Glycemic Variability and Autonomic Nervous System in Cardiac Surgery Patients

On-pump coronary artery bypass graft (CABG) and valve replacement surgeries are high-risk procedures. Among the risk factors for postoperative complications, perioperative hyperglycemia and blood glucose variability have been reported to be associated with increased morbidity and mortality. The treatment of hyperglycemia using intravenous insulin infusion improves the prognosis in cardiac surgery patients. However, the determinants of postoperative blood glucose variability and the mechanisms leading to its deleterious impact are unknown. Thus, to date, there is no therapeutic intervention that could effectively prevent and treat the deleterious impact of glycemic variability on postoperative outcome. The purpose of the study is to evaluate whether perioperative alteration of the autonomic nervous system and preoperative blood glucose variability could be related to perioperative glycemic variability.