Intravenous lidocaine decrease isoflurane requirements during posterior lumbotomy as monitored by bispectral index
Nakhli M.S., Kahloul M., Harrathi A., Chebbi N., Naija W., Mhamdi S.
Sahloul Hospital, Dept of Anaesthesiology & Intensive Care, Sousse, Tunisia
Background and Goal of Study: Peri operative effect of intravenous lidocaïne infusion was evaluated on pain relief, cytokine responses, recovery and length of hospital stay particularly in intra abdominal surgery. Our hypothesis is to show whether intravenous lidocaïne infusion can decrease the minimum alveolar concentration isoflurane required to keep Bispectral Index between 40 and 60 during anesthesia for lumbotomy.
Materials and Methods: Fifty ASA physical status 1 and 2 patients were scheduled for elective lumbotomy during general anesthesia. Exclusion criteria were: history of hepatic, renal or cardiac failure, allergy to local anesthetics, nephrecomy for renal transplantation. Patients with history psychiatric disorder, arrhythmia or seizures were also excluded. Patients were randomized to receive either intra operative systemic lidocaïne infusion (group L): 1.5 mg/kg before skin incision then perfusion of 1 mg/kg/hr or normal saline infusion (group C). BIS was maintained between 40-60. Primary endpoint was the Et-Iso concentration and MAC-Iso. Secondary endpoint was the consumption of remifentanil and the delay to extubation.
Results and Discussion: The two groups were comparable in terms of demographic and surgical data. The MAC-Iso and Et-Iso fractions recorded during the surgical procedure were less important to the group (L) then the group (S) with a statistically significant difference. The average consumption in remifentanil was less important in the group (L) then the group (s) [0.12 ± 0.04 µg/kg/mn vs 0.19 ± 0.05 µg/kg/mn; p < 0.01]. Time to extubation was shorter in the lidocaine group [5.6 ± 1.8 min vs 8 ± 2 min; p < 0.01].
This study showed that continuous infusion of intravenous lidocaine reduces requirement of remifentanil and isoflurane during the surgical procedure for lumbotomy. It also shortens the time to extubation. It was suggested an inhibitory effect of lidocaine on central nervous system potentiating the action of halogenated inhalational anesthetics.
Conclusion(s): Intra operative intravenous lidocaïne infusion reduced volatile agent requirement during urologic surgery for lumbotomy. It also reduced intra operative opioids consumption.