Intravenous paracetamol for persistent pain after endoscopic mucosal resection discriminates patients at risk of adverse events and those who can be safely discharged

Introduction The frequency and severity of abdominal pain after endoscopic mucosal resection (EMR) of colonic laterally spreading lesions (LSLs) of ≥ 20mm is unknown, as are the risk factors to predict its ccurrence. We aimed to prospectively characterize pain after colonic EMR , determine the rapidity and frequency of its resolution after analgesia, and estimate the frequency of needing further intervention. Methods Procedural and lesion data on consecutive patients with LSLs who underwent EMR at a single tertiary referral center were prospectively collected. If pain after colonic EMR, graded using a visual analogue scale (VAS), lasted > 5 minutes, 1 g of paracetamol was administered. Pain lasting > 30 minutes lead to clinical review and upgrade to opiate analgesics. Investigations and interventions for pain were recorded. Results 67/336 patients (19.9%, 95%CI 16.0%-24.5 %) experienced pain after colonic EMR (median VAS 5, interquartile range 3-7). Multivariable predictors of pain were: lesion size ≥ 40mm, odds ratio [OR] 2.15 (95%CI 1.22-3.80); female sex, OR 1.99 (95%CI 1.14-3.48); and intraprocedural bleeding requiring endoscopic control, OR 1.77 (95%CI 0.99-3.16). Of 67 patients with pain, 51 (76.1%, 95%CI 64.7%-84.7%) had resolution of their "mild pain"after paracetamol and were discharged without sequelae. The remaining 16 (23.9%) required opiate analgesia (fentanyl), after which 11/16 patients (68.8%; "moderate pain") could be discharged. The 5/67 patients (7.5 %) with "severe pain"had no resolution despite fentanyl; all settled during hospital admission (median duration 2 days), intravenous analgesia, and antibiotics. Conclusion Pain after colonic EMR occurs in approximately 20% of patients and resolves rapidly and completely in the majority with administration of intravenous paracetamol. Pain despite opiates heralds a more serious scenario and further investigation should be considered.