Parasternal Subpectoral Plane Blocks for Cardiac Surgery Via a Midline Sternotomy

Subjects will be randomized to receive PSPB catheters infusing either bupivacaine or saline. Randomization will be achieved using a computer-generated randomization scheme. The surgeon, nurse, anesthetist and patient will be blinded. The investigational drug service will prepare blinded solutions (bupivacaine 0.2% or saline syringes) for performance of the block. They will also prepare bags (either bupivacaine 0.125% or saline) to be infused through the catheter. Following skin closure, but before removal of the surgical drapes, regional anesthesiologists will scrub in, gown and perform the placement of PSPB catheters under strict surgical aseptic technique. Real-time ultrasound (US) imaging will be used to visualize the pectoralis major muscle and its corresponding rib cartilages, and a needle/introducer sheath will be guided parasternally into the fascial plane. The needle will be advanced in the plane, hydro-dissecting with 30 mL of bupivacaine 0.2% in the study group or 30 mL of saline in the control group per side. Following hydro-dissection, a 5 in. multiport catheter will be inserted via the sheath, and the catheter will be secured following US confirmation of appropriate catheter position. This procedure will then be repeated on the other side. After completion of bilateral PSPB catheters, patients will remain intubated and be transferred to the CSICU on a sedation regimen at the discretion of the intraoperative anesthesia team. Upon dropping off to the ICU, each catheter will be attached to a programmable pump infusing plain bupivacaine 0.125% at 10 mL/hr or saline infusing at 10 mL/hr. Once again, the solution to be infused postoperatively will be prepared by pharmacy and blinded from the patient, nurse, and postoperative pain service providers.