- ICH GCP
- US Clinical Trials Registry
- Clinical Trial NCT05681741
Impact of Cardiopulmonary Bypass Flow on Cerebral Autoregulation (FLOWMAPCA)
Impact of Cardiopulmonary Bypass Flow on Cerebral Autoregulation in Cardiac Surgery, a Cross-over Study
Cerebral autoregulation is defined by the capacity of the brain to maintain a constant cerebral blood flow (CBF) despite variations of arterial pressure. However, when the arterial pressure is below a critical threshold, cerebral blood decreases.
This critical threshold is called the lower limit of cerebral autoregulation (LLA).
Cardiopulmonary bypass is a unique environment wherein systemic blood flow is totally controlled by the cardiopulmonary bypass pump. High pump flows combined with low arterial pressures has been shown to not compromise neurologic postoperative outcomes.
Our hypothesis is that that LLA may depend on the cardiopulmonary bypass flow, ie the LLA may decrease when the cardiopulmonary bypass flow increases, explaining why low arterial pressure may be well tolerated.
Study Overview
Status
Intervention / Treatment
Detailed Description
Cerebral tissue perfusion is partly ensured by cardiac output and arterial pressure. In cardiac surgery, and especially during bypass surgery, one of the main objectives is to maintain sufficient blood flow and an optimal mean arterial pressure (MAP) to limit the deleterious consequences of organ hypoperfusion. To have a physiological regional organ blood flow, some organs, such as the brain, need a minimum MAP threshold (the lower limit of autoregulation, LLA) to ensure a constant cerebral blood flow (CBF). This is known as the cerebral autoregulation (CA). As the brain is at high risk of ischemia and definitive functional consequences in case of cerebral hypoperfusion, maintaining MAP above the LLA of the brain limit the deleterious postoperative neurological outcome.
CA can be determined by continuously calculating the correlation between MAP and CBF. CBF is assessed by continuous monitoring of the middle cerebral artery velocity (mV). moving Pearson correlation coefficient between 30 consecutive, paired MAP and cerebral blood flow velocity values will be calculated to generate the mean velocity index (Mx). The Blood pressure in the autoregulation range is indicated by an Mx value that approaches zero (there is no correlation between flow velocity and MAP), whereas an Mx approaching 1 indicates dysregulated cerebral blood flow (flow velocity and MAP are correlated). A value of 0.4 is accepted as the threshold of CA corresponding to the LLA.
During cardiopulmonary bypass (CPB), MAP is physiologically related to bypass flow and systemic vascular resistance. The adjustment of MAP during CPB is therefore achieved by the administration of vasoconstrictors or vasodilators as well as by the variations of the pump flow.
This research assumes that a change in the pump flow rate will lead to a change in the LLA. Therefore, if the flow rate is higher, it is possible that the LLA will be lower.
In this randomized trial, two different rates of pump flow will be compared with respect to LLA testing.
Regional brain oxygen saturation, assessed by near-infrared spectroscopy will also be monitored during surgery.
Study Type
Enrollment (Actual)
Phase
- Not Applicable
Contacts and Locations
Study Contact
- Name: Olivier Desebbe, MD
- Phone Number: +33472171825
- Email: oldesebbe@yahoo.com
Study Locations
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-
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Lyon, France, 69009
- Clinique de la Sauvegarde
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Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Description
Inclusion Criteria:
- Patient, male or female, over the age of 18
- Patient scheduled to undergo valvular heart surgery with planned CPB
- Patient with a Euroscore below 7%
- Patient affiliated or entitled to a social security scheme
- Patient having received informed information about the study and having signed a free and informed consent to participate in the study
Exclusion Criteria:
- Patient with untreated or uncontrolled severe hypertension despite treatment
- Patient with chronic renal failure, with glomerular filtration < 30 mL/min/1.73m² or requiring a kidney transplant
- Patient with left ventricular ejection fraction < 40%
- Patient with a history of ischemic stroke
- Patient having or about to benefit from renal vascular surgery
- Patient with preoperative sepsis
- Patient who required a norepinephrine infusion within 24 hours before surgery
- Patient presenting with an inaccessible temporal Doppler window
- Patient candidate for emergency surgery
- Pregnant, parturient or breastfeeding woman
- Patient with preoperative uni or bilateral carotid stenosis > 50%
- Protected patient: adult under guardianship, curators or other legal protection, deprived of liberty by judicial or administrative decision
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Diagnostic
- Allocation: Randomized
- Interventional Model: Crossover Assignment
- Masking: Double
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
---|---|
Sham Comparator: current pump flow (between 2 and 2.4 l/min/m²)
the pump flow will be constant during this randomized phase
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during each phase of randomized pump flow, arterial pressure will be increased from 40 to 90 mmHg with vasodilators and/or vasoconstrictors
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Active Comparator: high pump flow (between 2.6 and 3 l/min/m²)
the pump flow will be constant during this randomized phase
|
during each phase of randomized pump flow, arterial pressure will be increased from 40 to 90 mmHg with vasodilators and/or vasoconstrictors
|
What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
---|---|---|
measurement of MAP LLA (mmHg)
Time Frame: 15 to 25 min during the procedure
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Determination of MAP LLA according to the calculation of the mean velocity index
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15 to 25 min during the procedure
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Collaborators and Investigators
Sponsor
Collaborators
Investigators
- Principal Investigator: Olivier Desebbe, MD, Clinique de la Sauvegarde
Study record dates
Study Major Dates
Study Start (Actual)
Primary Completion (Actual)
Study Completion (Actual)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Actual)
Study Record Updates
Last Update Posted (Actual)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Keywords
Other Study ID Numbers
- Ramsay Sante Sauvegarde Clinic
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.
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