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.
Study Type
OBSERVATIONAL
Enrollment
200
Department of Anaesthesiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology
Wuhan, Hubei, China
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.
Time frame: After surgery through to postoperative day 7
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.
Time frame: During the stay of the patient in the operating room, after surgery through to postoperative day 7
Duration of delirium
Time frame: 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).
Time frame: 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).
Time frame: 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).
Time frame: After surgery through to postoperative day 7
Length of stay in the Intensive Care Unit (ICU)
Measured in days admitted in the ICU
Time frame: through study completion, an average of 5 days
Length of hospital stay
Measured in days admitted in the hospital
Time frame: through study completion, an average of 10 days
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