Liposomal Bupivacaine for Pain Control Following Thoracic Surgery.

Overview

The aims of the study are to compare the effectiveness and postoperative outcomes of liposomal bupivacaine vs plain bupivacaine following video-assisted thoracoscopic surgery. The investigators' hypothesis is that liposomal bupivacaine will decrease the postoperative pain and will be associated with more favorable postoperative outcomes when compared to plain bupivacaine following video-assisted thoracoscopic surgery.

Pain management remains a primary concern for many patients following thoracic surgery. Suboptimal analgesia leads to numerous postoperative complications like reduced cardiac, respiratory and gastrointestinal functions, more septic and thromboembolic complications, increased incidence of developing chronic pain states, increased mortality in high-risk patients with multiple comorbidities, and many others. Opioids have a distinct role in the postoperative analgesia. Although opioids have positively affected surgery for decades, they are associated with a number of potentially severe side effects including prolonged ileus, nausea, vomiting, central nervous system and respiratory depression, development of hyperalgesia, and the risk of dependency and abuse. These adverse effects increase the overall cost of treatment for these patients and can potentially result in longer hospital stays. Local infiltration and regional blocks of local anesthetics are increasingly utilized during thoracic surgery procedures as an alternative to epidural analgesia. Bupivacaine is widely used for intercostal nerve blocks but its utility is limited by its short duration of action (\<6 hours). Perineural catheters for continuous infusion of bupivacaine have been used to overcome this limitation but the need of expensive pumps and the risk of significant complications associated with the use of catheters (i.e. infection, septicemia, intravascular migration etc) has limited its use. Encapsulation of local anesthetics into liposomes is a novel method which extends drug delivery. The use of multivesicular liposomes has been shown to provide a slow and steady release of local anesthetics for several days after nonvascular administration. Liposomal bupivacaine is a novel formulary of bupivacaine, is designed for a single-dose local infiltration into the surgical site and produces postsurgical analgesia for up to 72-96 hours. Liposomal bupivacaine is not currently licensed by the U.S. Food and Drug Administration for peripheral nerve block but has been approved for single-dose infiltration into the surgical site. However, it has been shown in two retrospective studies of patients with open thoracotomies for lung, pleural or mediastinal pathologies that liposomal bupivacaine intercostal nerve blockade is associated with increased pain control and decreased length of hospital stay compared to thoracic epidural analgesia. This is a single-blind randomized prospective research study comparing pain control and postoperative outcomes following intercostal neural blockade with liposomal bupivacaine versus plain bupivacaine plus epinephrine during video-assisted thoracoscopic surgical procedures. Eligible patients would be all patients aged older than 18 years who undergo a video-assisted thoracoscopic lung resection at Massachusetts General Hospital. Pregnant women, prisoners, emergent cases, patients under 18 years, and patients with chronic pain, documented alcohol or drug abuse and allergies to bupivacaine will be excluded from this study. Primary end point will be self-reported pain score on a visual analog scale from 0 to 10 at postoperative day #1. By utilizing a mean difference in self-reported pain scores of 1 point with a standard deviation of 2.5 points, a sample size of 100 patients per group would be needed for a power (beta) of 0.8 and probability level (alpha) of 0.05. All patients would be enrolled at Massachusetts General Hospital. The video-assisted thoracoscopic surgeries and intercostal nerve blockade with plain bupivacaine plus epinephrine or liposomal bupivacaine will be performed by all thoracic surgeons at Massachusetts General Hospital. In the operating room after induction of general anesthesia patients will be positioned in a lateral decubitus position, prepared and draped in a sterile fashion. Under thoracoscopic guidance, a posterior intercostal nerve block will be performed with liposomal bupivacaine (13.3 mg/ml) or 0.5% bupivacaine with 1% epinephrine. In the liposomal bupivacaine group, a total dose of 266 mg of liposomal bupivacaine (one 20 ml vial of 13.3 mg/ml) per patient will be diluted to a total volume of 40 ml using 20 ml normal saline. In the bupivacaine group 20 ml of 0.5% bupivacaine with 1% epinephrine will be diluted to a total volume of 40 ml using 20 ml normal saline. From those 40 ml, 30 ml will be used for the posterior intercostal nerve block and 10 ml will be injected locally into the surgical wounds. If immediate postoperative pain scores were rated 4/10 or greater, an intravenous patient controlled analgesia device will be provided with hydromorphone 0.2 mg every 10 minutes or nonopioid analgesics as needed. No narcotics will be given in the spinal space. Oral metoclopramide or ondansetron will be given as needed to combat the side effects of the narcotics.