[Recommendations of the use of transcranial Doppler to determine the existence of cerebral circulatory arrest as diagnostic support of brain death].

INTRODUCTION

The clinical criteria for brain death consist of the demonstration of the absence of any clinical sign of encephalic activity. Confirmatory testing is usually not required for the diagnosis of brain death, except in some special situations that the Spanish law details. In these situations demonstrating cerebral circulatory arrest (CCA) by cerebral flow studies is necessary to support the diagnosis of brain death.

OBJECTIVE

To review the use of transcranial Doppler ultrasonography (TCD) for confirming brain death and to establish uniform criteria for the routine use of TCD as a confirmatory test.

METHODS

Based on literature analysis, the authors developed the guidelines for performance and interpretation of TCD in clinically brain-dead patients, in order to confirm the diagnosis. The active members of the Spanish Neurosonology Society (SONES) reviewed an initial draft, until a consensus was reached.

RESULTS

In a clinically brain-dead patient, specific intracranial flow patterns indicating CCA can be visualized by TCD. The specific flow patterns are the presence of reverberating flow and/or systolic spikes, and should be detected in both middle cerebral arteries and also in the basilar artery. We recommend to repeat the examination within 30 minutes to confirm the findings.

CONCLUSIONS

TCD is a useful method detecting CCA and therefore can be used to confirm brain death in a clinically brain-dead patient. The presence of reverberating flow, systolic spikes or absence of flow in the basilar and both middle cerebral arteries observed in two examinations is highly specific for the prediction of CCA and brain death in all patients.