Changes In The Bispectral Index During Sedation Induced By TCI Propofol And A Bolus Of Tramadol Under Epidural Block

Objective: To evaluate the feasibility and the anesthetic trait in patients undergoing target–controlled infusion (TCI ) with propofol and a bolus injection of tramadol for sedation in patients undergoing epidural anesthesia with 1% lidocaine and 0.3% dicaine .To investigate the bispectral Index changing regulation with the increase of tramadol. Methods :Fouty ASAⅠ~Ⅱpatients (6 male 34 famale ) aged 20~55 years undergoing operation in lower abdomen or on lower extremity under epidural anesthesia were included this study .The block height was lower than T4 .All patients were randomly divided into four groups A ,B,C and D. Four groups the target-controlled blood propofol concentration was set up 1.5μg/ml,whereas group B using a bolus of tramadol 1mg/kg ; group C 1.5mg/kg; group D 2mg/kg. Five minutes after given propofol ,tramadol planned was infused .Mean arterial press (MAP ) ,heart rate(HR ) ,pulse oxygen saturation (SPO2 ),bispectral Index (BIS ),Observe Assessment of Alartness score (OAA/S ) was recorded at eight times as follows :before TCI propofol (T1 ) ,before infusion of tramadol(T2 ) and every five minutes after infusion of tramadol (T3,T4,T5,T6,T7,T8 ) within thirty minutes . Result :The mean of sex ,age ,weight ,height and block height had no significant difference among four groups .The changes of MAP ,HR ,SPO2 did not show any statistic difference between groups .Bispectral Index score of time T3,T4,T5,T6,T7 and T8 had significant difference compare with Bispectral Index score of time T1,T2 .P <0.01. Mean of Bispectral Index value of groups increasingly reduced from group A to group D. The decrease btween groups had significant difference (P<0.05 or P<0.01). With the increase of tramadol OAA/S significantly decreased from 5 to 2,BIS significantly decreased from 90.19 ± 2.99 to 84.29 ± 2.36,to 80.58 ± 30,to 72.90 ±3.38( P<0.01) . Conclusion :In this study , with the increase of tramadol ,Bispectral Index value and OAA/S was significant reduced in patients undergoing epidural anesthesia with infusion during operation by TCI and a bolus of tramadol for sedation ,therefore BIS Index value is a reliable index of monitoring anesthetic depth and sedation depth .