Evaluation of Cerebral Oxygenation and Tissue Perfusion in Patients Ongoing Coronary Artery Surgery with Cardiopulmonary By-pass

ABS TRACT Objective: We aimed to determine whether there is a correlation between perfusion parameters [Lactate (lac), venoarterial carbondioxide gradient (∆pCO2), central venous oxygen saturation (ScVO2)] and the relationship between these parameters and cerebral oxygenation in normothermia (T2), hypothermia (T3) and re-warming (T4) periods in cardiopulmonary bypass procedure (CPB). Material and Methods: Forty patients aged 19-78 years who were scheduled for elective coronary artery bypass surgery were included in the study. Mean arterial pressure (MAP), cerebral oxygenation (rSO2), periferic oxygen saturation (SpO2) values were recorded and by taking blood samples from arterial cannula and central venous catheter simultaneously; hematocrit (Htc), ∆pCO2, lac, ScVO2, actual base excess (aBE), bicarbonate (HCO3) values were recorded in T1 (after anesthesia induction and central venous catheterization), T2 (normothermia, 36oC, at the start of CPB), T3 (hypotermia, 32oC) and in T4 (at the end of CPB, rewarming, 36oC). Results: Between ∆pCO2-lac values, only positive correlation was found in T4 and there was no correlation between them at other times. There was significant negative correlation between rSO2 and lac in T1, T3 and T4, but no significant correlation was found between rSO2-∆pCO2 parameters at any time. The correlations of lac and ∆pCO2 with cross-clamp and CPB durations were positive, whereas the correlations between ScVO2 and rSO2 with cross-clamp and CPB durations were negative. Conclusion: ∆pCO2 is not an early indicator of hypoperfusion in patients undergoing CPB in accordance with the literature and the lactate level is a guiding parameter in reporting the perfusion status. We recommend the intraoperative use of cerebral oximetry to prevent the brain from being affected by hypoperfusion during CPB and to prevent postoperative neurocognitive disorders in patients.