Backgrounds and objective: There is a high incidence of pain following intravenous injection of propofol, and many studies have been conducted to find a way of reducing this. The administration of lidocaine and, recently, remifentanil has also been used for this purpose, but it is only partially effective. Thus, the purpose of this study was to investigate the analgesic effect of a combination of pretreatment with remifentanil and premixture of lidocaine with propofol and to compare either treatment alone during propofol injection in dorsal hand-veins.
Methods: In a prospective, randomized, double-blinded trial, we studied 141 adult patients scheduled for elective surgery. The combination of pretreatment of remifentanil (0.35 microg kg(-1) min(-1)) and a premixture of lidocaine with propofol (mixture of propofol 1% and lidocaine 1% in a 10:1 ratio) was compared with either treatment alone in the prevention of pain on propofol injection. Pain was assessed on a four-point scale (0=none, 1=mild, 2=moderate, 3=severe) during propofol injection. Patients in Group B received remifentanil (0.35 microg kg(-1) min(-1)) 30 s before the injection of propofol.
Results: The reduction of pain on propofol injection was similar in both the remifentanil pretreatment and lidocaine premixture groups (62.2% vs. 62.2%). Combination therapy was associated with a higher incidence of patients without pain (91.3%) than either treatment alone (P<0.001). On analysing the injection pain scores, we found a significant reduction of the score in the remifentanil and lidocaine Group C compared with the lidocaine Group A (P<0.001) and the remifentanil Group B (P<0.001).
Conclusions: The combination of pretreatment of remifentanil and premixture of lidocaine with propofol was more effective in reducing the incidence of pain on injection of propofol than either treatment alone.