Impact of Cardiac Blood Flow on Cerebral Blood Flow in Patients With Severe Traumatic Brain Injury

Study Overview
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Brief Summary
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Severe traumatic brain injury with increased intracranial pressure can lead to decreased cerebral blood flow. Low cerebral blood flow is responsible for secondary lesions, leading to bad prognosis. It is not yet established whether increasing cardiac output in these patients can lead to an increase in cerebral blood flow, although there are some arguments in favor of this hypothesis. The aim of this study is to demonstrate that increasing cardiac output will improve cerebral blood flow in patients with severe traumatic injury and high cerebral pressure.

Conditions
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Severe Traumatic Brain Injury With High Cerebral Pressure

Intervention / Treatment
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* Drug: Norepinephrine
* Drug: Dobutamine and norepinephrine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Traumatic brain injury (TBI) with pattern of oligemia (diastolic velocity < 30cm/second and/or mean velocity < 45cm/second measured with transcranial doppler or oxygen tissue pressure < 15mmHg) Closed traumatic brain injury Isolated TBI or polytraumatism Age between 18 and 65 years old Affiliated to a social security system Exclusion Criteria: Instable episodes of high cerebral pressure Craniectomy High cerebral pressure without TBI No autoregulation Current hemorrhagic shock Chronic cardiac failure Chronic renal failure Hyperemia measured with transcranial doppler Short life expectancy Refused consent from the family Protected patients by the law Hypersensibility to one of the treatment or sulfites

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 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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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Noradrenaline alone<br>Treatment for 30 minutes with noradrenaline alone | Drug: Norepinephrine<br> <br> |
| Experimental: Noradrenaline + dobutamine<br>Treatment with noradrenaline and dobutamine for 30 minutes | Drug: Dobutamine and norepinephrine<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean blood flow velocity | Mean blood flow velocity averaged on the two middle cerebral arteries (right and left) measured one after after the initiation of treatment. Each velocity is calculated as an average on the 10 last minutes form continuous transcranial doppler monitoring | After one hour of treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evolution of brain oxygenation under treatment | Comparison of the brain tissue oxygenation curves (PbrO2) under treatment with and without dobutamine | During one hour of treatment | 
| Dobutamine doses | Dobutamine doses required to reach the same cerebral perfusion pressure than noradrenaline alone | After one hour of treatment | 
| Resistivity index on renal doppler | Measure of resistivity index on renal doppler after one hour of treatment with and without dobutamine | After one hour of treatment | 
| Pulsatility index on renal doppler | Measure of pulsatility index (PI) on renal doppler before and after one hour of treatment with and without dobutamine prediction of cerebral blood flow increase (patients with high initial renal PI) | After one hour of treatment | 
| Cardiac output modifications | Comparison of cardiac blood flow modifications under treatment for one hour with and without dobutamine | During one hour of treatment |