Comparison between bispectral index and entropy index values in patients during target-controlled infusion of propofol on induction of anesthesia

Abstract

Objective To evaluate the accuracy of bispectral index(BIS)and entropy index in monitoring the depth of anesthesia in patients during target-controlled infusion(TCI)of propofol on induction of anesthesia.Methods Fifty ASA grade Ⅰ-Ⅱ of chronic sinusitis patients who performed the surgery of nasal sinus patency were enrolled in this study.After into operation room(T0),anesthesia was induced with TCI of propofol,and it was added 0.3 μ g/ml after 30 seconds once the plasma drug level was 2.1 μ g/ml(T1)until loss of consciousness(T2),and added 0.5 μg/ml(T3).When tracheal intubation,the patients was injected 0.6 mg/kg rocuronium in their intravenous at the prospective plasma drug level(T4).Each case was monitored with BIS,state entropy index(SE)and response entropy index(RE).The data at following time were recorded:T0-T4,tracheal intubation(T5),1 minute and 3 minutes after tracheal intubation(T6,T7),skin incision(T8).Results The value of BIS,SE and RE were significantly decreased compared with T0 (P ＜0.05).Mean arterial pressure(MAP)and heart rate were in normal range.The value of RE was significantly higher than SE at all the time points(93 ± 9 vs.87 ± 5,88 ± 12 vs.82 ± 12,73 ± 25 vs.72 ± 21,57±21 vs.56±22,46± 16vs.43 ± 17,39± 14 vs.37± 12,36± 14vs.34± 11,35 ± 11 vs.32±9,39±15 vs.36 ± 12)(P ＜ 0.05),but there was no significantly difference between BIS and SE at all the time points(P ＞ 0.05).The value of BIS had significantly positive correlation with SE and RE(r =0.887,0.901 ;P ＜ 0.01).Conclusions During deep hypnosis,BIS,SE and RE all can provide information about the level of consciousness during TCI of propofol on induction of anesthesia.RE is more preponderant as a monitor than BIS and SE. Key words: Target-controlled infusion; Bispectral index; Entropy index