A comparison of a single-stimulation lateral infraclavicular plexus block with a triple-stimulation axillary block

BACKGROUND AND OBJECTIVES: A single-stimulation infraclavicular brachial plexus block (ICB) is safe and easy to perform, although underused. This technique was compared with a triple-stimulation axillary block (AxB). METHODS: One hundred patients scheduled for hand and forearm surgery were randomly allocated to 2 groups. ICB was performed with the needle inserted above the coracoid process in the upper lateral angle of the infraclavicular fossa and directed vertically until nerve stimulation elicited a distal motor response (median, radial, or ulnar). A single 40-mL bolus of ropivacaine 0.75% was injected. In the AxB group, 3 stimulations were performed to identify median or ulnar, radial, and musculocutaneous nerves, followed by an infiltration near the medial brachial and antebrachial cutaneous nerves. The same 40 mL of ropivacaine 0.75% was injected. Sensory and motor blocks were assessed at 5-minute intervals over 30 minutes. RESULTS: The time to block performance was shorter in the ICB than in the AxB group (2.5 +/- 1.9 minutes v 6.0 +/- 2.8 minutes, P <.001). The success rate (complete block in median, radial, ulnar, musculocutaneous, and medial antebrachial cutaneous nerves) was comparable in the 2 groups (90% v 88% in groups ICB and AxB, respectively). Block extension was comparable, except for a higher rate of block completion in the axillary nerve distribution in group ICB and in the medial brachial cutaneous nerve in group AxB. The onset of each nerve block was comparable except for a faster onset for the musculocutaneous nerve in group AxB (8 +/- 3 v 10 +/- 5 minutes). CONCLUSION: A single shot ICB is equally effective as a triple-nerve stimulation AxB.     

A comparison of stimulation patterns in axillary block: part 2

BACKGROUND AND OBJECTIVES: Radial plus musculocutaneous nerve stimulation may have a predominant role in the success of an axillary block, producing more extensive anesthesia of the upper limb than median plus musculocutaneous nerve stimulation. However, no comparison has been made with ulnar plus musculocutaneous nerve stimulation. We compared the extent of both sensory and motor block after ulnar plus musculocutaneous nerve stimulation or radial plus musculocutaneous nerve stimulation. METHODS: Sixty patients were randomly assigned to receive an axillary block using either radial plus musculocutaneous or ulnar plus musculocutaneous nerve stimulation with 40 mL plain 1.5% mepivacaine. Patients were assessed for sensory block by the pinprick method at 5 and 20 minutes. RESULTS: No statistically significant differences were found in the rates of anesthesia at 20 minutes in the cutaneous nerve distributions of the upper limb between radial plus musculocutaneous and ulnar plus musculocutaneous nerve stimulation except for the following nerves: radial (90% and 63.3%, respectively), medial cutaneous of the forearm (83.3% and 100%, respectively), and medial cutaneous of the arm (73.3% and 93.3%, respectively). Global sensory score (minimum: 0; maximum: 12 points) at 20 minutes was significantly higher after radial plus musculocutaneous than after ulnar plus musculocutaneous nerve stimulation: 12 (11-13) and 11 (10-12), respectively. The rates of median nerve blockade were 50% and 53%, respectively. CONCLUSIONS: Radial plus musculocutaneous nerve stimulation produced more extensive anesthesia of the upper limb than did ulnar plus musculocutaneous nerve stimulation. However, there is not an optimal combination of 2 responses in axillary brachial plexus block.     

Dexamethasone added to lidocaine prolongs axillary brachial plexus blockade

Different additives have been used to prolong regional blockade. We designed a prospective, randomized, double-blind study to evaluate the effect of dexamethasone added to lidocaine on the onset and duration of axillary brachial plexus block. Sixty patients scheduled for elective hand and forearm surgery under axillary brachial plexus block were randomly allocated to receive either 34 mL lidocaine 1.5% with 2 mL of isotonic saline chloride (control group, n = 30) or 34 mL lidocaine 1.5% with 2 mL of dexamethasone (8 mg) (dexamethasone group, n = 30). Neither epinephrine nor bicarbonate was added to the treatment mixture. We used a nerve stimulator and multiple stimulations technique in all of the patients. After performance of the block, sensory and motor blockade of radial, median, musculocutaneous, and ulnar nerves were recorded at 5, 15, and 30 min. The onset time of the sensory and motor blockade was defined as the time between last injection and the total abolition of the pinprick response and complete paralysis. The duration of sensory and motor blocks were considered as the time interval between the administration of the local anesthetic and the first postoperative pain and complete recovery of motor functions. Sixteen patients were excluded because of unsuccessful blockade. The duration of surgery and the onset times of sensory and motor block were similar in the two groups. The duration of sensory (242 +/- 76 versus 98 +/- 33 min) and motor (310 +/- 81 versus 130 +/- 31 min) blockade were significantly longer in the dexamethasone than in the control group (P < 0.01). We conclude that the addition of dexamethasone to lidocaine 1.5% solution in axillary brachial plexus block prolongs the duration of sensory and motor blockade.     

Comparison between 1.5% lidocaine with adrenaline and 1.5% plain mepivacaine in axillary brachial plexus block]

OBJECTIVES: To evaluate the distribution of sensory blockade, the onset time and the duration of the axillary plexus block obtained after the administration of 40 mL of 1.5% lignocaine with adrenaline or 40 mL of plain 1.5% mepivacaine. STUDY DESIGN: Prospective, randomised, comparative, double blind study. PATIENTS AND METHODS: One hundred and fifty five patients undergoing hand surgery were randomised into two groups: in group L, 73 patients were given 1.5% lignocaine with 1/200,000 adrenaline and in group M, 82 patients received 1.5% mepivacaine. The entire volume was injected on the first evoked motor activity obtained for a current less than 0.5 mA. Sensory and motor block of each of the four major nerves of the hand and forearm were assessed using light touch and motor strength respectively. The block was considered complete when all nerves were anaesthetised (median, radial, musculocutaneous and ulnar). RESULTS: The percentage of complete sensitive blockade was 22% in group L and 24% in group M. Complete motor blockade was respectively 27% in group L and 40% in group M. The median time required to obtain a complete sensory blockade was 18 min for both group. The median time required to obtain a complete motor blockade was 17 min in-group L and 16 min in-group M. The duration of the sensory blockade was not different for both groups (i.e., 255 +/- 76 min versus 231 +/- 70 min in group L and M respectively. The duration of the motor blockade was longer in group L compared to group M (199 +/- 64 min versus 231 +/- 74 min respectively, p < 0.05). CONCLUSION: Following axillary plexus block, 1.5% mepivacaine improves neither the extension nor the duration of sensory blockade achieved by 1.5% lignocaine with adrenaline.     

Steuerung der axillären Multiinjektionstechnik zur Plexusanästhesie

Background

Ultrasound guidance is still a young method in regional anesthesia when compared to nerve stimulation and only a few studies exist comparing these two techniques in an axillary multiple injection approach.

Aim

This prospective, randomized, observer-blinded study compared an ultrasound-guided (SONO) quadruple injection axillary block (out of plane, perineural) with a nerve stimulation-guided (STIM) triple injection axillary block for upper limb surgery.

Material and methods

A total of 60 patients were randomized to either the SONO (n?=?30) or STIM (n?=?30) group. For the block 40–50 ml mepivacaine 1.5?% (plexus) and 5–10 ml mepivacaine 0.5?% (subcutaneous in the medial skin of the arm) was used. Anesthesia time was recorded as the primary end point. After evaluation of block-related pain using a visual analog scale (VAS) a blinded observer tested sensory and motor function of the median nerve (MED), ulnar nerve (ULN), radial nerve (RAD), musculocutaneous nerve of the upper limb (MUC) and medial cutaneous nerve of the forearm (CAM) at defined times. The main outcome variable was onset time (defined loss of sensory/motor function).

Results

No differences were observed between the groups in terms of onset time (single nerves 10–20 min, plexus 20–25 min) and success rate (SONO 90?%, STIM 89?%). Patient satisfaction as measured by block-related pain score (VAS 2 cm), complications (vascular puncture SONO 7?%, STIM 11?%; paresthesia SONO 21?%, STIM 22?%) and patient acceptance (SONO 92?%, STIM 91?%) showed no differences. Performance time was shorter in the SONO group (6.68?±?1.72 min vs. 8.05?±?2.58, p?=?0.02).

Conclusion

Nerve stimulation-guided axillary plexus blocks performed by trained anesthesiologists may result in similar onset times and success rates compared to ultrasound-guided blocks.     

Magnesium added to prilocaine prolongs the duration of axillary plexus block

BACKGROUND AND OBJECTIVE: The aim of this study was to evaluate the effect of the addition of magnesium to prilocaine on the duration of sensory and motor-nerve block. METHODS: After institutional approval, 60 ASA physical status I and II patients, between 18 and 60 years of age and scheduled for forearm and hand surgery under axillary brachial plexus block, were included in the study. Patients were randomly assigned to 1 of 4 groups. All of the patients received 5 mg/kg of 2% prilocaine and isotonic sodium chloride solution in 35 mL total volume for axillary brachial plexus block. Group I received intravenous saline, and group II received 150 mg intravenous magnesium at the same time as local anesthetic administration. In group III, 100 mg of magnesium, and in group IV, 150 mg of magnesium, were added to local anesthetic solution. Sensory block and motor block of musculocutaneous, radial, median, and ulnar nerves were recorded at 5-minute intervals. RESULTS: The duration of motor block was significantly longer in group IV than in other groups (167 +/- 30, 177 +/- 17, 180 +/- 20, and 250 +/- 19 minutes in groups I to IV, respectively) (P < .01). Mean duration of sensory block in both of the perineural magnesium groups was statistically different than in groups I and II (P < .001). Duration of sensory block in group IV (304 +/- 30 minutes) was significantly longer than in group III (253 +/- 23 minutes) (P < .001). CONCLUSION: The admixture of magnesium to prilocaine for axillary brachial plexus block provided a pronounced prolongation of sensory and motor block without side effects.     

Double-injection method using peripheral nerve stimulator is superior to single injection in axillary plexus block

BACKGROUND AND OBJECTIVES: Axillary block using a single-injection method does not always provide effective analgesia. This study examined whether a double axillary block injection technique is superior to a single injection axillary block. METHOD: Fifty patients were randomly allocated to two groups. In group I (single injection), the whole volume of local anesthetic (0.7 mL/kg) was injected after locating only one of the median, radial, or ulnar nerves. In group 2 (double injection), half of the volume was injected after locating one nerve and the other half after locating another peripheral nerve. Bupivacaine 0.5% and prilocaine 1% (1:1 volumes) were used as local anesthetic. A peripheral nerve stimulator was used to identify the nerves. Sensory block of seven nerves and motor block of four nerves were tested after 40 minutes. RESULTS: Complete sensory and motor block (scores 2 or 3 on scale 0-3) in all four main nerves (median, ulnar, radial, musculocutaneous) was achieved in 3 (12%) versus 20 (80%) patients in groups 1 and 2, respectively (P = .000001). Primary success rate (no need for supplemental nerve block) was 52% in group 1 and 92% in group 2 (P = .0016). CONCLUSIONS: A double-injection method in axillary block provides excellent analgesia and motor block compared with a single-injection method. Moreover, the need for supplemental nerve blocks is significantly decreased.     

Tramadol does not prolong the effect of ropivacaine 7.5 mg/ml for axillary brachial plexus block

BACKGROUND: The aim of this prospective, randomized, double-blind study was to evaluate the effect of the addition of tramadol to ropivacaine on the onset and duration of sensory and motor block, and duration of analgesia, for axillary brachial plexus block. METHODS: After institutional approval and informed consent had been obtained, 45 patients scheduled for forearm or hand surgery under axillary brachial plexus block were randomly allocated into two groups. The ropivacaine group received 40 ml of ropivacaine 7.5 mg/ml plus 2 ml of isotonic sodium chloride solution, and the tramadol group received 40 ml of ropivacaine 7.5 mg/ml plus 2 ml (100 mg) of tramadol. The onset and duration of sensory and motor block in the distribution of the musculocutaneous, radial, median and ulnar nerves, the duration of analgesia, the time to first pain medication, hemodynamics and side-effects were recorded. RESULTS: The addition of tramadol did not improve the speed of onset or increase the duration of sensory and motor block. The durations of analgesia were 631 +/- 33 min and 633 +/- 37 min (mean +/- standard deviation) in the ropivacaine and tramadol groups, respectively (P > 0.05). Hemodynamic parameters and side-effects did not differ between the groups. CONCLUSION: The addition of 100 mg of tramadol to 7.5 mg/ml of ropivacaine, for axillary brachial plexus block, does not prolong the duration of motor and sensory block and analgesia.     

Brachial plexus nerve block exhibits prolonged duration in the elderly

BACKGROUND: Upper limb trauma occurs frequently in elderly patients for whom peripheral nerve blocks are often preferred for anesthesia. The characteristics of such regional blocks have, however, never been described in an elderly population. Therefore, the authors assessed prospectively the onset and duration of upper extremity peripheral nerve block (the mid-humeral block) in elderly and young patients undergoing emergency upper extremity surgery. METHODS: Consecutive patients aged > 70 yr or < 70 yr received a mid-humeral block with a small volume of ropivacaine, 0.75%. Five milliliters was injected onto each of the musculocutaneous, radial, ulnar, and median nerves. Time to complete sensory and motor block and durations of complete sensory and motor block were assessed. Results are shown as median and its 95% confidence interval. RESULTS: Median ages were 77 yr (95% CI, 72-81 yr) and 39 yr (95% CI, 27-46 yr) in the two groups. Both groups had similar times to complete sensory blockade. The elderly group had longer durations of complete sensory (390 min [range, 280-435 min] vs.150 min [range, 105-160 min]; P< 0.05) and motor (357 min [range, 270-475 min] vs. 150 min [range, 90-210 min]; P< 0.05) blockade. Duration of complete sensory block was significantly correlated with age (rho = 0.56; P< 0.05). CONCLUSIONS: Age is a major determinant of duration of complete motor and sensory blockade with peripheral nerve block, perhaps reflecting increased sensitivity to conduction failure from local anesthetic agents in peripheral nerves in the elderly population.     

A comparison of proximal and distal radial nerve motor responses in axillary block using triple stimulation

BACKGROUND AND OBJECTIVES: Stimulation of the radial nerve at the axilla may cause either a proximal movement (forearm extension) or distal movements (supination, wrist or finger extension). In the most recent studies on axillary block, only a distal twitch was accepted as valid. However, this approach was based only on clinical experience. The aim of this study was to verify if a proximal motor response can be considered a satisfactory endpoint. METHODS: This was a prospective, randomized, double-blinded study. One hundred fifty patients received a triple-injection axillary brachial plexus block in which the radial nerve was located by a proximal (group PROX) or a distal motor response (group DIST). Patients were assessed for sensory and motor block of the branches of the radial nerve by a blinded investigator at 5-minute intervals over 30 minutes. RESULTS: An 81% success rate for anesthetizing the sensory distal branches of the radial nerve was seen in group PROX; a significantly higher success rate was recorded in group DIST (95%). The onset time of sensory block for the distal branches of the radial nerve was significantly shorter in group DIST (9.9 +/- 6 v 15.4 +/- 7 minutes). The time to perform the block was slightly shorter and the localization of the nerve simpler in group PROX. The overall block success rate was not significantly different in the 2 groups. CONCLUSIONS: Local anesthetic injection at the proximal radial twitch significantly reduces the efficacy and prolongs the onset time of the radial nerve block. Searching for distal response is significantly more difficult and time consuming than searching for proximal response. However, it does not significantly increase patient discomfort or adverse effects.     

Brachial Plexus Nerve Block Exhibits Prolonged Duration in the Elderly

Background: Upper limb trauma occurs frequently in elderly patients for whom peripheral nerve blocks are often preferred for anesthesia. The characteristics of such regional blocks have, however, never been described in an elderly population. Therefore, the authors assessed prospectively the onset and duration of upper extremity peripheral nerve block (the mid-humeral block) in elderly and young patients undergoing emergency upper extremity surgery.

Methods: Consecutive patients aged > 70 yr or < 70 yr received a mid-humeral block with a small volume of ropivacaine, 0.75%. Five milliliters was injected onto each of the musculocutaneous, radial, ulnar, and median nerves. Time to complete sensory and motor block and durations of complete sensory and motor block were assessed. Results are shown as median and its 95% confidence interval.

Results: Median ages were 77 yr (95% CI, 72-81 yr) and 39 yr (95% CI, 27-46 yr) in the two groups. Both groups had similar times to complete sensory blockade. The elderly group had longer durations of complete sensory (390 min [range, 280-435 min]vs. 150 min [range, 105-160 min];P < 0.05) and motor (357 min [range, 270-475 min]vs. 150 min [range, 90-210 min];P < 0.05) blockade. Duration of complete sensory block was significantly correlated with age ([rho] = 0.56;P < 0.05).     

The effects of clonidine on ropivacaine 0.75% in axillary perivascular brachial plexus block

INTRODUCTION: The new long-acting local anesthetic ropivacaine is a chemical congener of bupivacaine and mepivacaine. The admixture of clonidine to local anesthetics in peripheral nerve block has been reported to result in a prolonged block. The aim of the present study was to evaluate the effects of clonidine added to ropivacaine on onset, duration and quality of brachial plexus block. METHODS: Patients were randomly allocated into two groups. In group I brachial plexus was performed using 40 ml of ropivacaine 0.75% plus 1 ml of NaCL 0.9%, and in group II brachial plexus was performed using 40 ml of ropivacaine 0.75% plus 1 ml (0.150 mg) of clonidine. Onset of sensory and motor block of radial, ulnar, median and musculocutaneous nerve were recorded. Motor block was evaluated by quantification of muscle force, according to a rating scale from 6 (normal contraction force) to 0 (complete paralysis). Sensory block was evaluated by testing response to a pinprick in the associated innervation areas. Finally, the duration of the sensory block was registered. Data were expressed in mean+/-SD. For statistical analysis a Student t-test was used. A P-value of < or = 0.05 was considered as statistically significant. RESULTS: The duration of blockade was without significant difference between the groups. Group I: 718+/-90 min; Group II: 727+/-117 min. There was no intergroup difference in sensory and motor onset or in quality of blockade. CONCLUSION: The addition of clonidine to ropivacaine 0.75% does not lead to any advantage of block of the brachial plexus when compared with pure ropivacaine 0.75%.     

A prospective, randomized comparison between ultrasound and nerve stimulation guidance for multiple injection axillary brachial plexus block

BACKGROUND: This prospective, randomized, blinded study tested the hypothesis that ultrasound guidance can shorten the onset time of axillary brachial plexus block as compared with nerve stimulation guidance when using a multiple injection technique. METHODS: Sixty American Society of Anesthesiology physical status I-III patients receiving axillary brachial plexus block with 20 ml ropivacaine, 0.75%, using a multiple injection technique, were randomly allocated to receive either nerve stimulation (group NS, n = 30), or ultrasound guidance (group US, n = 30) for nerve location. A blinded observer recorded the onset of sensory and motor blocks, the need for general anesthesia (failed block) or greater than 100 microg fentanyl (insufficient block) to complete surgery, procedure-related pain, success rate, and patient satisfaction. RESULTS: The median (range) number of needle passes was 4 (3-8) in group US and 8 (5-13) in group NS (P = 0.002). The onset of sensory block was shorter in group US (14 +/- 6 min) than in group NS (18 +/- 6 min) (P = 0.01), whereas no differences were observed in onset of motor block (24 +/- 8 min in group US and 25 +/- 8 min in group NS; P = 0.33) and readiness to surgery (26 +/- 8 min in group US and 28 +/- 9 min in group NS; P = 0.48). No failed block was reported in either group. Insufficient block was observed in 1 patient (3%) of group US and 2 patients (6%) of group NS (P = 0.61). Procedure-related pain was reported in 6 patients (20%) of group US and 14 patients (48%) of group NS (P = 0.028); patient acceptance was similarly good in the two groups. CONCLUSION: Multiple injection axillary block with ultrasound guidance provided similar success rates and comparable incidence of complication as compared with nerve stimulation guidance.     

A comparison of a triple-injection axillary brachial plexus block with the humeral approach

BACKGROUND AND OBJECTIVES: This prospective, randomized, and single-blind study compared effectiveness, performance, onset, and total anesthetic time and complications of the multiple axillary block (median, radial, and musculocutaneous nerves) with the humeral approach. METHODS: One hundred patients were randomly assigned to 2 groups. In group A (axillary) median, radial, and musculocutaneus nerves were located by a nerve stimulator and injections were made. In group H (humeral) all 4 terminal nerves of the brachial plexus were located and injections were made. A total of 40 mL mepivacaine of 1% was used. RESULTS: Complete sensory block of all 6 peripheral nerves occurred in 94% and 79% of patients in groups A and H, respectively (P < .05). The time to perform the block was shorter in group A (8 +/- 4 minutes v 11 +/- 4 minutes; P < .001); onset time was shorter in group A (16 +/- 8 minutes v 21 +/- 9 minutes; P < .05); total anesthetic time was shorter in group A (24 +/- 8 minutes v 33 +/- 10 minutes; P < .0001). Complete motor block was greater in group A (88% v 66%; P < .05). More vascular punctures occurred in group A (22% v 8%, P < .05). CONCLUSION: The triple-injection axillary block was more effective than the humeral approach as it was associated with more cases of sensory and complete motor block and gave shorter performance and onset times.     

A comparison of four stimulation patterns in axillary block

BACKGROUND AND OBJECTIVES: Insufficient spread of the local anesthetic toward the retroarterial region of the neurovascular space may be responsible for inconsistent anesthesia of the upper limb after single-injection axillary block. We hypothesized that injection of the local anesthetic on a single radial-nerve stimulation would produce the same extent of anesthesia as either a single median-nerve stimulation, a double-stimulation technique (radial and musculocutaneous nerves), or a triple-stimulation technique (radial, musculocutaneous, and median nerves). METHODS: One hundred twenty patients were randomly assigned to receive an axillary block by either median-nerve, radial-nerve, radial-nerve plus musculocutaneous-nerve, or triple-nerve stimulation with 40 mL of plain 1.5% mepivacaine. Patients were assessed for sensory block by the pinprick method at 5 and 20 minutes. RESULTS: Radial-nerve stimulation produced more extensive anesthesia than did median-nerve stimulation. The rate of anesthesia at 20 minutes in the median-nerve cutaneous distribution was similar after median-nerve stimulation or radial-nerve stimulation. The ulnar nerve was more frequently blocked at 20 minutes after radial-nerve stimulation than after median-nerve stimulation. Extent of anesthesia at 20 minutes after radial-nerve plus musculocutaneous-nerve stimulation was similar to that produced by triple-nerve stimulation, except for lower rates of anesthesia that corresponded to the median nerve. All of the differences were statistically significant. CONCLUSIONS: Musculocutaneous-nerve stimulation and radial-nerve stimulation play predominant roles in the success of axillary brachial plexus block, although a triple-nerve stimulation technique is still required to produce complete anesthesia of the upper limb.     

不同浓度罗哌卡因用于臂丛神经感觉与运动分离阻滞的效果

目的 探讨不同浓度罗哌卡因用于臂丛神经感觉与运动分离阻滞的效果.方法 择期上肢手术患者90例,ASA分级Ⅰ～Ⅲ级,年龄16～75岁,体重40～85 kg.均在超声引导联合神经刺激器辅助定位下行腋路臂丛神经阻滞,根据不同罗哌卡因浓度分为3组(n=30):0.15%罗哌卡因组(A组),0.10%罗哌卡因组(B组),0.05%罗哌卡因组(C组).于注射局麻药后10、30、60、240 min(T1～4)时记录感觉与运动分离阻滞情况、感觉阻滞完善情况和臂丛神经阻滞成功情况,术毕时评定麻醉效果.记录手术时间、镇痛时间.结果 与A组比较,B组T1.2时感觉阻滞完善率较低(P＜0.05),T3.4时感觉阻滞完善率差异无统计学意义(P＞0.05),感觉与运动分离阻滞率较高(P＜0.01),C组T1.2时感觉与运动分离阻滞率较低(P＜0.01),T3.4时感觉与运动分离阻滞率差异无统计学意义(P＞0.05),各时点感觉阻滞完善率较低(P＜0.01).与B组比较,C组各时点感觉阻滞完善率、感觉与运动分离阻滞率均较低(P＜0.01).A组麻醉效果优于B组,B组麻醉效果优于C组(P＜0.01),与A组和B组比较,C组臂丛神经阻滞成功率较低(P＜0.01),A组与B组差异无统计学意义(P＞0.05).结论 0.10%罗哌卡因用于臂丛神经阻滞可产生感觉与运动分离阻滞效果.     

Selective ulnar nerve localization is not essential for axillary brachial plexus block using a multiple nerve stimulation technique

BACKGROUND AND OBJECTIVES: The multiple-injection technique for axillary block, in which the 4 distal nerves of the plexus are located by a nerve stimulator and separately injected, has been shown to produce a rapid onset and a high success rate. However, this technique may be more difficult and time consuming than other axillary block methods. A simplified multiple-nerve stimulation technique, in which the ulnar nerve was not located, was compared in the present double-blind study to the 4-injection approach. METHODS: Eighty-four patients were randomly allocated to 2 groups. In group IV, all 4 distal nerves of the plexus were located by a nerve stimulator and injections made. In group III, all the nerves but the ulnar were located and injections made. The block was defined as complete when analgesia was present in all the sensory areas distal to the elbow. RESULTS: The time to perform the block was shorter in group III (5 +/- 2 v 8 +/- 3 minutes; P <.001). Block performance pain was lower in group III patients (8 +/- 2 v 13 +/- 2 mm; P <.001). The onset time (15 +/- 6 v 16 +/- 7 minutes) and the frequency (90% v 92%) of complete block were not different between the groups. CONCLUSIONS: A triple-injection method of axillary block in which the ulnar nerve was not purposely located provides a spread and a latency of sensory block equal to that obtained with a 4-injection technique. A shorter performance time is an advantage of this approach.     

Axillary block in children: single or multiple injection?

The goal of this double-blind prospective study was to compare the effect of a single injection versus multiple fractionated doses on the onset time and quality of motor and sensory block, obtained in 70 children anaesthetized with axillary block alone. The brachial plexus was identified with a peripheral nerve stimulator, and blocked with 0.5 ml.kg-1 of 1.5% lignocaine with adrenaline. In Group S (single injection), the total volume was injected after location of one nerve. In Group M (multiple fractionated doses), two nerves were located, including necessarily one nerve implicated in the surgical territory. Motor and sensory blocks were assessed according to Lanz's scale before surgery by a blinded observer. A block was considered complete if there was no feeling in at least three nerve territories at 30 min. No difference was found between groups for motor and sensory block quality. However the onset time of the block was faster after multiple fractionated doses (Group M, 25+/-7 min vs Group S, 29+/-4 min) and was faster in younger children (5-9 years: M=23+/-7 min vs S=28+/-5 min, 10-15 years: no difference). There was a significant difference in the quality of the sensory blockade of the musculocutaneous nerve: 18 versus 8 complete blocks, 10 versus 14 incomplete blocks, respectively for Group M versus Group S. No adverse effect was observed and analgesia was prolonged for more than 4 h. We can conclude that, unlike adults, fractionated doses in chilren bring no benefit to the quality of sensory and motor block. Selective block of the musculocutaneous nerve is recommended when a surgical procedure takes place in this territory.     

Spread of local anesthetic during an ultrasound‐guided interscalene block: does the injection site influence diffusion?

Background: During interscalene block (ISB) placement, ultrasound guidance (USG) enables the practitioner to measure the spread of local anesthetic around the nerve trunks or roots, and to adjust the needle position in order to optimize diffusion. Moreover, USG helps determine the best injection level, i.e. the point from which diffusion gives the most complete brachial plexus block. The aim of this study was to compare C5 and C6 level injections and to determine which level allows the best diffusion. Methods: Sixty randomized patients scheduled for shoulder surgery were divided into two groups. In group C5, injection was directed toward C5 while in group C6, the C6 nerve root was targeted. Block performance time was recorded. The onset of motor and sensory block of each nerve distribution was evaluated every 10 min over a 30‐min period. Results: The average time taken to perform a nerve block was 6.2+2.6 min in Group C6 and 6.0+2.1 min in Group C5 (NS). At 30 min, the number of patients with a satisfactory musculocutaneous and axillary nerve block was not notably greater in either group. By contrast, a significantly higher success rate was observed for other nerves in the C6 group as compared to the C5 group: ulnar nerve block: 93% vs. 19%, radial nerve block: 96% vs. 28%, median nerve block: 96%, vs. 69%. Conclusions: During USG ISB placement, injection below the C6 level provided the same efficiency in analgesia after shoulder surgery as an injection cranial to the C5 nerve root but a greater success rate of anesthesia in all distal nerve areas. This technique could be very interesting for trauma cases as an alternative to a supraclavicular block and offers a high success rate and is simple to perform, potentially promoting wide use and quicker learning for beginners.