Liposomal Bupivacaine Vs Bupivacaine with Dexmedetomidine in Erector Spinae Plane Blocks for Mastectomies

Inclusion Criteria: * Patients requiring any variation of mastectomy with or without axillary lymph node dissection. * Patient agrees to a peripheral nerve block. * Patient agrees to be a study participant. * APS team believes a peripheral nerve block would be appropriate for the patient after reviewing medical/surgical history. * Surgeon agrees with the block plan by APS. Exclusion Criteria: * Patient declines a peripheral nerve block. * Patient declines to be a study participant. * APS team believes a peripheral nerve block is not clinically indicated. * Surgeon does not want a peripheral nerve block. * Patient has allergy to local anesthestic. * Patient has an active infection at the site of the peripheral nerve block. * Patient with pre-existing neural deficits along the distribution of the block. * Patient with coagulopathy. * Patient taking antithrombotic drugs outside the ASRA guidelines. * Patients weight is less that 50 kg due to concerns for local anesthetic toxicity syndrome.