Intravenous infusion of lidocaine significantly reduces propofol dose for colonoscopy: a randomised placebo-controlled study

Background: Propofol use during sedation for colonoscopy can result in cardiopulmonary complications. Intravenous lidocaine can alleviate visceral pain and decrease propofol requirements during surgery. We tested the hypothesis that i.v. lidocaine reduces propofol requirements during colonoscopy and improves post-colonoscopy recovery. Methods: Forty patients undergoing colonoscopy were included in this randomised placebo-controlled study. After titration of propofol to produce unconsciousness, patients were given i.v. lidocaine (1.5 mg kg(-1) then 4 mg kg(-1) h(-1)) or the same volume of saline. Sedation was standardised and combined propofol and ketamine. The primary endpoint was propofol requirements. Secondary endpoints were: number of oxygen desaturation episodes, endoscopists' working conditions, discharge time to the recovery room, post-colonoscopy pain, fatigue. Results: Lidocaine infusion resulted in a significant reduction in propofol requirements: 58 (47) vs 121 (109) mg (P = 0.02). Doses of ketamine were similar in the two groups: 19 (2) vs 20 (3) mg in the lidocaine and saline groups, respectively. Number of episodes of oxygen desaturation, endoscopists' comfort, and times for discharge to the recovery room were similar in both groups. Post-colonoscopy pain (P< 0.01) and fatigue (P = 0.03) were significantly lower in the lidocaine group. Conclusions: Intravenous infusion of lidocaine resulted in a 50% reduction in propofol dose requirements during colonoscopy. Immediate post-colonoscopy pain and fatigue were also improved by lidocaine.