Described is a system and method which includes the following steps. A plurality of interventional agents are administered to a patient until the patient attains a predetermined plane of anesthesia. Brain waves of the patient are amplified and digitized before and after the administering step to generate a first set of digital data. The brain waves of the patient are amplified and digitized during a medical procedure to generate a second set of digital data. Separate trajectories for at least two different indices of an anesthetic state of the patient are computed during the medical procedure as a function of a comparison of the first and second sets of digital data. The indices include a Depth Index (DI), a Memory Index (MI) and a Pain Index (PI). The DI corresponds to a depth of anesthesia of the patient, the PI corresponds to a sensitivity of the patient to pain and the MI corresponds to an ability of the patient to form and store memories.