Cerebral vasospasm following post-traumatic subarachnoid hemorrhage evaluated by transcranial Doppler ultrasonography

We studied the incidence and time course of flow velocity changes suggesting a vasospasm following post-traumatic subarachnoid hemorrhage (SAH) considering the intracranial pressure (ICP) in 38 SAH patients as compared to 30 patients with spontaneous SAH. The first investigation was done within 24 h after onset of hemorrhage and regularly followed up during the clinical course. Additionally, the index of cerebral circulatory resistance was calculated and the ICP was measured using an epidural transducer. A significant correlation between middle cerebral artery maximum mean flow velocity and the quantity of blood seen on a computed tomographic scan in patients with post-traumatic SAH indicates a similar pathogenetic mechanism of the development of vasospasm to that after spontaneous SAH. In contrast, there was a significantly earlier occurrence of mean flow velocities over 120 cm/s following post-traumatic SAH irrespective of the ICP. Therefore, additional factors must be considered in the evaluation of these pathologically raised flow velocities after posttraumatic SAH. In both SAH groups there was a highly significant correlation between clinical outcome and clinical grade on admission, ICP and resistance index. The weak correlation between maximum mean flow velocity and clinical outcome following post-traumatic SAH supports the notion that final clinical outcome of these patients is of multifactorial origin.