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     

Efficacy of varying concentrations of hyaluronidase in peribulbar anaesthesia

We have compared the efficacy of adding varying concentrationsof hyaluronidase to a standard mixture of 2% lidocaine and 1%ropivacaine to provide peribulbar anaesthesia for cataract surgery.We used (i) the time to adequate anaesthesia for surgery and(ii) ocular and eyelid movement scores at 8 min after blockas clinical endpoints. Ninety patients were randomly allocatedto receive 7–10 ml of equal volumes of 2% lidocaine and1% ropivacaine without hyaluronidase or with hyaluronidase 15IU ml^–1or 150 IU ml^–1. Median time at which theblock was adequate for surgery was 6 min in all groups (interquartilerange 4–12 min). Median eyelid movement scores were similarin all groups, but the ocular movement scores at 8 min weresignificantly lower in the group which received hyaluronidase150 IU ml^–1 than in the group not given hyaluronidase(P<0.03). There were no differences between groups in theincidence of minor complications. A high concentration of hyaluronidaseresulted in a statistically significantly lower ocular movementscore at 8 min; the clinical relevance of this finding is uncertain. Br J Anaesth 2001; 86: 876–8     

Spinal anaesthesia with articaine 5% vs bupivacaine 0.5% for day-case lower limb surgery: a double-blind randomized clinical trial

BACKGROUND: A local anaesthetic with fast onset and short reliable duration of anaesthesia may be preferable for out-patient lower limb surgery. Articaine is believed to act faster and to have a shorter duration of action than bupivacaine, but there are no conclusive data available. The purpose of this study was to compare articaine and bupivacaine for day-case lower limb surgery. METHODS: Eighty patients planned for day-case lower limb surgery enrolled in this study. Patients were randomized to receive hyperbaric articaine 80 mg or plain bupivacaine 15 mg intrathecally. Primary outcome variable was recovery time from motor block. Secondary outcomes were: onset of sensory and motor block, maximum spread of sensory block, time to micturition, discharge from the hospital, and complications. RESULTS: The groups were comparable for the medians and the range of the maximum blocks after 30 min. Median time to complete regression of motor block was 101 min (range 80-129) for articaine compared with 307 min (range 225-350) for bupivacaine (P<0.0005). First spontaneous micturition occurred after 257 min (210-293) in the articaine group and after 350 min (304-370) in the bupivacaine group (P<0.0005). In the articaine and bupivacaine groups, patients were discharged after 300 min (273-347) and 380 min (332-431), respectively (P<0.0005). There was no significant difference in the occurrence of complications between the groups. CONCLUSIONS: Spinal anaesthesia with 80 mg of hyperbaric articaine has a shorter duration than a spinal anaesthesia with 15 mg of plain bupivacaine in lower limb surgery of approximately 1 h duration.     

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     

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     

Comparison of 0.75% levobupivacaine with 0.75% racemic bupivacaine for peribulbar anaesthesia

In a single centre, randomised, double-blind study 50 patients scheduled for intra-ocular surgery received 0.75% levobupivacaine or 0.75% racemic bupivacaine for peribulbar anaesthesia. There were no significant differences in the mean (SD) volume of levobupivacaine (11 (2.7) ml) or racemic bupivacaine (10 (2.6) ml) required, time to satisfactory block (levobupivacaine-13 (5.6) min; racemic bupivacaine-11 (4.4) min), peri-operative pain scores or frequency of adverse events between levobupivacaine and racemic bupivacaine. The safer side-effect profile of levobupivacaine may offer significant advantages in the elderly population undergoing cataract extraction in whom intercurrent disease is common.     

Comparison of ropivacaine 0.5% (in glucose 5%) with bupivacaine 0.5% (in glucose 8%) for spinal anaesthesia for elective surgery

Background. Hyperbaric solutions of ropivacaine have been usedsuccessfully to provide spinal anaesthesia. This study was designedto compare the clinical efficacy of hyperbaric ropivacaine withthat of the commercially available hyperbaric preparation ofbupivacaine. Methods. Forty ASA grade I–II patients undergoing lower-abdominal,perineal or lower-limb surgery under spinal anaesthesia wererecruited and randomized to receive ropivacaine 5 mg ml^–1(with glucose 50 mg ml^–1), 3 ml or bupivacaine 5 mg ml^–1(with glucose 80 mg ml^–1), 3 ml. The level and durationof sensory block, intensity and duration of motor block, andtime to mobilize and micturate were recorded. Patients wereinterviewed at 24 h and at 1 week to identify any residual problems. Results. All blocks were adequate for the proposed surgery,but there were significant differences between the two groupsin mean time to onset of sensory block at T10 (ropivacaine 5min; bupivacaine 2 min; P<0.005), median maximum extent (ropivacaineT7; bupivacaine T5; P<0.005) and mean duration of sensoryblock at T10 (ropivacaine 56.5 min; bupivacaine 118 min; P=0.001).Patients receiving ropivacaine mobilized sooner (ropivacainemean 253.5 min; bupivacaine 331 min; P=0.002) and passed urinesooner (ropivacaine mean 276 min; bupivacaine 340.5 min; P=0.01)than those receiving bupivacaine. More patients in the bupivacainegroup required treatment for hypotension (>30% decrease insystolic pressure; P=0.001). Conclusions. Ropivacaine 15 mg in glucose 50 mg ml^–1 providesreliable spinal anaesthesia of shorter duration and with lesshypotension than bupivacaine. The recovery profile for ropivacainemay be of interest given that more surgery is being performedin the day-case setting. Br J Anaesth 2003; 90: 304–8     

A double-blind randomised comparison of ropivacaine 0.5%, bupivacaine 0.375% - lidocaine 1% and ropivacaine 0.5% - lidocaine 1% mixtures for cataract surgery

This study evaluated the efficacy and side-effects of plain ropivacaine compared with ropivacaine-lidocaine and bupivacaine-lidocaine mixtures for peribulbar blocks in cataract surgery. Ninety patients were randomly allocated to three groups and received peribulbar blockade using one of the three solutions. Speed of onset and quality of blockade were assessed using akinesia, surgical satisfaction and patient satisfaction. Complications and cardiovascular side-effects were noted. There was a slower onset of akinesia using ropivacaine alone, although at 10 min after injection all groups were equal in this respect. There was no difference in surgical or patient satisfaction between the groups. There were no differences in pain on injection, preblock and postblock blood pressure, heart rate or oxygen saturation. The optimal time to surgical incision after peribulbar blockade is not less than 15 min and plain ropivacaine fulfils this criterion.     

Ropivacaine in peribulbar block: a comparative study with bupivacaine

BACKGROUND: Ropivacaine is a new local anesthetic with alleged lower systemic toxicity and slightly lower potency as compared with bupivacaine. The present study aimed to evaluate the efficacy of ropivacaine in peribulbar block, as compared with that of bupivacaine. METHODS: Eighty patients aged 45-92 years with physical status ASA I, II, or III were randomized to Group R (n=40) or Group B (n=40). Group R received 8.0 ml of 1.0% ropivacaine and Group B received 8.0 ml of 0.75% bupivacaine, both solutions with 50 IU/ml hyaluronidase, to induce peribulbar block according to the double-injection technique. Decreased ocular motility was the only criterion of successful block. RESULTS: The percentage of patients with decreased ocular motility showing successful block was higher in Group R 1 and 5 min after injection. A score indicating successful peribulbar block was found in all patients 10 min after injection. While no patient complained of a burning sensation during ropivacaine injection, 22.5% of the patients given bupivacaine reported this symptom. CONCLUSION: Both local anesthetics were effective in inducing peribulbar block for intraocular surgery. A tendency was noted to a faster onset of peribulbar block with ropivacaine; nevertheless, both drugs had a high degree of success for this block.     

Spinal anaesthesia for Caesarean section with bupivacaine 5 mg ml(-1) in glucose 8 or 80 mg ml(-1)

The standard spinal preparation of bupivacaine contains a highconcentration of glucose (80 mg ml^–1). However,the addition of only a small amount of glucose (8 mg ml^–1)to plain solutions of bupivacaine results in a solution which,although no more than marginally hyperbaric, produces a morepredictable block when used for spinal anaesthesia in non-pregnantpatients. However, bupivacaine 5 mg ml^–1 inglucose 8 mg ml^–1 has a density [1.00164 (SD0.00008) at 37°C] which is relatively greater than thatof the cerebrospinal fluid (CSF) of the pregnant patient atterm (1.0003 at 37°C) because CSF density decreases duringpregnancy. Therefore, a double-blind, randomized, controlledstudy was carried out to compare intrathecal bupivacaine (glucose8 mg ml^–1) with bupivacaine (glucose 80 mg ml^–1)in 40 pregnant patients at term. Although there was no differencebetween groups in onset of sensory block, dose of ephedrineor patient satisfaction, patients receiving bupivacaine (5 mg ml^–1)with glucose (8 mg ml^–1) had persistently highersensory blocks between 60 and 120 min after intrathecalinjection, suggesting that the spread of spinal solutions inthe pregnant patient at term is not dependent on density. Br J Anaesth 2001; 86: 805–7     

Hyperbaric articaine for day-case spinal anaesthesia

Background. Articaine and lidocaine are clinically very similarsuggesting that articaine could be suitable for day-case spinalanaesthesia. A dose–response study with articaine in ambulatoryspinal anaesthesia was therefore performed. Methods. In this randomized double-blind study, 90 day-casesurgery patients received spinal anaesthesia with 60 mg (A60),84 mg (A84) or 108 mg (A108) of hyperbaric articaine hydrochloride.Sensory block was tested with pinprick and motor block on amodified Bromage scale. A structured interview was performedon the first and seventh postoperative days. Results. Sensory block reached the T₁₀ dermatome in a median(range) of 5 (5–10) and was maintained at this level for70 (35–145), 70 (15–115) and 85 (20–115) minin the A60, A84 and A108 groups, respectively. Six patientsin the A108 group, two in the A84 group and one in the A60 grouphad maximum spread of analgesia to T₁ or higher (NS). Patientsin the A108 group needed more medication for hypotension (P=0.018),had more often nausea and vomiting (P=0.027), took oral fluidslater (P=0.031) and both sensory block recovery [median (range)][2.5 (2–4.5) h] (P=0.017) and motor block recovery [2(1.3–4) h] (P=0.009) were delayed. No patients in theA108 group needed opioid intraoperatively while fentanyl wasneeded in 5 (17%) and 2 (7%) patients in the A60 and A84 groups,respectively. Discharge criteria were attained in approximately4.5 h after articaine injection (NS) and no drug-related sequelaewere observed. Conclusions. Hyperbaric articaine 60 and 84 mg resulted in spinalanaesthesia allowing surgery of the lower extremities for about1 h. Recovery was rapid. Use of 108 mg of articaine is not recommendedbecause of frequent extensive cephalad spread of the block,accompanied by arterial hypotension and nausea.     

Venous levels of lignocaine and bupivacaine after peribulbar block

Twenty-five patients undergoing elective cataract day surgery were studied after receiving a dual-injection peribulbar block with a mixture consisting of equal volumes of 2% lignocaine and 0.75% bupivacaine with hyaluronidase. A maximum of 10ml of solution was used for the initial block; supplementary injections of up to 10 ml were given to five patients. Venous blood was taken prior to the block and then 1, 10, 20, 30, 60 and 90 min after the block. The peak mean concentrations of lignocaine (0.722 μg. ml⁻¹) and bupivacaine (0.353 μg. ml⁻¹)were found at 10–20 min after injection when no top-up was given and at 10 min after the top-up injection when required. All measured serum concentrations of lignocaine and bupivacaine were below the accepted toxic levels of the two drugs. However, the highest individual toxicity score after a top-up was 0.915 which was very close to the toxicity threshold (= 1) when a scoring system was used to assess the combined levels.     

Effects of peribulbar bupivacaine as an adjunct to general anaesthesia on peri-operative outcome following retinal detachment surgery

Sixty premedicated, ASA physical status I or II patients weighing > 25 kg scheduled for elective retinal detachment repair were randomly assigned to receive either peribulbar block with 10 ml of 0.25% bupivacaine (block group) or intravenous morphine 150 microg.kg-1 (morphine group), prior to the induction of general anaesthesia (n = 30 in each group). Patients were evaluated for intra-operative oculocardiac reflex, peri-operative pain relief, recovery from anaesthesia and postoperative nausea and vomiting. Apart from significantly reducing the incidence of oculocardiac reflex (30% vs. 70%, p = 0.0019), peribulbar bupivacaine also attenuated the severity of the reflex. Postoperative pain relief was superior in the block group. More block group patients had the maximum recovery score in the immediate postoperative period (80% vs. 27%, p < 0. 0001) and they achieved complete recovery significantly faster than the morphine group (17.3 (14.7) min vs. 66.7 (29.7) min, p < 0.0001). The incidence (40% vs. 77%, p = 0.004) and severity of postoperative nausea and vomiting were significantly less in the block group. In summary, peribulbar bupivacaine, when administered together with general anaesthesia, attenuated oculocardiac reflex, provided comparable intra-operative and superior postoperative analgesia, resulted in significantly earlier and better recovery from anaesthesia, and significantly reduced the incidence and severity of postoperative nausea and vomiting.     

Early exploration of diplopia with magnetic resonance imaging after peribulbar anaesthesia

We report the cases of five patients who have experienced postoperativediplopia after cataract surgery under peribulbar anaesthesiaand in whom orbital Magnetic Resonance Imaging was performedimmediately after the diagnosis. In four patients, the imagingstudy showed a T2 hyper-intensity signal and swelling of oneextraocular muscle that was interpreted as oedema. Therefore,these cases were most probably a result of an accidental i.m.injection of local anaesthetics. In the other patient, the imagingstudy revealed no abnormality. Br J Anaesth 2004; 92: 899–901     

Intraocular pressure and ropivacaine in peribulbar block: a comparative study with bupivacaine

BACKGROUND: The aim of this study was to compare the effects on intraocular pressure (IOP) of ropivacaine and bupivacaine in peribulbar block. METHODS: The study involved 40 patients with ASA physical status I, II or III undergoing cataract surgery under peribulbar block. Patients were allocated to two groups according to the local anesthetic used: Group R (n=20), 1.0% ropivacaine and Group B (n=20) 0.75% bupivacaine, both associated with 50 IU. ml-1 hyaluronidase, in peribulbar double injection technique. IOP was measured at four time points: 0=before block (control); 1=1 min after block; 2=5 min after block; 3=15 min after block. RESULTS: Mean values of IOP (mm Hg) after block were significantly lower in Group R in comparison to Group B: time point 1=13.4+/-3.2 vs 20.8+/-4.7; time point 2=10.9+/-3.7 vs 14.4+/-3.8; time point 3=7.7+/-4.0 vs 10.5+/-3.1. The variation of IOP was different in each group. In Group R, the mean values obtained at the three time points after block were significantly lower than the control; in Group B, the mean value of IOP rose significantly 1 min after block and was lower than control only at time point 3. CONCLUSIONS: Ropivacaine 1.0% associated with hyaluronidase in peribulbar block is better than 0.75% bupivacaine under the same standard conditions for lowering IOP in intraocular surgery. This effect is probably due to relaxation of the extraocular muscles after the block with both anesthetics, and possibly to a smaller intraocular blood volume due to vasoconstriction in the case of ropivacaine.     

Spinal anaesthesia with 0.5% hyperbaric bupivacaine in elderly patients: effects of duration spent in the sitting position

Sixty patients, aged 65–84 yr, undergoing minor urologicalsurgery under spinal anaesthesia remained sitting for 2 (group1, n=15), 5 (group 2, n=15), 10 (group 3, n=15), or 20 (group4, n=15) min after completion of the subarachnoid administrationof 3 ml of a 0.5% hyperbaric bupivacaine solution. They werethen placed in the supine position. Analgesia levels were assessedbilaterally using pinprick. Motor block was scored using a 12-pointscale. Systolic and diastolic arterial pressures and heart ratewere also recorded. Twenty minutes after the injection the upperanalgesia levels were lower (P<0.05) in group 4 (median T9.0)than in the groups 1–3 (medians T6.6–T8.5). Thehighest obtained levels (medians T5.7–T8.0) did not differbetween the groups, but occurred later (P<0.05) in group4 (median 35 min) than in groups 1–3 (medians 19–24min). There were no significant differences in the maximum degreeof motor block or haemodynamic changes between the four studygroups. Br J Anaesth 2001; 87: 738–42     

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     

Dose-response in infants receiving caudal anaesthesia with bupivacaine*

Caudal epidural anaesthesia was performed in 25 awake or sedated infants, the sensory levels measured and the dose-response determined (bupivacaine dose [ml kg^?1] v. sensory level). The infants were divided into two groups based on body weight, group 1 (1.9–2.6 kg) and group 2 (3.4–7.0 kg). There was a significant difference between the dose-response when comparing group 1 to group 2 (P < 0.01). Smaller infants require a larger volume (ml kg^?1) of local anaesthetic to achieve mid-thoracic sensory levels than larger infants. In small infants, we recommend increasing the volume of local anaesthetic while still limiting the total bupivacaine dose to 3.25 mg kg^?1 by using 1.6 ml kg^?1 of bupivacaine 0.20% (3.20 mg kg^?1) instead of 1.3 ml kg^?1 of bupivacaine 0.25% (3.25 mg kg^?1).     

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