Cerebral oximetry values in diabetic patients are lower than those in non-diabetic patients during adult cardiac surgery with cardiopulmonary bypass

Abstract

Introduction: Diabetes mellitus (DM) is one of the well-known risk factors of postoperative stroke in cardiac surgery. Cerebrovascular CO₂ reactivity and the changes in cerebral blood flow are impaired in diabetic patients. Regional cerebral oxygen saturation (rSO₂) measured using near-infrared spectroscopy (NIRS) has been utilized in cardiac surgery to evaluate cerebral oxygenation. However, the difference of the rSO₂ values between diabetic and non-diabetic patients during cardiopulmonary bypass (CPB) has not been well investigated. The aim of this study was to compare the rSO₂values of diabetic and non-diabetic patients who underwent cardiac surgery.
Methods: Thirty diabetic patients (DM group) and 30 age- and gender-matched non-diabetic patients (NDM [control] group) who underwent coronary artery bypass grafting (CABG), valve surgery, or both utilizing normothermic CPB were retrospectively investigated. The mean values of rSO₂ at nine time points during the entire period of cardiac surgery were measured.
Results: The rSO₂ values in the DM group were significantly lower than those in the NDM group (p < 0.01) and the difference between the groups increased with the time after the initiation of CPB.
Conclusions: The rSO₂ values in diabetic patients are lower than those in non-diabetic patients during cardiac surgery with normothermic CPB. A further large prospective study will be needed to investigate the relationship between lower rSO₂ values in diabetic patients and postoperative outcomes as well as the mechanism of the lower values.