Accuracy of EEG nonlinear indexes as a measure of sedation depth during TCI of propofol
- VernacularTitle:下肢手术患者脑电非线性参数预测异丙酚镇静深度的准确性
- Author:
Mingwen OUYANG
;
Hong ZHANG
- Publication Type:Journal Article
- Keywords:
Electroencephalography;
Forecasting;
Propofol;
Conscious sedation
- From:
Chinese Journal of Anesthesiology
1995;0(12):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To compare the prediction probability (Pk) of loss of consciousness (LOC) for the four EEG nonlinear indexes-correlation dimension ( D2), approximate entropy (ApEn) complexity (Cx) and bispectral index (BIS) and their relative accuracy. Methods Twenty ASA Ⅰ-Ⅱ patients aged 22-71 undergoing elective operation on lower limb under epidural anesthesia were studied. The patients were unpremedicated. Epidural catheter was placed at L2,3 or L3,4 interspace. The block height was 95% . Sedation was produced by target-controlled infusion (TCI) of propofol. The target plasma concentration of propofol (Cp) was initially set at 0.5 ?g?ml-1. Cp was gradually increased in increments of 0.3-0.5 ?g?ml-1 every 3 min until LOC. Depth of sedation was assessed using OAA/S scale (5 = alert, 1 = LOC) . LOC was maintained for 12 min. Cp was equal to effect-site concentration (Ce) by the end of 12 minutes. Cp was then gradually decreased in increments of 0.3-0.5 ?g?ml-1 until the patients regained consciousness. The same procedure was repeated 4 times in every patient. BIS, D2 , ApEn and Cx were recorded simultaneously every 3 min. The prediction probability of LOC for D2, ApEn, Cx and BIS was calculated and compared.Results The BIS value was 80.2?6.2 when the patients regained consciousness (T1) and 67.3?7.9 at LOC (T2); D2 was 3.45?0.18 (T1) and3.01?0.16 (T2); ApEn was 0.84?0.05 (T1) and 0.71?0.06 (T2); Cx was 0.55?0.05 (T1) and 0.44?0.05. There was no significant difference in Pk of LOC among the 4 indexes. Conclusion Our results show that all the 4 indexes can be used to monitor the level of sedation produced by propofol.
