Protection against cerebral ischemia: the role of barbiturates.

Cerebral ischemia is a complex injury process that occurs when the nutrient blood supply to cerebral structures is reduced below critical levels. The causes of cerebral ischemia are protean, but the underlying pathophysiologic mechanism that leads to injury is a mismatch between the supply of nutrients to a given cell (or population of cells) and the demand of the cell(s) for those essential nutrients. Extensive research is ongoing in our attempt to find a treatment strategy and/or pharmacologic agent that might protect cerebral structures when exposed to ischemia. To date, few strategies or agents have proven themselves truly "protective." In this communication, the complexities of the cerebral ischemia injury process will be reviewed, the principles of cerebral protection (both practical and theoretical) will be outlined, and the merits of barbiturate anesthesia with regard to planned temporary cerebral ischemia will be discussed.