Intravenous anesthesia


Anesthesia and Pain Medicine. 2001 Dec. 5(4): 206-209
ⓒ Korean Society for Intravenous Anesthesia
Effect of Epidural Lidocaine on the Hypnotic Requirement of Propofol
Hye-won Lee, Ji-yong Park, Hye-won Shin, Hun Cho, Hea-ja Lim, Suk-min Yoon
Department of Anesthesiology, College of Medicine, Korea University, Seoul, Korea

BACKGROUND: Epidural anesthesia has been shown to have direct sedative effect and to markedly reduce the amount of hypnotic agents required for sedation. In this study we investigate whether the epidural lidocaine reduce hypnotic requirement of propofol as measured by loss of response to verbal command.
METHODS: Twenty patients scheduled for elective upper abdominal surgery were randomly allocated into two group. Target controlled infusion (target effect concentraion 5 microgram/mL, induction time 3 min) of propofol was administered to the patients 20 min after epidural injection of 2% lidocaine or normal saline (15 ml) at the T10-11 level. Hypnotic endpoint were determined using loss of ability of opening eyes in response to verbal command. At the time of induction of hypnosis, onset of hypnosis, infused propofol dose, and the target concentration and targert effect concentration of propofol were recorded.
RESULTS: Epidural lidocaine significantly reduced the hypnotic requirement of propofol (0.6 +/- 0.1 mg/kg vs 1.4 +/- 0.2 mg/kg; P = 0.00044), target concentration (2.3 +/- 0.2 microgram/ml vs 3.7 +/- 0.4 microgram/ml; P = 0.00056) and the hypnotic target effect concentration (0.4 +/- 0.1
microgram/ml vs 1.5 +/- 0.2
microgram/ml; P = 0.00021). The onset of hypnosis was earlier in epidural group comparing to the control group (120.3 +/- 18.2 sec vs 278.6 +/- 32.9 sec; P = 0.00016).
CONCLUSIONS: Epidural lidocaine decreases hypnotic requirement of propofol. Therefore, the infusion dose should be reduced when propofol is used for the anesthetic induction or sedation under epidural anesthesia.
Key words : Anesthetics, local, lidocaine, Anesthetics, intravenous, propofol, Anesthetic techniques, epidural, Hypnosis
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