Ultrasound-guided Axillary Research Articles

Is the Musculocutaneous Nerve Really in the Coracobrachialis Muscle When Performing an Axillary Block? An Ultrasound Study

In reference textbooks describing axillary block, the ulnar, radial, and median nerves are located in a common sheath surrounding the axillary artery. In contrast, the musculocutaneous nerve is described as lying outside this sheath in the coracobrachialis muscle. In a recent case report of ultrasound-guided axillary block, the musculocutaneous nerve was joined to the median nerve outside this muscle. Our study evaluated the prevalence of atypical musculocutaneous nerve localizations during axillary block. All patients undergoing ultrasound-guided axillary block were included from December 2006 to December 2008. Before needle insertion, musculocutaneous, median, ulnar, and radial nerves were localized using ultrasound. Nerve stimulation confirmed atypical nerve localization. After injection of local anesthetics, musculocutaneous and median nerve anatomical relationships were observed. The musculocutaneous nerve was outside the coracobrachialis muscle in 83 of the 387 analyzed blocks (22%). It was near the axillary artery in 22 cases (6%). The musculocutaneous and median nerves appeared as a common neural structure in 61 cases (16%). After local anesthetic injection, a common trunk persisted in 16 of 61 cases (26%), musculocutaneous and median nerves separated in 37 cases (61%), and 2 roots of the median nerve appeared (with or without a separated musculocutaneous nerve) in 6 cases (10%). Two cases (3%) remained undefined. Ulnar nerve location of the 83 patients with atypical musculocutaneous nerve position differed from the ones with a classical musculocutaneous nerve localization. During axillary block, the musculocutaneous nerve is outside the coracobrachialis muscle in 1 of 5 patients. This atypical location should be considered during performance of axillary blockade to avoid repeated IM puncture.

A Prospective, Randomized, Double-Blind Comparison of Ultrasound-Guided Axillary Brachial Plexus Blocks Using 2 Versus 4 Injections

In this prospective, randomized, double-blind study, we compared the effectiveness and time efficiency of perioperative axillary blocks performed via 2 different techniques, 1 involving 2 and the other 4 separate skin punctures. One hundred twenty patients undergoing upper limb surgery were randomized to receive either (1) an axillary brachial plexus block involving 2 injections, with 30 mL local anesthetic injected posterior to the axillary artery (with redirection, as needed, to achieve circumferential spread), plus 10 mL local anesthetic to the musculocutaneous nerve, guided by ultrasound (group 1, n = 56); or (2) 4 separate 10-mL injections to the median, ulnar, radial, and musculocutaneous nerves, using a combined ultrasound and neurostimulation technique (group 2, n = 58). All patients received 40 mL of 0.5% ropivacaine with 1:400,000 epinephrine. The primary outcome was the success rate of the block, defined as anesthesia adequate for surgery. Secondary outcomes were the time to administer the block, time to the onset of motor-sensory block, time to surgical readiness, and incidence of adverse events. The 2-injection technique was slightly faster to administer (8 vs 11 minutes, P = 0.003). The mean nerve block score was slightly higher for the 4-injection group at the 10-, 15-, 20-, and 30-minute time points, but the cumulative percentages of blocks having taken effect were not significantly different over these time points, at 0.0%, 5.4%, 12.5%, and 37.5% among those who had received a 2-injection block versus 6.9%, 10.4%, 19.0%, and 48.3%, respectively, with the 4-injection block (P = 0.20). There was no difference in the percentage of patients with complete block by 30 minutes (32.1% vs 37.5%, P = 0.55) or in final block success rates (89.3% vs 87.9%, P = 0.99). An ultrasound-guided 2-injection axillary block may be as effective as, and more time efficient than, a 4-injection technique.

The learning process of the hydrolocalization technique performed during ultrasound-guided regional anesthesia

Because poor echogenicity of the needle remains a safety issue, we decided to analyze the learning process of the hydrolocalization technique (Hloc) performed to continuously identify needle-tip anatomical position during many ultrasound-guided regional anesthesia procedures. Ten senior anesthesiologists naïve to the Hloc agreed to participate in the study. They were requested to perform 40 out-of-plane (OOP) approach ultrasound-guided axillary blocks (AB) each using the Hloc. The Hloc, which is a needle-tip localization principle, was performed by means of repetitive injections of a small amount of a local anesthetic solution (0.5-1 ml) under an ultrasound beam. Details of the learning process and skill acquisition of the Hloc were derived from the following parameters: the duration of block placement, a measure of the perceived difficulty of needle-tip visualization, a measure of block placement difficulty, and the amount of local anesthetics solution required for the technique. Four hundred ABs were performed. The success rate of an ultrasound-guided AB was 98%. The Hloc was successful in all patients. Skill acquisition over time of the Hloc was associated with a significant reduction of both the duration and the perceived difficulty of ABs placement. Apprenticeship data revealed that 20 blocks were required to successfully place AB within 5 min in most cases using the Hloc. The Hloc performed during the OOP approach of ultrasound-guided regional anesthesia is a simple technique with a relatively short learning process feasible for efficient placement of ABs.

Ultrasound-Guided Axillary Brachial Plexus Block with 20 Milliliters Local Anesthetic Mixture Versus General Anesthesia for Upper Limb Trauma Surgery: An Observer-Blinded, Prospective, Randomized, Controlled Trial

Ultrasound-Guided Axillary Brachial Plexus Block with 20 Milliliters Local Anesthetic Mixture Versus General Anesthesia for Upper Limb Trauma Surgery: An Observer-Blinded, Prospective, Randomized, Controlled Trial

A Slide to the Radial Nerve During Ultrasound-Guided Axillary Block

A Slide to the Radial Nerve During Ultrasound-Guided Axillary Block

A Musculocutaneous Nerve Variation Described During Ultrasound-Guided Axillary Nerve Block

A Musculocutaneous Nerve Variation Described During Ultrasound-Guided Axillary Nerve Block

Failure of lipid emulsion to reverse neurotoxicity after an ultrasound-guided axillary block with ropivacaine and mepivacaine

lipid a second generalized convulsion appeared and this was terminated by 125 mg of thiopental. Blood samples were taken 1 h after the anesthetic procedure to assess the venous plasma concentration of ropivacaine and mepivacaine. Because of the patient’s history of syncope, brain computed tomography (CT) was performed after the surgery. It was normal. The concentrations of local anesthetics were high, at 1.45 μg·ml −1 for ropivacaine and 4.80 μg·ml −1 for mepivacaine. Postoperative electrocardiogram showed no signs of arrhythmia or changes in the PQ or QT intervals or QRS width. After 3 h the tracheal tube was removed. The brachial plexus showed no impairment of sensory function. The patient woke up without any sequelae. Intralipid (Baxter Healthcare) has been reported as being able to reverse neurologic and cardiac complications due to the administration of local anesthetics [5]. We report here a second convulsion after the administration of Intralipid in a patient anesthetized with propofol and mechanically ventilated (to control acidosis). Several hypotheses can be suggested to explain this fi nding: fi rst, the dose of Intralipid (4.16 ml·kg −1 ; 250 ml) was insuffi cient; second, Intralipid was not effi cient enough to decrease the blood concentration of the local anesthetics; and third, the administration of the lipid emulsion was too late (15 min after the beginning of the seizure). Moore [6] advises injecting lipid emulsion after classical resuscitation failure. We think it must be administered as soon as possible after intubation concomitantly with other drugs. Furthermore, with ultrasonographic guidance, direct intravascular injection could probably have been avoided. However, the resorption of local anesthetic into cellular tissues 20 min after the injection cannot be excluded. Ultrasonographic guidance associated with electric stimulation may make the technique of peripheral nerve block more secure, but it is not an absolute guarantee of safety.

Ultrasound-Guided Axillary Brachial Plexus Block with 20 Milliliters Local Anesthetic Mixture Versus General Anesthesia for Upper Limb Trauma Surgery: An Observer-Blinded, Prospective, Randomized, Controlled Trial

We performed a randomized, controlled trial comparing low-dose ultrasound-guided axillary block with general anesthesia evaluating anesthetic and perioperative analgesic outcomes. Patients were randomized to either ultrasound-guided axillary block or general anesthesia. Ultrasound-guided axillary block was performed using a needle-out-of-plane approach. Up to 5 mL of local anesthetic injectate (equal parts 2% lidocaine with 1:200,000 epinephrine and 0.5% bupivacaine with 7.5 mg/mL clonidine) was injected after identifying the median, ulnar, radial, and musculocutaneous nerves. A maximum of 20 mL local anesthetic injectate was used. General anesthesia was standardized to include induction with fentanyl and propofol, maintenance with sevoflurane in an oxygen/nitrous oxide mixture. Pain scores were measured in the recovery room and at 2, 6, 24, 48 h, and 7 days. Ability to bypass the recovery room and time to achieve hospital discharge criteria were also assessed. All ultrasound-guided axillary block patients achieved satisfactory anesthesia. The ultrasound-guided axillary block group had lower visual analog scale pain scores in the recovery room (0.3 [1.3] vs 55.8 [36.5], P < 0.001), and visual rating scale pain scores at 2 h (0.3 [1.3] vs 45 [29.6], P < 0.001), and at 6 h (1.1 [2.7] vs 4 [2.8], P < 0.01). All ultrasound-guided axillary block patients bypassed the recovery room and attained earlier hospital discharge criteria (30 min vs 120 min 30/240 P < 0.0001 median [range]). Ultrasound-guided axillary brachial plexus block with 20 mL local anesthetic mixture provided satisfactory anesthesia and superior analgesia after upper limb trauma surgery when compared with general anesthesia.

An Estimation of the Minimum Effective Anesthetic Volume of 2% Lidocaine in Ultrasound-guided Axillary Brachial Plexus Block

Ultrasound guidance facilitates precise needle and injectate placement, increasing axillary block success rates, reducing onset times, and permitting local anesthetic dose reduction. The minimum effective volume of local anesthetic in ultrasound-guided axillary brachial plexus block is unknown. The authors performed a study to estimate the minimum effective anesthetic volume of 2% lidocaine with 1:200,000 epinephrine (2% LidoEpi) in ultrasound-guided axillary brachial plexus block. After ethical approval and informed consent, patients undergoing hand surgery of less than 90 min duration were recruited. A step-up/step-down study model was used with nonprobability sequential dosing based on the outcome of the previous patient. The starting dose of 2% LidoEpi was 4 ml per nerve. Block failure resulted in a dose increase of 0.5 ml; block success in a reduction of 0.5 ml.A blinded assistant assessed sensory and motor blockade at 5-min intervals up to 30 min. Block performance time and duration were measured. Two predetermined stopping points were used; a minimum of five consecutive block success/failures and five consecutive successful blocks at 1 ml per nerve. The study was terminated when five consecutive patients had successful blocks using 1 ml of 2% LidoEpi per nerve (overall group n = 11). All five patients had surgical anesthesia within 10 min. The mean (SD) block performance time was 445 (100) s, and block duration was 190 min (range 120-310 min). All surgical procedures were performed under regional anesthesia with anxiolytic sedation provided in 3 of 11 cases. Successful ultrasound-guided axillary brachial plexus block may be performed with 1 ml per nerve of 2% LidoEpi.

Early Detection of Intravascular Injection During Ultrasound-Guided Axillary Brachial Plexus Block

Early Detection of Intravascular Injection During Ultrasound-Guided Axillary Brachial Plexus Block

Ultrasound-guided Peripheral Nerve Blocks and Intravascular Injection

Clement Zablocki VA Medical Center and Medical College of Wisconsin, Milwaukee, Wisconsin. hshankar@mcw.eduTo the Editor: —In the April issue of Anesthesiology, Loubert et al. 1and Zetlaoui et al. 2reported about possible intravascular injection after an ultrasound-guided axillary block. Their reports highlight the need for vigilance in the performance of ultrasound-guided blocks. This and similar reports of complications3–5after ultrasound-guided regional blocks reinforce the need for proper training, and the understanding that ultrasound, after all, is only a tool. Any tool should be used with full cognizance of its limitations. The major limitations of ultrasound-guided blocks are technical,6including the angle of incidence, needle visualization, and possibly artifacts.7,8Training in the proper holding of the probe while analyzing and while injecting help overcome some of the complications. Sometimes even with proper training, complications do occur.4The reports1,2have similarities and differences besides the ultrasound-guided axillary block and intravascular complication leading to seizure. One of them described the changes in vital signs,1and the other reports some technical difficulties in getting the data.2Needle visualization was an issue in both reports. Using an out-of-plane approach may have prevented proper needle visualization because only a cross section of the needle anywhere in the length of the needle may be seen and mistaken for the tip, although tissue movement may have been seen. With the in-plane approach used in the other report, needle artifacts may have prevented proper visualization, which will only be discerned when the injectate spread is noticed. Both reports mention distortion of tissues, one due to probe pressure and the other due to local anesthetic already injected.There is no documentation in either of the reports of having seen other vessels in the proximity before the actual needle placement. Assuming they used color flow Doppler, the default settings for the color Doppler cannot detect small vessels unless the color velocity range and the angle of steering are adjusted. It is possible that they did not visualize the needle during the performance of the block and hence did not adhere to one of the safety principles that they have mentioned. Any of these situations could have led to the complication. Most importantly, they were both performed by residents.My practice is to perform a preliminary scout scan, including a color flow study, to visualize the target and its associated neighboring structures and demonstrate to the trainee. This permits proper guidance during the actual performance of the block. Could they have avoided the intravascular injection by using landmarks or nerve stimulation? Probably not.To elevate ultrasound-guided to the next level and call it a “bulletproof technique” by the more “vocal proponents”6is a dream awaiting fruition with some more technological advancements and changes in needle design. In the meantime, adhering to some basic principles will avoid potential complications. To blame the ultrasound for complications due to technical and possibly inadequate training is, in my opinion, tarnishing a useful technique without understanding its advantages and mainly its limitations. There is an increasing need for a proper curriculum and training to fully understand the technique, the potential pitfalls, and the complications of ultrasound-guided blocks.9Clement Zablocki VA Medical Center and Medical College of Wisconsin, Milwaukee, Wisconsin. hshankar@mcw.edu

Intravascular Injection During Ultrasound-Guided Axillary Block: Negative Aspiration Can Be Misleading

Needle visualization is an advantage of ultrasound-guided nerve blocks compared to traditional methods of nerve localization. However, visualization of local anesthetic spread is also important. During an ultrasound-guided axillary block, there was negative aspiration for blood. However, the absence of local anesthetic spread on ultrasound imaging suggested possible intravascular injection. The ultrasound transducer was removed from the patient's arm and venous blood was aspirated from the nerve block needle. Pressure applied to an ultrasound transducer can occlude venous structures making negative aspiration of blood unreliable for excluding intravascular needle placement.

522: An Anatomical Study of the Radial Nerve in Patients Undergoing Ultrasound-Guided Axillary Brachial Plexus Blockade

522: An Anatomical Study of the Radial Nerve in Patients Undergoing Ultrasound-Guided Axillary Brachial Plexus Blockade

An Anatomical Study of the Radial Nerve in Patients Undergoing Ultrasound-Guided Axillary Brachial Plexus Blockade

An Anatomical Study of the Radial Nerve in Patients Undergoing Ultrasound-Guided Axillary Brachial Plexus Blockade

An Estimation of the Minimum Effective Anaesthetic Volume of 2% Lidocaine in Ultrasound-Guided Axillary Brachial Plexus Block

An Estimation of the Minimum Effective Anaesthetic Volume of 2% Lidocaine in Ultrasound-Guided Axillary Brachial Plexus Block

87: Ultrasound-Guided Axillary Brachial Plexus Block Versus General Anaesthesia for Upper Limb Trauma Surgery: An Observer Blinded Prospective, Randomised, Controlled Trial

87: Ultrasound-Guided Axillary Brachial Plexus Block Versus General Anaesthesia for Upper Limb Trauma Surgery: An Observer Blinded Prospective, Randomised, Controlled Trial

522. An Anatomical Study of the Radial Nerve in Patients Undergoing Ultrasound-Guided Axillary Brachial Plexus Blockade

522. An Anatomical Study of the Radial Nerve in Patients Undergoing Ultrasound-Guided Axillary Brachial Plexus Blockade

87. Ultrasound-Guided Axillary Brachial Plexus Block Versus General Anaesthesia for Upper Limb Trauma Surgery: An Observer Blinded Prospective, Randomised, Controlled Trial

87. Ultrasound-Guided Axillary Brachial Plexus Block Versus General Anaesthesia for Upper Limb Trauma Surgery: An Observer Blinded Prospective, Randomised, Controlled Trial

369. An Estimation of the Minimum Effective Anaesthetic Volume of 2% Lidocaine in Ultrasound-Guided Axillary Brachial Plexus Block

369. An Estimation of the Minimum Effective Anaesthetic Volume of 2% Lidocaine in Ultrasound-Guided Axillary Brachial Plexus Block

Ultrasound-Guided Axillary Brachial Plexus Block Versus General Anaesthesia for Upper Limb Trauma Surgery: An Observer Blinded Prospective, Randomised, Controlled Trial

Ultrasound-Guided Axillary Brachial Plexus Block Versus General Anaesthesia for Upper Limb Trauma Surgery: An Observer Blinded Prospective, Randomised, Controlled Trial