Effect of different target plasma concentrations of remifentanil on sedative effect of propofol

Objective To investigate the effect of different target plasma concentrations (Cp) of remifentanil on sedative effect of propofol. Methods Eighty adult ASA Ⅰ or Ⅱ patients aged 18-60 yr undergoing elective laparoscopic cholecystectomy were randomly assigned into 4 groups (n = 20 each). Anesthesia was induced with TCI of remifentanil (Cp = 2, 4 and 8 ng/ml in group Ⅱ-Ⅳ respectively) and propofol TCI (the initial Cp of propofol was 2 μg/ml in the 4 groups). Then the Cp of propofol increased by 0.5 μg/ml every 1 min until BIS value decreased to 50. BIS value and the Cp of propofol were recorded as the patient lost consciousness.The Cp and consumption of propofol were recorded when BIS value decreased to 50. Results BIS value was significantly increased, while the Cp of propofol was significantly decreased as the patient lost consciousness, and the Cp and consumption of propofol were significantly decreased when BIS value decreased to 50 in group Ⅲ - Ⅳ compared with group Ⅰ (P ＜ 0.05). Conclusion Remifentanil 4 ng/ml is the suitable Cp for anesthesia when combined with propofol. Key words: Piperidines;  Propofol;  Conscious sedation;  Drug delivery systems