title: Intraoperative maintenance of normoglycemia with insulin and glucose preserves verbal learning after cardiac surgery.
abstract: OBJECTIVE
  The hyperglycemic response to surgery may be a risk factor for cognitive dysfunction. We hypothesize that strict maintenance of normoglycemia during cardiac surgery preserves postoperative cognitive function.
  
  
  METHODS
  As part of a larger randomized, single-blind, interventional efficacy study on the effects of hyperinsulinemic glucose control in cardiac surgery (NCT00524472), consenting patients were randomly assigned to receive combined administration of insulin and glucose, titrated to preserve normoglycemia (3.5-6.1 mmol L(-1); experimental group), or standard metabolic care (blood glucose 3.5-10 mmol L(-1); control group), during open heart surgery. The patients' cognitive function was assessed during three home visits, approximately two weeks before the operation, and two months and seven months after surgery. The following tests were performed: Rey Auditory Verbal Learning Task (RAVLT for verbal learning and memory), Digit Span Task (working memory), Trail Making A & B (visuomotor tracking and attention), and the Word Pair Task (implicit memory). Questionnaires measuring specific traits known to affect cognitive performance, such as self-esteem, depression, chronic stress and social support, were also administered. The primary outcome was to assess the effect of hyperinsulinemic-normoglycemic clamp therapy versus standard therapy on specific cognitive parameters in patients receiving normoglycemic clamp, or standard metabolic care.
  
  
  RESULTS
  Twenty-six patients completed the study with 14 patients in the normoglycemia and 12 patients in the control group. Multiple analysis of covariance (MANCOVA) for the RAVLT showed a significant effect for the interaction of group by visit (F = 4.07, p = 0.035), and group by visit by recall (F = 2.21, p = 0.04). The differences occurred at the second and third visit. MANCOVA for the digit span task, trail making and word pair association test showed no significant effect.
  
  
  CONCLUSIONS
  Preserving intraoperative normoglycemia by intravenous insulin and glucose may prevent the impairment of memory function, both short and long-term, after cardiac surgery.
authors.affiliation: Department of Anesthesia, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schricker
authors.affiliation: Department of Anesthesiology, Yamanashi University, Yamanashi, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sato
authors.affiliation: Department of Psychiatry, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Beaudry
authors.affiliation: Department of Anesthesia, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Takumi
authors.initials: T
authors.lastname: Codere
authors.affiliation: Department of Anesthesia, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Roupen
authors.initials: R
authors.lastname: Hatzakorzian
authors.affiliation: Department of Psychiatry, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Jens C
authors.initials: JC
authors.lastname: Pruessner
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D006348:Cardiac Surgical Procedures; D016022:Case-Control Studies; D005260:Female; D005947:Glucose / Q000627:therapeutic use*; D006801:Humans; D007328:Insulin / Q000627:therapeutic use*; D007430:Intraoperative Care; D008297:Male; D008875:Middle Aged; D019990:Perioperative Care; D014706:Verbal Learning
chemical_list: D001786:Blood Glucose; D007328:Insulin; D005947:Glucose