Transcranial Doppler: correlation of blood velocity measurement with clinical status in subarachnoid hemorrhage

Abstract

Subarachnoid hemorrhage affects approximately 30,000 people each year in North America. Up to 50% of patients who survive the initial hemorrhage experience cerebral vasospasm, often resulting in permanent disability or death. Early detection allows interventions which may prevent catastrophic complications. Diagnosing vasospasm has always been dependent on invasive testing and correlation of the clinical picture. Alterations in neurological assessment, including Glasgow Coma Scale score changes, merely reflect poor cerebral perfusion secondary to the vasospasm, and may not be apparent for days. Transcranial Doppler (TCD) ultrasonography is an exciting diagnostic alternative. This noninvasive test may be done daily at the bedside, and may accurately predict impending vasospasm.