Parecoxib sodium has opioid-sparing effects in patients undergoing total knee arthroplasty under spinal anaesthesia

Background. This multicentre, double-blind, placebo-controlledstudy compared the opioid-sparing effectiveness and clinicalsafety of parecoxib sodium over 48 h, in 195 postoperativepatients after routine total knee replacement surgery. Methods. Elective total primary knee arthroplasty was performedunder spinal anaesthesia, with a single dose of spinal bupivacaine10–20 mg, and intraoperative sedation with midazolam0.5–1.0 mg i.v., or propofol <6 mg kg^–1h^–1. Patients were randomized to receive either parecoxibsodium 20 mg twice daily (bd) i.v. (n=65), parecoxib sodium40 mg bd i.v. (n=67), or placebo (n=63) at the completionof surgery, and after 12, 24, and 36 h. Morphine (1–2 mg)was taken by patient-controlled analgesia or by bolus dosesafter 30 min. Results. Patients receiving parecoxib sodium 20 mg bd and40 mg bd consumed 15.6% and 27.8% less morphine at 24 hthan patients taking placebo (both P<0.05). Both doses ofparecoxib sodium administered with morphine provided significantlygreater pain relief than morphine alone from 6 h (P<0.05).A global evaluation of study medication demonstrated a greaterlevel of satisfaction among patients taking parecoxib sodiumthan those taking placebo. Parecoxib sodium administered incombination with morphine was well tolerated. However, a reductionin opioid-type side-effects was not demonstrated in the parecoxibsodium groups. Conclusion. Parecoxib sodium provides opioid-sparing analgesiceffects in postoperative patients. Br J Anaesth 2003; 90: 166–72     

Fast-track cardiac anaesthesia in the elderly: effect of two different anaesthetic techniques on mental recovery

Elderly patients may be considered for ‘fast-track’cardiac anaesthesia, but can suffer psychological complicationsand slow recovery of mental function after surgery, which caninterfere with recovery. Reduced metabolism and changed distributionof anaesthetic and sedative agents can cause poor recovery.We made a prospective randomized comparison of mental function,haemodynamic stability and extubation and discharge times inelderly patients (65–79 yr) receiving two premedication,anaesthetic and sedative techniques. Patients received eitherpropofol (n=39) (fentanyl 10–15 µg kg^–1and propofol 2–6 mg kg^–1 intraoperativelyand a propofol infusion for 3 h postoperatively) or premedicationwith lorazepam followed by midazolam for anaesthesia (n=39)(fentanyl 10–15 µg kg^–1 and midazolam0.05–0.075 mg kg^–1 intraoperatively anda midazolam infusion for 3 h postoperatively). Impairmentof mental function was noted in 41% of patients in the propofolgroup and 83% in the lorazepam and midazolam group (P=0.001)18 h after extubation. Patients in the propofol group wereextubated earlier [1.4 (SD 0.6) vs 1.9 (0.8) h, P=0.02];and reached standard intensive care unit discharge criteria[7.6 (4.6) vs 14.2 (13) h, P=0.02] and hospital dischargecriteria [4.3 (1.0) vs 4.9 (1.1) days, P=0.04) sooner than patientsin the lorazepam and midazolam group, but actual discharge timesdid not differ between the groups. Haemodynamic values werestable in both groups.Br J Anesth 2001; 86: 68–76     

Evaluation of effects of magnesium sulphate in reducing intraoperative anaesthetic requirements

Background. The present randomized, placebo-controlled, double-blindstudy was designed to assess the effect of peroperatively administeredi.v. magnesium sulphate on anaesthetic and analgesic requirementsduring total i.v. anaesthesia. Methods. Eighty-one patients (36 women, 45 men) undergoing electivespinal surgery were included in one of two parallel groups.The magnesium group received magnesium sulphate 30 mg kg^–1as a bolus before induction of anaesthesia and 10 mg kg^–1h^–1 by continuous i.v. infusion during the operation period.The same volume of isotonic solution was administered to thecontrol group. Anaesthesia was maintained with propofol (administeredaccording to the bispectral index) and remifentanil (adjustedaccording to heart rate and arterial blood pressure) infusions. Results. A significant reduction in hourly propofol consumptionwas observed with magnesium administration. For example, themean infusion rate of propofol in the second hour of the operationwas 7.09 mg kg^–1 h^–1 in the controlgroup vs 4.35 mg kg^–1 h^–1 in themagnesium group (P<0.001). The magnesium group required significantlyless remifentanil (P<0.001) and vecuronium (P<0.001).No side-effects were observed with magnesium administration. Conclusion. The administration of magnesium led to a significantreduction in the requirements for anaesthetic drugs during totali.v. anaesthesia with propofol, remifentanil and vecuronium. Br J Anaesth 2002; 89: 594–8     

Predictive performance of computer-controlled infusion of remifentanil during propofol/remifentanil anaesthesia

Background. The predictive performance of the available pharmacokineticparameter sets for remifentanil, when used for target-controlledinfusion (TCI) during total i.v. anaesthesia, has not been determinedin a clinical setting. We studied the predictive performanceof five parameter sets of remifentanil when used for TCI ofremifentanil during propofol anaesthesia in surgical patients. Methods. Remifentanil concentration–time data that hadbeen collected during a previous pharmacodynamic interactionstudy in 30 female patients (ASA physical status I, aged 20–65 yr)who received a TCI of remifentanil and propofol during lowerabdominal surgery were used in this evaluation. The remifentanilconcentrations predicted by the five parameter sets were calculatedon the basis of the TCI device record of the infusion rate–timeprofile that had actually been administered to each individual.The individual and pooled bias [median performance error (MDPE)],inaccuracy [median absolute performance error (MDAPE)], divergenceand wobble of the remifentanil TCI device were determined fromthe pooled and intrasubject performance errors. Results. A total of 444 remifentanil blood samples were analysed.Blood propofol and remifentanil concentrations ranged from 0.5to 11 µg ml^–1 and 0.1 to 19.6 ng ml^–1respectively. Pooled MDPE and MDAPE of the remifentanil TCIdevice were –15 and 20% for the parameter set of Mintoand colleagues (Anesthesiology 1997; 86: 10–23), 1 and21%, –6 and 21%, and –6 and 19% for the three parametersets described by Egan and colleagues (Anesthesiology 1996;84: 821–33, Anesthesiology 1993; 79: 881–92, Anesthesiology1998; 89: 562–73), and –24 and 30% for the parameterset described by Drover and Lemmens (Anesthesiology 1998; 89:869–77). Conclusions. Remifentanil can be administered by TCI with acceptablebias and inaccuracy. The three pharmacokinetic parameter setsdescribed by Egan and colleagues resulted in the least biasand best accuracy. Br J Anaesth 2003; 90: 132–41     

Propofol 1% versus propofol 2% in children undergoing minor ENT surgery

Background. The induction characteristics of propofol 1% and2% were compared in children undergoing ENT surgery, in a prospective,randomized, double-blind study. Methods. One hundred and eight children received propofol 1%(n=55) or 2% (n=53) for induction and maintenance of anaesthesia.For induction, propofol 4 mg kg^–1 was injectedat a constant rate (1200 ml h^–1), supplementedwith alfentanil. Intubating conditions without the use of aneuromuscular blocking agent were scored. Results. Pain on injection occurred in 9% and 21% of patientsafter propofol 1% and 2%, respectively (P=0.09). Loss of consciousnesswas more rapid with propofol 2% compared with propofol 1% (47 svs 54 s; P=0.02). Spontaneous movements during inductionoccurred in 22% and 34% (P=0.18), and intubating conditionswere satisfactory in 87% and 96% (P=0.19) of children receivingpropofol 1% or 2%, respectively. There were no differences betweenthe two groups in respect of haemodynamic changes or adverseevents. Conclusions. For the end-points tested, propofol 1% and propofol2% are similar for induction of anaesthesia in children undergoingminor ENT surgery. Br J Anaesth 2003: 90: 375–7     

Cerebrospinal fluid and blood propofol concentration during total intravenous anaesthesia for neurosurgery

Background. The aim of this paper is to compare the propofolconcentration in blood and cerebrospinal fluid (CSF) in patientsscheduled for different neurosurgical procedures and anaesthetizedusing propofol as part of a total intravenous anaesthesia technique. Methods. Thirty-nine patients (ASA I–III) scheduled forelective intracranial procedures, were studied. Propofol wasinfused initially at 12 mg kg^–1 h^–1 and thenreduced in steps to 9 and 6 mg kg^–1 h^–1. Duringanaesthesia, bolus doses of fentanyl and cis-atracurium wereadministered as necessary. After tracheal intubation the lungswere ventilated to achieve normocapnia with an oxygen-air mixture(FI_O2=0.33). Arterial blood and CSF samples for propofol examinationwere obtained simultaneously directly after intracranial drainageinsertion and measured using high-performance liquid chromatography.The patients were divided into two groups depending on the typeof neurosurgery. The Aneurysm group consisted of 13 patientswho were surgically treated for ruptured intracranial aneurysm.The Tumour group was composed of 26 patients who were undergoingelective posterior fossa extra-axial tumour removal. Results. Blood propofol concentrations in both groups did notdiffer significantly (P>0.05). The propofol concentrationin CSF was 86.62 (SD 37.99) ng ml^–1 in the Aneurysm groupand 50.81 (26.10) ng ml^–1 in the Tumour group (P<0.005). Conclusions. Intracranial pathology may influence CSF propofolconcentration. However, the observed discrepancies may alsoresult from quantitative differences in CSF composition andfrom restricted diffusion of the drug in the CSF. Br J Anaesth 2003; 90: 84–6     

Addition of meperidine to bupivacaine for spinal anaesthesia for Caesarean section

Background. In a prospective, randomized, double-blind, placebo-controlledtrial, we investigated the effect of adding meperidine 10 mgto intrathecal bupivacaine on the duration of early postoperativeanalgesia in 40 patients having elective Caesarean section underspinal anaesthesia. Methods. Patients received intrathecal injection of 0.5% hyperbaricbupivacaine 2.0 ml plus either normal saline 0.2 ml (salinegroup) or 5% meperidine 0.2 ml (meperidine group). Afteroperation, all patients were given i.v. patient-controlled analgesiausing morphine. Results. The duration of effective analgesia, defined as thetime from intrathecal injection to first patient-controlledanalgesia demand, was greater in the meperidine group (mean234 min, 95% confidence interval 200–269 min)compared with the saline group (mean 125 min, 95% confidenceinterval 111–138 min; P<0.001). The 24 hmorphine requirement was similar in the two groups. The meperidinegroup had a greater incidence of intraoperative nausea or vomitingcompared with the saline group (11 vs 3; P=0.02). Conclusion. Addition of meperidine 10 mg to intrathecalbupivacaine for Caesarean section is associated with prolongedpostoperative analgesia but with greater intraoperative nauseaand vomiting. Br J Anaesth 2002; 88: 379–83     

Effect of sevoflurane/nitrous oxide versus propofol anaesthesia on somatosensory evoked potential monitoring of the spinal cord during surgery to correct scoliosis

Background. Use of intraoperative somatosensory evoked potential(SSEP) monitoring is helpful in spinal corrective surgery butmay be affected by anaesthetic drugs. An anaesthetic techniquethat has less effect on SSEP or allows faster recovery is anadvantage. We compared the effects on SSEP and the clinicalrecovery profiles of sevoflurane/nitrous oxide and propofolanaesthesia during surgery to correct scoliosis. Methods. Twenty adolescent patients were randomized into twogroups of 10. One group received sevoflurane–nitrous oxideanaesthesia and the other received propofol i.v. anaesthesia.An alfentanil infusion was used for analgesia in both groups. Results. Changes in anaesthetic concentration produced littleeffect on the latency of SSEP, but the effect on the variabilityof SSEP amplitude was significant (P<0.05). Sevoflurane produceda faster decrease in SSEP and a faster recovery than propofol(P<0.05). On emergence, patients who received sevofluranetended to have shorter recovery times to eye opening (mean 5.1vs 20.6 min, P=0.09) and toe movement (mean 7.9 vs 15.7 min,P=0.22). Those who had received sevoflurane were significantlymore lucid and cooperative in recovery. Conclusions. Sevoflurane produces a faster decrease and recoveryof SSEP amplitude as well as a better conscious state on emergencethan propofol. Br J Anaesth 2002; 88: 502–7     

BIS guided sedation with propofol during spinal anaesthesia: influence of anaesthetic level on sedation requirement

Background. In this prospective, clinical study we tested thehypothesis whether two different doses of spinal administeredbupivacaine and accordingly, two different levels of spinalanaesthesia can affect the dose requirement of propofol duringBIS guided sedation. Methods. Fifty women undergoing vaginal hysterectomy (high spinalgroup, HS) or transvaginal tape (TVT) procedure for urinaryincontinence (low spinal group, LS) under spinal anaesthesiawere enrolled to the study. In group HS, 17.5 mg and in groupLS, 7.5 mg of hyperbaric bupivacaine were given intrathecally.After 15 min to obtain the appropriate level of spinal anaesthesia,propofol infusion was started at a rate of 100 µg kg^–1min^–1 to reach a BIS level of less than 75 (onset time),and titrated to maintain the BIS value between 65 and 75. Propofolinfusion was stopped 45 min after placing the spinal to measurethe time to reach a BIS level of 90 (recovery time). Results. Median anaesthetic level was T3 (T1–4) in theHS group and T10 (T9-11) in the LS group. In both the HS andthe LS groups, onset time was 226 (47) vs 273 (48) s (P=0.001),recovery time was 234 (47) vs 202 (56) s (P=0.03), total doseof propofol was 2.17 (0.43) vs 3.14 (0.56) mg kg^–1 (P<0.001),respectively. Conclusion. A high spinal block obtained with hyperbaric bupivacaine17.5 mg was associated with a faster onset, delayed recoveryand lower doses of propofol sedation compared with a low spinalblock with 7.5 mg of the same drug.     

Antagonism of neuromuscular blockade but not muscle relaxation affects depth of anaesthesia

Background. Conflicting effects of neuromuscular blocking drugsand anticholinesterases on depth of anaesthesia have been reported.Therefore we evaluated the effect of atracurium and neostigmineon bispectral index (BIS) and middle-latency auditory evokedpotentials (AAI). Methods. We studied 40 patients (ASA I–II) aged 18–69yr. General anaesthesia consisted of propofol and remifentanilby target-controlled infusion and neuromuscular function wasmonitored by electromyography. When BIS reached stable values,patients were randomly assigned to one of two groups. Group1 received atracurium 0.4 mg kg^–1 and, 5 min later, thesame volume of NaCl 0.9%; group 2 received saline first andthen atracurium. When the first twitch of a train of four reached10% of control intensity, patients were again randomized: onegroup (N) received neostigmine 0.04 mg kg^–1 and glycopyrrolate0.01 mg kg^–1, and the control group (G) received onlyglycopyrrolate. Results. Injection of atracurium or NaCl 0.9% had no effecton BIS or AAI. After neostigmine–glycopyrrolate, BIS andAAI increased significantly (mean maximal change of BIS 7.1[SD 7.5], P<0.001; mean maximal change of AAI 9.7 [10.5],P<0.001). When glycopyrrolate was injected alone BIS andAAI also increased (mean maximal change of BIS 2.2 [3.4], P=0.008;mean maximal change of AAI 3.5 [5.7], P=0.012), but this increasewas significantly less than in group N (P=0.012 for BIS; P=0.027for AAI). Conclusion. These data suggest that neostigmine alters the stateof propofol–remifentanil anaesthesia and may enhance recovery.     

Clonidine decreases propofol requirements during anaesthesia: effect on bispectral index

Assessment of the effect of clonidine on depth of anaesthesiais difficult because clonidine combines analgesic, sedativeand direct haemodynamic effects. We thus evaluated the influenceof clonidine on the bispectral index (BIS) and its potentialdose-sparing effect on propofol. After induction of anaesthesiawith target-controlled infusion of propofol and obtaining anunchanged bispectral index (pre-BIS), clonidine 4 µg kg^–1or placebo was administered randomly to 50 patients in a double-blindmanner. Subsequently, if there was a decrease in BIS we reducedthe target concentration of propofol until pre-BIS was reached.The pre-BIS was maintained and a remifentanil infusion was addedduring surgery. The courses of the BIS, heart rate and bloodpressure were recorded and the total amounts of intra-operativepropofol and remifentanil were determined. Assessment of implicitmemory during anaesthesia was performed with an auditory implicitmemory test consisting of item sequences. Administration ofclonidine resulted in a decrease in the BIS from 45 (SD 4) to40 (6) (P<0.001), which allowed a reduction of propofol targetconcentration from 3.3 (0.6) to 2.7 (0.7) µg ml^–1(P<0.001) and measured propofol concentration from 2.9 (0.6)to 2.5 (0.7) µg ml^–1 (P=0.009) in order tomaintain the pre-BIS value. During subsequent surgery, propofolrequirements were reduced by 20% (P=0.002) in the clonidinegroup and a similar amount of remifentanil was used in eachgroup. The increase in anaesthetic depth given by clonidinecan therefore be measured with bispectral EEG analysis and allowsreduction of the propofol dose to achieve a specific depth ofanaesthesia. Br J Anaesth 2001; 86: 627–32     

Rate of injection through whitacre needles affects distribution of spinal anaesthesia

A prospective, randomized, double-blind study was performedto investigate whether altering the rate of injection of localanaesthetic through a Whitacre needle had any effect on thespinal block achieved. Twenty patients scheduled for electiveurological surgery under spinal anaesthesia received an injectionof 3 ml of 0.5% plain bupivacaine either by hand (fast)over 10 s (18 ml min^–1) or by infusionpump (slow) over 3 min (1 ml min^–1). Allpatients were in the sitting position both during insertionof the spinal needle and for 3 min after the start of spinalinjection, and they then changed to the supine position. Theslow injection group achieved peak sensory block earlier, aftera median interval of 20 (95% confidence interval 12.5–30) minvs 30 (22.5–45) min (P<0.05) for the fast group. Thelevel of peak sensory block was similar: T3.5 (T2–T4.5)vs T4 (T1.5–T6.5). The time to lowest mean arterial pressureoccurred earlier in the slow group, at 10 (8 to 18) vs 20 (15–31) min(P<0.05). Duration of the motor block was shorter in theslow group: 180 (152–242) vs 270 (225–300). We concludethat a slow spinal injection of plain bupivacaine results ina block of more rapid onset and recovery. Br J Anaesth 2001; 86: 245–8     

Comparison of remifentanil and alfentanil during anaesthesia for patients undergoing direct laryngoscopy without intubation

Background. Remifentanil and alfentanil are opioids often usedduring direct laryngoscopy (DL). This prospective, randomizedstudy compared these agents with respect to haemodynamic andBispectral Index (BIS) responses, glottic visualization, andrapidity of recovery (spontaneous ventilation, eye opening)in DL without intubation. Methods. A total of 60 patients undergoing DL were randomizedinto two groups: remifentanil (R) and alfentanil (A). Anaesthesiawas induced with propofol 2.5 mg kg^–1 and the opioid wasadministered 1 min later (R=2 µg kg^–1 or A=30 µgkg^–1 over 30 s). DL was commenced 1 min after (correspondingto 3 min after the beginning of induction). Glottic visualization,opioid and/or propofol re-injection, spontaneous ventilationrecovery, and eye opening were recorded. Results. During DL, mean arterial pressure (MAP) increased by6% in the R group vs 20% in the A group (P<0.05) when comparedwith post-induction values without affecting heart rate or BIS.No significant difference was observed between groups with respectto glottic exposure, opioid and/or propofol re-injection, andspontaneous ventilation recovery (mean (SEM) 3.8 (0.6) min,R group vs 3.2 (0.7) min, A group, NS) or eye opening (7.1 (1.1)min, R group vs 7.4 (0.9) min, A group, NS). Thirty minutesafter postanaesthesia care unit (PACU) admission, MAP returnedto its pre-induction value in the R group (104 (3) vs 109 (3)at baseline, NS), whereas in the A group MAP remained significantlylower at this time point (96 (4) vs 106 (3) at baseline, P<0.05). Conclusion. This study showed that only remifentanil preventedMAP increase without adverse effects such as bradycardia duringDL, and prevented MAP decrease 30 min after PACU admission. Br J Anaesth 2003; 91: 421–3     

Sevoflurane and propofol decrease intraocular pressure equally during non-ophthalmic surgery and recovery

Background. To provide good control of intraocular pressure(IOP) during anaesthesia and surgery, we conducted a study comparingthe effects on IOP during maintenance and recovery of sevofluranevs propofol anaesthesia in 33 patients (ASA I–II) undergoingelective non- ophthalmic surgery. Methods. Anaesthesia was induced with propofol 2 mg kg^–1,fentanyl 2 µg kg^–1 and vecuronium 0.1 mg kg^–1.Patients were allocated randomly to receive either propofol4–8 mg kg^–1 h^–1 (group P; n=16)or 1.5–2.5 vol% sevoflurane (group S; n=17) for maintenanceof anaesthesia. Fentanyl 2–4 µg kg^–1was added if necessary. The lungs were ventilated with 50% airin oxygen. Blood pressure, heart rate, oxygen saturation andend-tidal carbon dioxide were measured before and throughoutanaesthesia and in the recovery room. IOP was determined withapplanation tonometry (Perkins) by one ophthalmologist blindedto the anaesthetic technique. Results. There was a significant decrease in IOP after inductionand during maintenance of anaesthesia in both groups. No significantdifferences in IOP between the two groups was found. Conclusion. Sevoflurane maintains the IOP at an equally reducedlevel compared with propofol. Br J Anaesth 2002; 89: 764–6     

Comparison of the effects of sevoflurane and propofol on cooling and rewarming during deliberate mild hypothermia for neurosurgery

Background. Because the time available for cooling and rewarmingduring deliberate mild hypothermia is limited, studies of therate of the cooling and rewarming are useful. The decrease incore hypothermia caused by heat redistribution depends on theanaesthetic agent used. We therefore investigated possible differencesbetween sevoflurane and propofol on the decrease and recoveryof core temperature during deliberate mild hypothermia for neurosurgery. Methods. After institutional approval and informed consent,26 patients were assigned randomly to maintenance of anaesthesiawith propofol or sevoflurane. Patients in the propofol group(n=13) received propofol induction followed by a continuousinfusion of propofol 3–5 mg kg^–1 h^–1.Patients in the sevoflurane group (n=13) received propofol inductionfollowed by sevoflurane 1–2%. Nitrous oxide and fentanylwere also used for anaesthetic maintenance. After inductionof anaesthesia, patients were cooled and tympanic membrane temperaturewas maintained at 34.5°C. After surgery, patients were activelyrewarmed. Results. There was no difference in the rate of decrease andrecovery of core temperature between the groups. There was alsono difference in skin surface temperature gradient (forearmto fingertip), heart rate and mean arterial blood pressure betweenthe groups. Conclusions. Sevoflurane-based anaesthesia did not affect coolingand rewarming for deliberate mild hypothermia compared withpropofol-based anaesthesia. Br J Anaesth 2003; 90: 32–8     

Randomized controlled study of colloid preload before spinal anaesthesia for caesarean section

We randomized women having elective Caesarean section to receiveeither no preload (control group, n=33) or 4% gelatin solution(Gelofusine) 15 ml kg^–1 (colloid group, n=35)i.v. before spinal anaesthesia. Intravenous metaraminol wastitrated at 0.25–0.75 mg min^–1 to maintainsystolic arterial pressure (SAP) in the target range 90–100%of baseline after the spinal injection. The control group requiredmore vasopressor in the first 10 min [median 1.7 (range 0–2.9)mg vs 1.4 (0–2.8), P=0.02] at a greater maximum infusionrate [0.5 (0–0.75) vs 0.25 (0–0.5) mg min^–1,P=0.0005] and had a lower minimum SAP [90 (51–109) vs101 (75–127) mm Hg, P=0.006] than the colloid group. Nauseawas less frequent in the colloid group (6 vs 24%) but neonataloutcome was similar in the two groups. Colloid preload improvedhaemodynamic stability but did not affect neonatal outcome whenarterial pressure was maintained with an infusion of metaraminolduring spinal anaesthesia for Caesarean section. Br J Anaesth 2001; 87: 772–4     

Comparison of articaine and bupivacaine/lidocaine for single medial canthus peribulbar anaesthesia

In a single-centre, randomized, double-blind study, we comparedthe efficacy of 2% articaine with that of a mixture of 0.5%bupivacaine and 2% lidocaine for peribulbar anaesthesia in cataractsurgery, using a single medial canthus injection technique.Eighty-two patients were allocated randomly to receive 7–9 mlof a mixture of 0.5% bupivacaine and 2% lidocaine or an equalvolume of 2% articaine with 1:200 000 epinephrine. Hyaluronidase30 iu ml^–1 was added to both solutions. Thedegree of akinesia was scored 1, 5 and 10 min after theblock, at the end of surgery and at discharge from the day caseunit. Primary outcome measures were the difference in ocularmovement scores 5 min after block and the need for supplementaryinferolateral injections. There was greater akinesia in thearticaine group at 5 min (P=0.01). Ten patients (24%) inthe articaine group and 21 patients (51%) in the bupivacaine/lidocainegroup required a supplementary injection (P=0.02). The mean(SD) volume of local anaesthetic required to achieve adequateblock for surgery was 9.7 (2.1) ml in the articaine group and11.0 (2.2) ml in the bupivacaine/lidocaine group (P=0.01). Therewas a faster offset of akinesia after surgery in the articainegroup (P=0.01). There were no differences between groups inthe incidence of reported pain or of minor complications. Inour study, 2% articaine with 1:200 000 epinephrine wassafe and efficacious for single medial canthus peribulbar anaesthesia. Br J Anaesth 2001; 87: 584–7     

Suppressive effect of nitrous oxide on motor evoked potentials can be reversed by train stimulation in rabbits under ketamine/fentanyl anaesthesia, but not with additional propofol

The effect of nitrous oxide on myogenic motor evoked potentials(MEPs) after multipulse stimulation is controversial. We investigatedthe effects of propofol in this paradigm. MEPs were elicitedelectrically by a single pulse and by trains of three and fivepulses in rabbits anaesthetized with ketamine and fentanyl.Nitrous oxide 30–70% was given and MEPs were recorded.After washout of nitrous oxide, propofol was given as a bolusof 10 mg kg^–1 followed by 0.8 (n=9) or 1.6 mg kg^–1 min^–1(n=8) as a continuous infusion. Nitrous oxide was then readministeredand MEPs were recorded. Without propofol, nitrous oxide significantlyreduced the amplitude of MEPs dose-dependently, but this effectwas reversed by multipulse stimulation. Administration of low-dosepropofol enhanced nitrous oxide-induced suppression, and thiseffect was reversed by five-pulse stimulation. However, high-dosepropofol produced a greater increase in suppression, such thateven five-pulse stimulation did not overcome the suppression.The results suggest that the degree of reversal of nitrous oxide-inducedMEP suppression produced by multipulse stimulation is affectedby the administration of propofol. Br J Anaesth 2001; 86: 395–402     

Effects of intramuscular administration of lidocaine or bupivacaine on induction and maintenance doses of propofol evaluated by bispectral index

Background. Interest in combining local and general anaesthesiahas lead to studies investigating possible interactions. Ina prospective, randomized, double-blind study, we tested whetherlocal anaesthetics administered i.m. potentiate the hypnoticeffect of propofol. Methods. Sixty patients (three groups, n=20) undergoing lowerabdominal surgery with total i.v. propofol anaesthesia wereinvestigated. Patients in Group B received i.m. bupivacaine(5 mg ml^–1) 1 mg kg^–1, patients in Group Lreceived i.m. lidocaine (100 mg ml^–1) 2 mg kg^–1and patients in Group C received i.m. saline 5 ml beforeoperation. Hypnosis was measured with bispectral index (BIS). Results. The induction (BIS <45), and the maintenance dosesof propofol (BIS between 40 and 50) were significantly lessin Group B and Group L compared with the control group. Inductiondoses were 1.58 (SD 0.39), 1.56 (0.24) and 2.03 (0.33) mg kg^–1respectively; P<0.0001. Maintenance doses were 6.33 (2.06),7.08 (1.23) and 9.95 (2.02) mg kg^–1 respectively in thefirst hour; P<0.0001. Groups B and L were associated withan attenuated haemodynamic response to both induction and intubation. Conclusion. I.M. administered local anaesthetics are associatedwith a decrease in both the induction and maintenance dosesof propofol during total i.v. anaesthesia and a reduction inhaemodynamic responses. Br J Anaesth 2002; 89: 849–52     

Dextromethorphan and intrathecal morphine for analgesia after Caesarean section under spinal anaesthesia

Background. Dextromethorphan is an N-methyl-D-aspartic acidantagonist which can attenuate acute pain with few side-effects.In this prospective, randomized, double-blind study of dextromethorphanand intrathecal morphine, we investigated postoperative pain,pruritus, nausea and vomiting in women undergoing Caesareansection under spinal anaesthesia. Methods. Women were allocated randomly to one of six groups,to receive intrathecal morphine 0.05, 0.1 or 0.2 mg plusoral dextromethorphan 60 mg or placebo. Results. The addition of dextromethorphan did not reduce postoperativepain scores (P=0.83). Compared with women receiving intrathecalmorphine 0.05 mg, women receiving higher doses had a significantlyhigher incidence of nausea and vomiting [odds ratio for intrathecalmorphine 0.1 mg, 4.0 (95% confidence interval 1.2–14.1);for intrathecal morphine 0.2 mg, 7.9 (2.3–27.1)].Compared with women receiving intrathecal morphine 0.05 mg,women receiving higher doses also had a significantly higherincidence of pruritus [odds ratio for intrathecal morphine 0.1 mg,3.2 (95% confidence interval 1.3–8.2); for intrathecalmorphine 0.2 mg, 3.7 (1.4–9.5)]. Women receivingdextromethorphan had a lower incidence of nausea and vomiting[odds ratio 2.6 (1.1–6.3)]. Conclusions. Postoperative pain after Caesarean section underspinal anaesthesia was not reduced by the addition of oral dextromethorphanto a multimodal approach including intrathecal morphine. Br J Anaesth 2003; 90: 653–8