The effect of pre-operative anxiety on induction of anaesthesia with propofol.
In this prospective study, we investigated the effects of anxiety on the induction dose of propofol and subsequent cardiovascular changes in 197 patients. Pre-operative state and trait anxiety scores were measured using the State Trait Anxiety Inventory. Propofol was administered at 40 mg x kg(-1) x h(-1). Propofol dose was recorded at loss of verbal response and when EEG Bispectral Index decreased to 50. Thereafter, propofol infusion rate was reduced to 8 mg x kg(-1) x h(-1). Cardiovascular data were collected for 15 min after starting induction. Maximum percentage decreases in heart rate and mean arterial pressure, and the point at which the latter occurred, were recorded. On multivariate analysis, anxiety scores did not significantly affect propofol dose or cardiovascular end-points, although Bispectral Index at loss of verbal response decreased with increasing trait anxiety (p = 0.02). Anxiety, measured using State Trait Anxiety Inventory, does not appear independently to affect the induction characteristics of propofol.