Median effective dose of intravenous lidocaine in advance in preventing propofol medium/long chain triglyceride emulsion injection-induced pain

  Objective  To ensure the median effective dose (ED₅₀) of intravenous lidocaine in advance in preventing propofol medium-/long-chain triglyceride emulsion injection pain.

  Methods  Patients for elective surgery undergoing general anesthesia American Society of Anesthesiologists (ASA) grade Ⅰ or Ⅱwere selected. Lidocaine was administered intravenously prior to propofol medium-/long-chain triglyceride at an initial dose of 0.5 mg/kg lean body mass (LBW). The dose of lidocaine was adjusted by Dixon sequential method according to injection pain. Injection pain and adverse reactions were recorded. The ED₅₀ and 95%CI of lidocaine were calculated. Patients'memory of injection pain in postanesthesia care unit (PACU) was recorded and Visual Analogue Scale (VAS) was evaluated.

  Results  A total of 30 patients completed the trial, including 19 patients with effective pain relief and 11 patients with ineffective pain relief. The ED₅₀ of lidocaine in advance to prevent propofol medium-/long-chain triglyceride emulsion injection pain was 0.306 mg/kg (95%CI, 0.262 to 0.357 mg/kg) LBW. In PACU, 90.9% of the pain-experienced patients had memory of injection pain, and VAS score was (2.8±1.8).

  Conclusion  Prophylactic intravenous lidocaine for 0.306 mg/kg LBW could effectively prevent propofol medium-/long-chain triglyceride emulsion injection pain in 50.0% of patients for elective surgery undergoing general anesthesia without adverse reactions occurred.