Cerebral Circulation in Critically Ill Children
Condition: Arterial Hypotension; Shock; Cerebral Lesion
MeSH terms: Hypotension
Study type: Observational

Summary: 
      The principal purpose of this study is to describe the changes in cerebral circulation
      (assessed by transcranial ultrasound) and oxygenation (assessed by Near InfraRed
      spectroscopy, NIRS) during resuscitation for hemodynamic failure (arterial hypotension or
      shock) in critically ill children treated with vasoactive or inotropic drugs.

      The secondary objectives are :

      i) to evaluate the association between an alteration of cerebral circulation and/or
      oxygenation and an alteration in macro-circulatory parameters (Mean Arterial Blood Pressure
      and cardiac output) or a bad outcome, ii) to study if cerebral autoregulation is impaired
    

Detailed description: 
      Pediatric shock is a frequent and serious cause of hospitalization in pediatric intensive
      care unit that can lead to multi-organ failure and death.

      Its early recognition improves patients' outcome, as well as the establishment of targeted
      guidelines pursuing normalization of macro-circulatory parameters (ie blood pressure and
      lactate).

      However, regional hypoperfusion leading to organ failure can be present before the alteration
      of these parameters, and persist after their restoration.

      Brain lesions are common in critically ill children with cerebral hypoperfusion, since they
      may have impaired autoregulation and permeable blood-brain barrier. Vasoactive and inotropic
      drugs used for hemodynamic resuscitation should restore systemic and regional circulation,
      but may be inadequate on brain perfusion because of i) their variable and unpredictable
      cardiovascular effects , and ii) a strong interindividual variability between patients. As
      such, the impact of this medication on cerebral circulation and oxygenation is unknown.

      Monitoring cerebral circulation and oxygenation during a hemodynamic resuscitation using
      catecholamines is a first step to identify risk factors of an altered brain perfusion, and to
      improve treatment of shock.
    

Intervention name(s): Near InfraRed Spectroscopy assessment; Transcranial Doppler Ultrasound assessment; Cardiac output assessment
Intervention type(s): Device; Device; Device
Intervention description(s): Regional Cerebral Oxygen saturation (rScO2 ) values will be collected for all patients during the procedure using a 2-wavelength (730-810 nm) cerebral oxymeter (monitor INVOS 5100C®, Medtronics). Two transducers will be placed on both fronto-parietal sides of the patient's head.
To assess the balance between oxygen delivery and consumption, the Fractional cerebral Tissue Oxygen Extraction (FTOE) will be calculated as this ratio: FTOE=[SpO2-rScO2]/SpO2.
Data will be collected for a period of 3 hours starting from the beginning of catecholamine treatment.; Transcranial Doppler ultrasound will be performed for all patients during the procedure using a VIVID S-5 (General Electric®) echograph. All examinations will be performed by a single trained operator. A 3 MHz probe will be placed on left and right temporal window to detect signal from the middle cerebral artery. 2 measures will be performed for each side to have the mean of the two measures; In case of difference in measures of more than 20%, a third measure will be performed.
Measures will be performed for a period of 3 hours starting from the beginning of catecholamine treatment.; Transthoracic echocardiography will be realized for all patients during the procedure using a transthoracic ultrasound device (VIVID S-5, General Electric®) with a 3 to 6 MHz probe. All examinations will be performed by a single trained operator.
Two echocardiographic views will be examined to assess cardiac output : the two-chamber long-axis view to measure sub-aortic diameter (d), and the four-chamber view to measure the Left ventricular outflow tract velocity time integral (LVOT VTI). Cardiac output (Qc) will then be calculated taking account these parameters and heart rate with this formula : Qc = [π x d2 x VTI x HR] / 4 2 measures will be performed to have the mean of the two measures; In case of difference in measures of more than 20%, a third measure will be performed.
Measures will be performed for a period of 3 hours starting from the beginning of catecholamine treatment.
Other intervention name(s): NIRS assessment; TCD assessment
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Pediatric patients hospitalized in 4 french Pediatric Intensive Care Units
      
Keywords: Near InfraRed Spectroscopy; Brain perfusion; Pediatric shock; Catecholamines