%0 Journal Article
%T Transcranial Sonography and Cerebral Circulatory Arrest in Adults: A Comprehensive Review
%A Juan Antonio Llompart-Pou
%A Josep Maria Abadal
%A Albrecht G¨¹enther
%A Luis Rayo
%A Juan Pedro Mart¨ªn-del Rinc¨®n
%A Javier Homar
%A Jon P¨¦rez-B¨¢rcena
%J ISRN Critical Care
%D 2013
%R 10.5402/2013/167468
%X The diagnosis of brain death remains a clinical challenge for intensive care unit physicians. Worldwide regulations in its diagnosis may differ, and the need of ancillary tests after a clinical examination is not uniform. Transcranial sonography is a noninvasive, bedside, and widely available technique that can be used in the diagnosis of the cerebral circulatory arrest that preceeds brain death. In this paper we review the general concepts, the technical requisites, the patterns of Doppler signal confirming cerebral circulatory arrest, the vessels to insonate, and the options in cases with poor acoustic window. Future research perspectives in the field of transcranial sonography are discussed as well. 1. Introduction The diagnosis of clinical death in many critically ill patients has evolved from a cardiopulmonary event to the development of brain death, which is characterized by the irreversible loss of brain function [1, 2]. Involved pathophysiology in the development of brain death varies depending on the predominant location of the brain injury. This location can be divided into primarily supratentorial or infratentorial damage or global damage (secondary brain injury) [3]. Increased intracranial pressure (ICP) and a loss in cerebral autoregulation due to various mechanisms may gradually affect cerebral blood flow and lead to cerebral circulatory arrest (CCA) [3]. The diagnosis of brain death remains a clinical diagnosis and it can be usually declared when brainstem reflexes, motor responses, and respiratory drive are absent in patients with massive brain injuries [1, 2]. Clinical tests must be performed following strict criteria and prerequisites. Under some circumstances, it is for necessary, the realization of ancillary tests to confirm the diagnosis [1¨C3]. 1.1. Prerequisites [1¨C3] (i)Clarification of the etiology of coma, mainly by means of cranial computed tomography or magnetic resonance imaging in accordance to medical history review.(ii)Exclude potential causes of loss of brain stem function. For example, acute arterial hypotension, hypothermia, which may mimic complete and irreversible brain injury and therefore the body temperature should be above 32¡ãC or 90¡ãF, drug intoxication and acute and severe metabolic causes of coma (glucose, electrolytes, acid-base, or endocrine disturbances) have to be ruled out. 1.2. Clinical Diagnosis of Brain Death Includes the following [1¨C3].(i)Coma nonreactive to painful or verbal stimuli.(ii)Absence of brain stem reflexes.(iii)Abolished response to atropine [4]. This test is required by Spanish law [4],
%U http://www.hindawi.com/journals/isrn.critical.care/2013/167468/