Cerebral Hemodynamics and Oxygenation in Critically Ill Patients

Study Overview
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Brief Summary
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Critically-ill patients frequently experience marked changes in mean arterial pressure and carbon dioxide partial arterial pressure, the two major determinants of the cerebral blood flow. In addition, many therapeutics (fluids, vasopressors or inotropes administration, blood transfusion, prone positioning...) can influence these two determinants of cerebral blood flow and thus cerebral blood flow, especially in patients with altered cerebral autoregulation. Nevertheless, cerebral hemodynamics and oxygenation, as well as the effects of the different therapeutics on it have been poorly studied in critically-ill patients. In addition, it has been suggested that impaired cerebral blood flow and impaired cerebral microcirculation may be involved in the pathophysiology of septic encephalopathy in patients with sepsis and/or septic shock. In this study, we aimed to characterize and investigate the effects of different therapeutics on cerebral hemodynamics and oxygenation in critically-ill patients.

Official Title
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Cerebal Hemodynamics and Oxygenation in Critically Ill Patients : Characterization and Effects of Therapeutics

Conditions
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Septic Shock

Intervention / Treatment
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* Procedure: mechanical ventilation
* Drug: Sedation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria : Patients under mechanical ventilation and sedated within the first 72h of ventilation onset Indication to one of the studied therapeutics left at the discretion of the attending physician Exclusion criteria Age < 18 years Pregnancy Inability to obtain a Doppler signal Medical history or clinical evidence of neurological disease Known severe carotid stenosis (>70%) Significant cardiac arrhythmias Care-limitation decision.

Ages Eligible for Study
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Minimum Age: 18 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 |
| --- | --- |
| patients admitted in medical intensive care unit who require mechanical ventilation and sedation<br>The main goals of the study are to characterize cerebral hemodynamics and oxygenation as well as to study the effects of therapeutics on it in critically-ill patients. For this purpose, we plan to include all consecutive patients admitted in our medical intensive care unit who require mechanical ventilation and sedation and in whom the attending physician decides to perform one of the studied therapeutics (fluids, vasopressors or inotropes administration, blood transfusion, prone positioning, passive leg raising test, end-expiratory occlusion test) within the first 72h of ventilation onset. Cerebral hemodynamics (cerebral blood flow and cerebral autoregulation) as well as cerebral oxygenation will be non-invasively studied before and after therapeutics. | Procedure: mechanical ventilation<br>* mechanical vantilation will be performed<br>Drug: Sedation<br>* sedation wil be performed<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cerebral blood flow | Use of transcranial Doppler | Within the first 72 hours of ventilation onset, before and after therapeutics | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cerebral autoregulation | Use of transcranial Doppler | Within the first 72 hours of ventilation onset, before and after therapeutics |