Etomidate: Cerebrovascular Effects

Unconsciousness after intravenous etomidate results from binding to the GABA receptor and increasing its affinity for GABA. It has several cerebral vascular effects of note. Like most induction agents beside ketamine, cerebral metabolic rate and blood flow are both reduced. Similar to barbiturates, etomidate lowers cerebral blood flow by increasing cerebral vascular resistance. It also acts to lower cerebral metabolic rate, and exerts this effect more strongly in the cortex compared to the brainstem.

Etomidate also decreases production and increases absorption of CSF, and acts to lower intracranial pressure. With lower ICP and little effect on blood pressure, cerebral perfusion pressure is typically well maintained. As with other agents, cerebral autoregulation and responsiveness to CO₂ are not altered by etomidate.