Making a Painless Drain: Proof of Concept.

Chest tubes account for a large proportion of postoperative pain after cardiothoracic operations. The objective of this study was to develop a novel, cost-effective, easy-to-use, lidocaine-eluting coating to reduce pain associated with postoperative chest tubes. A lidocaine-eluting hydrogel was developed by dispersing lidocaine-loaded nanoparticles in an aqueous solution containing gelatin (5%). Glutaraldehyde (1%) was added to crosslink the gelatin into a hydrogel. The hydrogel was dehydrated, resulting in a thin, stable polymer. Sterile lidocaine hydrogel-coated silicone discs and control discs were prepared and surgically implanted in the subcutaneous space of C57B6 mice. Using von Frey filaments, mice underwent preoperative baseline pain testing, followed by pain testing on post-procedure day 1 and 3. On post-procedure day 1, mice implanted with control discs demonstrated no change in pain tolerance compared to baseline, while mice implanted with 20 mg and 80 mg lidocaine-loaded discs demonstrated a 2.4-fold (P = 0.36) and 4.7-fold (P = 0.01) increase in pain tolerance, respectively. On post-procedure day 3, mice implanted with control discs demonstrated a 0.7-fold decrease in pain tolerance compared to baseline, while mice implanted with 20 mg and 80 mg lidocaine-loaded discs demonstrated a 1.8-fold (P = 0.88) and 8.4-fold (P = 0.02) increase in pain tolerance, respectively. Our results demonstrate successful development of a lidocaine-eluting chest tube with hydrogel coating, leading to improved pain tolerance in vivo. The concept of a drug-eluting drain coating has significant importance due to its potential universal application in a variety of drain types and insertion locations.