Incidence of propofol injection pain and effect of lidocaine pretreatment during upper gastrointestinal endoscopy

Background/Aims Propofol has been used in the past for sedation in upper gastrointestinal (GI) endoscopic procedures. This study aimed to measure the incidence of propofol injection pain and evaluate the effect of lidocaine on pain caused during sedative upper GI endoscopic examinations. Methods Subjects scheduled to undergo sedative diagnostic upper GI endoscopy were randomly assigned to lidocaine and placebo groups. Pretreatment with a bolus of 1% lidocaine 2 ml or normal saline 2 ml into the largest dorsal vein of the non-dominant hand was followed by propofol administration. Pain intensity was estimated by an examiner blinded to the group assignment using a fourpoint verbal rating scale. A score of 1-3 was regarded as pain. Results A total of 121 patients (males, 69; age, 58.6 ± 12.1 years) completed the study; 61 and 60 subjects were randomly assigned to the lidocaine and placebo groups, respectively. The incidence of pain during upper GI endoscopy was 60%. The lidocaine group showed a lower incidence of pain than the placebo group (37.7% vs. 60.0%, P = 0.018). The lidocaine group perceived significantly less pain than the placebo group (median pain score, 0 vs. 1, P = 0.008). Only lidocaine pretreatment was an independently associated factor against pain perception (OR, 0.380; 95% CI, 0.177-0.815; P = 0.013). Conclusions Pretreatment using lidocaine was found to be effective in reducing propofol injection-induced pain. However, its usefulness for GI endoscopic procedures in daily clinical practice needs further evaluation because of the low intensity of pain.