Non-invasive cerebrovascular autoregulation monitor

The "Vittamed 505" non-invasive cerebrovascular autoregulation monitor offers the non-invasive technique of continuously and non-invasively monitoring the cerebrovascular autoregulation dynamic in real time.

The monitor provides information about the blood volume dynamics in the smallest vessels responsible for cerebral blood flow autoregulation, the small arterial vessels and arterioles. In a healthy brain, small arteries in the brain expand and contract automatically to compensate for rises and falls in cerebral perfusion pressure which is equal to the difference between arterial blood pressure (ABP) and intracranial pressure (ICP).

Cerebral autoregulation can compensate to an extent to swelling of the brain from traumatic brain injury. However once the arteries are fully expanded, no further compensation can occur. The scientific studies 1,2 have found that impairment of cerebral autoregulation is associated with worse outcome in severe traumatic brain injuries (TBI) and the authors suggested that loss of autoregulation may be an early sign that ICP will rise. Another study 3 found that patients who lose cerebral autoregulation should be managed using special treatment protocol in order to improve outcomes.

Cerebral autoregulation monitor provides useful clinical information as an early prognostic marker for patients with traumatic brain injury, allowing more focused and more reliable treatment decisions in the cases of still intact or impaired cerebrovascular autoregulation. A recent consensus paper suggested that treatment targets should be adjusted based on the state of cerebral autoregulation 4.

The "Vittamed 505" ultrasonic device consists of a portable monitoring unit and a disposable headframe, designed to be easily fitted to a patient’s head with minimal training. No accurate location of the transintracranial acoustic path is required on the head to generate a signal, and results can be obtained in a few minutes, generating a continuous monitoring trace.

Cerebrovascular autoregulation

In a healthy brain, small arteries in the brain expand and contract automatically to compensate for rises and falls in cerebral perfusion pressure and to keep cerebral blood flow stable. This is known as cerebral autoregulation. Cerebral autoregulation can compensate to an extent the swelling of the brain from traumatic brain injury. However once the arteries are fully expanded, no further compensation can occur. Indeed two studies 1,2 have found that impairment of cerebral autoregulation is associated with worse outcome in severe traumatic brain injury and the authors suggested that loss of autoregulation may be an early sign that ICP will rise. Another study found that patients who lose cerebral autoregulation should be managed using special and different treatment protocols than the TBI patients with still intact autoregulation. Autoregulation targeted therapy is the only way to improved TBI patients’ outcomes 3, leading to a recent consensus paper suggesting that treatment targets should be adjusted based on the state of cerebral autoregulation 4.

 

Technology Description

Clinical Evidence

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1 Hiler et al, J Neurosurg. 2006 May;104(5):731-7
2 Balestreri et al, Acta Neurochir (Wien). 2004 Feb;146(2):131-41
3 Howells et al, J Neurosurg 2005 102: 311-317
4 Andrews et al: NICEM consensus: Intensive Care Med 2008: 43: 1362-1370