An update on postoperative delirium: Clinical features, neuropathogenesis, and perioperative management

Abstract

Purpose of review: We present a focused review on postoperative delirium for anesthesiologists, encompassing clinical features, neuropathogenesis, and clinical identification and management strategies based on risk factors and current delirium treatments.

Recent findings: The literature on postoperative delirium is dominated by non-experimental studies. We review delirium phenotypes, diagnostic criteria, and present standard nomenclature based on current literature. Disruption of cortical integration of complex information (CICI) may provide a framework to understand the neuropathogenesis of postoperative delirium, as well as risk factors and clinical modifiers in the perioperative period. We further divide risk factors into patient factors, surgical factors, and medical/pharmacological factors, and present specific considerations for each in the preoperative, intraoperative, and postoperative periods.

Summary: Postoperative delirium is prevalent, poorly understood, and often missed with current screening techniques. Proper identification of risk factors is useful for perioperative interventions and can help tailor patient-specific management strategies.

Keywords: Aging; Anesthesiology; Cortical integration of complex information (CICI); Electroencephalography (EEG); Functional connectivity; Postoperative delirium.

Figure 1.. Classification of delirium subtypes.

Postoperative delirium is a subtype of delirium that occurs between postoperative days 0–5. PACU delirium is a further subtype of postoperative delirium that occurs in the PACU. ICU delirium is defined by its identification in the ICU; there may be some overlap depending on when patients are admitted to the ICU. Emergence agitation is seen on emergence from anesthesia and has unique etiologies and treatments. Abbreviations: PACU - post-anesthesia care unit; ICU - intensive care unit.