Supplementary Material for: PlAcebo versus erector spINae pLane block for mEdical thoracoScopy Study (PAINLESS)

Background: Post-procedural pain is the most common complication following medical thoracoscopy (MT), and can lead to increased morbidity, delayed recovery and decreased patient satisfaction. Effective pain management is essential to optimize patient recovery. This study evaluates the efficacy of the Erector Spinae Plane Block (ESPB) with bupivacaine for pain reduction after MT. Methods: This prospective, triple-blind, randomized controlled trial was conducted at a single center. Patients undergoing MT for pleural biopsy without pleurodesis were randomized to receive either ESPB with bupivacaine or placebo. The primary outcome was post-procedure pain, measured using Visual Analog Scale (VAS). Secondary outcomes included numerical pain scores post procedure and at 24 hours follow up, analgesic needs, and quality of recovery post-procedure and at 24 hours follow-up. Results: At the time of an interim analysis, the study was terminated prematurely due to a lack of perceived clinical benefit and development of provider bias. A total of 33 patients completed the protocol. There was no significant difference in post-procedure VAS pain scores between the bupivacaine and placebo groups (median 33 mm vs. 37.5 mm, p=0.890). Similarly, no significant differences were observed in post procedure (median 4 vs. 4, p=0.485) and 24-hour numerical pain scores (median 4 vs. 4, p=0.556), opioid requirement (p=0.343), or quality of recovery (QoR-15) (p=0.547). Conclusion: ESPB with bupivacaine may not reduce post-MT pain. The role of regional anesthesia for intraprocedural analgesia or post procedure analgesia in patients undergoing pleurodesis during MT should be further investigated.