Risk factors for disordered cerebral autoregulation during hypothermic cardiopulmonary bypass

Abstract

Disordered cerebral autoregulation during cardiopulmonary bypass (CPB) is regarded as one of the causes of neurological dysfunction after cardiac surgery. However, little documentation of risk factors associated with cerebral autoregulation during CPB has been reported. Sixty consecutive patients undergoing coronary artery bypass were classified into subgroups according to whether they had preoperative cerebrovascular disease (CVD), hypertension (HT), or diabetes (DM). Cerebral oxygenation was monitored by jugular venous bulb oxygen saturation (SjvO2) and near-infrared spectroscopy parameter (%Oxy-Hb) during the operation, and the relationships between these values and intraoperative parameters were evaluated. The results showed that SjvO2 and %Oxy-Hb in the CVD+group were lower than in the CVD-group. Multiple stepwise regression analysis on SjvO2 and %Oxy-Hb in the CVD+ group revealed that only MAP was a predictive factor and that there was a positive correlation between MAP and both SjvO2 and %Oxy-Hb (r=.651,r=.693, respectively,P 0.0001), and the correlation was stronger in patients without any risk factors (r=.671,P=0.0001). The results suggested that patients with CVD, HT, and DM may experience failure of cerebral pressureflow autoregulation and cerebrovascular reactivity during CPB.