Comparison of propofol LCT and propofol MCT/LCT regarding the injection pain at different sites and the memory

Background: Incidence and intensity of pain on intravenous injection of propofol LCT were compared with those of propofol MCT/LCT. Methods: Eighty adult patients scheduled to receive general anesthesia were divided into two groups, propofol LCT (Group L, AstraZeneca) and propofol MCT/LCT (Group M, Maruishi Pharmaceutical). The peripheral vein was inserted with an 18 gauge intravenous catheter at the dorsal hand, the wrist, or the anterior brachial region. Propofol 2.0 mg · kg^-1 was injected at the speed of 5 mg · sec^-1. Noninvasive arterial blood pressure, heart rate, a BIS value and a degree of pain were measured. We used x² analysis and Wilcoxon t-test for statistical evaluation. Results: There was a significantly larger incidence of injection pain in the Group L than the Group M (70% vs. 30%). The pain at the brachial region was significantly less as compared with the wrist or the dorsal hand in both groups. The ratio of patients having the memory of pain on the next day to those complaing the injection pain was 50% in the Group L and 36% in the Group M. There were no significant differences between the two groups in changes in BIS values and doses of propofol necessary for the loss of consciousness. Conclusions: The results suggest that propofol MCT/LCT elicits less pain on injection than propofol LCT. The injection pain is less at the brachial region than the wrist or the hand. Amnesia of pain may be obtained both with propofol MCT/LCT and propofol LCT.