A Novel Nerve Block Technique for a Patient Undergoing Cardiac Device Implantation

A woman with type 1 myotonic dystrophy received an implantable cardioverter-defibrillator using a novel combination of ultrasound-guided supraclavicular nerve and pectoral nerve blocks. The entire procedure was completed without any procedural sedation or local anesthetic, and the patient did not experience any pain during or after the procedure. (Level of Difficulty: Advanced.)


PAST MEDICAL HISTORY
The patient has a history of myotonic dystrophy type 1, paroxysmal AF, urinary incontinence, and postural hypotension.

INVESTIGATIONS
Her 14-day Holter monitor did not capture any presyncopal spells but recorded AF 100% of the time. Her electrocardiogram demonstrated AF and a normal

LEARNING OBJECTIVES
To describe the relevant neuroanatomy of the chest wall to a colleague or patient undergoing CIED implantation to ensure they understand and are comfortable with the procedure. To weigh the advantages and disadvantages of the nerve block procedure in patients undergoing CIED implantation to ensure appropriate patient selection. To perform the SCN and pectoral nerve block technique in patients undergoing CIED implantation to improve perioperative pain control. The nerve block was performed at least 30 to 60 minutes pre-procedure to allow adequate time for the block to take effect. For the supraclavicular (SCN) nerve block, 20 mL of 0.5% bupivacaine, long-acting local anesthetic, was prepared (ropivacaine 0.5% is another option). A high-frequency linear ultrasound transducer (at least 13 MHz) was used to locate the SCN in the lower third of the lateral neck. The nerve is superficial to the prevertebral fascia above the middle scalene muscle (Figure 1). A 25-G needle was used to instill 3 to 5 mL of local anesthetic next to the nerve under direct ultrasound visualization.
Pectoral nerve (PECS) 1 block was performed by placing the transducer 1 to 2 cm below the clavicle to visualize the thoracic branch of the thoracoacromial artery as a landmark lying in the space between the pectoralis major and minor muscles, as the nerves cannot be reliably visualized under ultrasound in this region ( Figure 2). Approximately 15 mL of local anesthetic was injected into the plane between the pectoralis major and minor muscles, which distributes along the muscular plane to anesthetize the PECS.
Small injections with fine needle adjustments were required to ensure anesthetic was injected into the interfacial layer, and not into the muscle.
After the nerve block procedure was completed, the patient was observed for 60 minutes, which allowed the anesthetic to take effect. Pre-procedural pin-prick test revealed dense and complete sensory loss over the infraclavicular zone, extending 5 cm below the clavicle, indicating a successful SCN block.
Advancing the needle to the muscle confirmed a successful sensory block of the PECS 1. As both nerve blocks were successful, no additional local anesthetic was given up front.
The patient then underwent routine implantation of a dual-chamber implantable cardioverterdefibrillator in the left pre-pectoral area. The patient was comfortable and awake during the entire procedure and did not require local anesthetic or  (C) Injection of the local anesthetic into the fascia between the pectoralis major and minor muscles taking care not to injure the blood vessels. PEC ¼ pectoral nerve; SCN ¼ supraclavicular nerve.

SUMMARY
The SCN and PECS 1 nerve blocks can be used as a primary mode of anesthesia for patients undergoing pre-pectoral CIED implantation to minimize or eliminate the use of intravenous sedation and local anesthetic. Further studies are required to assess the feasibility, safety, and benefits of using this as a routine approach.

FUNDING SUPPORT AND AUTHOR DISCLOSURES
The authors have reported that they have no relationships relevant to the contents of this paper to disclose. Antiperovitch@lhsc.on.ca.