Transcranial Doppler evaluates cerebral hemodynamics in patients with brain injury
and is a useful technical tool in diagnosing cerebral circulatory arrest, usually
present in the brain-dead patient. This Latin American Consensus was formed by a
group of 26 physicians experienced in the use of transcranial Doppler in the context
of brain death. The purpose of this agreement was to make recommendations regarding
the indications, technique, and interpretation of the study of transcranial
ultrasonography in patients with a clinical diagnosis of brain death or in the
patient whose clinical diagnosis presents difficulties; a working group was formed to
enable further knowledge and to strengthen ties between Latin American physicians
working on the same topic.A review of the literature, concepts, and experiences were exchanged in two meetings
and via the Internet. Questions about pathophysiology, equipment, techniques,
findings, common problems, and the interpretation of transcranial Doppler in the
context of brain death were answered. The basic consensus statements are the
following: cerebral circulatory arrest is the final stage in the evolution of
progressive intracranial hypertension, which is visualized with transcranial Doppler
as a "pattern of cerebral circulatory arrest". The following are accepted as the
standard of cerebral circulatory arrest: reverberant pattern, systolic spikes, and
absence of previously demonstrated flow. Ultrasonography should be used - in
acceptable hemodynamic conditions - in the anterior circulation bilaterally (middle
cerebral artery) and in the posterior (basilar artery) territory. If no
ultrasonographic images are found in any or all of these vessels, their proximal
arteries are acceptable to be studied to look for a a pattern of cerebral circulatory
arrest.