Correlation between ultrasound parameters of internal carotid artery blood flow and regional cerebral oxygen saturation in elderly patients undergoing coronary artery bypass grafting under CPB / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the correlation between ultrasound parameters of internal carotid artery blood flow and regional cerebral oxygen saturation (rScO 2) in elderly patients undergoing coronary artery bypass grafting (CABG) under cardiopulmonary bypass (CPB). Methods:Sixty-four elderly patients undergoing elective CABG under CPB, aged 60-80 yr, regardless of gender, with body mass index of 18.1-28.9 kg/m 2, of American Society of Anesthesiologists Physical Status classification Ⅱ or Ⅲ, with New York Heart Association class Ⅱ or Ⅲ, with left ventricular ejection fraction≥50%, were selected. The rScO 2 and ultrasonic parameters of internal carotid artery including peak systolic velocity (PSV-ICA), end-diastolic velocity (EDV-ICA), diameter (D-ICA) and blood flow volume (Q-ICA) were recorded before anesthesia induction (T 0), at surgical skin incision (T 1), at 30 and 60 min of CPB (mean value was calculated, T 2), and at 30 and 60 min after termination of CPB (mean value was calculated, T 3). The ratio of unilateral internal carotid artery blood flow to cardiac output (Q/CO) was calculated. The receiver operating characteristic curve was used to analyze the accuracy of ultrasound parameters of internal carotid artery blood flow in predicting rScO 2 < 60%. Results:PSV-ICA was positively correlated with rScO 2 at T 0, T 1 and T 3 ( P<0.05), but no correlation was found between PSV-ICA and rScO 2 at T 2 ( P>0.05). There was no correlation between EDV-ICA and rScO 2 at each time point ( P>0.05). Q-ICA was positively correlated with rScO 2 at each time point ( P<0.05). Q/CO was not correlated with rScO 2 at T 1 ( P>0.05), but Q/CO was positively correlated with rScO 2 at T 2 and T 3 ( P<0.05). During the non-CPB period (T 0, T 1, T 3), the cutoff values of PSV-ICA and Q-ICA in predicting rScO 2< 60% were 51.35 cm/s and 283.5 ml/min respectively, the sensitivity was 0.900 and 0.900 respectively, and the specificity was 0.610 and 0.857 respectively (AUC=0.761, P=0.006; AUC=0.903, P< 0.001). During the CPB period, the cutoff values of Q-ICA and Q/CO in predicting rScO 2<60% were 296.5 ml/min and 5.84% respectively, the sensitivity was 0.900 and 0.800, and the specificity was 0.545 and 0.659 (AUC=0.764, P=0.001; AUC=0.748, P=0.002), respectively. Conclusions:PSV-ICA and Q-ICA are positively correlated with rScO 2 during the non-CPB period, and Q-ICA and Q/CO are positively correlated with rScO 2 during the CPB period in elderly patients undergoing CABG. PSV-ICA, Q-ICA and Q/CO can accurately predict rScO 2<60%.