Cerebral Perfusion Variation During Blood Pressure Changes in ICU

Condition(s) studied

Investigational drug(s) / intervention(s)

Non-invasive Measurement of cerebral blood velocity in the middle cerebral artery by transcranial pulsed Doppler (TCD) (Mean velocity, Vm, cm/s): Measurement of cerebral blood velocity in the middle cerebral artery by transcranial pulsed Doppler (TCD) (Mean velocity, Vm, cm/s) (recorded on Data Warehouse Connect). For all patients Vm in (cm/s) will be collected during the adjustment of the mean arterial pressure level between 90% and 70% of the baseline value, without ever going below 60 mmHg for the patients at low risk and 80 mmHg for the patients at high cardiovascular risk. For neuro-injured patients with intracranial pressure monitoring (ICP), the lower limit of cerebral perfusion pressure (CPP = MAP - ICP) will be set at 50 mmHg

Study summary

The risk associated with arterial hypotension during anesthesia for intensive care sedation 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 (1) and a reduction of less than 30-50% from the value measured before sedation are commonly used to ensure good perfusion of all organs. In intensive care, it is recommended to maintain a MAP between 60 and 70 mmHg and a Cerebral Perfusion Pressure (CPP) \> 50 mmHg for neurocompromised patients with Intra Cranial pressure (ICP) measure. Normally, cerebral blood flow is self-regulated, allowing adaptation of cerebral blood flow to oxygen requirements at 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 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 or without cardiovascular risk factors during controlled variations performed during routine care to set the blood pressure level within the recommended safety standards during sedation in intensive care unit.

What is the tolerable target BP level for a patient under continuous sedation in the ICU? Is there a simple and non-invasive way to measure the level of cerebral blood flow autoregulation and especially the adequacy of the brain's oxygen requirements?

Eligibility

Primary outcome measure(s)

• Mean arterial pressure — 1 day
  Continuous non-invasive measurement of mean arterial pressure (MAP, mmHg)
• Cerebral blood velocity in the middle cerebral artery — 1 day
  Measurement of cerebral blood velocity in the middle cerebral artery by transcranial pulsed Doppler (TCD) (Mean velocity, Vm, cm/s)
• Burst suppression — 1 day
  Continuous measurement of burst suppression (BS) (%)
• 95% spectral frequency front — 1 day
  Continuous measurement of spectral frequency front (SEF95) on the frontal EEG
• delivered doses of hypnotics, morphine and paralytic agents — 1 day
  Quantification of delivered doses of hypnotics, morphine and paralytic agents

Trial sites (1)

More Assistance Publique - Hôpitaux de Paris trials in France

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