Grant: Cat Gr: Develop./validation of new biomedical techniques/technolo.- General Pool

Recent data show that current interventions in the critical care management of traumatic brain injury (TBI) patients fail to correct dysfunctional cerebral autoregulation (CA). Acute phase treatment of critically ill TBI patients consists of reducing the intra-cranial pressure (ICP), employing various therapies, including high levels of sedation. High dose sedatives have been linked with worse neurologic outcomes in the general intensive care unit (ICU) population, with burst suppression showing deterioration in CA. Our ability to titrate these sedative agents is commonly limited to clinical examination, with high patient-to-patient heterogeneity and poor temporal resolution. Electroencephalogram (EEG) based bispectral index (BIS) is a method that has been commonly employed in anesthesia to confirm depth of sedation for surgical procedures, with sedation titration to target BIS values. Recent pilot work from our group has evaluated the link between objective depth of sedation (measured by BIS) and continuously measured CA, showing a novel patient-specific depth of sedation associated with CA (BISopt), where CA is the least deranged. This suggests that both low and high levels of sedation are linked with worse CA in TBI and non-TBI populations, with preliminary evidence showing independence from drug type and other physiologic metrics (ICP, arterial blood pressure (ABP) and optimal cerebral perfusion pressure (CPPopt). It is possible that poor cognitive outcomes related to sedation in critical illness are a function of secondary insult exposure from impaired CA. However, previous BISopt work required artifact clean signal sources through cumbersome manual methods prior to derivation, and only described the metric as an "after the fact" phenomenon (requiring physiologic data from the entire ICU stay to derive), leaving critical technologic knowledge gaps. This study aims to create novel BIS artifact detection and continuous BISopt derivation pipelines.