Blood propofol concentration and psychomotor effects on driving skills

We studied psychomotor performance in 10 healthy volunteersduring recovery after a target-controlled infusion of propofol.Choice reaction time, dual task tracking with secondary reactiontime and a within-list recognition task were assessed at targetblood propofol concentrations of 0.8, 0.4 and 0.2 µg ml^–1.Performance was impaired most at the highest blood propofolconcentration (choice reaction time increased by a mean of 247ms and secondary reaction time by a mean of 178 ms). Choicereaction time and dual task tracking with secondary reactiontime were the most sensitive and reliable methods of assessment(significant difference from baseline (P<0.05) at a propofolconcentration of 0.2 µg ml^–1 with choice and secondaryreaction time testing). Within-list recognition assessment ofmemory was not sufficiently sensitive at very low propofol concentrations.The impairment in choice and secondary reaction time with ablood propofol concentration of 0.2 µg ml^–1 wasless than that observed with a blood alcohol concentration of50 mg 100 ml^–1 and no greater than that observed witha blood alcohol concentration of 20 mg 100 ml^–1 in a previousstudy involving healthy volunteers. Br J Anaesth 2000; 85: 396–400 ^* Corresponding author