Comparison Between The Performance Of Bispectral Index And Skin Conductance Monitoring During Propofol Sedation With Target-controlled Infusion

Objective:The purpose of this study was to compare the performance of bispectral index(BIS) and skin conductance(SC) to predict the level of consciousness during sedation produced by propofol with target-controlled infusion(TCI) and compare the changes of bispectral index(BIS) and skin conductance(SC) under the different effect site concentration(Ce). Methods:Thirty ASA class I or II orthopaedics surgery patients under general anesthesia were enrolled into this study. The exclusion criteria were known contraindications to potential anesthetic drugs, psychoactive medication, neurological disorder or neuropathy and the use of atropine or other anticholinergics in the pre-operative phase. None of the participants received premedication on the day of surgery. the MAP,HR,BIS and SC monitors were connected when the patient was on the table in a supine position. TCI of propofol was initiated at target effect compartment concentration of 0.5μg/ml, increased by 0.5μg/ml until 3.0μg/ml stop the target controlled infusion, every 3 minutes evaluation OAA/S, SC and BIS values were recorded. BIS and SC values were recorded at 0.5,1.0,1.5,2.0,2.5 and 3.0(μg/ml)Ce of propofol. Using Spearman rank correlation, ROC curves(Receiver Operating Characteristic) comparing the two methods for monitoring the relevance and accuracy of awareness. Results:OAA/S score and BIS,SC were significantly correlated, the r are 0.920,-0.859(P<0.01); In the OAA/S score(5～4,4～3), The under curve of SC(0.919,0.949)to be significantly better than the BIS(0.761,0.493), In the OAA/S score(2～1), BIS(0.959) is better than SC(0.730). Conclusion:SC and BIS can correctly reflect the TCI the depth of sedation during propofol sedation, BIS index is more accurate in monitoring the transition from unconsciousness to consciousness, SC is more advantage in monitoring the transition conscious patients for the difference of sedation level,It has fixed guidance meaning to sedative medication for no loss of consciousness for special surgery.