Cerebral Perfusion Variation During Blood Pressure Changes Under General Anesthesia: Relationship Between Transcranial Doppler, Frontal EEG, and Cerebral Oximetry: a Prospective Observational Study
Trial Snapshot
- Phase
- Not Applicable
- Status
- Recruiting
- Enrollment
- 100
- Locations
- 1
- Primary Endpoint
- burst suppression
Study Overview
Brief Summary
The risk associated with arterial hypotension during general anesthesia for surgery has been demonstrated , but the threshold at which consequences for perfusion of one or more organs appear varies according to the mechanism of hypotension, associated abnormalities (HR, cardiac output, and oxygen transport), and the patient's terrain.
Currently, a mean arterial pressure greater than 60 mm Hg and a reduction of less than 30-50% from the value measured before general anesthesia are commonly used treatment thresholds to ensure good perfusion of all organs.
Normally, cerebral blood flow is auto-regulated, which allows cerebral blood flow to adapt to oxygen requirements and to different levels of blood pressure, both high and low. However, this protective mechanism may fail for a degree of hypotension that depends on several factors such as the age or vascular status of the patient.
The aim of the study is to measure non-invasively, easily and reliably the variations of cerebral perfusion in patients with and without cardiovascular risk factors during controlled variations performed during routine care to set the blood pressure level within the recommended safety standards during general anesthesia.
What is the target level of blood pressure tolerable for a patient under general anesthesia? Is there a simple and non-invasive way to measure the level of cerebral blood flow autoregulation and especially its adequacy to the brain's oxygen needs?
Detailed Description
The risk associated with arterial hypotension during general anesthesia for surgery or interventional procedure has been demonstrated, but the threshold at which consequences for perfusion of one or more organs appear varies according to the mechanism of hypotension, associated abnormalities (Heart rate, cardiac output, and oxygen transport), and the patient's terrain.
Currently, a mean arterial pressure greater than 60 mm Hg and a reduction of less than 30-50% from the value measured before general anesthesia are commonly used treatment thresholds to ensure good perfusion of all organs.
These values are based on large cohort studies that associate these blood pressure thresholds with the occurrence of postoperative complications or during the resuscitation stay. They cannot be generalized to certain subpopulations that are underrepresented, such as women and elderly patients.
Normally, cerebral blood flow is self-regulated, which allows cerebral blood flow to adapt to oxygen requirements and to different levels of high and low blood pressure.
However, this protective mechanism may fail for a degree of hypotension that depends on several factors such as the age or vascular health of the patient. For example, in patients with preexisting hypertension, the autoregulatory capacity of the brain is likely impaired making organs more susceptible to ischemia at low blood pressure.
Study Design
- Study Type
- Observational
- Observational Model
- Case Only
- Time Perspective
- Prospective
Eligibility Criteria
- Ages
- 18 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Patients of legal age (≥ 18 years)
- •Eligible for scheduled surgery at Lariboisière Hospital
- •Informed patient who has expressed no objection to participating in this research
Exclusion Criteria
- •Patients under 18 years of age.
- •Patient opposed to participation in the protocol
- •Pregnant woman
- •Patient under judicial protection
- •Patient not affiliated to a social health system
Outcomes
Primary Outcomes
burst suppression
Time Frame: 1 day
Continuous measurement of burst suppression (BS) (%)
cerebral blood velocity in the middle cerebral artery
Time Frame: 1 day
Measurement of cerebral blood velocity in the middle cerebral artery by Transcranial Pulsed Doppler. This corresponds to the Mean velocity (Vm) expressed in cm/s.
95% spectral frequency front
Time Frame: 1 day
Continuous measurement of a 95% spectral frequency front (SEF95) on the frontal EEG
mean arterial pressure
Time Frame: 1 day
Continuous non-invasive measurement of mean arterial pressure (MAP, mmHg)
delivered doses of hypnotics, morphine and paralytic agents
Time Frame: 1 day
Quantification of delivered doses of hypnotics, morphine and paralytic agents
Secondary Outcomes
- Cerebral O2 saturation(1 day)