Final answer:
The anesthetic agent that requires monitoring for hallucinations and agitation by the perioperative nurse is Ketamine (Ketalar).
Step-by-step explanation:
The perioperative nurse should monitor the patient for hallucinations and agitation when Ketamine (Ketalar) is administered as an anesthetic agent. Unlike other anesthetic agents such as Nitrous oxide, THIOpental (Pentathal), or Halothane (Fluothane), Ketamine is known to cause dissociative effects, which can lead to hallucinations and agitation during the postoperative period. It is an injectable anesthetic used in situations requiring rapid anesthesia, like field anesthesia or in an operative setting, but its psychoactive properties necessitate close monitoring for psychological and neurological side effects.