The Guedel's classification describes four stages of anesthesia. Stage 1 Is known as the "induction", is the period between the initial administration of the induction agents. During this stage, the subject progresses from analgesia without amnesia to analgesia with amnesia. Stage 2 Is known as the "excitement stage", where loss of consciousness is marked by excitement and delirious activity. In this stage, respiration and heart rate may become irregular. Stage 3 Is "surgical anesthesia". Where, the skeletal muscles relax, Eye movements slow and stop, the subject is unconscious and ready for surgery. Stage 4 Is known as "overdose", where too much medication is given relative to the amount of surgical stimulation. This stage is lethal without cardiovascular and respiratory support.