Perioperative Changes of Cerebrovascular Autoregulation and Association With Cognitive Function

Study Overview
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Brief Summary
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Cerebral blood flow is tightly regulated to ensure constant cerebral perfusion independently from systemic blood pressure fluctuations. This mechanism is termed cerebrovascular autoregulation and preserves adequate cerebral perfusion in a range between 50 and 150 mmHg of cerebral perfusion pressure. Upper and lower autoregulatory limits may vary individually. Beyond the autoregulatory range the protective autoregulatory response is lost, facilitating cerebral ischemia or hyperemia. The cerebrovascular response may be altered during general anesthesia, through direct effects of anesthetic agents on the vascular tone, changes of arterial partial pressure of carbon dioxide or the administration of vasoactive substances. The association of perioperative impairment of cerebral autoregulation and postoperative cognitive function has been discussed controversially.

Detailed Description
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continuous monitoring of cerebrovascular autoregulation using the correlation method based on near-infrared spectroscopy and invasive blood pressure measurement an index (COx) will be calculated autoregulation monitoring from anesthesia induction until emergence from anesthesia assessment of preoperative cognitive function during preanesthesia evaluation or on the day before surgery assessment of postoperative cognitive function between day 3 and 14 following surgery evaluation of subjective cognitive complaints or attention deficits 3 months after surgery

Official Title
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Cerebrovascular Autoregulation During Major Non-cardiac Surgery and Risk for Postoperative Cognitive Dysfunction in Elderly Patients

Conditions
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Cognitive Function Abnormal, Anesthesia, Surgery

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: elective major non-cardiac/non-vascular surgery anticipated surgical duration >120 minutes age >= 60 years indication for invasive blood pressure measurement native German speaker Exclusion Criteria: history of cerebrovascular disease preexisting cognitive impairment history or presence of neurological disease

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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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative change of cognitive function from baseline | change of cognitive function following surgery compared with preoperative cognitive performance, defined as: z-score <-1.96/>1.96 in two or more neuropsychological tests (California Verbal Learning Test for verbal learning, Grooved Pegboard Test for visual motoric coordination, Digit Span forward task for attention and memory, Trail-Making-Test A and B for executive function) and/or a combined z-score >1.96 | preoperative psychometric evaluation on the day before surgery, postoperative psychometric evaluation between day 3 and 14 after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| cognitive failures three months following surgery | Self-assessment of cognitive failures using a validated questionnaire (Cognitive Failures Questionnaire). The questionnaire evaluates self-reported failures in perception, memory, and motor function. The questionnaire contains 25 items on a 5-point Likert scale. Total sum score from 0 (minimum) to 100 (maximum). | three months after elective surgery |