Alternatives to the vertical approach for infraclavicular brachial plexus block

In this article the possible alternatives for blocking the brachial plexus by infraclavicular route are approached. According to the direction of the needle at the end of the block technique proximal, vertical and distal approaches are separately displayed. Anatomical knowledge of the brachial plexus is presented as a basis for performing the anesthetic technique according to the surgical indication involved, and for avoiding possible complications associated with damage to the neighboring structures. According cumulated experience, brachial plexus block with the distal and perpendicular infraclavicular techniques offer efficacy and topographic distribution performances similar to those of the axillary approach. Proximal approach offers maximum reliability in blocking the five principal nerve trunks. The positioning is comfortable for the patient, and the outcome depends on the situation of the needle or catheter tip on the trunk and/or divisions of the brachial plexus. © 2003 Elsevier Inc. All rights reserved.     

超声引导下患儿肋锁间隙臂丛神经阻滞的研究进展

肋锁间隙(CCS)臂丛神经阻滞是一种锁骨下臂丛神经阻滞方式。臂丛内侧束、外侧束、后束在CCS集中于腋动脉外侧,位置关系固定,使用较少的局麻药即可达到良好的阻滞效果。近年来,CCS臂丛神经阻滞逐渐应用于患儿区域麻醉。患儿CCS臂丛神经解剖位置表浅,易于超声定位,但血管、神经、胸膜等结构距离较近,超声引导增加了患儿CCS臂丛神经阻滞的有效性和安全性。本文就CCS臂丛神经阻滞的解剖基础及超声定位、阻滞方法及药物用量、患儿临床应用和相关并发症进行综述,以期为患儿CCS臂丛神经阻滞的应用提供参考。     

Spread of injectate associated with radial or median nerve-type motor response during infraclavicular brachial-plexus block: an ultrasound evaluation

BACKGROUND AND OBJECTIVES: We have compared ultrasound characteristics of spread during infraclavicular brachial-plexus blocks by use of electrically evoked radial-nerve- or median-nerve-type distal motor responses to guide the injection of 30 mL of 1.5% mepivacaine. METHODS: Consecutive patients who required surgery distal to the upper arm were prospectively included in this study. With radial- or median-evoked distal motor response at a stimulating current intensity of less than 0.5 mA, patients were distributed into 2 equal groups. An independent investigator blinded to the evoked response described ultrasound characteristics of the spread of local anesthetic and assessed block quality 30 minutes after placement. A quality diffusion score proportional to the extent and intensity of spread around the axillary artery was used, and dynamic movements during injection were noted. RESULTS: Thirty-two patients were included. With radial-nerve-type motor response, the success rate of infraclavicular plexus block was 100%, but 3 supplemental axillary blocks were requested with median-nerve-type motor response. Quality diffusion scores were significantly higher with radial-nerve-type as compared with median-nerve-type motor response (P = .03). Injection after radial-nerve-type motor response resulted in a typical and reproducible ultrasound feature of posterior local-anesthetic spread associated with medial and upper movement of the axillary artery. With median-nerve-type motor response, failed blocks were associated with a specific posterior displacement of the axillary artery that resulted from superficial spread. CONCLUSION: We have demonstrated that as compared with median-nerve-type motor response, injection performed after a radial-nerve-type motor response promoted reproducible and remarkable ultrasound spread characteristics associated with complete sensory block of the 3 cords at 30 minutes.     

Preliminary evaluation of infraclavicular catheters inserted using ultrasound guidance: through-the-catheter anesthesia is not inferior to through-the-needle blocks

BACKGROUND AND OBJECTIVES: This prospective study compared the initial block quality and surgical anesthesia rates of ultrasound-guided infraclavicular blocks with local-anesthetic injected through a catheter versus through a needle. We hypothesized that positioning of the catheter immediately posterior to the axillary artery would produce through-the-catheter (TTC) anesthesia with rates of complete block not inferior to through-the-needle (TTN) injection. METHODS: Eighty patients undergoing hand or forearm surgery extensive enough to require regional anesthesia were randomized into 2 groups of 40. In group TTN, local anesthetic was deposited posterior, lateral, and medial to the axillary artery using as few injections as necessary. In group TTC, a 20-gauge, multiorifice catheter was positioned between the posterior wall of the axillary artery and the posterior cord of the brachial plexus. All blocks were performed by use of ultrasound visualization with a 6-MHz to 10-MHz 38-mm linear probe. Local-anesthetic solution consisted of 0.5 mL/kg lidocaine 2% with epinephrine. Sensory and motor blocks, as well as supplementation rates, were evaluated for the musculocutaneous, median, radial, and ulnar nerves. RESULTS: Complete sensory block of all nerve territories was achieved in 92% of patients in group TTN and 90% in group TTC (P = .51). In group TTN, 90% of patients had satisfactory anesthesia for surgery (no discomfort and no need for anesthetic supplementation of any type) compared with 92% in group TTC (P = .51). CONCLUSION: Ultrasound-guided TTC infraclavicular block produced perioperative anesthesia that was not inferior to a TTN technique.     

Ultrasound-guided supraclavicular brachial plexus block

In this study, we evaluated state-of-the-art ultrasound technology for supraclavicular brachial plexus blocks in 40 outpatients. Ultrasound imaging was used to identify the brachial plexus before the block, guide the block needle to reach target nerves, and visualize the pattern of local anesthetic spread. Needle position was further confirmed by nerve stimulation before injection. The block technique we describe aligned the needle path with the ultrasound beam. The block was successful after one attempt in 95% of the cases, with one failure attributable to subcutaneous injection and one to partial intravascular injection. Pneumothorax did not occur. Our preliminary data suggest that a high-resolution ultrasound probe can reliably identify the brachial plexus and its neighboring structures in the supraclavicular region. The technique of real-time guidance during needle advancement can quickly localize nerves. Distinct patterns of local anesthetic spread observed on ultrasound can further confirm accurate needle location. IMPLICATIONS: Real-time ultrasound imaging during supraclavicular brachial plexus blocks can facilitate nerve localization and needle placement and examine the pattern of local anesthetic spread.     

Use of ultrasound guidance and contrast enhancement: a study of continuous infraclavicular brachial plexus approach

Purpose: We describe our experience of combining the use of ultrasound (US) guidance with contrast enhancement and peripheral nerve stimulation for the insertion of infraclavicular brachial plexus catheters. Methods: Thirty patients scheduled to have upper limb surgery under regional block were studied. Under US guidance and peripheral nerve stimulation assistance, continuous peripheral nerve block needle and stimulating catheter were placed in the infraclavicular area. Needle and catheter tip location was confirmed with agitated 5% dextrose and seen under colour Doppler with US before injecting local anaesthetic (LA). Patients were evaluated in terms of onset times and efficacy of block. Post‐operatively, on block recession a catheter was stimulated and visualization of spread of LA during injection through the catheter was done. Secondary block (subsequent to re‐injection of LA) was assessed. Patients were followed‐up for a week. Results: Mean time to onset of block was 19.7 (± 4.9) min. There were no incomplete blocks and all components of the plexus were blocked completely. Post‐operatively, in 95.7% of patients, the spread of hand‐agitated LA via the catheter could be seen by color Doppler with ultrasonography. All patients had excellent post‐operative analgesia and high degree of satisfaction. There were no complications. Conclusion: Contrast enhancement with US guidance during infraclavicular brachial plexus block enables direct visualization of needle and catheter tip location. Our early experience suggests that this leads to successful initial and subsequent post‐operative block. Further controlled studies are needed to compare this technique with more prevalent and conventional techniques of catheter insertion.     

Efficacy of vertical infraclavicular plexus block vs. modified axillary plexus block: a prospective, randomized, observer-blinded study

BACKGROUND: Despite containing severe risks, infraclavicular approaches to the brachial plexus gained increasing popularity. Likewise, the vertical infraclavicular plexus block improved anesthesia compared to the standard axillary approach but contains the risk of pneumothorax. Therefore we modified the standard axillary technique by inserting a proximal directed catheter, referred to as a high axillary plexus block. We prospectively compared quality and onset of neural blockade after vertical infraclavicular plexus block (VIP) and high axillary plexus block (HAP) in two randomized groups (30 patients in each). METHODS: In group VIP the insulated needle was inserted midway between the ventral process of the acromion and the jugular notch. In group HAP, first an axillary needle was placed. Through this a stimulating catheter was inserted in a proximal direction (10-15 cm); correct placement was confirmed by nerve stimulation. All patients received 40 ml ropivacaine 0.75% (300 mg). Discriminating between analgesia and anesthesia, a blinded observer assessed progression of neural blockade every 5 min for 60 min by pin prick. Incomplete blocks were supplemented 60 min after initial injection. RESULTS: All patients in both groups demonstrated sufficient surgical anesthesia. No patient needed systemic supplementation or general anesthesia. However, vertical infraclavicular plexus block indicated superior anesthesia compared to high axillary plexus block, regarding musculocutaneous, axillary and radial nerve, which were completely blocked with a higher success rate and in a shorter time interval (P < 0.05). CONCLUSIONS: While both techniques provide sufficient surgical anesthesia, vertical infraclavicular plexus block demonstrated a partially higher success rate and a faster onset than high axillary plexus block.     

Neurostimulation in ultrasound-guided infraclavicular block: a prospective randomized trial

Ultrasound guidance (USG) for infraclavicular blocks provides real time visualization of the advancing needle and local anesthetic distribution. Whether visualization of local anesthetic spread can supplant neurostimulation as the end point for local anesthetic injection during USG block has never been formally evaluated. Therefore, for this prospective randomized study, we recruited 72 patients scheduled for hand or forearm surgery and compared the speed of execution and quality of USG infraclavicular block with either USG alone (Group U) or USG combined with neurostimulation (Group S). In Group U, local anesthetic was deposited in a U-shaped distribution posterior and to each side of the axillary artery using as few injections as possible (1, 2, and 3 injections in 29, 6, and 3 patients, respectively). In Group S, a single injection was made after obtaining a distal motor response with a stimulating current between 0.3 and 0.6 mA. The anesthetic solution consisted of 0.5 mL/kg of lidocaine 1.5%, bupivacaine 0.125%, and epinephrine 1:200 000 (final concentrations). Procedure times were significantly shorter in Group U compared with Group S (3.1 +/- 1.6 min and 5.2 +/- 4.7 min, respectively; P = 0.006). In Group S, anesthetic spread was mainly anterior to the axillary artery in 37% of patients and mainly posterior in 63% of patients. Thirty minutes after the injection, 86% of patients in Group U had complete sensory block in the musculocutaneous, median, radial, and ulnar nerve territories compared with 57% in Group S (P = 0.007). Patients blocked in Group U with a single injection had the same rate of complete block (86%) as those blocked with more than one injection (86%). Block supplementation rates were 8% in Group U versus 26% in Group S (P = 0.049). Block failure occurred in one patient in Group S because of an inability to obtain a distal stimulation after 20 min. We conclude that USG infraclavicular block is more rapidly performed and yields a higher success rate when visualization of local anesthetic spread is used as the end point for injection. Posterolateral spread of local anesthetic around the axillary artery predicts successful block, circumventing the need for direct nerve visualization.     

Applying ultrasound imaging to interscalene brachial plexus block

OBJECTIVE: Previous studies have examined ultrasound-assisted brachial plexus blocks, but few have applied this imaging technology to the interscalene region. We report a case of interscalene brachial plexus block using ultrasound guidance to show the clinical usefulness of this technology. CASE REPORT: A nerve stimulator-guided interscalene block was attempted for arthroscopic shoulder surgery but failed. Subsequent nerve localization was accomplished by ultrasound imaging using a high-frequency probe (5-12 MHz) and the Philips ATL HDI 5000 unit. Ultrasound showed nerves between the scalene muscles, block needle movement at the time of advancement, and local anesthetic spread during injection. Interscalene block was successful after 1 attempt of nerve localization and needle placement. CONCLUSIONS: Advanced ultrasound technology is useful for nerve localization and can generate brachial plexus images of high resolution in the interscalene groove, guide block needle placement and advancement in real time to targeted nerves, and assess adequacy of local anesthetic spread at the time of injection. Ultrasound imaging guidance can potentially improve success during interscalene brachial plexus block.     

Ultrasound-guided block of the axillary nerve: a volunteer study of a new method

Background: Interscalene brachial plexus block (IBPB) is the gold standard for perioperative pain management in shoulder surgery. However, a more distal technique would be desirable to avoid the side effects and potential serious complications of IBPB. Therefore, the aim of the present study was to develop and describe a new method to perform an ultrasound‐guided specific axillary nerve block. Methods: After initial investigations, 12 healthy volunteers were included. We performed an in‐line ultrasound‐guided specific axillary nerve block by injecting 8 ml local anesthetic (lidocaine 20 mg/ml) after placing the tip of a nerve stimulation needle cranial to the posterior circumflex humeral artery in the neurovascular space bordered by the teres minor muscle, the deltoid muscle, the triceps muscle and the shaft of the humerus. Needle placement was aided by simultaneous nerve stimulation. We assessed sensory (pinprick and cold stimulation) and motor (active resistive force) block of the axillary nerve before, 15, 30, 60, 90 and 120 min after performing the block and every 30 min until termination of the block. Results: All 12 volunteers demonstrated sensory block of the axillary nerve and 10 volunteers demonstrated complete motor block. Even though it was difficult to directly visualize the axillary nerve, the block was easy to perform with easily recognizable ultrasonographic landmarks. Block duration was approximately 120 min. Conclusions: We describe a new ultrasound‐guided technique to specifically block the axillary nerve. The potential clinical role of this new block remains to be determined.     

Volume mínimo efetivo de bupivacaína a 0,5% para abordagem retroclavicular guiada por ultrassom no bloqueio do plexo braquial por via infraclavicular

Background and objectivesThe current study aimed to determine the minimum effective volume (MEV) of bupivacaine 0.5% in 50% of patients for an ultrasound‐guided retroclavicular approach to infraclavicular brachial plexus block.MethodsA total of 25 adult patients who were scheduled for upper limb surgery received an ultrasound‐guided retroclavicular approach to infraclavicular brachial plexus block with bupivacaine 0.5%. The needle insertion point was posterior to the clavicle and the needle was advanced from cephalad to caudal. Block success was defined as a composite score of 14 at 30 min after local anesthetic (LA) injection. The minimum effective volume in 50% of patients was determined using the Dixon‐Massey up‐and‐down staircase method. Minimum effective volume for a successful block in 95% of the patients was also calculated using logistic regression and probit transformation.ResultsThe minimum effective volume of bupivacaine 0.5% resulting in successful block in 50% of patients (MEV50) according to the up‐and‐down staircase method was found to be 9.6 mL (95% confidence interval (CI), 5.7–13.4). The calculated minimum effective volume required for a successful block in 95% of patients (MEV95) using the probit transformation and logistic regression analysis was 23.2 mL (95% CI, 18.8–36.7).ConclusionsThe MEV50 of bupivacaine 0.5% for US‐guided retroclavicular approach to infraclavicular brachial plexus block was 9.6 mL and the calculated MEV95 was 23.2 mL. Future studies are required for infraclavicular brachial plexus block with different approaches, other LA agents and different concentrations of bupivacaine.     

Seizure complicating placement of a nerve stimulator-guided infraclavicular block: could the use of ultrasound decrease the risk?

The case of a patient who suffered a seizure following a nerve stimulator-guided coracoid infraclavicular brachial plexus block, is reported. Following the seizure, an ultrasound machine was used to image the patient's infraclavicular region, which showed an anatomical variation in the position of the axillary vein relative to the axillary artery. The use of ultrasound in regional anesthesia provides additional safety information beyond nerve stimulation, which may help decrease the likelihood of such complications.     

Brachial plexus examination and localization using ultrasound and electrical stimulation: a volunteer study

BACKGROUND: Current techniques of brachial plexus block are "blind," and nerve localization can be frustrating and time consuming. Previous studies on ultrasound-assisted brachial plexus blocks are mostly performed with scanning probes of 10 MHz or less. The authors tested the usefulness of a state-of-the-art, high-resolution ultrasound probe (up to 12 MHz) in identifying the brachial plexus in five locations of the upper extremity and in guiding needle advancement to target before nerve stimulation. METHODS: In this prospective observational study, 15 volunteers underwent brachial plexus examination using an L12-L5 MHz probe and a Philips-ATL 5000 ultrasound unit in the interscalene, supraclavicular, infraclavicular, axillary, and midhumeral regions. Thereafter, an insulated block needle was advanced under direct ultrasound guidance to target nerves before confirmation by electrical nerve stimulation in five volunteers in each of the interscalene, supraclavicular, and axillary regions. The quality of brachial plexus images, anatomic variations, and the technique of needle advancement for nerve localization were recorded. RESULTS: The brachial plexus components were successfully identified in the transverse view as round to oval hypoechoic structures with small internal punctuate echos in all regions examined except the infraclavicular area (visualized in 27% of the cases). The authors' technique of advancing the needle in-line with the ultrasound beam allowed moment-by-moment observation of the needle shaft and tip movement at the time of nerve localization. Hypoechoic structures were stimulated electrically and confirmed to be nerves. CONCLUSIONS: These preliminary data show that the high-resolution L12-L5 probe provides good quality brachial plexus ultrasound images in the superficial locations i.e., the interscalene, supraclavicular, axillary, and midhumeral regions. The needle technique described here for ultrasound-assisted nerve localization provides real-time guidance and is potentially valuable for brachial plexus blocks.     

Brachial Plexus Examination and Localization Using Ultrasound and Electrical Stimulation: A Volunteer Study

Background: Current techniques of brachial plexus block are "blind," and nerve localization can be frustrating and time consuming. Previous studies on ultrasound-assisted brachial plexus blocks are mostly performed with scanning probes of 10 MHz or less. The authors tested the usefulness of a state-of-the-art, high-resolution ultrasound probe (up to 12 MHz) in identifying the brachial plexus in five locations of the upper extremity and in guiding needle advancement to target before nerve stimulation.

Methods: In this prospective observational study, 15 volunteers underwent brachial plexus examination using an L12-L5 MHz probe and a Philips-ATL 5000 ultrasound unit in the interscalene, supraclavicular, infraclavicular, axillary, and midhumeral regions. Thereafter, an insulated block needle was advanced under direct ultrasound guidance to target nerves before confirmation by electrical nerve stimulation in five volunteers in each of the interscalene, supraclavicular, and axillary regions. The quality of brachial plexus images, anatomic variations, and the technique of needle advancement for nerve localization were recorded.

Results: The brachial plexus components were successfully identified in the transverse view as round to oval hypoechoic structures with small internal punctuate echos in all regions examined except the infraclavicular area (visualized in 27% of the cases). The authors' technique of advancing the needle in-line with the ultrasound beam allowed moment-by-moment observation of the needle shaft and tip movement at the time of nerve localization. Hypoechoic structures were stimulated electrically and confirmed to be nerves.     

Ultrasound-guided posterior approach to brachial plexus for the treatment of upper phantom limb syndrome

The purpose of the case is to report the clinical value of the ultrasound-guided posterior approach to the brachial plexus in the treatment of phantom limb syndrome after an upper extremity amputation. The author experienced ultrasound guidance as sole technique to localize the brachial plexus for the purpose of placing a catheter for continuous infusion of a local anesthetic in a patient where standard landmark-based nerve stimulation for placement of a continuous perineural block was not possible.     

Interscalene block with a nerve stimulator: a deltoid motor response is a satisfactory endpoint for successful block

BACKGROUND AND OBJECTIVES: The interscalene brachial plexus block (ISB) is an effective and well-established anesthetic technique for shoulder surgery. Using nerve stimulation as an aid in block placement, a motor response (twitch) in the biceps or a more distal upper limb muscle has been recommended to indicate accurate needle placement. Our clinical experience, as well as anatomic reasoning, suggests that a deltoid twitch may be just as effective as one in the biceps for predicting successful block. This prospective clinical study was undertaken to compare a deltoid with a biceps twitch with respect to onset and success of motor block. METHODS: A total of 160 patients scheduled for shoulder surgery were studied prospectively. Interscalene blocks were performed using neurostimulation according to our standard technique. Twitches of the deltoid or biceps or both, whichever appeared first, were accepted and used as the endpoint for needle placement and injection of local anesthetic. Motor block success, i.e., patient inability to lift the arm against gravity, and minutes to motor block onset were recorded. RESULTS: There was 1 failed motor block in the deltoid group and none in the other groups (not a statistically significant difference). When the same local anesthetic was used, there were no statistically significant differences in onset times between the biceps, deltoid, or biceps/deltoid groups. CONCLUSIONS: A deltoid twitch is as effective as a biceps twitch in determining accurate needle placement for ISB and in predicting successful motor block. Acceptance of a deltoid twitch during ISB eliminates the need for further probing and may translate into better patient acceptance and in a smaller risk of needle-induced nerve damage.     

Upper limb nerve blocks

Regional anaesthesia of the upper limb can be achieved by injecting local anaesthetic solutions into the brachial plexus according to many described techniques. The level at which injections are made into the neurovascular sheath will largely determine the block pattern. Terminal nerves of the brachial plexus can also be blocked further distal than the brachial plexus, either as a sole regional anaesthetic technique, or as a supplement to a brachial plexus block. The popular axillary approach has been the subject of a significant amount of research and it is now largely accepted that multiple-injection techniques provide more complete and reliable analgesia of the arm. A single injection into the plexus using median nerve stimulation often results in insufficient spread of the local anaesthetic to the retroarterial region. This could lead to incomplete anaesthesia because the radial nerve is not blocked. The musculocutaneous nerve also needs to be blocked separately. The advance of ultrasound-guided regional anaesthesia may improve the safety, success rate and ease of performance of some of the methods of brachial plexus block. It has helped the renewed interest in some of the less popular approaches to the brachial plexus, such as the infraclavicular block. However, further research is required to establish the definitive role of ultrasound in this area.     

Bloqueio costoclavicular guiado por ultrassonografia como alternativa para anestesia de membro superior em paciente obeso

Background and objectivesCostoclavicular brachial plexus block is an anesthesia performed through the infraclavicular route described in the literature as a safe and effective route for upper limb anesthesia distal to the elbow. The following report describes the case of a patient whose traditional plexus blocking techniques presented ultrasound visualization difficulty, but the costoclavicular approach was easy to visualize for anesthetic blockade.Case reportA grade 3 obese patient scheduled for repair of left elbow fracture and dislocation. Ultrasound examination revealed a distorted anatomy of the supraclavicular region and the axillary region with skin lesions, which made it impossible to perform the blockade in these regions. It was decided to perform an infraclavicular plexus block at the costoclavicular space, where the brachial plexus structures are more superficial and closer together, supported by a muscular structure, lateral to all adjacent vascular structures and with full view of the pleura. The anesthetic block was effective to perform the procedure with a single injection and uneventfully.ConclusionCostoclavicular brachial plexus block is a good alternative for upper limb anesthesia distal to the elbow, being a safe and effective option for patients who are obese or have other limitations to the use of other upper limb blocking techniques.     

Comparative evaluation of ultrasound-guided continuous infraclavicular brachial plexus block with stimulating catheter and traditional technique: a prospective-randomized trial

Background: Secondary catheter failure has been reported in up to 40% of patients with continuous peripheral nerve blocks resulting in failure to provide pain relief after the initial block wears off. Introduction of stimulating catheters as well as ultrasound for regional anaesthesia has facilitated correct placement of catheter tip, closer to the plexus. This randomized study was conducted to compare the efficacy of continuous infraclavicular brachial plexus blocks using non-stimulating catheter, stimulating catheter and ultrasound-guided catheter placement with nerve stimulation assistance.
Methods: Patients undergoing elective hand surgery were randomly allocated to receive continuous infraclavicular brachial plexus block using non-stimulating catheter [group traditional nerve stimulation (TR)], stimulating catheter [group stimulating catheter (ST)] or ultrasound-guided catheter placement with nerve stimulation assistance [group ultrasound guidance with nerve stimulation assistance (US)]. Motor and sensory blocks were assessed every 5 min and primary block success was determined at 30 min. After resolution of the primary block, threshold stimulating current and resulting response, spread of drug on re-injection as seen ultrasonographically and the capacity to re-establish block was documented. Complications and need for supplement was noted.
Results: The primary block success was significantly higher in the US group [96% US, 58% ST, 59% TR ( P =0.0005)]. Secondary catheter failure was significantly lower in the US group [9% US, 17% ST, 86% TR ( P <0.0001)]. Axillary nerve was blocked more predictably in the US group (100% US, 79% ST, 50% TR ( P =0.0003).
Conclusion: In this study, ultrasound guidance with nerve stimulation assistance significantly improved primary success and reduced secondary catheter failure in continuous infraclavicular brachial plexus blocks.     

Ultrasound-guided infraclavicular brachial plexus block

Background. Peripheral nerve blocks are almost always performedas blind procedures. The purpose of this study was to test thefeasibility of seeing individual nerves of the brachial plexusand directing the block needle to these nerves with real timeimaging. Methods. Using ultrasound guidance, infraclavicular brachialplexus block was performed in 126 patients. Important aspectsof this standardized technique included (i) imaging the axillaryartery and the three cords of the brachial plexus posteriorto the pectoralis minor muscle, (ii) marking the position ofthe ultrasound probe before introducing a Tuohy needle, (iii)maintaining the image of the entire length of the needle atall times during its advancement, (iv) depositing local anaestheticaround each of the three cords and (v) placing a catheter anteriorto the posterior cord when indicated. Results. In 114 (90.4%) patients, an excellent block permittedsurgery without a need for any supplemental anaesthetic or conversionto general anaesthesia. In nine (7.2%) patients local or perineuraladministration of local anaesthetic, and in three (2.4%) conversionto general anaesthesia, was required. Mean times to administerthe block, onset of block and complete block were 10.0 (SD 4.4),3.0 (1.3) and 6.7 (3.2) min, respectively. Mean lidocaine dosewas 695 (107) mg. In one patient, vascular puncture occurred.In 53 (42.6%) patients, an indwelling catheter was placed, butonly three required repeat injections, which successfully prolongedthe block. Conclusion. The use of ultrasound appears to permit accuratedeposition of the local anaesthetic perineurally, and has thepotential to improve the success and decrease the complicationsof infraclavicular brachial plexus block. Br J Anaesth 2002; 89: 254–9