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October 17-21, 2009 New Orleans, LA Home Abstract Archive Search Abstracts 2009 Session Grid 2009 Meeting Website Policy Statements ASA Website Feedback 
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A1138
October 20, 2008 2:00 PM - 4:00 PM Room Hall E2-Area N, |
| Analgesic Effect of Iv Lidocaine during Propofol and Remifentanil Anesthesia Assessed by BIS and AAI |
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Gregory A. Hans, M.D., Vincent Bonhomme, M.D., Severine Lauwick, M.D., Pol C. Hans, M.D., Jean L. Joris, M.D. Anesthesia and Intensive Care Medidicine, CHU of Liege, University of Liege, Liege, Liege, Belgium |
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Background and goal: Intravenous lidocaine (iv LIDO) reduces both sevoflurane1 and propofol2 requirements during BIS-guided anesthesia. Whether this is due to an analgesic or a hypnotic effect remains open. Simultaneous recording of BIS and AAI (A-line ARX index) has been shown helpful in assessing the nociceptive-antinociceptive balance during surgical stimulation3. We studied the dose-response effect of iv LIDO on BIS and AAI during surgical stimulation (thyroid surgery) under propofol-remifentanil anesthesia. Material and methods: After IRB approval and written informed consent, 20 ASA I-II patients received propofol and remifentanil using TCI devices (Schnider's and Minto's model). Cis-atracurium was given to provide a TOF ratio of 0. After tracheal intubation, remifentanil was set to 3 ng.ml-1 and propofol was titrated to achieve a stable BIS around 50. Immediately before skin incision, patients were randomized into four groups of 5 patients each: A. Saline; B. 0.75 mg.kg-1 bolus of LIDO followed by an infusion of 1 mg.kg-1.h-1; C. 1.5 mg.kg-1 bolus, 2 mg.kg-1.h-1 infusion; D. 3 mg.kg-1 bolus, 4 mg.kg-1.h-1 infusion. BIS and AAI were continuously recorded during 20 minutes after skin incision. Propofol and remifentanil targets were kept unchanged during the study. Plasma LIDO concentration over time was estimated using Rowland's pharmacokinetic parameters implemented in the Stanpump software©4. After 20 minutes, a blood sample was drawn for plasma LIDO concentration measurement. Data analysis was performed using Pearson's correlation and sigmoidal dose-response regression analysis with Graphpad prism 5.0©. Results: Propofol effect-site concentrations were similar in the 4 groups (Overall: 2.23 ± 0.6 µg.ml-1). Measured and estimated plasma LIDO concentrations after 20 minutes of infusion were strongly correlated (Pearson's r = 0.95, P<0.0001). During surgery, an inverse sigmoidal relationship was observed between estimated plasma LIDO and AAI or BIS. LIDO produced a greater reduction in AAI than in BIS, 40 % and 17 % of preincision values respectively. The IC95 was calculated at 1.4 mg.ml-1 for both BIS and AAI.[figure1]Conclusion : Clinically relevant doses of iv LIDO reduce AAI and BIS during surgery in a dose-dependent manner with a ceiling effect. The stronger effect of LIDO on AAI than on BIS suggests an analgesic rather than a hypnotic mechanism of action. References : 1. Kaba A et al, Anesthesiology 2007, 106:11-8. 2. Hans G et al, Eur. J. Anaesth. 2006, 23(S37):A-581 3. Bonhomme V et al, BJA 2006, 96:353-60 4. Benowitz et al., Clin. Pharmacol. Ther. 1974, 16(1) :87-98. Anesthesiology 2008; 109 A1138 |
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