The effect of intravenous epinephrine on the bispectral index and sedation.

Eight patients were given a propofol infusion until they no longer responded to loud verbal stimuli, a sedation score of two (modified Observer Assessment of Alertness and Sedation Scale). After receiving 15 microg of intravenous epinephrine, changes in sedation score and bispectral index (BIS) were observed. Mean pulse rate increased from 68 to 96 (SD 10) beat.min-1, mean blood pressure increased from 107/60 (SD 10/8) mmHg to 140/70 (SD 27/14) mmHg, and mean BIS level rose from 63 to 76 (p < 0.005). Sedation scores increased in six of the eight patients. Exogenous catecholamines seem to have an arousal effect on lightly anaesthetised patients. This could be due to changes in neurotransmitter levels in the brain, or due to the effects consequent on increased cardiac output.