Bupivacaine Liposomal Injection (Exparel) for Postsurgical Analgesia in Patients Undergoing Laparoscopic Gastric Bypass

Introduction

Despite the increasing use of patient-controlled anesthesia (PCA) for postoperative pain
management, efforts are continuing to find effective methods to relieve pain after abdominal
surgery. Some studies have already suggested that infusion with local anesthetics at the
wound site can decrease postoperative pain levels. Further, other studies have shown equal
amounts of opiate analgesic requirements (administered on patient demand) with placebo and
local anesthetic administration. However, varying anesthetic administration techniques used
in the different studies may explain why the controversy in the literature exists.

Although opioid is an effective analgesic it has opioid related adverse events (ORAEs).
Bupivacaine should reduce postoperative pain but it has relatively shorter duration of
action. Liposome bupivacaine (Exparel) has been approved as a single dose infiltration for
longer postoperative period analgesic. It provides up to 72 hours analgesia postoperatively;
results in lesser opioids usage and reduce the ORAEs.

Transversus abdominis plane (TAP) block is a relatively new regional anesthetic technique
that targets blockage of the neural afferent of the lower intercostal, iliohypogastric and
ilioinguinal nerves in the neurovascular plane between the internal oblique and the
transversus abdominis muscle. TAP blocks have been performed to reduce opioid use and control
pain in several laparoscopic surgical procedures, including colorectal resections,
cholecystectomy and bariatric surgery.

Efficacy of wound infiltration with or without TAP block using immediate-release bupivacaine
HCl for acute postsurgical pain is well established; EXPAREL has been proposed as a method
for postoperative pain management. Moreover, the administration and the optimal dosage in the
bariatric surgical population have not been studied.

The objective of this study is to examine postoperative pain after laparoscopic gastric
bypass with TAP block and port sites infiltration using Exparel versus Bupivacaine

Background and significance

Exparel is a FDA approved long-acting, local anesthetic. This is for single-dose infiltration
into the surgical site to produce postsurgical analgesia. Exparel offers longer-acting local
formulation and can be administered as a single dose. Exparel has a longer duration of action
with slower absorption. The mean elimination half-life of local administration of Exparel is
approximately 24-34 hours 19-20 versus 2.7 hours for bupivacaine.

Liposomal bupivacaine is for single-dose infiltration and the recommended dose depends on the
surgical site but the maximum dose of liposomal bupivacaine is 266 mg and it is injected into
soft tissues of the surgical site with frequent aspirations to prevent intravascular
injection.

A pooled analysis evaluating the effect of Exparel on pain intensity scores and opioid
consumption was published by Dasta et al. This study included 5 surgical procedures (inguinal
hernia repair, total knee replacement, hemorrhoidectomy, breast augmentation and
bunionectomy) comparing Exparel with bupivacaine HCl, on 912 patients; it showed
significantly lower pain score and opioid usage, delayed use of rescue opioid and reduced
ORAEs in the Exparel group; as compared to bupivacaine HCL group.

Medication SafetLiposomal bupivacaine has been classified as a high-alert medication by the
Institute of Safe Medication Practices due to its similar appearance to propofol. If
liposomal bupivacaine were administered intravenously as if it were propofol, adverse cardiac
effects may result.

Hypothesis

Exparel (1.3%) and 0.5% Bupivacaine usage with infiltration and TAP block decreases opiate
usage, nausea and pain at 48 hours as compared to 0.5% Bupivacaine only.

Primary Objective of the study:

To study the opiate usage, pain and nausea post laparoscopic gastric bypass or sleeve
gastrectomy using EXPAREL versus Bupivacaine as TAP block and port sites infiltration.

Inclusion Criteria:

- Fulfills NIH criteria for bariatric surgery

- Planned operation of laparoscopic Roux-en Y gastric bypass (LRYGB) or laparoscopic
sleeve gastrectomy (LSG) as primary bariatric procedure

Exclusion Criteria:

- BMI <35 and > 60 kg/m2

- Inability to walk (bed-bound or wheelchair dependence)

- Previous major abdominal surgery (possible adhesions and longer operation) defined as:

- open abdominal surgeries except simple appendectomy and common OB/GYN procedures
in the pelvis (hysterectomy, C-section, and oophorectomy, tubal ligation)

- laparoscopic bowel or solid organ resection except laparoscopic cholecystectomy

- ventral hernia repair with mesh

- Preoperative chronic opiate use for chronic pain defined as opiate usage at least 60
mg/day of morphine equivalent for ≥ 3 months (as defined by International Association
for the Study of Pain22) in the one year period prior to the bariatric surgery

- The American Society of Anesthesiologists (ASA) score > 3

- History of hypersensitivity or adverse reaction to bupivacaine or narcotics

- Inability to speak English

- Concurrent surgical procedure including:

- ventral hernia repair

- Cholecystectomy

- hiatal hernia repair with posterior cruroplasty

- extensive lysis of adhesions

- other procedures that mandate addition of "trocar(s)" or "feeding tube"

- Addition of trocar(s) or conversion of surgery to hand-assisted or open