Effects of epidural infusion of different concentrations of lidocaine on the depth of anesthesia during combined general-epidural anesthesia / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effects of epidural infusion of different concentrations of lidocaine on the amount of propofol needed to induce anesthesia and the end-tidal isoflurane concentration needed to maintain BIS at 50-55 during operation. Methods Forty-five ASA Ⅰ-Ⅱ patients of both sexes (24 males, 21 females) aged 21-60 yrs, weighing 46-77 kg undergoing elective upper abdominal surgery were randomly divided into 3 groups with 15 patients in each group group Ⅰ epidural normal saline ( NS); group Ⅱ epidural 1 % lidocaine (Lido) and group Ⅲ 2 % Lido. An epidural catheter was inserted at T9-10 into epidural space and advanced 3-4 cm cephalad. After a test dose of 3 ml, NS or 1% or 2% Lido 10 ml was injected into the epidural space. Anesthesia was induced with propofol infusion at 25 mg?min-1. Propofol infusion was stopped when the patients stopped responding to loud voice (OAAS/2) and the amount of propofol infused was recorded. Then fentanyl 2 ?g?kg-1 and vecuronium 0.15 mg?kg-1 were given i.v. . The patients were intubated and mechanically ventilated and PETC02 was maintained at 35 mm Hg. Anesthesia was maintained with isoflurane inhalation and epidural infusion of Lido or NS at 7 ml?h-1 . BIS was maintained at 50-55 during operation. Results The amount of propofol needed to induce anesthesia was 1.23?0.34 mg?kg-1 in group Ⅱ and 1.02?0.25 mg?kg-1 in group Ⅲ compared to 1.67?0.38 mg?kg-1 in control group (group Ⅰ) (P