Emergence delirium is associated with

Ketamine causes postoperative delirium and hallucinations. It is also contraindicated in delirium tremens and head injury. Ketamine increases cerebral metabolism, CBF, and ICP. So contraindicated in neurosurgeries. Ketamine, like other phencyclidines, produces undesirable psychological reactions, which occur during awakening from ketamine anesthesia and are termed emergence reactions. The common manifestations of these reactions, which vary in severity and classification, are vivid dreaming, extracorporeal experiences (sense of floating out of body), and illusions (misinterpretation of a real, external sensory experience). These incidents of dreaming and illusion are often associated with excitement, confusion, euphoria, and fear. They occur in the first hour of emergence and usually abate within 1 to several hours. These psychic emergence reactions are secondary to ketamine-induced depression of auditory and visual relay nuclei, thus leading to misperception or misinterpretation of auditory and visual stimuli. The incidence of the psychic emergence reactions ranges from 3% to 100%. Ref: Miller's anesthesia 8th edition Ref: Morgan & Mikhail's clinical anesthesiology 6e