OBJECTIVES—To evaluate the efficacy of transcutaneous electrical nerve stimulation (TENS) as analgesia during colonoscopy. DESIGN—In a randomised controlled trial, patients undergoing diagnostic colonoscopy were assigned to one of three groups: standard medication only (midazolam); active TENS plus standard medication; or non-functioning TENS and standard medication. Efficacy of TENS was determined using numerical rating scores for pain and the post-procedural evaluation questionnaire. SETTING—Patients undergoing diagnostic colonoscopy in a teaching hospital. MAIN OUTCOME—There was no statistically significant differences between the three groups. However in the active TENS group there was a greater variation in "physical discomfort" and "psychological distress", suggesting TENS may be effective in subgroup of patients.
