title: Is peri-operative cortisol secretion related to post-operative cognitive dysfunction?
abstract: BACKGROUND
  The pattern of cortisol secretion is influenced by surgery. As cortisol can adversely affect neuronal function, this may be an important factor in the development of post-operative cognitive dysfunction (POCD). We hypothesized that the incidence of POCD would be related to changes in cortisol level.
  
  
  METHODS
  We studied 187 patients aged over 60 years undergoing major non-cardiac surgery with general or regional anaesthesia. Saliva cortisol levels were measured pre-operatively and at 1 day, 7 days and 3 months post-operatively in the morning (08.00 h) and in the afternoon (16.00 h) using salivettes. Cognitive function was assessed pre-operatively, on day 7 and at 3 months using four neuropsychological tests. POCD was defined as a combined Z score of greater than 1.96.
  
  
  RESULTS
  After surgery, salivary cortisol concentrations increased significantly. POCD was detected in 18.8% of subjects at 1 week and in 15.2% after 3 months. The pre-operative ratios between the morning and afternoon cortisol concentrations (am/pm ratios) were 2.8 and 2.7 in patients with POCD at 1 week vs. those without POCD at 1 week, respectively. The am/pm ratios decreased significantly post-operatively to 1.9 and 1.6 at 1 week, respectively (P = 0.02 for both). In an analysis considering all am/pm ratios, it was found that the persistent flattening in am/pm ratio was significantly related to POCD at 1 week.
  
  
  CONCLUSIONS
  The pattern of diurnal variation in cortisol level was significantly related to POCD. Thus, circadian rhythm disturbance or metabolic endocrine stress could be an important mechanism in the development of cognitive dysfunction after major surgery.
authors.affiliation: Department of Anaesthesia, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
authors.forename: L S
authors.initials: LS
authors.lastname: Rasmussen
authors.forename: J T
authors.initials: JT
authors.lastname: O'Brien
authors.forename: J H
authors.initials: JH
authors.lastname: Silverstein
authors.forename: T W
authors.initials: TW
authors.lastname: Johnson
authors.forename: V D
authors.initials: VD
authors.lastname: Siersma
authors.forename: J
authors.initials: J
authors.lastname: Canet
authors.forename: J
authors.initials: J
authors.lastname: Jolles
authors.forename: C D
authors.initials: CD
authors.lastname: Hanning
authors.forename: H M
authors.initials: HM
authors.lastname: Kuipers
authors.forename: H
authors.initials: H
authors.lastname: Abildstrom
authors.forename: A
authors.initials: A
authors.lastname: Papaioannou
authors.forename: J
authors.initials: J
authors.lastname: Raeder
authors.forename: A
authors.initials: A
authors.lastname: Yli-Hankala
authors.forename: J R
authors.initials: JR
authors.lastname: Sneyd
authors.forename: L
authors.initials: L
authors.lastname: Munoz
authors.forename: J T
authors.initials: JT
authors.lastname: Moller
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D000765:Anesthesia, Conduction; D000768:Anesthesia, General; D002940:Circadian Rhythm / Q000502:physiology; D003072:Cognition Disorders / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology*; D012463:Saliva / Q000378:metabolism
chemical_list: D006854:Hydrocortisone