Patient Controlled Epidural Analgesia Versus Intravenous Patient Controlled Analgesia for Post-Operative Pain Control in Patients Undergoing Elective Liver Resection

Inclusion Criteria: * Adults (age 18 years or older) who are able to provide informed consent. * Patients undergoing open elective liver resection for primary liver pathology (benign or malignant) or secondary metastatic liver disease, including patients undergoing concomitant surgical procedures (such as colorectal resection or debulking procedures), with no contraindication to the insertion of an epidural catheter (localized infection, septicemia, or pre-operative coagulopathy). Exclusion Criteria: * Patients with a history of documented anaphylaxis or contraindication to any of the study medications or standardized intra-operative medications. These include dilaudid, fentanyl, and bupivacaine. * Patients with pain at rest or with movement measured by NRS \>2. * Patients receiving high dose opioids on a chronic basis (greater than or equivalent to 60mg of morphine per day). * Patients with severe chronic obstructive pulmonary disease (COPD) defined as an FEV1 \<50%. * Patients with significant cognitive impairment or documented psychologic impairment. * Contraindication to epidural catheter placement including bleeding diathesis (essential thrombocythemia, idiopathic thrombocytopenic purpura, von Willebrand disease, and hemophilia A or B), neurological dysfunction (multiple sclerosis, subacute myelo-opticoneuropathy or preexisting lower limb neurological deficit), prior extensive spinal surgery or major spinal deformity, pre-operative use of anti-coagulant with planned use of therapeutic dose of anti-coagulant in post-operatively, documented pre-operative coagulopathy (INR greater than 1.3 not on Coumadin or PTT greater than 42), platelets less than 100,000/μL, or evidence of infection at potential epidural site. * Cirrhotic patients. When incidentally discovered intra-operatively, patients will be excluded from the study and replaced, but will be followed for primary and secondary endpoints. * Patients with poor performance status preoperatively such that they are unable to walk up two flights of stairs. * Patients taking any opioid agonist/antagonist medication (i.e. Buprenorphine)