Table 1 Six levels of anesthesia

A

α(8-12 Hz) and β (13-30 Hz) activity, with intermixed eye movement/blinking and myogenic artifact from talking/swallowing

Not applicable (awake)

B

Fast β and θ (4-7 Hz) but rare δ (1-3 Hz)

Light

C

δ activity for at least 20% but no more than 50% of epoch

Light to moderate

D

δ activity for at least 50% of epoch; brief periods of suppression not to exceed 10 s

Moderate

E

Burst-suppression pattern, with at least 10 s but no more than 20 s of suppression per epoch

Profound

F

Burst-suppression pattern, with at least 20 s of suppression per epoch

Very profound