POSTOPERATIVE DELIRIUM IN OLDER ADULTS: RISK FACTORS, PREVENTION AND PROGNOSIS — A CRITICAL NARRATIVE REVIEW WITH EVIDENCE GRADING

Abstract

Introduction: postoperative delirium is a frequent neurocognitive complication in older adults and remains underdiagnosed, especially in its hypoactive presentation. Objective: to critically analyse risk factors, preventive strategies and prognostic consequences while distinguishing direct clinical evidence, indirect or extrapolated evidence, and pathophysiological inference. Method: a SANRA-oriented critical narrative review with a targeted update in PubMed/MEDLINE, the Cochrane Library, SciELO and LILACS until July 2026, complemented by citation tracking and consultation of guidelines and official documents; Google Scholar was used only as a supplementary tool. The final corpus comprised 59 sources. Results: baseline cognitive vulnerability, frailty and potentially modifiable perioperative exposures interact cumulatively. Multicomponent non-pharmacological interventions have the most consistent support, with moderate-certainty evidence of reduced incidence. Dexmedetomidine, ketamine, corticosteroids and antipsychotics do not support universal prophylaxis; regional and general anaesthesia do not materially differ in delirium risk. Electroencephalographic monitoring may help avoid unnecessarily deep anaesthesia, but its preventive effect remains uncertain because trials are discordant and meta-analyses are heterogeneous. Delirium is associated with mortality, institutionalisation and cognitive decline, although causality remains unresolved. Conclusion: structured prevention, serial screening and early correction of precipitants are the evidence-based core of care. In Brazil, multicentre epidemiological and implementation studies are priorities.