Four Quadrants Transverse Abdominus Plane (4Q-TAP) Block With Plain and Liposomal Bupivacaine vs. Thoracic Epidermal Analgesia (TEA) in Patients Undergoing Cytoreductive Surgery With Hyperthermic Intraperitoneal Chemotherapy (CRS-HIPEC) on an Enhanced Recovery Pathway

Baseline Tests:

If participant agrees to take part in this study, within 60 days before participant's surgery:

• Participant will have a physical exam.
• Blood (about 8 teaspoons) will be drawn for routine tests.
• Participant will complete a questionnaire about the quality of recovery. Participant's responses before surgery will be compared to participant's responses after surgery. It should take about 5 minutes to complete.

Study Groups/Procedures:

Participant will be randomly assigned (as in the flip of a coin) to 1 of 2 study groups on the morning of participant's surgery. This is done because no one knows if one study group is better, the same, or worse than the other group.

• If participant is in Group 1, participant will receive standard-of-care TEA before participant goes to sleep.
• If participant is in Group 2, participant will receive the 4Q-TAP block injections after participant is asleep.

If participant is in Group 1, participant will have a catheter placed in participant's back before surgery so that the TEA can be infused. If needed, participant may receive an injection of numbing medication and/or pain medication before the catheter is placed. Participant will sign a separate consent for the placement of the catheter.

If participant is in Group 2, participant will receive up to four (4) injections of 4Q-TAP block directly into different parts of the abdomen. These injections will take place after participant has been given general anesthesia. An ultrasound will be used to guide these injections. Participant will not be awake for these injections.

Both groups will sign a separate consent for the surgery that explains the procedures and the risks. Participant may receive standard drugs during surgery. The study staff can tell participant about the risks of these drugs and how they are given.

For both groups, information about the surgery will be collected while participant is in the operating room.

Post-Surgery:

After surgery, participant will receive standard drugs for pain as needed. Participant will be asked to complete a questionnaire about the quality of participant's recovery on the following days after surgery:

• Days 1-3
• Day 5
• Day 7
• Day 10 and
• Day 30

The questionnaire should take about 5 minutes each time. Participant will complete the questionnaire in person or participant will be called on the phone to complete it if participant has already left the hospital.

On Days 1, 2, and 7 after surgery, blood (about 8 teaspoons each time) will be drawn for routine tests.

After participant leaves the hospital, researchers will collect information from participant's medical record about participant's standard follow-up visits.

Length of Study Participation:

Active participation in this study will be complete 30 days after the surgery.

Inclusion criteria

• Written Informed consent
• 18 years old or older
• American Society of Anesthesiologists physical status (ASA) 1-3
• Scheduled surgery: open elective CRS-HIPEC
• Able to complete the QoR 15 questionnaire
• Patients scheduled to receive intraoperative chemotherapy

Exclusion criteria

• Thrombocytopenia (platelet count: <100,000 cell/dL), coagulopathy (International Normalized Ratio > 1.5, PT>16.5 seconds or aPTT > 35.9 seconds)
• Bupivacaine or liposomal bupivacaine sensitive or known allergy;
• Pregnancy or breastfeeding patients
• Patients with recent (within 60 days preoperatively) history severe hepatic disease (defined as liver injury with encephalopathy plus impaired synthetic liver function (i.e. >1.5)
• Patients with recent (within 15 days preoperatively) history deteriorate kidney function (creatinine serum concentrations > 2.5 mg/dL or eGFR < 30 mL/kg/min)
• Chronic opioid use defined as daily opioid use for more than one month prior the scheduled date of surgery