Delirium and postoperative cognitive dysfunction after general anesthesia

Abstract

Background: General anesthesia is characterized by unconsciousness, analgesia, muscle relaxation, and depression of reflexes, generally in response to the administration of chemical agents that induce reversible unconsciousness. Study of the cognitive neuroscientific basis of general anesthesia involves evaluation of the effect of anesthetic agents on consciousness and the brain mechanisms underlying cognitive function. Central nervous system dysfunction after anesthesia and/or surgery can occur at any age but is a particular issue for elderly patients. Studies of delirium and postoperative cognitive dysfunction have been published in many countries since the end of the last century. We present a discussion of delirium disorders and a review of the literature.

Case report: We also present case reports for 2 patients who underwent general surgery for epilepsy. The first patient experienced postoperative visual illusions, hallucination, and time and space disorientation. The second patient experienced a postoperative zombie-like delirium state. The status of both patients was improved in response to treatment with methylprednisolone. The first patient also received amantadine sulfate, and the second patient received antiepileptic drugs.

Conclusions: The brain is the main target organ for anesthetic and adjuvant drugs, and age-associated changes in the brain have important implications with respect to general anesthesia. Anesthetists and surgeons have suspected for many years that some patients suffer a postoperative decline in cognitive function. The condition generally has a good outcome because oxidative nerve cell derangements and neurotransmitter imbalances are transient.