Recent advances in predicting, preventing, and managing postoperative delirium

Abstract

Postoperative delirium (POD) is a major public health problem associated with poor patient outcomes such as increased hospital lengths of stay, loss of functional independence, and higher mortality. Depending on the study, the reported incidence ranges from 5% to 65%, with the highest incidence in hip and cardiac surgery. Anesthesiologists should be familiar with the predisposing and precipitating factors of POD, particularly screening for preoperative cognitive impairment and frailty syndrome. Screening tools, for example, the Mini-Mental State Exam, Mini-Cog, 4 A's test for delirium screening, and Montreal Cognitive Assessment, can be used to assess for cognitive impairment and the Clinical Frailty Scale to assess for frailty syndrome. The Hospital Elder Life Program is the standard prevention protocol that is tried and tested in reducing the incidence of POD. Prehabilitation, lung protective strategies, pharmacologic agents such as ramelteon, a melatonin receptor agonist, glucocorticoids, dexmedetomidine, and non-pharmacologic agents, such as noise reduction strategies and the encouragement of nocturnal sleep, have all led to a decrease in the incidence of POD and are being studied for their efficacy. However, the data are inconclusive to date. Intraoperatively, preventing hypotension and blood pressure swings, ensuring adequate pain control and anesthetic depth, and using age-adjusted minimum alveolar concentration (MAC) titration reduce the incidence of POD. The incidence of POD using regional or general anesthesia is similar. In this narrative review, we will discuss the current understanding of the predictors, pathophysiology, prevention, and management of POD and identify areas of further research.