[Transcranial Doppler ultrasound in intensive care medicine]

Transcranial Doppler sonography (TCD) enables measurement of blood flow velocities in the basal intracerebral vessels. The most important applications of TCD in the ICU are the diagnosis and monitoring of vasospasms caused by subarachnoid hemorrhage after rupture of an aneurysm. Further indications are the non invasive diagnosis of critical decreases of cerebral perfusion pressure, the evaluation of brain death and the monitoring of thrombolysis of occlusions of the middle cerebral artery. TCD lends itself as a valuable non invasive bedside-monitoring tool, which enables continuous or intermittent monitoring of intracerebral hemodynamics without strain for the patients. Disadvantages to be mentioned are the dependence of experienced examiners and the long lasting training phase required to achieve the requisite experience.