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 ≥ 20 mm is unknown, as are the risk factors to predict its occurrence. 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 ≥ 40 mm, 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.