Cognitive Decline, Cognitive Impairment, Delirium, Postoperative Cognitive Dysfunction
Conditions
Keywords
Electroencephalography, Delirium, Neurofilament light chain, Tau protein
Brief summary
Loss of cognitive function after major surgery is a significant risk in older people. It can occur acutely in the days after surgery as delirium or in months to years later as a persistent reduction in brain function termed neurocognitive decline. Together these conditions are called post operative cognitive dysfunction (POCD). They can be acutely distressing for patients and are associated with other problems after surgery. The causes of post operative cognitive dysfunction are poorly understood. Studies have been limited by a lack of biomarkers to predict which patients are at high risk of developing POCD. Research suggests silent strokes occurring during surgery and different sensitivities to anaesthetic medicines are associated with POCD. The project consists of a feasibility study to investigate markers that might predict people over 65 years old getting POCD. The first biomarker is a non-invasive monitor of anaesthetics effects on brain function called electroencephalography (EEG): The investigators will identify which EEG patterns predict delirium within five days surgery. The second set of biomarkers are two blood tests of proteins that increase after strokes: these are neurofilament light chains and tau proteins. The investigators will establish if these can be used to predict having POCD up to one year after surgery and long term cognitive impairment up to 5 years after surgery.
Interventions
PROCEDUREIntraoperative electroencephalography recording
Intraoperative electroencephalography measurements, a non-invasive routine monitoring device used during anaesthesia to measure the brain's electrical activity
PROCEDURENeurofilament light chain measurement
Measurement of the level of neurofilament light chain in a blood sample
PROCEDURETau protein measurement
Measurement of the level of tau protein in a blood sample
Sponsors
Oxford University Hospitals NHS Trust
University of Oxford
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
65 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Greater than or equal to 65 years of age * Having elective non-cardiac surgery under general anaesthesia * Anticipated to have at least 48 hours of inpatient admission * Able & willing to give informed consent
Exclusion criteria
* Unable to participate in neurocognitive assessments * Presence of delirium prior to surgery * Contraindication to use of EEG electrodes (e.g. known allergy to a component of the electrodes) * Known history of severe traumatic brain injury * Learning disability specifically with a known structural brain lesion * Known history of dementia * Participants undergoing operations on the carotid artery
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Feasibility to conduct the study | 1 year after surgery | The total number of participants who are successfully recruited, receive the study procedures and complete both 90 day and 1 year follow up after surgery. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Postoperative delirium incidence and severity | Up to 5 days after surgery | Postoperative delirium identified as being present according to a positive result using 3-Minute Diagnostic Interview for Confusion Assessment Method (3D-CAM) and severity according to the absolute value on the 3D-CAM-Severity which is a scale converting the 3-Minute Diagnostic Interview for Confusion Assessment Method into a scale from 0-7. Higher scores are associated with worse outcome. |
| Days alive and at home up to 90 days after surgery | 90 days after surgery | The number of days a participant is alive and how many are spent at home after surgery |
| Change in neurofilament light chains and tau proteins levels pre- to post operatively | Up to 2 days after surgery | Measurements of the level of the biomarkers neurofilament light chain and tau protein in plasma |
| Postoperative neurocognitive dysfunction and severity | Up to 1 year after surgery | Cognitive impairment measured on Montreal Objective Cognitive Assessment administered by telephone. The scale is 0-22 with higher scores representing better outcome. |
| Long term cognitive impairment | Up to 5 years after surgery | Incidence of new diagnosis in primary or secondary care of dementia or mild cognitive impairment |
Countries
United Kingdom
Outcome results
None listed