Effects Of A Single Injection Of Opioids Or Combined With Propofol On The Bispectral Index

ObjectivesTo compare the effects of equipotent doses of fentany、 sufentanil and remifentanil as sole agent infusion or combined target controlled infusion of propofol on Bispectral index to anesthesia induction, and in order to provide a refercence for selection of the appropriate opioid in clinical anesthesia.MethodsEighty patients (age between18to65years old, ASA1-Ⅱ) undergoing elective surgery under general anesthesia were enrolled in this study. The patients were randomly divided into eight groups(n=10cases):Saline group(group C)、Saline plus propofol group(group CP); Fentanyl group(group F)、 Fentanyl plus propofol group(group FP); Remifentanil group(group R)、 Remifentanil plus propofol group(group RP); Sufentanil group(group S)、 Sufentanil plus propofol group(group SP); No premedication was given. All patients were sedated by propofol via TCI under the same scheme. The propofol infusion was started to provide an initial plasma concentration of2.5μg/ml, and increased by0.5μg/ml every10min until BIS value was less than or equal to65(T1). Then the infusion was stopped. When the patients with BIS restored to80(T2),we carried out the second administration:saline10ml、 fentanyl2.4μg/kg、remifentanil2μg/kg-sufentanil0.2μg/kg, as a single intravenous injection respectively or combined target controlled infusion of propofol (plasma concentration of3.0μg/ml).At each time point, the BIS, HR、 MAP、 SpO2were recorded.ResuItsIn the first phase of the observation, there was no significant difference among the groups between ΔT1、 the propofol plasma concentration and the drug doses when BIS≤65.The time required (ΔT2) respectively were7.2±2.6min、8.5±3.2min、8.2±3.2min、6.5±2.Omin、5.1+1.5min、6.6±1.8min、7.4±1.8min、8.5±2.0min in each group (group C、group CP、group F、group FP、 group R、group RP、group S、group SP) when the BIS value from less than equal to65to return to80.The time group S required was longer than group R (P <0.05);The time group CP、 group SP required was significantly longer than group R (P<0.01).In the second phase of the observation:there was no significan differences with BIS when a single injection of sufentanil or fentanyl, compared with the saline, between T:, to T9. The BIS value was reduced in group R at T3-T5, but there was significant difference only at T3(P <0.01),however there were no significant differences compared with other groups;At T4-T5, there were no significant, differences in group R compared to T2with BIS, yet, statistieally signilicant compared with other groups (P<0.01); Compared with the T2time point, the BIS decreased at. T3、T4、T5、T6、T7、T8、 T9in group CP、FP、RP、SP(P<0.01), the BIS were higher in group FP、RP、 SP at T9than in group CP(P<0.05). Moreover, the BIS were higher in group RP at T8than in group CP(P<0.05).ConclusionThere was no significant effect on Bispectral when giving clinical doses of fentanyl、 sufentanil as sole agent infusion, also has not seen to strengthen the role of suppression of propofol on BIS. There may be a short-term inhibition on BIS, after the single injection of remifentanil.