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Blockade of the brachial plexus effectively provides anesthesia to the upper limb from the shoulder to the fingertips. Approaches to blocking the brachial plexus depend on the indication, planned surgery or procedure, patient-specific body habitus, medical comorbidities, and individual anatomical variants. This activity will address the indications, ultrasound probe placement, sonoanatomy, and steps in the technique of the ultrasound-guided interscalene block, superior trunk block, supraclavicular brachial plexus block, infraclavicular brachial plexus block, and axillary brachial plexus block. This activity also highlights the role of the interprofessional team in implementing use of brachial plexus blocks to improve patient outcomes in the perioperative period. Objectives: Identify the sonoanatomy of the brachial plexus that is relevant to brachial plexus blockade. Select a brachial plexus block that best suits the clinical presentation. Manage the complications of a brachial plexus block. Apply effective strategies to improve care coordination among interprofessional team members to facilitate positive outcomes for patients undergoing a brachial plexus block. Access free multiple choice questions on this topic.

Blockade of the brachial plexus effectively provides anesthesia to the upper limb from the shoulder to the fingertips. Approaches to blocking the brachial plexus depend on the indication, planned surgery or procedure, patient-specific body habitus, medical comorbidities, and individual anatomical variants. This review addresses the indications, ultrasound probe placement, and sonoanatomy for the ultrasound-guided interscalene block, superior trunk block, supraclavicular brachial plexus block, infraclavicular brachial plexus block, and axillary brachial plexus block.[1][2][3] It is well established that brachial plexus blocks provide superior postoperative pain management compared to general anesthesia alone. Using catheter-based continuous infusions for brachial plexus blocks is superior to single-injection brachial plexus blocks for decreasing perioperative pain scores and opioid consumption requirements for various upper extremity surgeries.[4][5] Intraoperative intra-articular shoulder infiltration is generally less effective than preoperative brachial plexus blocks.[6] While there may be some cost-saving aspects to using brachial plexus blocks as the sole anesthetic compared to general anesthesia, this is only true if there is no need to utilize general anesthesia as a rescue technique. This emphasizes the supreme importance of successful block placement and management in maintaining cost-efficient practices.[7] Exact needle placement is vital for successful block delivery. The choice and placement of the ultrasound probe are key factors in successfully using brachial plexus blocks. In addition, proper anatomic recognition is essential for successful ultrasound-guided brachial plexus blockade and patient safety.[8] Ultrasound-guided interscalene block requires a high-frequency linear transducer placed on the posterolateral aspect of the neck at an angle parallel to the skin surface, between the anterior and middle scalene muscles. A low-frequency curvilinear transducer can guide a supraclavicular block, while a curved array transducer can be used for infraclavicular and axillary blocks.

Exact needle placement is vital for successful block delivery. The choice and placement of the ultrasound probe are key factors in successfully using brachial plexus blocks. In addition, proper anatomic recognition is essential for successful ultrasound-guided brachial plexus blockade and patient safety.[8] Ultrasound-guided interscalene block requires a high-frequency linear transducer placed on the posterolateral aspect of the neck at an angle parallel to the skin surface, between the anterior and middle scalene muscles. A low-frequency curvilinear transducer can guide a supraclavicular block, while a curved array transducer can be used for infraclavicular and axillary blocks. The anatomy of the brachial plexus comprises six anatomical structures: nerve roots, trunks, divisions, cords, and terminal branches.[9] The nerve roots are superimposed on the vertebral bodies in the posterior triangle, and their visualization depends upon proper probe positioning. When scanned in short axis orientation, the nerve appears hyperechoic with a hypoechoic background. The nerves are encased in connective tissue sheaths, which appear hypoechoic on ultrasound imaging.[10] These anatomical structures should be identified during an ultrasound-guided brachial plexus block procedure before injection.[11] Identifying vascular structures, such as arterial vessels that traverse through or around neurovascular bundles during brachial plexus blockade, is essential.[12] Various color Doppler techniques may help identify vascular structures before needle insertion, especially during axillary blocks with a greater possibility of traversing vessels than other approaches. In conclusion, blockade of the brachial plexus can provide significant postoperative pain relief in upper extremity surgery compared to general anesthesia alone. However, to ensure safety and efficacy, it is essential to have accurate knowledge of sonoanatomy and select the best approach based on patient characteristics. Furthermore, careful consideration must be given to needle placement and avoidance of vascular structures.[13]

All nerve blocks risk nerve injuries such as neuropraxia or neurotmesis due to multiple factors, including inadvertent intraneural injection, local anesthetic neurotoxic properties, hematoma formation, and physical damage from the block needle. However, a recent systematic review found no association between the type of brachial plexus block and the peripheral nerve injury incidence.[33] Local anesthetic systemic toxicity should also be considered a complication for all nerve blocks. Before placing a nerve block, ensure that the total dose of local anesthetic to be injected is less than the theoretical toxic dose for the used anesthetic. Listed below are complications unique to each approach for brachial plexus blockade.[34][35] The interscalene brachial plexus block may cause ipsilateral phrenic nerve palsy resulting in hemidiaphragmatic paralysis, vascular injury including vertebral artery puncture, Horner syndrome, subdural block, and injury to brachial plexus. The superior trunk block may also cause ipsilateral phrenic nerve palsy, although at a possibly lower incidence than the interscalene block. Other complications include injury to the brachial plexus, surrounding vasculature, or the dorsal scapular nerve, which typically courses through the middle scalene muscle where the superior trunk inserts. The supraclavicular brachial plexus block carries the clinically-significant risks of pneumothorax and subclavian arterial puncture. Ipsilateral hemidiaphragmatic paralysis is a known complication, but the risk is much lower than an interscalene block. In addition, ulnar nerve sparing may occur if full anesthetic spread is not achieved between the first rib and the plexus. Complications of the infraclavicular brachial plexus block include injury to the brachial plexus, specifically the lateral and posterior cords, and injury to axillary vessels. Sparing of the medial cord may occur with the inadequate spread of local anesthetic around the axillary artery. In addition, the thoracoacromial artery and cephalic vein may lie in the needle path of the traditional approach. The axillary brachial plexus block has virtually no risk of causing a pneumothorax. The color Doppler is recommended to avoid an inadvertent vascular puncture and injection resulting in local anesthetic systemic toxicity.[33]

Skills Knowing how to perform a brachial plexus block is very useful as it allows the surgeon to perform a range of procedures on the ipsilateral arm. While an anesthesiologist usually performs a brachial plexus block, the nurse's role is vital. During the block, a nurse must observe the patient's vital signs for changes. Additionally, the nurse must frequently auscultate lung sounds to ensure that air entry is bilateral and equal; these procedures can be associated with a pneumothorax.[39] After the procedure, a portable x-ray is recommended to ensure no pneumothorax or diaphragmatic elevation.[40] Adept anesthesia providers can confirm the presence or absence of pneumothorax and elevated diaphragm in real-time via ultrasound, which is both sensitive and specific and avoids delays in diagnosis.[41] Strategy It is most appropriate and ideal to maintain continuous closed-loop communication between all members of the perioperative care team regarding the need, technique, and potential management issues associated with the brachial plexus block utilized. Ethics It is necessary to obtain thorough and comprehensive informed consent from either the patient or patients without the capacity to consent from their designated and authorized decision maker before placing any brachial plexus block. It is most appropriate for all team members to feel empowered to state any concerns they might have regarding the process, as this ensures buy-in from all stakeholders and provides additional layers of review and insight into any problematic matters as soon as possible. Responsibilities All team members must communicate their concerns, responsibilities, and activities with all other team members contemporaneously and as indicated throughout the perioperative period, based on their professional discretion. Interprofessional Communication All team members should respect the free flow of information and concerns among team members without allowing or producing an environment of hostility. Care Coordination All interprofessional team members should consider it their duty to neither disrupt the work done by other team members nor to, through their actions or inaction, create additional issues or increase the workload for other team members. [Level 5]