A system and method includes administering interventional agents to Patient until Patient attains a predetermined plane of anesthesia; amplifying and digitizing brain waves of Patient before and after administering step to generate first set of digital data; amplifying and digitizing brain waves of Patient during a medical procedure to generate second set of digital data; computing separate trajectories for at least two different indices of an anesthetic state of Patient during the medical procedure using a comparison of first and second sets (the indices including Depth Index (DI)—a depth of anesthesia, Memory Index (MI)—an ability to form and store memories, and Pain Index (PI)—sensitivity to pain); and determining an amount of at least one of the interventional agents to be delivered to Patient as a function of the trajectories, the interventional agents include anesthetic, analgesic and/or amnesic agents corresponding to DI, MI and/or PI trajectories.