Ultrasound-guided Pec Infiltration With Liposomal Bupivacaine for Breast Surgery: A Prospective Randomized Study

For the Pec infiltration, the patient will be in the supine position. The pectoralis major and pectoralis minor muscle layers will be identified via ultrasound. Using sterile technique, a nerve block needle will be inserted and advanced under ultrasound guidance until it is below the fascial covering of the pec minor muscle layer. Gentle aspiration for air or blood will be performed in 5cc incremental doses. Then injection of 10 mL of bupivacaine 0.25% with epinephrine 1:200,000 and 10mL of a mixture of liposomal bupivacaine and saline (5 mL liposomal bupivacaine and 5 mL saline) for a total injection for pec 1 block of 20 mL. For each 5cc of local anesthetic injected, aspiration will be performed. Upon completion of the injection the needle will be removed. The investigators will then use the ultrasound probe to identify the second rib on anterolateral chest wall and move the probe to the 4th rib. Here the investigators will identify the pec minor and serratus anterior muscles. They will advance their needle under ultrasound-guidance beneath pec minor and above serratus anterior. Here an injection 10 mL 0.25% bupivacaine with epinephrine 1:200,000 followed by 20 mL mixture of 15 mL liposomal bupivacaine and 5 mL saline for a total volume of 30ml for Pec 2. block will occur.

Upon completion of the injection, the needle will then be removed and the patient will be monitored in the preoperative area until he/she is brought into the operating room for their procedure.

If deemed necessary for coverage the surgeon will be allowed to inject additional local anesthetic up to a maximum of 40 mL of 0.25% bupivacaine. This will be noted in the chart.

For the surgeon infiltration, the patient will be brought directly to the operating room where intraoperative anesthetic with an opioid-sparing MAC technique will be provided as described below. Just prior to the skin incision, 0.25% bupivacaine will be used to infiltrate the dermis and subcutaneous space in the proposed incision. Throughout the procedure, additional incisional bupivacaine infiltration into the surrounding tissues will be performed as needed for local anesthesia. A total of up to 30 mL of 0.25% bupivacaine will be divided equally for the two sides of the incision. An additional 5 mL of 0.25% bupivacaine will be infiltrated into the pectoralis major muscle at the deep margin of resection. Accidental intravascular injection is minimized by continuous needle movement and frequent aspiration.

The following vital signs will be monitored throughout the procedure: Heart rate, blood pressure, oxygen saturation, and respirations, and patient's state of consciousness. The investigators will monitor the patient until they are brought to the operating room for surgery.