title: Postoperative delirium: age and low functional reserve as independent risk factors.
abstract: OBJECTIVE
  The aim of this study was to determine the incidence of postoperative delirium (POD) and the presence of previous conditions related to its development.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  The study was performed in adult patients (n=221) scheduled for elective surgery and admitted to the postanesthesia care unit (PACU).
  
  
  METHODS
  The presence of POD was assessed by the Nursing Delirium Screening Scale at discharge from the PACU and 24hours after surgery. Descriptive analyses were carried out, and statistical comparisons were performed with Mann-Whitney U, χ(2), or Fisher exact test. Logistic regression analysis was used for evaluation of independent determinants of POD.
  
  
  RESULTS
  POD was found in 25 patients (11%). Patients who developed POD were older (median age, 69 vs 57years; P<.001); had a higher American Society of Anesthesiologists physical status score (≥3) (60% vs 19%, respectively, had American Society of Anesthesiologists physical status III/IV; P<.001); and showed higher incidences of ischemic heart disease (24% vs 6%; P=.001), chronic kidney disease (20% vs 5%; P=.005), hypertension (80% vs 45%; P=.001), chronic obstructive pulmonary disease (20% vs 6%; P=.009), and low functional reserve (LFR) (24% vs 2%; P<.001). Age (odds ratio, 1.06; 95% confidence interval, 1.02-1.10; P=.003) and LFR (odds ratio, 8.04; 95% confidence interval, 3.95-32.27; P=.003) were considered independent risk factors for POD.
  
  
  CONCLUSIONS
  The incidence of POD in the study population (11%) is consistent with that described in the literature (5%-15%). The comorbidities associated with its development were ischemic heart disease, hypertension, chronic kidney disease, LFR, and chronic obstructive pulmonary disease. Age ≥65years and LFR were independent risk factors for POD development.
authors.affiliation: Department of Anaesthesiology, Hospital de São João, Porto, Portugal.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Pinho
authors.affiliation: Department of Anaesthesiology, Hospital de São João, Porto, Portugal.
authors.forename: Sofia
authors.initials: S
authors.lastname: Cruz
authors.affiliation: Department of Anaesthesiology, Hospital de São João, Porto, Portugal.
authors.forename: Alice
authors.initials: A
authors.lastname: Santos
authors.affiliation: Department of Anaesthesiology, Hospital de São João, Porto, Portugal; Department of Anaesthesiology and Perioperative Medicine, University of Porto Faculty of Medicine, Portugal. Electronic address: fernando.abelha@gmail.com.
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Abelha
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000758:Anesthesia; D001938:Brazil / Q000453:epidemiology; D015897:Comorbidity; D003422:Critical Care; D003693:Delirium / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology* / Q000503:physiopathology; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult
keywords: Low functional reserve; Postoperative care; Postoperative delirium; Risk factors for postoperative delirium