Background: Pain upon the injection of propofol is a common adverse effect. This study was conducted to evaluate the analgesic effect of remifentanil and cold propofol during propofol injection for the induction of anesthesia and to determine if a combination of cold propofol and remifentanil produced additional analgesic efficacy.
Methods: A total of 160 patients aged 20-65 years old were randomly allocated into one of four groups (n = 40, in each). Control and remifentanil group patients received 2 mg/kg propofol that had been stored at room temperature (20-23℃), while the cold and combination group received cold (4℃) propofol. The patients received remifentanil 0.5 µg/kg IV in the remifentanil and combination groups or saline in the control and cold groups. Ninety seconds after administration the patients were administered propofol over a 30 second period. The pain intensity and incidence were then evaluated using a 4-point verbal rating scale.
Results: The incidence of pain was significantly reduced in groups that received remifentanil in the cold and combination groups when compared with the control group (27.5%, 30%, and 2.5% vs. 70%, respectively). Moreover, the severity of pain was significantly lower in groups that received remifentanil in the cold and combination groups when compared with the control group. The incidence and severity of pain from the propofol injection in the combination group was significantly lower than that in the remifentanil and cold groups.
Conclusions: The combination of cold propofol and pretreatment with remifentanil more effectively reduced the incidence of pain upon the injection of propofol than either treatment alone.
Keywords: Injections; Pain; Propofol; Remifentanil; Temperature.