ABSTRACT
Objective To investigate the efficacy of spectral entropy measurement in reflection of depth of anesthesia and noxious stimulation. Methods Forty-five patients of ASAⅠorⅡ were randomly divided into three groups(n=15).Group A,B and C received fentanyl 1,3 and 5 ?g/kg,respectively,3 min before target controlled infusion(TCI) of propofol.Intubation was performed when the effect-site concentration(CE)reached 3.5 ?g/mL,which was maintained until 5 min after incision.Response entropy(RE),State entropy(SE) as well as heart rate(HR),mean arterial pressure(MAP) were measured at the time points of before fentanyl and 2,3 min after fentanyl,every CE of propofol steps,before intubation,immediately and 1,3,5 min after intubation,before skin incision,and 0.5,1,3,5 min after skin incision,respectively. Results Three minutes after receiving fentanyl,the values of RE and SE in the three groups decreased significantly in a dose-dependent manner,and increased obviously at the same degree during intubation and after skin incision.The values recovered to the level before stress stimulation 1 min after intubation and 5 min after skin incision.There were no differences in the fluctuation of RE and SE among the three groups when the CE of propofol reached 1.0 ?g/mL.Conclusion Spectral entropy may effectively reflect the depth of anesthesia,but not analgesia during anesthesia.