoundguidance for sciatic and femoral nerve blocks prolongs sensoryblockade in comparison with nerve stimulator guidance in children. Methods: Forty-six children scheduled for surgery of one lower extremitywere randomized to receive a sciatic and femoral nerve blockunder either ultrasound or nerve stimulator guidance. Afterinduction of general anaesthesia, the blocks were performedusing an ultrasound-guided multiple injection technique untilthe nerves were surrounded by levobupivacaine, or by nerve stimulatorguidance using a predefined dose of 0.3 ml kg^–1 of levobupivacaine.An increase in heart rate of more than 15% of baseline duringsurgery defined a failed block. The duration of the block wasdetermined from the injection of local anaesthetic to the timewhen the patient received the first postoperative analgesic. Results: Two blocks in the nerve stimulator group failed. There wereno failures in the ultrasound group. The duration of analgesiawas longer in the ultrasound group mean (SD) 508 (178) vs 335(169) min (P < 0.05). The volume of local anaesthetic insciatic and femoral nerve blocks was reduced with ultrasoundcompared with nerve stimulator guidance [0.2 (0.06) vs 0.3 mlkg^–1 (P < 0.001) and 0.15 (0.04) vs 0.3 ml kg^–1(P < 0.001), respectively]. Conclusions: Ultrasound guidance for sciatic and femoral nerve blocks inchildren increased the duration of sensory blockade in comparisonwith nerve stimulator guidance. Prolonged sensory blockade wasachieved with smaller volumes of local anaesthetic when usingultrasound guidance.     

Block of the sacral segments in lumbar epidural anaesthesia

Background. Block of the first sacral segment is often delayedin lumbar epidural anaesthesia. The addition of either epinephrineor sodium bicarbonate to the local anaesthetic enhances theefficacy of epidural block. We assessed the block of lumbo-sacralsegments in lumbar epidural anaesthesia adding epinephrine and/orbicarbonate to lidocaine. Methods. Twenty-seven patients undergoing lumbar epidural anaesthesiawith lidocaine 2%, 17 ml at L4-5 or L5-S1 were randomly dividedinto three groups. Plain lidocaine, lidocaine with 1:200 000epinephrine or lidocaine–epinephrine–bicarbonatewas administrated via an epidural catheter. The pain thresholdafter repeated electrical stimulation was used to assess thesensory block at the L2, S1, and S3 segments. Motor block wasevaluated using the Bromage scale. Results. Patient characteristics were comparable between thegroups. The pH of lidocaine in the lidocaine–epinephrine–bicarbonategroup was significantly higher than that in other groups. Painthresholds at the S1 and S3 segments in the lidocaine–epinephrine–bicarbonategroup were significantly higher than those in the lidocaine–epinephrinegroup. However, differences in the pain threshold at the L2segment between groups were insignificant. The time to onsetof sensory block at the S1 and S3 in the lidocaine–epinephrine–bicarbonategroup was significantly shorter than that in the lidocaine group.Pain threshold by pinprick test was approximately within the30–50 mA range. Conclusion. A combination of lidocaine, bicarbonate, and epinephrineincreases the pain threshold over the sacral segments. Br J Anaesth 2003; 90: 173–8     

Comparison of three different volumes of mepivacaine in axillary plexus block using multiple nerve stimulation

Background. The multiple injection technique for axillary block,in which the four distal nerves of the plexus are located bya nerve stimulator and separately injected, has been shown toprovide a high success rate and a short onset time. This randomizeddouble-blind study was conducted to compare the effectivenessof three different volumes of mepivacaine 10 mg ml^–1 inpatients undergoing elective distal upper limb surgery underaxillary brachial plexus block with the four-nerve approach.The number of complete sensory blocks was the primary efficacyvariable. Methods. A total of 114 adult patients were randomly allocatedto receive 36 (n=38), 28 (n=38), and 20 ml (n=38) of mepivacaine10 mg ml^–1. In each group, volumes were equally distributedin the four nerve territories. In all patients, performancetime, latency time, block characteristics, need of supplementaryblocks, tourniquet tolerance, duration of analgesia, and complicationswere recorded. Results. Complete sensory block was obtained in 97% of patientsreceiving a volume of 36 ml, 97% of those receiving 28 ml, and94% of those receiving 20 ml. One patient in the group of 28ml and five patients in the group of 20 ml experienced painon inflation of the tourniquet. Two months after surgery, nocase of postoperative neurological dysfunction was observed. Conclusions. The three volumes (38, 28, and 20 ml) of mepivacaine10 mg ml^–1 ensured a similar and high percentage of completesensory blocks in axillary brachial plexus anaesthesia withnerve stimulation involving the location of four motor responses. Br J Anaesth 2003; 91: 519–24     

Evaluation of costs and effects of epidural analgesia and patient-controlled intravenous analgesia after major abdominal surgery

Background. The outcome of different treatment strategies forpostoperative pain has been an issue of controversy. Apart fromefficacy and effectiveness a policy decision should also considercost-effectiveness. Since economic analyses on postoperativepain treatment are rare we developed a decision model in a pilotcost-effectiveness analysis (CEA) comparing epidural analgesia(EDA) and patient-controlled intravenous analgesia (PCIA) aftermajor abdominal surgery in routine care. Methods. Using a decision-tree model, treatment with EDA (ropivacaineand morphine) was compared with PCIA (morphine). Effects andcosts of treatment were established. The number of pain-freedays at rest (pain intensity <30 using visual analogue scale1–100 mm) was the primary measure of effect. An incrementalcost-effectiveness ratio (ICER) was calculated as the differencein direct costs divided by the difference in effect. A databaseon 644 patients collected for the purpose of quality controlduring the period of 1997 to 1999 was the main data source.Sensitivity analysis was used to test uncertain data. Results. EDA was more effective in terms of pain-free days butmore expensive. The additional cost for each pain-free day was5652 Euros. Conclusion. It is a judgement of value if the additional costis reasonable. When the cost of around 55 000 Euros per gainedlife-year with full health for other interventions is debated,our result indicates poor cost-effectiveness for EDA. Beforeany conclusion can be drawn concerning policy recommendationsthe difference in costs has to be related to other outcome measuresas length of hospital stay, morbidity and mortality are required.     

Intrathecal morphine overdose during combined spinal-epidural block for Caesarean delivery

We describe a 25 mg intrathecal morphine overdose duringa combined spinal–epidural block for a Caesarean delivery.Naloxone infusion (5.24 mg over 24 h) was startedprior to the patient becoming symptomatic and almost immediatelyafter the overdose. Invasive therapeutics such as mechanicalventilation were avoided. Br J Anaesth 2002; 89: 925–7     

Continuous spinal microcatheter (28 gauge) technique for arterial bypass surgery of the lower extremities and comparison of ropivacaine with or without morphine for postoperative analgesia

Background. The aim of this study was to evaluate a microcathetertechnique for continuous spinal anaesthesia (CSA) and continuousspinal postoperative analgesia (CSPA) in vascular surgery. Methods. A total of 47 patients (range 51–95 yr, ASA II–IV)undergoing peripheral bypass surgery of the lower extremitiesreceived a spinal microcatheter (28 gauge) at L3–L4 orL2–L3. For CSA, ropivacaine 7.5 mg ml^–1 was givenin small increments. Central venous pressure was maintained3 mm Hg. Of 47 patients, 44 received CSPA, either using ropivacainealone 2 mg h^–1 (group R, n=22) or ropivacaine 1 mg h^–1with morphine 8 µg h^–1 (group RM, n=22) for 24 hafter surgery (randomized, double-blinded). Results. Intraoperative haemodynamic control was good; duringthe initial 60 min only four patients received phenylephrinei.v. for hypotension. Up to 30% of the patients felt mild painat incision but surgery [mean duration 173 min (range 66–327)]was successfully completed under CSA in 45 patients. In fourinstances of acute revision surgery, a new block was administeredutilizing the spinal catheter in place. Postoperative pain reliefwas comparably adequate in both groups with no difference inrescue pain medication. Four patients (three in R, one in RM)had weak motor blockade in the first postoperative morning. Conclusions. The described CSA technique offered good haemodynamiccontrol, ease of maintaining spinal anaesthesia, and ease ofproviding a new spinal block for revision. The combination oflow-dose ropivacaine and morphine for CSPA did not offer anybenefit compared with the higher ropivacaine dose alone. Presented in part at the 28th Congress of the Scandinavian Societyof Anaesthesiology and Intensive Care Medicine, Reykjavik, Iceland,June 29–July 3, 2005     

Prospective evaluation of deep topical fornix nerve block versus peribulbar nerve block in patients undergoing cataract surgery using phacoemulsification

We compared the efficacy of deep topical fornix nerve blockanaesthesia (DTFNBA) versus peribulbar nerve block in patientsundergoing cataract surgery using phacoemulsification. We studied120 patients, allocated randomly to two groups. Group 1 (n=60)received peribulbar block with 5 ml of a 1:1 mixture of 0.5%plain bupivacaine and 2% lidocaine supplemented with hyaluronidase300 i.u. ml^–1. Group 2 received DTFNBA with placementof a sponge soaked with 0.5% bupivacaine deep into the conjunctivalfornices for 15 min. No sedation was given to either group.Analgesia was assessed by the reaction to insertion of the superiorrectus suture and by questioning during the procedure. A three-pointscoring system was used (no pain=0, discomfort=1, pain=2). Scoringwas repeated at keratotomy, hydrodissection and hydrodelineation,phacoemulsification, irrigation and aspiration, and at intraocularlens insertion. If the patient’s pain score was 0 or 1,no further action was taken. If the pain score at any stageof the operation was 2, intracameral injection of 1% preservative-freelidocaine was given. One patient in Group 2 needed intracamerallidocaine at the stage of phacoemulsification (P>0.05) andfour experienced discomfort at irrigation and aspiration (P=0.043).We conclude that DTFNBA may be a useful needle-free anaesthetictechnique in patients undergoing cataract surgery using phacoemulsification. Br J Anaesth 2000; 85: 314–6 Footnotes ^* Corerspondign author     

Analgesia with sevoflurane during labour: ii. Sevoflurane compared with Entonox for labour analgesia

Background. We determined the optimal inspired sevoflurane concentrationfor use during labour as 0.8% in our previous study. This studycompared sevoflurane at a concentration of 0.8% and Entonox^®(nitrous oxide 50%: oxygen 50%) for analgesia during labourin 32 healthy parturients. Methods. Each mother underwent two open-label, three-part sequencesin random order, Entonox-sevoflurane-Entonox or sevoflurane-Entonox-sevoflurane.In each part the agent was self-administered during 10 contractions.A 100 mm visual analogue scores for pain relief and sedationwas completed immediately after each contraction. Results. Two patients withdrew during administration of sevoflurane(because of its odour) and five during Entonox (requesting epiduralanalgesia). Of the remaining women, data were available foranalysis from 29 participants: median (IQR [range]) pain reliefscores were significantly higher for sevoflurane 67 (55–74[33–100]) mm than for Entonox 51 (40–69.5 [13–100])mm (P<0.037). Nausea and vomiting were more common in theEntonox group [relative risk 2.7 (95% CI 1.3–5.7); P=0.004].No other adverse effects were observed in the mothers or babies.There was significantly more sedation with sevoflurane thanwith Entonox {74 (66.5–81 [32.5–100]) and 51 (41–69.5[13–100]) mm, respectively; P<0.001}. Twenty-nine patientspreferred sevoflurane to Entonox and found its sedative effectshelpful. Conclusions. We conclude that self-administered sevofluraneat subanaesthetic concentration (0.8%) can provide useful painrelief during the first stage of labour, and to a greater extentthan Entonox. Although greater sedative effects were experiencedwith sevoflurane, it was preferred to Entonox.      

Comparison of the effects of intrathecal ropivacaine, levobupivacaine, and bupivacaine for Caesarean section

Background. This study aimed to detect if intrathecal (i.t.)ropivacaine and levobupivacaine provided anaesthesia (satisfactoryanalgesia and muscular relaxation) and postoperative analgesiaof similar quality to bupivacaine in patients undergoing Caesareansection. Methods. Ninety parturients were enrolled. A combined spinal-epiduraltechnique was used. Patients were randomly assigned to receiveone of the following isobaric i.t. solutions: bupivacaine 8mg (n=30), levobupivacaine 8 mg (n=30), or ropivacaine 12 mg(n=30), all combined with sufentanil 2.5 µg. An i.t. solutionwas considered effective if an upper sensory level to pinprickof T4 or above was achieved and if intraoperative epidural supplementationwas not required. Sensory changes and motor changes were recorded. Results. Anaesthesia was effective in 97, 80, and 87% of patientsin the bupivacaine 8 mg, levobupivacaine 8 mg, and ropivacaine12 mg groups, respectively. Bupivacaine 8 mg was associatedwith a significantly superior success rate to that observedin the levobupivacaine group (P<0.05). It also provided alonger duration of analgesia and motor block (P<0.05 vs levobupivacaineand ropivacaine). Conclusions. The racemic mixture of bupivacaine combined withsufentanil remains an appropriate choice when performing Caesareansections under spinal anaesthesia. Br J Anaesth 2003; 91: 684–9     

Efficacy of three doses of tramadol with bupivacaine for caudal analgesia in paediatric inguinal herniotomy

Background. This study was designed to evaluate the analgesicefficacy of three doses of tramadol, administered caudally withbupivacaine, in providing postoperative pain relief in children. Methods. Eighty children, aged between 2 and 8 yr, undergoinginguinal herniotomy were randomly allocated to receive bupivacaine0.25% 0.75 ml kg^–1 (Group B; n=20), bupivacaine 0.25%0.75 ml kg^–1 with tramadol 1 mg kg^–1 (Group BT1;n=20), bupivacaine 0.25% 0.75 ml kg^–1 with tramadol 1.5mg kg^–1 (Group BT1.5; n=20), or bupivacaine 0.25% 0.75ml kg^–1 with tramadol 2 mg kg^–1 (Group BT2; n=20)by the caudal route immediately after induction of general anaesthesia.Heart rate, arterial pressure and oxygen saturation were monitored.Postoperative pain was assessed at regular intervals for 24h using All India Institute of Medical Sciences pain score.Analgesia was supplemented whenever pain score was 4. Durationof analgesia and requirement for additional analgesics was noted. Results. Duration of analgesia was longer in Group BT2 [(mean(SD) 12 (0.9) h] compared with Group B [4 (1) h], Group BT1[8 (0.9) h], or Group BT1.5 [11 (1) h]; all P<0.001. Totalconsumption of rescue analgesic was significantly lower in groupBT2 compared with other groups (P<0.001). There were no significantchanges in heart rate, arterial pressure and oxygen saturationbetween groups. Adverse effects were not observed. Conclusions. Caudal tramadol 2 mg kg^–1, combined withbupivacaine 0.25% 0.75 ml kg^–1, provided longer durationof postoperative analgesia and reduced requirement for rescueanalgesic compared with tramadol 1 mg kg^–1 or 1.5 mg kg^–1in children undergoing inguinal herniotomy.     

Influence of thoracic epidural analgesia on cardiovascular autonomic control after thoracic surgery

Background. Thoracic epidural analgesia (TEA) is effective inalleviating pain after major thoracoabdominal surgery and mayalso reduce postoperative mortality and morbidity. This studyinvestigated cardiovascular autonomic control in patients undergoingelective thoracic surgery and its modulation by continuous TEA. Methods. Thirty-eight patients were randomly assigned to receivepatient-controlled analgesia (PCA group) or thoracic epiduralanalgesia (TEA group) with doses of bupivacaine (0.25% duringoperation, 0.125% after operation) and fentanyl (2 µg ml^–1).Heart rate variability (HRV), baroreflex function and pressureresponse to nitroglycerine and phenylephrine were assessed beforeoperation, 4 h after the end of surgery (POD 0) and on the firstand second postoperative days (POD 1 and POD 2). Results. Early after surgery, all HRV variables and baroreflexsensitivities were markedly decreased in both groups. In theTEA group, total HRV and its high-frequency components (HF)increased towards preoperative values at POD 1 and POD 2,whereas the ratio of low to high frequencies (LF/HF) was significantlyreduced (mean (SD), –44 (15)% at POD 0, –38 (17)%at POD 1, –37 (18%) at POD 2) and associatedwith blunting of the postoperative increase in heart rate andblood pressure. In the PCA group, the ratio of LF/HF remainedunchanged and the decrements in HRV variables persisted untilPOD 2. In the two groups, baroreflex sensitivities andpressure responses recovered preoperative values at POD 2. Conclusions. In contrast with PCA management, TEA using lowconcentrations of bupivacaine and fentanyl blunted cardiac sympatheticneural drive, resulting in vagal predominance, while HRV variableswere better restored after surgery. Br J Anaesth 2003; 91: 525–31