Postoperative delirium: risk factors, diagnosis and perioperative care

Postoperative delirium (PD) relates to increased morbidity -associated with prolonged hospital stay, institutionalization and persistent functional and cognitive decline- poor long term outcome and higher perioperative mortality. Aim of this literature review is to identify established risk factors for PD and to categorize them according timing of occurrence (pre, intra and post operative), and clinical impact (Odds ratio [OR], % increase in incidence of PD).

medical literature databases (medline and embase) were searched for published manuscripts on "postoperative delirium". Predictors and preoperative risk factors for PD were categorized into 4 groups: demographics; co morbidities; surgery and anesthesia-related (age, education, laboratory anomalies, smoking habits, benzodiazepines premedication, cardiac and thoracic surgery, etc). Intra operative risk factors for PD were categorized into 2 groups: surgery and anesthesia-related (anemia, duration and type of surgery, selected opioid, intraoperative hypotension, etc). Post operative risk factors and precipitating factors include various pathophysiological and environmental conditions, (i.e., ICU admission, low cardiac output requiring inotropes infusion; new onset atrial fibrillation; persistent hypoxia or hypercarbia; use of narcotic analgesics, delayed ambulation, inadequate nutritional status; sensory deprivation, etc). In conclusion, the effective identification, prevention and treatment of pre, intra and postoperative risk factors are the cornerstones for the prevention of PD. A dedicated perioperative care path that encompasses a tailored selection of drugs used perioperatively, the appropriate anesthesia strategy, qualified nursing surveillance, systematic use of diagnostic tools and accurate staff communication reduces the incidence and clinical impact of PD.