Delirium, Intraoperative Cerebral Perfusion and EEG Abnormalities After Total Hip Arthroplasty

Pathophysiology of Delirium in Patients Undergoing Total Hip Arthroplasty: Role of Intraoperative Cerebral Perfusion and EEG Abnormalities

The overall objective of this study is to test for perturbations in intraoperative electroencephalogram (EEG) , cerebral blood flow (CBF), cerebral metabolic rate of oxygen consumption (CMRO2), oxygen extraction fraction (OEF), and serum and cerebral spinal fluid biomarkers associated with delirium in high risk population having elective hip arthroplasty at Penn Presbyterian Medical Center (PPMC).

All prospective patients will be given a copy of the informed consent which explains the details and responsibilities of the study.

Each patient will have a preoperative baseline 3D-CAM and MOCA to document preoperative cognitive function and possible criteria for exclusion.

1. The 3D -Confusion Assessment Method (CAM) test is a clinician evaluation and algorithm for the binary determination of presence or absence of delirium.
2. Montreal Confusion Assessment (MOCA) - to be given preoperatively to determine if element of pre-existing cognitive impairment

Intraoperatively each patient will have a NIR Optode patch placed to measure intraoperative cerebral blood flow and oxygen extraction fraction and cerebral metabolic rate of oxygen consumption.

A non-invasive frontal EEG patch will be placed prior to or at the start of anesthesia. Anesthetic depth will be measured using the SEDline® by Masimo. Continuous raw EEG, spectral edge, compressed spectral analysis and percentage suppressed will be recorded from the SEDline® monitor.

The investigators will be drawing blood from patients who agree to participate in the study. Preoperative blood sampling will be done while the investigators place the intravenous line, or if present, from an arterial line.

If a spinal anesthetic is being used, 5 mL of cerebral spinal fluid (CSF) will be collected at the time of dural puncture prior to the administration of the neuraxial blockade.

Members of the research team will administer 3D-CAM testing on post-operative days 1 and 2.

Inclusion Criteria:

1. Patients 65 years of age and over scheduled for elective total joint arthroplasty
2. Mentally competent and able to give consent for enrollment in the study
3. Patients at any age with a pre-existing diagnosis of dementia or acquired cognitive deficit. Consented by legally authorized representative (LAR).

Exclusion Criteria:

1. Patients currently delirious
2. Acute neurological disease like stroke or brain tumor
3. Current alcohol or substance abuse at risk of postoperative withdrawal