Prevention of microemulsion propofol injection pain: a comparison of a combination of lidocaine and ramosetron with lidocaine or ramosetron alone

Background: A microemulsion propofol causes a high incidence of pain during intravenous injection. In this study, we investigated the effect of ramosetron on pain induced by microemulsion propofol injection. Methods: After prospective power analysis and institutional review board approval, a total of 200 ASA I and II patients undergoing general anesthesia were divided into 4 groups. They received one of the following intravenously after tourniquet application on the forearm 1 min before induction of anesthesia using microemulsion propofol; normal saline (Group N, n = 50), lidocaine 20 mg (Group L, n = 50), ramosetron 0.3 mg (Group R, n = 50) and lidocaine 20 mg plus ramosetron 0.3 mg (Group LR, n = 50) diluted into a 5 ml solution. The occlusion was released after 30 seconds and microemulsion propofol was injected over 10-15 seconds. The patients were observed and asked immediately if they had pain in the arm, and their responses were assessed. Results: The incidence of pain in groups N, L, R and LR was 96%, 76%, 60% and 38%, respectively (P < 0.008). Two patients in Group LR (4.0%) and nine in Group R (18.0%) had moderate to severe pain, which was significantly lower than pain in Groups N (84.0%), L (40.0%) and R (P < 0.008). Conclusions: Pretreatment with ramosetron 0.3 mg with or without lidocaine 20 mg with a tourniquet on the forearm 30 seconds before the injection of microemulsion propofol is more effective than lidocaine 20 mg or normal saline in preventing pain from a microemulsion propofol injection. (Korean J Anesthesiol 2011; 61: 30-34)