title: Postoperative cognitive dysfunction is independent of type of surgery and anesthetic.
abstract: BACKGROUND
  Postoperative cognitive dysfunction (POCD) has been documented after cardiac and noncardiac surgery. The type of surgery and anesthetic has been assumed to be associated with the incidence but there are few prospective data comparing the incidence after different procedures. In this study, we sought to determine the association of the type of surgical procedure and anesthesia on the incidence of POCD after procedures involving light sedation, general anesthesia for noncardiac surgery, and general anesthesia for cardiac surgery involving cardiopulmonary bypass.
  
  
  METHODS
  Eight neuropsychological tests were administered at baseline and at 7 days and 3 months postoperatively to subjects from 3 procedure groups and a nonoperative control group. Reliable change index was used to calculate POCD. The study sample consisted of subjects involved in 3 separate trials investigating coronary angiography (CA) (percutaneous diagnostic procedure) under sedation, major noncardiac surgery (total hip joint replacement [THJR] surgery) under general anesthesia, and coronary artery bypass graft (CABG) surgery under general anesthesia.
  
  
  RESULTS
  Data were collected from 644 patients in the patient groups and 34 subjects in the control group. Neuropsychological results were available for POCD at day 7 for THJR surgery (n=162) and CABG surgery (n=281). The incidence of POCD at day 7 was 17% for THJR surgery and 43% for CABG surgery (adjusted odds ratio=0.2, 95% confidence interval [CI]: 0.1, 0.4; P<0.01). At 3 months, the incidence of POCD for all groups combined (n=636) was 17% (21% for CA under sedation, 16% for THJR surgery, and 16% for CABG surgery). The mean (95% CI) for the difference in proportions of POCD among groups was 0.00 (-0.07, 0.07) (P=0.91) for CABG versus THJR; -0.05 (-0.12, 0.03) (P=0.21) for CABG versus CA; and -0.05 (-0.13, 0.03) (P=0.24) for THJR versus CA. There were no significant differences among groups (adjusted odds ratio=1.21, 95% CI: 0.94, 1.55; P=0.13).
  
  
  CONCLUSIONS
  The incidence of POCD in old and elderly patients at day 7 was higher after CABG surgery than THJR surgery, but POCD at 3 months was independent of the nature or the type of procedure or anesthetic when comparing CA, THJR, and CABG surgery groups. Cardiovascular risk factors were not predictive of POCD after any procedure.
authors.affiliation: BSc, Department of Anaesthesia, St. Vincent's Health, PO Box 2900, Fitzroy, Vic, Australia, 3065. lis.evered@svhm.org.au
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Evered
authors.forename: David A
authors.initials: DA
authors.lastname: Scott
authors.forename: Brendan
authors.initials: B
authors.lastname: Silbert
authors.forename: Paul
authors.initials: P
authors.lastname: Maruff
mesh_terms: D000367:Age Factors; D000368:Aged; D000768:Anesthesia, General / Q000009:adverse effects*; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects; D001315:Australia; D002315:Cardiopulmonary Bypass; D016009:Chi-Square Distribution; D002986:Clinical Trials as Topic; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000139:chemically induced / Q000175:diagnosis / Q000209:etiology* / Q000523:psychology; D016292:Procedural Sedation / Q000009:adverse effects*; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000009:adverse effects; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009483:Neuropsychological Tests; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D013514:Surgical Procedures, Operative / Q000009:adverse effects* / Q000523:psychology; D013997:Time Factors; D016896:Treatment Outcome