Table 1.

Description of Anesthetic Stages

Anesthetic stage	Description
Stage 1	beginning of anesthesia, initial hyperactivity followed by decreased movement and respiration rate, strong reflex response following audible startle
Stage 2	continued reduction in movement, loss of consciousness, equilibrium, and muscle tone, further decrease in voluntary respiration rate, reduced reflex response following audible startle
Stage 3	immobility, loss of reflex response following audible startle, further reduction in voluntary respiration to respiratory arrest
Stage 4	respiratory arrest to death

Description of criteria used to evaluate anesthetic stage.