Evaluation of posttraumatic vasospasm, hyperaemia, and autoregulation by transcranial colour-coded duplex sonography

Serial transcranial colour-coded duplex sonography (TCCS) was performed on 24 adult patients with severe head injury (GCS 8 or less). Flow velocities were obtained from the middle cerebral artery (MCA) and extracranial internal carotid artery (EICA). An autoregulation study was done using the transient hyperaemic response test, evidence of vasospasm (V-MCA greater than 100 cm/s and Lindegaard ratio more than 3) was found in nine patients (37%). Two of these developed non-contusion-related infarction and two others contusion-related infarction. This was significant (p < 0.05). Vasospasm started around day 2, reaching maximum around day 4 and persisting until the second week. Vasospasm was significantly associated with a poor outcome (p < 0.05). There was no correlation between the extent of SAH as seen on CT and vasospasm. Evidence of hyperaemia were observed in two patients (8%) and impaired autoregulation in seven patients (29%). Impaired autoregulation was significantly associated with development of hyperaemia (p < 0.05). TCCS studies permit a non-invasive evaluation of cerebral haemodynamics that will help in the management of head injured patients.