Postoperative delirium and cognitive dysfunction

Abstract

Postoperative delirium and cognitive dysfunction are common manifestations of acute brain dysfunction, occurring in up to 70% of post - surgical patients. The development of postoperative delirium and postoperative cognitive dysfunction have long-term consequences, such as higher morbidity and mortality and increased hospital stay, and it increases the risk of dependency and institutionalisation. Delirium presents clinically with differing subtypes ranging from hyperactive to hypoactive. Despite the relevance of these cognitive disorders, the specific aetiology is still unknown, and there are many factors that have been associated with its development. In many forms of delirium, the brains reaction to a peripheral inflammatory process is considered to be a pathophysiological key element and the aged brain seems to react more markedly to a peripheral inflammatory stimulus than a younger brain. The risk factors for delirium are categorised as predisposing or precipitating factors. In the presence of many predisposing factors, well documented predisposing factors are age, medical comorbidities, cognitive, functional, visual and hearing impairment and institutional residence. Important precipitating factors apart from surgery are admission to an ICU, anticholinergic drugs, alcohol or drug withdrawal, infections, iatrogenic complications, metabolic derangements, pain and the exposure to analgesics ( opioids ) and hypnotics ( benzodiazepines). Several bedside instruments are available for the routine ward and ICU setting. The Confusion Assessment Method (CAM) and a version specifically developed for the intensive care setting (CAM - ICU) have emerged as a standard. Non - pharmacological multicomponent strategies and pharmacological prophylaxis may be useful to reduce the incidence of postoperative delirium. Perioperative administration of haloperidol has been shown to reduce the severity and the incidence of delirium. The multicomponent interventions for prevention and treatment have been shown to reduce the incidence and severity of episodes.