Microglia in Anesthesia and Perioperative Brain Health

Microglia, the brain's resident immune cells, constantly survey the brain environment via their dynamic processes. They promptly respond to changes in neuronal activity and regulate neural circuits and behaviors. Emerging evidence indicates that microglia modulate anesthetic states and perioperative brain health. Specifically, microglia influence all phases of anesthesia, including facilitating induction, sustaining unconsciousness, and shaping emergence through dynamic interactions with neuronal elements and synapses. These context‐dependent actions vary across anesthetic classes, highlighting opportunities for tailored intervention. Since microglia are also activated by perioperative stressors, they plausibly link anesthetic exposure to postoperative brain outcomes, including delirium and cognitive decline. Bridging mechanistic insights with clinical translation, this review outlines how microglia sense and regulate neuronal activity during anesthesia and presents potential perioperative strategies targeting microglia for precision anesthesia. Integrating microglial biology into perioperative care reframes anesthesia not merely as a means of inducing unconsciousness but as a modifiable determinant of long‐term brain health.