Positive Correlation Between Regional Cerebral Oxygen Saturation and Mixed Venous Oxygen Saturation During Off-Pump Coronary Artery Bypass Surgery.

BACKGROUND: The balance of oxygen delivery and consumption is essential in patients who are critically ill. Mixed venous oxygen saturation (S-<(v)overbar>O2) is a standard method to evaluate oxygen delivery and consumption during anesthesia. However, S-<(v)overbar>O2 is monitored through a pulmonary artery catheter, which is invasive. Regional cerebral oxygenation (rScO(2)) reflects oxygen saturation in a small region of the frontal lobes and is monitored noninvasively through near-infrared spectroscopy. In the present study, the correlation between rScO(2) and S-<(v)overbar>O2 was calculated during off-pump coronary artery bypass grafting surgery to determine whether a positive correlation exists between rScO(2) and S-<(v)overbar>O2. METHODS: A total of 56 subjects were consecutively enrolled in the study. Then rScO(2) and S-<(v)overbar>O2 were simultaneously monitored. The parameters were recorded at 5 time points: T-1, 10 min after intubation (1.0 F-IO2 for 10 min); T-2, 20 min after intubation (0.60 F-IO2 for 10 min); T-3, at the end of the revascularization of the left anterior descending artery (0.60 F-IO2); T-4, after protamine infusion (0.60 F-IO2); and T-5, 10 min after protamine infusion (1.0 F-IO2 for 10 min). The correlation between rScO(2) and S-<(v)overbar>O2 and the variation trend between rSco(2) and S-<(v)overbar>O2 when F-IO2 increased from 0.60 to 1.O were analyzed. RESULTS: There was a significant positive correlation between rScO(2) and S-<(v)overbar>O2 at these 5 time points (r(2) = 0.77, 0.81, 0.70, 0.83, and 0.92, respectively). There also was a significant positive correlation between Delta rScO(2) and Delta S-<(v)overbar>O2 (n = 112, r(2) = 0.72, P < .001). Linear regression analysis revealed that S-<(v)overbar>O2 had a positive correlation with rScO(2) and cardiac output (r(2) = 0.68, P = .013). CONCLUSIONS: There was a positive correlation between rScO(2) and S-<(v)overbar>O2 during off-pump coronary artery bypass grafting surgery, and there also was a positive correlation in the variation trend between rScO(2) and S-<(v)overbar>O2. [Respir Care 2018;63(8):988-993. (C) 2018 Daedalus Enterprises]