Effects of different doses of dexmedetomidine on effect-site concentration of propofol during intubation of general anesthesia induction

Objective To investigate the effects of different doses of dexmedetomidinthe in patients safety and availability during intubation of general anesthesia induction effect-site concentration (Ce) of propofol.Methods Sixty patients undergoing elective upper abdominal surgery under general anesthesia were randomly divided into 4 groups,15 cases each. Patients in the group D1, group D2, group D3 and group C were respectively administered with dexmedetomidine 0.25, 0.5, 1.0 mg/kg,or sodium chloride injection by micro-pump in 10 minutes before anesthesia induction. After infusion, anesthesia was induced with target-controlled infusion (TCI) of propofol, the initial Ce of propofol was set 1.5 mg/ml, according to bispectral index (BIS) increased 0.5 μg/ml every one minute, remifentanil was infused at 0.2 mg·kg-1·min-1. Rocuronium 0.9 mg/kg were injected and tracheal were intubated when BIS ≤60 and BIS ≤50 maintained 5 s, respectively. SBP, DBP, HR, BIS, and propofol Ce were recorded at the time before dexmedetomidine infusion (T0), before induction (T1), just before tracheal intubation (T2) and 1,3,5,10 minutes (T3-T6) after intubation.Results Compared with T0, HR in groups D2 and D3 were decreased and SBP and DBP in group D3 were increased at T1 (P0.05). Compared with T1, there were decreased for SBP,DBP and HR in group C and group D1 at T2. Compared with T2, SBP, DBP and HR in group C and group D1 were higher than those at T3-T5. BIS at T3 was elevated in group C (P0.05). The propofol Ce of group D1, D2 and D3 were lower than in group C at T2-T6 (P0.05). In addition, there was a negative correlation that different dose at different time points of propofol Ce.Conclusion There is a negative correlation that intravenous infusion different dose dexmedetomidine before given propofol Ce induction of anesthesia. Intravenous infusion 0.5mg/kg dexmedetomidine, the concentration of propofol can significantly decrease and cardiovascular response may steady.