Perioperative EEG-Monitoring and Postoperative Delirium in Patients Undergoing Cardiovascular Surgery

Study Overview
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Brief Summary
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Postoperative delirium is common in patients undergoing cardiovascular surgery and associated with poor outcomes. However the pathogenesis of postoperative delirium is poorly understood. Multichannel electroencephalogram is a recognized tool for identifying neurophysiologic states during anesthesia, sleep, and arousal. The aim of the current study is to evaluate the mechanisms and predictors of postoperative delirium in patients undergoing cardiovascular surgery using electroencephalogram.

Official Title
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Perioperative EEG-Monitoring and Postoperative Delirium in Patients Undergoing Cardiovascular Surgery: a Prospective Observational Study

Conditions
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Delirium

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age of at least 18 years normal cognitive function at the time of enrollment evidenced by a Mini-Mental State Examination (MMSE) score of more than 24 of 30 Chinese Mandarin as the native language providing informed consent Exclusion Criteria: pre-existing delirium assessed according to the Confusion Assessment Method (CAM) history of neurological or psychiatric disease impaired vision or auditory function which may effect the assessments unwillingness to participate in the study

Ages Eligible for Study
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Minimum Age: 18 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Delirium is determined by CAM or CAM-ICU score<br> | |
| No delirium is determined by CAM or CAM-ICU score<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of postoperative delirium | The incidence of postoperative delirium was determined according to the Confusion Assessment Method (CAM) diagnostic algorithm. The algorithm consists of four clinical criteria: (1) acute onset and fluctuating course, (2) inattention, (3) disorganized thinking, and (4) altered level of consciousness. To define a patient as having delirium, both the first and the second criteria have to be present, as well as either the third or the fourth criteria. The CAM-ICU will be used for patients who are intubated in the postoperative period. | After surgery through to postoperative day 7 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Relative power of each brain waves | Electroencephalogram data were acquired using a 32-channel electroencephalogram recording system (Brain Products, Germany). A 5 min, baseline, eyes-closed recording was conducted at the preoperative holding room when the patient was at rest. Recording of electroencephalogram was commenced before the start of anesthetic induction and was stopped before discharge of the patient from the operating room. We defied delta (1 to 3 Hz), theta (4 to 7 Hz), alpha (8 to 12 Hz), and beta (13 to 40 Hz) frequency bands. And then, the relative power of each frequency bands to the total power of the sum is calculated. | During the stay of the patient in the operating room, after surgery through to postoperative day 7 | 
| Duration of delirium |  | After surgery through to postoperative day 7 | 
| Severity of delirium | Delirium severity is evaluated both as the peak (highest) and sum Confusion Assessment Method - Severity (CAM-S) score over all hospital days. The CAM-S includes two forms: a Short Form (CAM-S Short Form, based on the 4-item algorithm, the sum of score ranging from 0 to 7, with 7 being the most severe) and a Long Form (CAM-S Long Form, based on the 10-item CAM instrument, the sum of score ranging from 0 to 19, with 19 being the most severe). | After surgery through to postoperative day 7 | 
| Worst daily pain scores at rest | Pain scores will be collected three times daily using a numeric rating scale (0, no pain, to 10, worst possible pain). | After surgery through to postoperative day 7 | 
| Worst daily pain scores with exertion (deep breathing and cough) | Pain scores will be collected three times daily using a numeric rating scale (0, no pain, to 10, worst possible pain). | After surgery through to postoperative day 7 | 
| Length of stay in the Intensive Care Unit (ICU) | Measured in days admitted in the ICU | through study completion, an average of 5 days | 
| Length of hospital stay | Measured in days admitted in the hospital | through study completion, an average of 10 days |