Comparison of articaine and bupivacaine/lidocaine for sub-Tenon's anaesthesia in cataract extraction

Background. Articaine is the most widely used local anaestheticfor dental anaesthesia in Germany, Italy and The Netherlandsand has recently been introduced and licensed for dental usein the UK. We have previously shown articaine to be superiorto a standard mixture of bupivacaine 0.5%/lidocaine 2% for peribulbaranaesthesia. Sub-Tenon’s anaesthesia arguably providesa safer method of anaesthetic delivery for cataract surgery.A blunt cannula is used in this technique, thus greatly reducingthe risk of globe perforation, intrathecal injection and sight-threateningperiocular haemorrhage. Methods. We compared articaine and bupivacaine/lidocaine forsub-Tenon’s anaesthesia in cataract surgery. Results. Sub-Tenon’s anaesthesia using articaine 2% resultedin a more rapid onset of motor block compared with a bupivacaine/lidocaine(P=0.0076). Ocular movement scores were significantly lowerfrom 2 min after injection until the end of surgery (P=0.031ANOVA). Conclusion. Articaine 2% is safe and effective for sub-Tenon’sanaesthesia and is a suitable alternative to the traditionalbupivacaine 0.5%/lidocaine 2% mixture. Br J Anaesth 2004; 92: 228–30     

Sub-Tenon's administration of local anaesthetic: a review of the technique

Br J Anaesth 2003; 90: 787–93     

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     

Spread of injectate with superficial cervical plexus block in humans: an anatomical study

Background. This study was undertaken to investigate why thesuperficial cervical plexus block for carotid endarterectomyis so effective. Initial consideration would suggest that asuperficial injection would be unlikely to block all terminalfibres of relevant nerves. One possibility is that the localanaesthetic crosses the deep cervical fascia and blocks thecervical nerves at their roots. Methods. Superficial cervical plexus blocks (injections justbelow the investing fascia) were performed using methylene blue(30 ml) in four cadavers. In one additional control cadaver,a deep cervical plexus injection was performed. In a secondcontrol cadaver, a subcutaneous injection (superficial to investingfascia) was performed at the posterior border of the sternomastoidmuscle. Results. Anatomical dissection showed that with superficialblock there was spread of the dye to structures beneath thedeep cervical fascia. In the first control, dye remained inthe deep cervical space. In the second control, dye remainedsubcutaneous. Conclusions. The superficial cervical space communicates withthe deep cervical space and this may explain the efficacy ofthe superficial block. The method of communication remains unknown.Our findings also indicate that the suitable site of injectionfor the superficial cervical plexus block is below the investingfascia of the neck, and not just subcutaneous. Br J Anaesth 2003; 91: 733–5     

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     

Comparison of L-bupivacaine 0.75% and lidocaine 2% with bupivacaine 0.75% and lidocaine 2% for peribulbar anaesthesia

Background. L-Bupivacaine has a safer side-effect profile thanbupivacaine. We compared the efficacy of a mixture of L-bupivacaine0.75% and lidocaine 2% with bupivacaine 0.75% and lidocaine2% for peribulbar anaesthesia in cataract surgery. Methods. Ninety patients were allocated randomly to receive8 ml of a mixture of equal parts of bupivacaine 0.75% and lidocaine2% or an equal volume of L-bupivacaine and lidocaine 2%. Hyaluronidase15 IU ml^–1 was added to both solutions. Results. There were significant differences between the groupsin clinical end-points. The median time at which the block wasadequate to start surgery was 4 min (interquartile range4–8 min) in the bupivacaine group and 8 min (5–12min) in the L-bupivacaine group (P=0.002). Median ocular andeyelid movement scores were similarly significantly decreasedin the bupivacaine group compared with the L-bupivacaine groupat all times (P0.03). There was no difference between groupsin the incidence of minor complications. Conclusions. A mixture of bupivacaine 0.75% and lidocaine 2%provides faster onset time than a mixture of L-bupivacaine 0.75%and lidocaine 2%. Br J Anaesth 2003; 90: 512–14     

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     

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     

High plasma ropivacaine concentrations after fascia iliaca compartment block in children

Background. The pharmacokinetic profile of local anaestheticsis influenced by the mode of administration. We sought to comparethe pharmacokinetics of two doses of ropivacaine after fasciailiaca compartment (FIC) block in children. Methods. In this prospective, double-blind study, children receivedan FIC block as a part of their anaesthetic management duringelective orthopaedic surgery on the thigh. They were randomizedto receive ropivacaine 0.7 ml kg^–1 using either a0.375% or 0.5% solution. Venous blood samples were drawn upto 6 h after injection. Plasma concentrations of ropivacainewere measured by gas–liquid chromatography. Results. Six children (10.2 (range 5–15) yr, 35.6 (SD10) kg were included. FIC block provided satisfactory peroperativepain relief. No signs of toxicity were observed, but high maximalplasma concentrations (C_max 4.33–5.6 µg ml^–1),were observed for three of four patients in the ropivacaine0.5% group. The two patients in the 0.375% group showed valueswithin the safe range (C_max 0.66 and 0.98 µg ml^–1respectively). Even though no toxic effects were observed, theseresults led us to discontinue the study. Conclusions. The administration of ropivacaine 3.5 mg kg^–1can be associated with sustained high plasma concentrationsof ropivacaine, outside the tolerable range. In view of theseresults, we recommend the use of lower ropivacaine dosage duringFIC block in children. Br J Anaesth 2004: 92: 416–18     

Superficial or deep cervical plexus block for carotid endarterectomy: a systematic review of complications

Carotid endarterectomy is commonly conducted under regional(deep, superficial, intermediate, or combined) cervical plexusblock, but it is not known if complication rates differ. Weconducted a systematic review of published papers to assessthe complication rate associated with superficial (or intermediate)and deep (or combined deep plus superficial/intermediate). Thenull hypothesis was that complication rates were equal. Complicationsof interest were: (1) serious complications related to the placementof block, (2) incidence of conversion to general anaesthesia,and (3) serious systemic complications of the surgical-anaestheticprocess. We retrieved 69 papers describing a total of 7558 deep/combinedblocks and 2533 superficial/intermediate blocks. Deep/combinedblock was associated with a higher serious complication raterelated to the injecting needle when compared with the superficial/intermediateblock (odds ratio 2.13, P = 0.006). The conversion rate to generalanaesthesia was also higher with deep/combined block (odds ratio5.15, P < 0.0001), but there was an equivalent incidenceof other systemic serious complications (odds ratio 1.13, P= 0.273; NS). We conclude that superficial/intermediate blockis safer than any method that employs a deep injection. Thehigher rate of conversion to general anaesthesia with the deep/combinedblock may have been influenced by the higher incidence of directcomplications, but may also suggest that the superficial/combinedblock provides better analgesia during surgery.     

Effects of ultrasound guidance on the minimum effective anaesthetic volume required to block the femoral nerve

Background: We tested the hypothesis that ultrasound guidance may reducethe minimum effective anaesthetic volume (MEAV₅₀) of ropivacaine0.5% required to block the femoral nerve compared with nervestimulation guidance. Methods: After standard premedication and sciatic nerve block were given,60 patients undergoing knee arthroscopy were randomly allocatedto receive a femoral nerve block with ropivacaine 0.5% usingeither nerve stimulation (group NS, n = 30) or ultrasound (groupUS, n = 30) guidance. The volume of the injected solution wasvaried for consecutive patients based on an up-and-down staircasemethod according to the response of the previous patient. Theinitial volume was 12 ml. A double-blinded observer evaluatedthe occurrence of complete loss of pinprick sensation in thefemoral nerve distribution, with concomitant block of the quadricepsmuscle: positive or negative responses within 30 min after theinjection determined a 3 ml decrease or increase for the nextpatient, respectively. Results: The mean (SD) MEAV₅₀ for femoral nerve block was 15 (4) ml (95%CI, 7–23 ml) in group US and 26 (4) ml (95% CI, 19–33ml) in group NS (P = 0.002). The effective dose in 95% of cases(ED₉₅) calculated with probit transformation and logistic regressionanalysis was 22 ml (95% CI, 13–36 ml) in group US, and41 ml (95% CI, fs 24–66 ml) in group NS. Conclusions: Ultrasound guidance provided a 42% reduction in the MEAV ofropivacaine 0.5% required to block the femoral nerve as comparedwith the nerve stimulation guidance.     

A comparison of plasma levobupivacaine concentrations following transversus abdominis plane block and rectus sheath block

Levobupivacaine is commonly used as the local anaesthetic of choice in peripheral nerve blocks, but its pharmacokinetics have not been fully investigated. We compared the changes in plasma concentrations of levobupivacaine following transversus abdominis plane block and rectus sheath block. Fifty woman undergoing laparoscopy were randomly allocated to receive either a transversus abdominis plane block or an rectus sheath block. In both groups, 2.5 mg.kg^?1 levobupivacaine was administered, and blood samples were obtained 15 min, 30 min, 60 min and 120 min after injection. The mean maximum plasma concentration (Cmax) and mean time to reach Cmax (Tmax) as determined by non‐linear regression analysis were 1.05 μg.ml^?1 and 32.4 min in the transversus abdominis plane group and 0.95 μg.ml^?1 and 60.9 min in the rectus sheath group, respectively. The plasma concentration of levobupivacaine peaked earlier in the transversus abdominis plane group than in the rectus sheath group and the maximum plasma concentration depended on the dose administered but not the procedure.     

Axillary brachial plexus block for perioperative analgesia in 250 children

A cannula technique for axillary brachial plexus block in combination with general anaesthesia has been in use since 1994 for children undergoing surgical correction of congenital hand anomalies. During a 4-year period data were collected on 250 procedures in 185 patients of median age 3 years detailing the block technique and the intraoperative and postoperative analgesic requirements. Fifteen patients (6%) required supplemental intravenous opioid intraoperatively and this is taken as a marker of failure of the block. Ninety-five patients (38%) required postoperative codeine phosphate with a mean time to receiving codeine phosphate of 9 h. Postoperative pain was controlled in this series with oral analgesia in all but six patients who received parenteral codeine. It is proposed that a cannula technique is an effective and safe method of producing axillary brachial plexus block in children.     

Double-blind comparison of ropivacaine 7.5 mg ml(-1) with bupivacaine 5 mg ml(-1) for sciatic nerve block

Two groups of 12 patients had a sciatic nerve block performedwith 20 ml of either ropivacaine 7.5 mg ml^–1 or bupivacaine5 mg ml^–1. There was no statistically significant differencein the mean time to onset of complete anaesthesia of the footor to first request for post-operative analgesia. The qualityof the block was the same in each group. Although there wasno statistically significant difference in the mean time topeak plasma concentrations the mean peak concentration of ropivacainewas significantly higher than that of bupivacaine. There wereno signs of systemic local anaesthetic toxicity in any patientin either group. Br J Anaesth 2001; 86: 674–7     

Comparison of 1% and 2% lidocaine epidural anaesthesia combined with sevoflurane general anaesthesia utilizing a constant bispectral index

Background. The authors compared the effects of epidural anaesthesiawith lidocaine 1% and lidocaine 2% on haemodynamic variables,sevoflurane requirements, and stress hormone responses duringsurgery under combined epidural/general anaesthesia with bispectralindex score (BIS) kept within the range 40–50. Methods. Thirty-three patients undergoing lower abdominal surgerywere randomly divided into two groups to receive lidocaine 1%or 2% by epidural with sevoflurane general anaesthesia. Sevofluranewas adjusted to achieve a target BIS of 40–50 during maintenanceof anaesthesia with nitrous oxide 60% in oxygen. Measurementsincluded the inspired (FI_SEVO) and the end-tidal sevofluraneconcentrations (E'_SEVO), blood pressure (BP), and heart rate(HR) before surgery and every 5 min during surgery for2 h. Plasma samples were taken immediately before and duringsurgery for measurements of catecholamines, cortisol, and lidocaine. Results. During surgery, both groups were similar for HR, BPand BIS, but FI_SEVO and E'_SEVO were significantly higher andmore variable with lidocaine 1% than with 2%. Intraoperativeplasma concentrations of epinephrine and cortisol were foundto be higher with lidocaine 1% as compared with 2%. Conclusions. To maintain BIS of 40–50 during combinedepidural/general anaesthesia for lower abdominal surgery, sevofluraneconcentrations were lower and less variable with lidocaine 2%than with 1%. In addition, the larger concentration of lidocainesuppressed the stress hormone responses better. Br J Anaesth 2003; 91: 825–9     

Articaine versus lidocaine plus bupivacaine for peribulbar anaesthesia in cataract surgery

Background. We compared the efficacy and safety of articaine2% with a mixture of lidocaine 2% and bupivacaine 0.5% withouthyaluronidase for peribulbar anaesthesia in cataract surgery. Method. In this double-blind randomized clinical study, 58 cataractpatients were allocated to receive either articaine 2% withepinephrine 1:200 000 or a mixture of equal parts of lidocaine2% with epinephrine 1.25:100 000 and bupivacaine 0.5%. Ocularand eyelid movement scores, the number of supplementary injections,total volume of solution used and pain and complications duringinjection and surgery were used as clinical end-points. Results. Articaine produced greater akinesia after 5 min (P=0.03).Eighteen patients (60%) in the articaine group and 26 (93%)in the lidocaine/bupivacaine group required a second injection(P=0.003). A third injection was needed by two patients (7%)in the articaine group and 12 (43%) in the lidocaine/bupivacainegroup (P=0.001). The total mean volume of local anaestheticrequired to achieve akinesia was mean 9.4 (SD 1.7) ml in thearticaine group and 11.28 (1.86) ml in the lidocaine/bupivacainegroup (P<0.001). Median pain score was lower in the articainegroup than in lidocaine/bupivacaine group during injection (P=0.004)and surgery (P=0.014). There was no difference between the groupsfor the incidence of complications. Conclusion. Articaine 2% without hyaluronidase is more advantageousthan a mixture of lidocaine 2% and bupivacaine 0.5% withouthyaluronidase for peribulbar anaesthesia in cataract surgery. Br J Anaesth 2004; 92: 231–4     

Randomized double-blind clinical trial comparing topical and sub-Tenon's anaesthesia in routine cataract surgery

Background. Several local anaesthetic techniques are availablefor cataract surgery. Recently, topical anaesthesia has gainedin popularity. A randomized trial was designed to compare patientdiscomfort and intraoperative complications following routinecataract surgery under topical or sub-Tenon's anaesthesia. Methods. A randomized double-blinded placebo-controlled clinicaltrial of 210 patients assigned to either a sub-Tenon's group(sub-Tenon's anaesthesia with placebo topical balanced saltsolution, n=140) or a topical anaesthesia group (topical anaesthesiawith placebo sub-Tenon's injection of balanced salt solution,n=70) was carried out. All patients underwent phacoemulsificationwith intraocular lens implantation. Patients in the sub-Tenon'sgroup received a single injection (3 ml) of a combination oflidocaine 2% (2 ml) and bupivacaine 0.75% (1 ml), and four dosesof topical placebo (balanced salt solution). Patients in thetopical anaesthesia group received four doses of topical proxymethocaine0.5% and a placebo sub-Tenon's injection (3 ml) of balancedsalt solution. No intracameral injection of local anaestheticwas given. A 10-point visual analogue pain scale was used preoperativelyand for postoperative pain assessment immediately after theoperation and 30 min postoperatively. The intraoperative complicationsin the two groups were recorded. Results. The mean pain score immediately after surgery was 2.42(SD 2.2) in the sub-Tenon's group and 3.44 (2.3) in the topicalanaesthesia group (P=0.0043). The mean pain score 30 min aftersurgery was 1.24 (1.7) in the sub-Tenon's group and 2.25 (2.2)in the topical anaesthesia group (P=0.0009). Conclusions. Patients undergoing cataract surgery under topicalanaesthesia experience more postoperative discomfort than patientsreceiving sub-Tenon's anaesthesia. Surgery-related complicationswere similar in both groups.      

Spinal anaesthesia indirectly depresses cortical activity associated with electrical stimulation of the reticular formation

Background. Neuraxial blockade reduces the requirements forsedation and general anaesthesia. We investigated whether lidocainespinal anaesthesia affected cortical activity as determinedby EEG desynchronization that occurs following electrical stimulationof the midbrain reticular formation (MRF). Methods. Six goats were anaesthetized with isoflurane, and cervicallaminectomy performed to permit spinal application of lidocaine.The EEG was recorded before, during and after focal electricalstimulation (0.1, 0.2, 0.3 and 0.4 mA) in the MRF while keepingthe isoflurane concentration constant. Results. During lidocaine spinal anaesthesia, the spectral edgefrequency (SEF) after MRF electrical stimulation (13.6 (SD 1.0)Hz, averaged across all stimulus currents) was less than theSEF during control and recovery periods (18.6 (3.6) Hz and 17.2(2.2) Hz, respectively; P<0.05). Bispectral index valueswere similarly affected: 69 (10) at control compared with 55(6) during the spinal block (P<0.05). Conclusions. These results suggest that lidocaine spinal anaesthesiablocks ascending somatosensory transmission to mildly depressthe excitability of reticulo–thalamo–cortical arousalmechanisms. Br J Anaesth 2003; 91: 233–8     

Effect of peri- and postoperative epidural anaesthesia on pain and gastrointestinal function after abdominal hysterectomy

In a double blind study we have investigated the effects ofepidural local anaesthesia (LA), when added to general anaesthesia(GA) and postoperative paracetamol and NSAID, on postoperativepain and gastrointestinal function in patients undergoing openhysterectomy. Sixty patients were randomized into three studygroups: GA, and postoperative paracetamol and NSAID (GA, n=20);GA, paracetamol, NSAID, intraoperative epidural lidocaine and24-h postoperative epidural saline (Saline, n=20); or GA, paracetamol,NSAID, intraoperative epidural lidocaine and 24-h postoperativeepidural bupivacaine (Bupi, n=20). Patients were observed for72 h postoperatively. Pain at rest, during cough, and mobilization,request for supplementary morphine, and time to first postoperativeflatus, was reduced in patients receiving 24-h postoperativeepidural anaesthesia, compared with the two other groups. However,these effects of epidural LA, were not sustained beyond theperiod of infusion, and no differences in PONV, time to firstpostoperative defecation, mobilization or time to dischargefrom hospital were observed between groups. A 24 h postoperativeepidural infusion with bupivacaine, when added to postoperativeparacetamol and NSAID, reduces pain and opioid requirements,but has only limited effects on gastrointestinal function andpatient recovery. Br J Anaesth 2001; 87: 577–83     

Decreasing the toxic potential of intravenous regional anaesthesia

In an attempt to reduce the dose of local anaesthetic agent during intravenous regional anaesthesia (IVRA) of the upper limb, we have used a forearm tourniquet in 12 adult volunteers. The volume of the forearm venous system was predetermined angiographically. We performed IVRA with three solutions of lidocaine (0.25, 0.375, 0.5 per cent) administered in a volume equal to the forearm venous system. Angiographic results indicate that: a forearm tourniquet provides adequate vascular isolation; the volume of the forearm venous system can be correlated with body weight; the progression of the fluid in the venous system follows a pattern that is similar for all patients with the small veins of the distal forearm and proximal hand being filled last. With this technique, lidocaine 0.5 per cent resulted in a dose of 1.5 mg.kg-1 and provided excellent analgesia. Lower concentrations were unsatisfactory. We conclude that the use of a forearm tourniquet allows reduction of the local anaesthetic dose to a non-toxic level and thus increases the safety of IVRA.