Diagnosis of brain death by transcranial Doppler sonography: solutions for cases of difficult sonic windows.

Delays in diagnosis of brain death have definite consequences for the organ retrieval and transplantation process. It is advisable to use accurate diagnostic methods. Transcranial Doppler sonography is a well-accepted technique for diagnosing cerebral circulatory arrest. However, in some cases, the access to the intracranial circulation via the temporal window is difficult. In 43 brain-dead patients we evaluated the rate of impossibility of insonation of middle cerebral artery using a temporal window and the usefulness of an orbital window for insonation of the carotid siphon. In 39 patients the usual protocol of insonation (temporal window and foramen magnum window) was sufficient to demonstrate cerebral circulatory arrest. In 10 patients, including all the cases in which it was impossible to use a temporal approach, the carotid siphon was successfully insonated, showing in all the cases the existence of a sonographic pattern compatible with cerebral circulatory arrest. It may be concluded that the use of an orbital window for exploring intracranial circulation by transcranial Doppler sonography can be a useful tool in cases of difficult sonic windows.