Drug Eluting Chest Tube with Sustained Release of Local Anesthetic Agents for Pain Reduction

Chest tubes are frequently used in patients following major cardiothoracic surgeries to remove fluid and air from the pleural space. Tube implantation in the intercostal space and the irritation of the mucous membranes by the tube in the pleural space results in significant pain to the patient that often requires systemic treatment with narcotics to control. Opioid use often leads to extended hospital stays and increased risk of addiction. In this work, we created and optimized a drug eluting chest tube that can release anesthetic agents locally to reduce the need for systemic opioid use following chest tube implantation. The drug eluting chest tube consists of a porous polymer tube made from sintered ultra-high molecular weight polyethylene. The porous of this tube are loaded with bupivacaine in solid cast poly(lactic-co-glycolic acid) or loaded in to PLGA microparticles. This approach is advantageous in allowing a large amount of drug to be loaded into the tube and to protect the drug eluting polymer from damage during implantation or due to patient motion. The microparticle approach was effective in releasing drug from the tube but not in the amounts needed for long term effectiveness following implantation. The solid casting strategy released high amounts of the drug for at least 14 days. For a typical length of tubing, the dose released was equivalent to the maximal daily recommended dose of bupivacaine. We also tested the mechanical properties of the tubes and optimized processing conditions to reduce their stiffness. Our work demonstrates a robust and simple strategy for creating chest tubes that release local anesthetic agents while protecting the drug during tube insertion and following implantation.