title: Cardiopulmonary bypass, rewarming, and central nervous system dysfunction.
abstract: BACKGROUND
  During cardiopulmonary bypass a nasopharyngeal temperature greater than 38 degrees C at the end of rewarming may indicate cerebral hyperthermia. This could exacerbate an ischemic brain injury incurred during cardiopulmonary bypass.
  
  
  METHODS
  In a cohort of 150 aortocoronary bypass patients neuropsychologic test scores of 66 patients whose rewarming temperature exceeded 38 degrees C were compared with those who did not. There were no differences between groups with respect to demographic and intraoperative variables.
  
  
  RESULTS
  A trend was seen for hyperthermic patients to do worse on all neuropsychologic tests in the early postoperative period but not at 3-month follow-up. By analysis of covariance hyperthermic patients did worse on the visual reproduction subtest of the Weschler memory scale at 3 months (p = 0.02), but this difference was not found by linear regression (p = 0.10).
  
  
  CONCLUSIONS
  We were unable to demonstrate any significant deterioration in patients rewarmed to greater than 38 degrees C in the early postoperative period. The poorer performance in the visual reproduction subtest of the Wechsler memory scale at 3 months in the group rewarmed to more than 38 degrees C is interesting but far from conclusive. Caution with rewarming is still advised pending more in-depth study of this issue.
authors.affiliation: Department of Anaesthesia, Sunnybrook Health Science Centre, University of Toronto, Ontario, Canada.
authors.forename: M I
authors.initials: MI
authors.lastname: Buss
authors.forename: R F
authors.initials: RF
authors.lastname: McLean
authors.forename: B I
authors.initials: BI
authors.lastname: Wong
authors.forename: S E
authors.initials: SE
authors.lastname: Fremes
authors.forename: C D
authors.initials: CD
authors.lastname: Naylor
authors.forename: E M
authors.initials: EM
authors.lastname: Harrington
authors.forename: W G
authors.initials: WG
authors.lastname: Snow
authors.forename: M
authors.initials: M
authors.lastname: Gawel
mesh_terms: D001831:Body Temperature; D002315:Cardiopulmonary Bypass / Q000379:methods*; D003072:Cognition Disorders / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011184:Postoperative Period; D017694:Rewarming; D014888:Wechsler Scales