Neuropsychological dysfunction after cardiac surgery. Cerebral saturation and bispectral index: A longitudinal study Disfunción cognitiva después de cirugía cardiaca. Saturación cerebral e índice biespectral: Estudio longitudinal

Abstract

Background: Neuropsychological dysfunction is a major cause of morbidity and mortality after cardiac surgery. Aim: To evaluate if intraoperative cerebral desaturation and depth of anesthesia measured by bispectral index are related to postoperative cognitive dysfunction in cardiac surgery. Material and Methods: Prospective study in patients undergoing elective cardiac surgery with cardiopulmonary bypass. A comprehensive neuropsychological assessment was applied preoperatively and 3 months after surgery. Postoperative dysfunction was defined as a decrease of at least one standard deviation in two or more neuropsychological tests. Cerebral oxygenation and bispectral index were continuously recorded and corrected throughout surgery. Cerebral oxygenation data were analyzed by the mean value and at three thresholds: 50%, 40% and < 25% of the basal value. Bispectral index was analyzed at threshold of 45. Results: Fifty-six patients were initially enrolled and 48 completed the study. Nine of