Taking Brain Monitoring to the Next Level

This study will test the hypothesis that a goal directed therapy intervention, which optimizes depth of anesthesia and intraoperative blood pressure can decrease the incidence of postoperative neurocognitive dysfunction

Subjects will be recruited for the study and the protocol explained. In addition to standard American Society of Anesthesiologists (ASA) monitoring, we will monitor continuous non-invasive blood pressure and 4 lead electroencephalogram (EEG) channels. Patients will receive standardized anesthesia care in addition to a goal directed therapy hemodynamic management (MAP > 60 mmHg) and processed EEG-guided anesthesia (PSI targeted between 30-50).

Neurocognitive testing: In order to assess general cognitive function, the Montreal Cognitive Assessment test will be used. Cognitive function will be measured preoperatively and postoperatively at discharge, 1 month and 6 months after surgery. For delirium measurement, we will administer daily the Confusion Assessment Method (CAM-ICU) for up to 3 days.

The Montreal Cognitive Assessment (MoCA) is a screening tool to assess mild cognitive dysfunction. It assesses different cognitive domains: attention and concentration, executive functions, memory, language, visuoconstructionals skills, conceptual thinking, calculations, and orientation. Time to administer the MoCA is approximately 10 minutes. The total possible score is 30 points; a score of 26 or above is considered normal.

The Wide Range Assessment of Memory and Learning (WRAML2) is a broad-based memory battery that provides a flexible measure of memory functioning and learning and takes approximately 45-60 minutes to administer. This assessment will be conducted at the first MRI visit and at the 6 month follow up.

The Confusion Assessment Method for the ICU (CAM-ICU) screens for the development of delirium and assesses four features: 1) acute change or fluctuation in mental status from baseline, 2) inattention, 3) altered level of consciousness, and 4) disorganized thinking. The CAM-ICU is positive, and the patient is considered to have delirium, if features 1 and 2 and either feature 3 or 4 are present.

Brain imaging: The timing of pre-operative brain imaging will be as allowed by patient factors and scanner availability, typically less than 15 days before surgery, when the patient comes for the preoperative evaluation, and postoperatively within 2 weeks after surgery.

Optional Blood Draws: Patients will be asked to provide 2 optional blood samples, drawn the day of their brain imaging visit and post-operatively (within 2 days). These samples will be used to asses blood inflammatory biomarkers in obstructive sleep apnea (OSA) subjects and non-OSA subjects between baseline and post-surgery.

Inclusion criteria

• 45-75 years old,
• undergoing abdominal, orthopedic, gynecological, or urological surgery
• expected to stay in hospital for at least 24hours

Exclusion criteria

• Substantial hearing impairment or inability to understand English, since there needs to be neurocognitive testing done
• status post craniotomy
• severe dementia