title: A comparison of the effect of high- and low-dose fentanyl on the incidence of postoperative cognitive dysfunction after coronary artery bypass surgery in the elderly.
abstract: BACKGROUND
  Postoperative cognitive dysfunction (POCD) after coronary artery bypass graft surgery is a common complication for which, despite many clinical investigations, no definitive etiology has been found. The current use of both high- and low-dose fentanyl as anesthetic techniques allowed us to investigate the effect of fentanyl on the incidence of POCD.
  
  
  METHODS
  Three hundred fifty patients scheduled to undergo elective coronary artery bypass graft surgery were randomized to receive either high-dose fentanyl (50 microg/kg) or low-dose fentanyl (10 mug/kg) as the basis of the anesthetic. All patients underwent neuropsychological testing before surgery and at 1 week, 3 months, and 12 months after surgery.
  
  
  RESULTS
  One hundred sixty-eight patients in the low-dose group and 158 patients in the high-dose group were included in the final analysis. Neuropsychological testing was performed on 88%, 93%, and 92% of patients at 1 week, 3 months, and 12 months, respectively. There was no difference between group mean scores at any of the three testing times. Analysis of individual patients by the 20% rule did not detect any differences between groups. The one SD rule, which has fewer false-positive results, detected significantly more patients with POCD in the low-dose group than in the high-dose group at 1 week (23.6% vs. 13.7%; P = 0.03) but not at the other testing times. Patients with POCD spent an average of 1.2 days longer in the hospital than those without POCD (P = 0.021).
  
  
  CONCLUSIONS
  High-dose fentanyl is not associated with a difference in the incidence of POCD at 3 or 12 months after surgery. Low-dose fentanyl leads to shorter postoperative ventilation times and may be associated with a greater incidence of POCD 1 week after surgery. Early POCD is associated with an increased duration of stay in the hospital.
authors.affiliation: Department of Anaesthesia, St. Vincent's Hospital, Melbourne, Australia. silberbs@svhm.org.au
authors.forename: Brendan S
authors.initials: BS
authors.lastname: Silbert
authors.forename: David A
authors.initials: DA
authors.lastname: Scott
authors.forename: Lisbeth A
authors.initials: LA
authors.lastname: Evered
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Lewis
authors.forename: Mario
authors.initials: M
authors.lastname: Kalpokas
authors.forename: Paul
authors.initials: P
authors.lastname: Maruff
authors.forename: Paul S
authors.initials: PS
authors.lastname: Myles
authors.forename: Konrad
authors.initials: K
authors.lastname: Jamrozik
mesh_terms: D000368:Aged; D003072:Cognition Disorders / Q000209:etiology*; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage*; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009294:Narcotics / Q000008:administration & dosage*; D011183:Postoperative Complications / Q000209:etiology*
chemical_list: D009294:Narcotics; D005283:Fentanyl