Intraoperative Maintenance of Normoglycemia with Insulin and Glucose Preserves Verbal Learning after Cardiac Surgery

Abstract

ObjectiveThe 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.MethodsAs 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.ResultsTwenty-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.ConclusionsPreserving intraoperative normoglycemia by intravenous insulin and glucose may prevent the impairment of memory function, both short and long-term, after cardiac surgery.

Neurocognitive Function after Cardiac Surgery

“…37 However, this study did not assess delirium before surgery, 232 so it is unclear how many of these cases of postoperative delirium might have reflected pre-existing cognitive deficits or delirium before surgery. 37 Another recent pilot study found that the use of glucose and insulin infusions to maintain serum glucose at ~64-110 mg/dL preserved auditory learning and executive function after cardiac surgery, 233 suggesting that avoiding hyperglycemia may result in improved postoperative cognitive function. Thus, as with oxygen delivery and cerebral perfusion management (discussed above), these data suggest that it may be equally important to avoid hypoglycemia and hyperglycemia in order to avoid postoperative delirium and POCD.…”

Postoperative Cognitive Decline After Cardiac Surgery: A Narrative Review of Current Knowledge in 2019

“…Interestingly, type I diabetes does not contribute more significantly to cerebrovascular incidents than does type II diabetes [74]. Nevertheless, intraoperative hyperglycemia over 10 mmol·L −1 , even in patients without diabetes, is associated with POCD occurrence, likely through SIRS activation [75]. Next, chronic obstructive pulmonary disease due to altered cerebral blood flow [76,77], as well as chronic kidney disease and liver disease accompanied by vascular encephalopathy, disruption of the blood-brain barrier, high ammonia levels and anemia may be included in the pathogenesis of POCD [76,78].…”

Photonic crystal based biosensors: Emerging inverse opals for biomarker detection

“…The sensing of blood glucose in clinical practice especially in the management of diabetes has been a valuable tool. The standard clinical amount for blood glucose is between 3.5 and 6.1 mM, but abnormal glucose levels can reach as high as 18 mM [ 92 ]. Therefore, to maintain the usual blood glucose ranges, the development of point-of-care devices for the detection of glucose has been recommended.…”