Obstetric Liposomal Bupivacaine Via Surgical Transversus Abdominis Plane Block for Post Cesarean Pain Control

This study seeks to identify whether the addition of liposomal bupivacaine to regular bupivacaine and saline administered via surgical transversus abdominis plane (TAP) block will reduce the cumulative opioid dose in the first 48 hours after cesarean. 60 women scheduled for cesarean at Unity-Point Health Meriter Hospital in Madison, Wisconsin will be enrolled and can be expect to be on study for up to 6 weeks post-partum.

The purpose of this study is to determine whether liposomal bupivacaine administered via surgical TAP block at the time of Cesarean delivery will reduce the total dose of opioids received. The hypothesis is that liposomal bupivacaine will reduce the total dose of opioids received in the immediate 48 hours post-delivery.

Secondary outcomes will include participant self-reported pain scores, participant-reported incidence of side effects, and development of objective complications such as dysrhythmias. Other outcomes collected will include length of stay, time to first rescue analgesic medication, total dose of opioids at 12, 24, 36, 72 hours and during the hospital stay, use of supplemental oxygen during hospitalization, breastfeeding rates, both exclusive and in combination with formula use, amount of opioid prescribed at discharge and whether refills were requested or administered, rates of chronic pain at six weeks postpartum, and six week Edinburgh Depression Screen scores. Neonatal outcomes such as fetal weight, five-minute Apgar scores and development of adverse outcomes such as neonatal intensive care unit (NICU) admission will also be collected because NICU admission can impact maternal opioid use.

Primary Objective:

* To determine whether liposomal bupivacaine administered via surgical TAP block at the time of cesarean delivery will reduce the total dose of opioids received in the first 48 hours after surgery.
* Hypothesis: The hypothesis is that liposomal bupivacaine administered via surgical TAP block at the time of cesarean delivery will reduce the total dose of opioids received in the first 48 hours after surgery.
* Developmental Sub Aim: If liposomal bupivacaine administered via surgical TAP block does reduce the total dose of opioids received, to determine the degree of the reduction in order to allow for an adequately powered randomized-controlled trial.

Secondary Objective:

* To determine whether liposomal bupivacaine administered via surgical TAP block at the time of cesarean delivery will reduce patient-reported pain scores and opioid-related side effects, including respiratory compromise.
* Hypothesis: The hypothesis is that liposomal bupivacaine administered via surgical TAP block at the time of cesarean will reduce patient-reported pain scores and opioid related side effects.

Eligibility Criteria:
Inclusion Criteria:

* Maternal age greater than or equal to 18
* Singleton or multifetal pregnancy
* Able to receive neuraxial analgesia
* Planned/ scheduled Cesarean delivery OR non-urgent Cesarean delivery at UnityPoint-Health Meriter with adequate time to consider and consent to the study
* Able to provide consent in English

Exclusion Criteria:

* Known hypersensitivity to bupivacaine (defined as a history of a reaction or allergy to bupivacaine (injectable, intravenous, or transdermal) reported by patient or documented in the medical record
* Contraindication to regional analgesia
* Positive urine drug screen at admission to the hospital, if ordered for clinical purposes.
* Current opioid use or opioid use disorder per patient report or documented in the medical record
* Chronic opioid use or opioid use disorder, either patient reported or documented in the medical record, defined as opioid use on most days for greater than 3 months
* Planned cesarean hysterectomy (excluded due to anticipated blood loss and alternative pain control measures, possible prolonged intubation)
* Planned vertical midline incision (excluded due to possible different postpartum pain)
* Presence of renal dysfunction precluding the use of NSAIDs (NSAIDs are part of the usual postpartum pain regimen/ hospital protocol) per discretion of the treating physician or PI
* Ischemic heart disease, congestive heart failure, or cardiomyopathy of pregnancy precluding the use of NSAIDs (NSAIDs are part of the usual postpartum pain regimen/ hospital protocol) per discretion of the treating physician or PI
* Significant liver dysfunction precluding the use of acetaminophen (acetaminophen is part of the usual postpartum pain regimen/ hospital protocol) per discretion of the treating physician or PI
* Coagulopathy
* Planned discharge from the hospital less than 48 hours postpartum
* Unable to receive post-operative scheduled acetaminophen for any reason, such as allergy to acetaminophen or elevated liver function tests precluding acetaminophen use
* Unable to receive post-operative scheduled NSAIDs for any reason, such as allergy to ketorolac or ibuprofen, or renal dysfunction precluding NSAID use
* Seizure disorder: Specifically, poorly controlled seizure disorder defined as having had a seizure within the last three years despite antiepileptic use or poorly managed seizure disorder due to medication non-compliance.
* Cardiac disease or arrhythmia: Defined as ischemic heart disease, peripartum cardiomyopathy, heart failure (with reduced or preserved ejection fraction, compensated or decompensated). Patients with a remote history of non-cyanotic pediatric cardiac surgery (like a VSD closure or PDA ligation as a child) do not need to be excluded. History of adult cardiac surgery without ongoing problems or treatments other than chronic anticoagulation (mitral valve repair for MVP or aortic valve replacement for bicuspid aortic valve for example) would not need to be excluded. History of repaired congenital cyanotic heart disease should be considered for exclusion, ultimately up to the anesthesiologist that day. A patient with a history of arrhythmias not requiring medication or ablation would NOT need to be excluded and could be included in the study. History of ablation or active anti-arrhythmic medication should be considered for exclusion.
* Hypoxia: Defined as requiring supplemental oxygen during the day.
* Acidosis. This will be uncommon in our population, but if someone has active diabetic ketoacidosis will exclude.