Cerebral Vasospasm is typically the outcome of Subarachnoid Hemorrhage (SAH) as a result of an aneurysm rupture. Early detection of vasospasm is critical since it allows timely intervention.
TCD is rather specific for this condition, and allows non-invasive, continuous bed-side monitoring. Vasospasm is characterized by increased velocities due to arterial narrowing. Severe vasospasm is defined in various international guidelines, and typically when mean velocities exceed 200 cm/sec, moderate conditions are with mean velocities between 120-200 cm/sec, and mild vasospasm is for mean velocities near 120 cm/sec. Additionally, velocities in the middle cerebral artery can be compared to internal carotid artery velocities, and the resulting ratio (Lindergaard index) can indicate cerebral vasospasm when it is greater than 3.
Typically, vasospasm is a developing pathology, and requires day by day monitoring of blood flow velocity values. The IMUSA Dolphin system provides a dedicated vasospasm protocol that allows setting velocity thresholds for immediate identification of the severity of the vasospasm condition. In addition, an immediate day by day velocity trend analysis is provided in order to help identify the critical time whereby intracranial velocities are dramatically increased, and immediate clinical intervention is required.
The Dolphin also provides an ideal platform for the identification of the critical highest intracranial velocities. All data is saved both in the time domain and at all depths along the ultrasound beam, which allows the examiner to review the data after freeze to explore the measured blood flow velocities.