Postoperative Delirium: Brain Vulnerability and Recovery

Study Overview
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Brief Summary
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In this study, we propose to use EEG and a brain imaging technique known as diffuse optical tomography (DOT) to study when people are in delirium and when they recovery. We plan to also compare brain function of patients who recovered from delirium to patients who did not have delirium using DOT and fMRI. We will also continually monitor the participant's EMR to help coordinate timing of study procedures, as well as to collect information pertaining to their surgery, recovery progress, and indicators of mental status including delirium.

Detailed Description
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Postoperative delirium - a mental state of confusion, inattention, and impaired thought - is a potentially life-threatening condition. As many as half of patients that have heart and non heart-related surgery will experience postoperative delirium. Patients diagnosed with postoperative delirium have poorer outcomes and longer hospitalizations. Unfortunately, it is an under-diagnosed condition with a variable delay in when it appears. Additionally, there are no objective tools or tests that can be before or after surgery to anticipate and identify those patients who are at risk. Electroencephalography [EEG] and functional magnetic resonance imaging [fMRI] have helped us understand the changes in the brain during delirium. These suggest that a weakening in correlated activity within a group of brain regions, known as the default mode network (DMN), may be related to delirium.

Official Title
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Postoperative Delirium: Brain Vulnerability and Recovery

Conditions
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Delirium, Postoperative Complications

Intervention / Treatment
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* Device: EEG
* Device: fcDOT
* Device: fcMRI


Participation Criteria
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Eligibility Criteria
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Common inclusion criteria: Age ≥ 60 Surgery requiring cardiopulmonary bypass (CPB) for coronary artery bypass grafting, septal myectomy and/or heart valve repair/replacement English speaking. Common exclusion criteria: Implanted pacemaker Automatic internal cardiac defibrillator or other implant for which non-contrast magnetic resonance imaging (MRI) is contraindicated Concomitant aortic or cerebrovascular procedure Inability to lay flat or still for MRI Legal blindness or severe deafness Seizure history Known focal brain lesion larger than 3 cm. Delirium Case Arm: 1. Delirious as diagnosed by the Confusion Assessment Method (CAM)/ Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) at some point during postoperative day 1-5. Postoperative Control Arm: 1. Not delirious as diagnosed by the CAM/CAM-ICU on postoperative day 1-5.

Ages Eligible for Study
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Minimum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: delirium<br>Patients in the cardiothoracic ICU diagnosed with postoperative delirium. Subjects will wear a diffuse optical tomography device in addition to the normal monitors. A non-contrast functional MRI will be performed. | Device: EEG<br>* Brain activity will be recorded to evaluate differences in brain activity between patients with a delirium diagnosis and non-delirious control patients.<br>* Other names: brain monitoring in delirious postoperative patients;Device: fcDOT<br>* Brain activity will be recorded to evaluate differences in brain activity between patients with a delirium diagnosis and non-delirious control patients.<br>* Other names: brain monitoring in delirious postoperative patients;Device: fcMRI<br>* Brain activity will be recorded to evaluate differences in brain activity between patients with a delirium diagnosis and non-delirious control patients.<br>* Other names: brain monitoring in delirious postoperative patients;|
| Other: no delirium<br>Patients in the cardiothoracic ICU not diagnosed with postoperative delirium. Subjects will be monitored in the same way as the delirium arm | Device: EEG<br>* Brain activity will be recorded to evaluate differences in brain activity between patients with a delirium diagnosis and non-delirious control patients.<br>* Other names: brain monitoring in delirious postoperative patients;Device: fcDOT<br>* Brain activity will be recorded to evaluate differences in brain activity between patients with a delirium diagnosis and non-delirious control patients.<br>* Other names: brain monitoring in delirious postoperative patients;Device: fcMRI<br>* Brain activity will be recorded to evaluate differences in brain activity between patients with a delirium diagnosis and non-delirious control patients.<br>* Other names: brain monitoring in delirious postoperative patients;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| EEG During Delirium and After Recovery and in Patient Controls. | Delta (0.5-4 Hz), theta (4-8 Hz), and alpha (8-12 Hz) EEG waveforms. | Data acquisition will occur on 4 separate days between postoperative days 1-8. | 
| Functional Connectivity Diffuse Optical Tomography (fcDOT) in Patients During Delirium and After Recovery and in Patient Controls | Functional connectivity between anterior and posterior Default Mode Network regions using diffuse optical imaging. | Data acquisition will occur on 4 separate days between postoperative days 1-8. | 
| Functional Connectivity Magnetic Resonance Imaging (fcMRI) in Patients After Recovery From Delirium and in Patient Controls. | Functional connectivity between anterior and posterior Default Mode Network regions assessed from resting-state fcMRI acquired during eyes open wakefulness. Scored using r-value, using a scale of -1 to +1. -1 = strong negative correlation, +1 = strong positive correlation | Within one month after hospital discharge. |