Transcranial Doppler ultrasonography: a diagnostic tool of increasing utility

Purpose of review Since its introduction in 1982, transcranial Doppler ultrasonography has become an important diagnostic and monitoring tool in patients with surgical disease. It has applications in the perioperative period, as well as in the intensive care unit. It is therefore appropriate for the anesthesiologist to maintain an understanding of its current utility. Recent findings Transcranial Doppler has an established role in diagnosing cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage and for guiding transfusion therapy in children with sickle cell disease. It has application in the preoperative evaluation of patients with cerebrovascular disease, as well as that of an intraoperative monitor in carotid endarterectomy and carotid stenting. It is useful for detecting right-to-left shunts in settings in which transesophageal echocardiography is not desirable. Its value in settings such as traumatic brain injury, hepatic failure, and migraine headache has yet to be fully clarified. Summary Although there are several settings in which transcranial Doppler has well established usefulness, there are many more in which it is likely valuable, such as traumatic brain injury, ischemic stroke, and fulminant hepatic failure. Further research is needed in these fields to elucidate the exact role for transcranial Doppler.