Continuous Subpleural Infusion of Bupivacaine

Overview

Rationale: For the past 3 years the investigators have routinely used an axial subpleural tunneling technique that del Study Design: All patients over the age of 18 having an isolated thoracoscopic procedure performed at Inova Fairfax Hospital for therapeutic or diagnostics purposes will be screened. Patients will be excluded if they have: previous ipsilateral thoracic surgery, need for operative pleurectomy or pleurodesis, chronic use of pain medication, sedatives or hypnotics, drug allergies, liver dysfunction, renal dysfunction, history of peptic ulcerative disease, sleep apnea in need of Bipap, severe chronic obstructive pulmonary disease (COPD), inability to consent, or are pregnant. All patients included will be screened, consented, and operated on by the one year anniversary of institutional review board (IRB) approval. Study Methodology: Eighty-six consented patients will be randomized into the study arm (use of a pain catheter with 0.125% bupivacaine) or the standard of care group (no pain catheter). The primary outcome is the use of narcotic pain medication post-operatively, compared between study groups. Secondary outcomes will include postoperative pain scores, hospital and length of stay. The On-Q pump delivers local anesthetic to the intercostal space, without leakage elsewhere, creating a functional multi level rib block. Despite positive subjective results, objective data is lacking. The investigators have also noted that some patients develop an annoying short term paresthesia that has been minimized by using lower anesthetic concentrations than described in other publications. Objectives: To evaluate visual analog pain scores post-operatively up to 30 days post-operative, and to determine any association between pain management and length of stay. Study Type: A prospective randomized 2-arm study will be performed. Statistical Methodology: Total amount of narcotic pain medication administered through postoperative day 7, will be compared between the study groups using student's t-tests and Wilcoxon rank-sum tests. Secondary outcomes, overall sum of pain scores through postoperative day 7, then at day 30 post-operatively, hospital length of stay, and overall hospital cost, will also be compared among study groups using student's t-tests and Wilcoxon rank-sum tests.

Video-Assisted Thoracic Surgery (VATS) has been shown to hasten patient recovery by attenuating the physiologic stress of surgery and decreasing post-operative pain. Despite this approach, incisions in the chest are proportionally more painful than in other parts of the body, and most patients require some form of narcotic pain medication. Multiple strategies for post-operative pain control have been attempted in thoracic surgery with no obvious superiority of one versus another. Pain catheters have been increasingly used over the past decade in different surgical procedures in order to minimize incisional pain for the first 3 to 7 days after an operation. The published literature is equivocal as to the efficacy of such approach following thoracic surgery with most recent series reporting no benefit in the use of these catheters. Of utmost importance is the placement techniques described thus far, which in our opinion, have been suboptimal. In order for a pain catheter to work, the infused local anesthetic has to constantly bathe the nerve in question thus preventing painful stimuli from being transmitted. It is hard to dispute the ability of local anesthetic to block pain conduction. Consequently, the success of the intervention is directly dependent on the placement technique to achieve such goal, hence the rationale for our study.