Cardiac Valve Replacement Surgery, Cerebral Oxygenation Status Monitoring And Protective Effect Of Erythropoietin Hormone Brain Research

Part 1The feasibility of evaluating cerebral ischemia with near-infrared oxygen monitor during cardiac valve replacement surgeryBackgroudNear-infrared oxygen monitor (NIRO) using the method of near-infrared spectroscopy (NIRS) has been utilized to monitor regional cerebral oxygen saturation (rScO₂) continuously and non-invasively during cardiac surgery with cardiopulmonary bypass (CPB) and carotid endarterectomy. The results correlated well with jugular bulb oxygen saturation (SvjO₂), trans-cranial doppler and somatosensory evoked potential. But the relationship between rScO₂ and neurobiochemical and neuropsychological markers of cerebral ischemia was far below understood. This study was designed to observe the changes of cerebral oxygenation status measured by spatially resolved spectroscopy ( NIRO-200), to correlate the tissue oxygen parameters with serum concentrations of neuron-specific enolase and S100 protein, to study the relationship between tissue oxygenation status and neuropsychological and neuropsychiatric index and ultimately to elucidate the feasibility of NIRO for evaluating ischemic injury in patients undergoing cardiac surgery with CPB.Materials and methodsSeventeen patients undergoing cardiac valve replacement under mild to moderate hypothermia were studied. NIRS parameters including tissue oxygenation index, tissue hemoglobin index, changes of oxyhemoglobin, deoxyhemoglobin and total hemoglobin were assessed continuously and the proportion of patients whose minimal rScO₂ decreased to less than 50% were recorded. Blood samples were taken intravenously before anesthesia induction, before rewarming, after nasal temperature rewarming to 36.5 degree centigrade and 1h, 5h and 20h after pump off. Using enzyme-linked immunosorbent assay to detect serum concentration of NSE and S100 protein. A series of neuropsychological and neuropsychiatric tests were performed 1 day before surgery and 8 days after surgery, which included Mini-Mental State Examination, the Digit Span subtest of the Wechsler...