The effect depends on the type of nerve involved. A local anesthetic agent blocks motor nerves less easily and sympathetic nerves more easily. An anesthetic agent is not considered metabolized until all three systems (motor, sensory, and autonomic) are no longer affected. The patient receiving regional anesthesia is awake and aware of his or her surroundings, unless drugs are given to produce mild sedation or to relieve anxiety. Local anesthesia, on the other hand, is the injection of a solution containing the anesthetic agent into the tissues at the planned incision site (Brunner, p..