Perioperative Electroencephalography Characteristics of Postoperative Delirium in Elderly

Study Overview
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Brief Summary
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The investigators aim to identify preoperative Electroencephalogram (EEG) markers indicating patients at risk to develop postoperative delirium (POD), so that the anesthetist may adjust medications and dosages in order to avoid POD. Second, the investigators aim to specify intraoperative EEG signatures and EEG states that are related to POD and long-term cognitive dysfunction, again to enable physicians to adapt their procedure. Third, the investigators aim to identify EEG signatures during stay in the recovery room that is directly related to POD, and may therefore be used as diagnostic tool, as well as a predictor for the development of long-term cognitive deficits (POCD).

Detailed Description
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The investigators conduct this observational study to identify pre-, intra- and postoperative Electroencephalogram (EEG) signatures / intraoperative EEG states related to postoperative delirium (POD) and postoperative cognitive deficit (POCD) in elderly patients > 70 years. This includes the following tasks at five different time-points Pre-operative frontal EEG recording during anesthesia evaluation one day before surgery / anesthesia to develop an EEG marker to predict the development of POD. This includes the stratification of EEG data related to age, gender, and pre-operative cognitive function. Pre-operative POCD assessment (CANTAB connect, word pair recognition test, Mini Mental State Test, and Trail Making Test A and B) to classify cognitive capacity of each patient before start of anesthesia. Intra-operative frontal EEG recording from start of anesthesia procedure until discharge to the recovery room to identify EEG signatures / EEG states to predict the development of POD / POCD. This includes the stratification of EEG data related to age, gender, pre-medication, anesthetics, and analgesics used during anesthesia procedure. Post-operative frontal EEG recording during the recovery room stay to develop an EEG marker / identify EEG signatures to diagnose POD and predict POCD. This includes the stratification of EEG data related to age, gender, anesthesia procedure, and analgesics administered during the recovery room stay. POD will be assessed during stay in the recovery room by the NuDesc Score and DSM V criteria. Follow-up POD assessments until the 5th postoperative day, where the patient will be visited twice daily (8a.m.-10a.m. and 5p.m.-7p.m.) and assessed via DSM V / NuDesc criteria on the peripheral ward, or via Confusion Assessment Method for intensive Care Unit (CAM-ICU) criteria during an intensive care unit stay. Follow-up POCD assessments one day before and 3 months after surgery, where the patient will undergo a  1 hour cognitive testing with the CANTAB connect.

Official Title
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Perioperative Electroencephalography Characteristics of Postoperative Delirium in Elderly

Conditions
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Postoperative Delirium

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients aged >70 years Planned operation time >1 hour Expected hospital treatment period of 5 days, Anesthesia induction, anesthesia maintenance with either Propofol or an inhalative anesthetic agent as Sevoflurane or Desflurane, The ability to give informed consent Exclusion Criteria: Patients with a history of neurological or psychiatric disorders Known carotid artery Stenosis Obstructive sleep apnea Syndrome Planned neurosurgery Current medication of tranquilizers / antidepressants Isolation of patients with multi-resistant Bacteria Inability of the patients to speak and/or read German Homelessness or other circumstances where the patient would not be reachable by phone or postal services during follow-up Intraoperative EEG data file analysis will be excluded ex post, when intraoperative use of any other anesthetic agent for induction as Propofol occurred or by use of any other anesthetic agent for anesthesia maintenance other than Propofol or volatile anesthetics as Sevoflurane or Desflurane or when anesthesia agents as Ketamine, Nitrous oxide, Etomidate or Dexmedetomidine were given or if body temperature drops below 34° or rises above 38° during surgery

Ages Eligible for Study
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Minimum Age: 70 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 |
| --- | --- |
| Propofol group<br>This is a prospective, observational study in surgical patients undergoing elective surgery under general anesthesia stratified for the anesthetic agent used intraoperatively - i.v. Propofol - focusing on pre-, intra- and postoperative EEG spectral parameters in elderly patients. | |
| Volatile group<br>This is a prospective, observational study in surgical patients undergoing elective surgery under general anesthesia stratified for the anesthetic agent used intraoperatively - volatile anesthetic agent as Sevoflurane or Desflurane - focusing on pre-, intra- and postoperative EEG spectral parameters in elderly patients. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of Postoperative Delirium- Diagnostic and Statistical Manual of Mental Disorders (DSM-V) | Postoperative delirium rate, defined according to Diagnostic and Statistical Manual of Mental Disorders (DSM-V) | Patients will be follow until hospital discharge, or maximal until postoperative day 5 | 
| Incidence of Postoperative Delirium - Nursing Delrium Scale (Nu-DESC) | Postoperative delirium rate, defined according to ≥ 2 cumulative points in the nursing Delirium Screening Scale (Nu-DESC) | Patients will be follow until hospital discharge, or maximal until postoperative day 5 | 
| Incidence of Postoperative Delirium - Intensive Care Unit (CAM-ICU) | Postoperative delirium rate, defined according to positive Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) score | Patients will be followed on intensive care unit until hospital discharge, or maximal until postoperative day 5 | 
| Incidence of Postoperative Delirium - Confusion Assessment Method (CAM) | Postoperative delirium rate, defined according to positive Confusion Assessment Method (CAM) | Patients will be followed on peripheral ward until hospital discharge, or maximal until postoperative day 5 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of postoperative cognitive deficit (POCD) - CANTAB | POCD will be measured by a defined Cambridge Neuropsychological Test Automated Battery (CANTAB) on the day before the operation and after 3 months | Up to 3 months | 
| Incidence of postoperative cognitive deficit (POCD) - MMSE | POCD will be measured by Mini Mental State Examination (MMSE) on the day before the Operation, on day 5 and after 3 months | Up to 3 months | 
| Incidence of Neurocognitive disorder | Neurocognitive Disorder is evaluated according to DSM-V (postoperative cognitive deficit, activities of daily living, instrumental activities of daily living, subjective memory sensing. | Up to 3 months | 
| Incidence of postoperative cognitive deficit (POCD) - Word pair recognition test | POCD will be measured by Nürnberger-Altersinventar-Test - word pair recognition test on the day before the operation, day 1 ,3 and 5 | Up to 5 days | 
| Post-operative, bi-frontal alpha-band power | Bi-frontal EEG recording with surface electrodes (Fp1, Fp2, F7 and F8), Spectral analysis by Matlab code | Up to discharge from the recovery room | 
| Bi-frontal overall EEG band power | Postoperative bi-frontal EEG recording with surface electrodes (Fp1, Fp2, F7 and F8), Spectral analysis by Matlab code | Up to discharge from the recovery room | 
| Burst suppression duration | Intraoperative bi-frontal EEG recording with surface electrodes (Fp1, Fp2, F7 and F8), raw EEG analysis | During anesthesia procedure | 
| Pain monitoring | Intraoperative pain monitoring is measured by Nociception Level Index (NOL | During anesthesia procedure | 
| Duration of Delirium (DSM-V) | Postoperative duration of delirium, defined according to Diagnostic and Statistical Manual of Mental Disorders (DSM-V) | Participants will be followed for the duration of hospital stay, or maximal until postoperative day 5 | 
| Duration of Delirium (Nu-DESC) | Postoperative duration of delirium, defined according to Nursing Delirium Screening Scale (Nu-DESC) | Participants will be followed for the duration of hospital stay, or maximal until postoperative day 5 | 
| Duration of Delirium (CAM-ICU) | Postoperative duration of delirium, defined according to Confusion Assessment Method for the Intensive Care Unit (CAM-ICU)Confusion Assessment Method (CAM), Chart Review | Participants will be followed for the duration of hospital stay, or maximal until postoperative day 5 | 
| Duration of Delirium (CAM) | Postoperative duration of delirium, defined according to Confusion Assessment Method (CAM) | Participants will be followed for the duration of hospital stay, or maximal until postoperative day 5 | 
| Intensive care unit length of stay | Intensive care unit length of staywill be assessed by chart review at hospital discharge. | Participants will be followed for the duration of intensive care unit stay, an expected average of 5 days | 
| Hospital length of stay | Hospital length of stay will be assessed by chart review at 3 months. | Participants will be followed for the duration of hospital stay, an expected average of 7 days | 
| Mortality | Mortality will be assessed by chart review at 3 months. | Up to 3 months |