Anticipating and managing postoperative delirium and cognitive decline in adults

The brain is vulnerable during the perioperative period in people of all ages. Neurobehavioural disturbances are common complications of perioperative care, manifesting in three distinct forms: emergence delirium, postoperative delirium, and postoperative cognitive decline. Delirium is defined by the presence of disturbed consciousness (reduced clarity of awareness of the environment with reduced ability to focus, sustain, or shift attention) and a change in cognition (such as memory deficit, disorientation, or language disturbance) or the development of a perceptual disturbance that is not better accounted for by a pre-existing, established, or evolving dementia. Emergence delirium occurs on emergence from anaesthesia and sedation, with no lucid interval, and lasts approximately 30 minutes. Postoperative delirium lasts hours or longer, with or without lucid intervals. Postoperative cognitive decline refers to a more subtle cognitive impairment noted on neuropsychological tests that typically assess attention and memory. Postoperative delirium is the most severe of the three disorders, tantamount to an acute brain failure, and should be considered akin to other postoperative organ failures. We review delirium and long term cognitive decline associated with perioperative care in adults and discuss potential mechanisms and preventive/intervention strategies in light of recent randomised controlled trials, meta-analyses, and prospective cohort studies. #### Sources and selection criteria Each author had previously conducted a search of published work. In addition a formal Medline search was undertaken in March 2011 with keywords “delirium”, “hip”, and “fracture” to provide data for the figure. Studies were identified by RDS and selected based on published criteria for meta-analysis10 by Nina Frasen. Joost Witlox and Pim Van Gool analysed the data and kindly provided the figure. Young adults seem particularly vulnerable to emergence delirium, whereas in older patients (over 60) postoperative delirium, and its subsequent sequelae, are more common. Three large cohort studies have shown that emergence delirium occurs in about 5-21% …