Intravenous lidocaine increases the depth of anaesthesia of propofol for skin incision - a randomised controlled trial

• Published in: Acta anaesthesiologica Scandinavica 2015-03, Vol.59 (3), p.310-318
• Main Authors: WEBER, U., KRAMMEL, M., LINKE, S., HAMP, T., STIMPFL, T., REITER, B., PLÖCHL, W.
• Format: Article
• Language: English
• Subjects: Adult; Anesthetics, Intravenous - pharmacology; Anesthetics, Local - pharmacology; Dermatologic Surgical Procedures; Dose-Response Relationship, Drug; Double-Blind Method; Drug Synergism; Female; Humans; Injections, Intravenous; Lidocaine - pharmacology; Male; Middle Aged; Propofol - pharmacology; Prospective Studies
• ISSN: 0001-5172; 1399-6576
• DOI: 10.1111/aas.12462

Background The anaesthetic potency of intravenous propofol is quantified by its Cp50 value, which is defined as the plasma concentration required to prevent movement response in 50% of patients to surgical stimuli. We hypothesised that, in addition to propofol anaesthesia, an intravenous bolus of lidocaine 1.5 mg/kg will decrease the Cp50 value of propofol during anaesthesia. Methods We enrolled 54 elective surgical patients undergoing propofol‐based anaesthesia, and randomised them to either lidocaine 1.5 mg/kg, lidocaine 0.5 mg/kg or placebo (NaCl 0.9%) 3 min before skin incision. The propofol Cp50 value was then calculated using the ‘up‐and‐down’ method of Dixon and Massey. Results There was no significant reduction in propofol requirements after the administration of 0.5 mg/kg lidocaine from 8.5 μg/ml [confidence interval (CI) 6.0–11.625] to 8.25 μg/ml (CI 6.75–9.76); however, a bolus of 1.5 mg/kg lidocaine decreased the Cp50 value of propofol by 42% from 8.5 μg/ml (CI 6.0–11.625) to 4.92 μg/ml (CI 4.5–5.78) (P