The Association of Preoperative Cognitive Dysfunction to Common Intraoperative Electroencephalographic Parameters and Cerebral Hypoxia During Cardiac Surgery

BACKGROUND: Older cardiac surgery patients have a higher prevalence of cognitive dysfunction and elevated risk of perioperative neurocognitive disorders (PND), both independently related to adverse postoperative outcomes. Neuromonitoring using electroencephalogram (EEG) and cerebral oximetry (CO) may predict PND. However, preoperative factors influencing intraoperative neurophysiological characteristics are not well understood. We conducted a study in a cardiac surgery cohort to better understand the relationship of preoperative cognitive dysfunction to intraoperative burst suppression (BS), spectral edge frequency (SEF), cerebral hypoxia/desaturation, and dual cerebral events involving both BS and cerebral desaturation to potentially link preoperative cognitive dysfunction to intraoperative neuromonitoring variables associated with PND. METHODS: This is a secondary analysis of a triple-blinded, ongoing, multi-center randomized trial assessing the efficacy of postoperative intravenous acetaminophen to reduce postoperative delirium (POD) in older cardiac surgery patients. We studied 110 patients ≥60 years who underwent CABG and/or valve surgery under general (inhalational) anesthesia at a single academic center. Preoperative cognitive status was assessed using the Montreal Cognitive Assessment (MoCA) and classified as normal (MoCA score≥26) or impaired (MoCA