Cerebral hemodynamic disturbances following penetrating craniocerebral injury and their influence on outcome.

Available data on the subject of cerebrovascular dynamics after penetrating craniocerebral injury and their effect on outcome were reviewed. Following penetrating injury, CBF is depressed, as is cerebral metabolism. This decreased flow likely is associated with poor outcome as previously shown in closed head injuries. A phenomenon interrelated with a decreased blood flow is posttraumatic vasospasm. Vasospasm occurs in a significant percentage of patients as demonstrated both by TCD and angiography, and there is a strong relationship with SAH. Vasospasm following penetrating injury has an onset and time course similar to that seen in both closed head injury and aneurysmal SAH. Vasospasm following penetrating craniocerebral injury may be a cause of secondary ischemic injury, but further study is needed before the prognostic significance of this phenomenon is defined. For now, drawing a parallel with closed head injury and aneurysmal SAH, it can be inferred that vasospasm following cranial gunshot wound may be an important pathophysiologic factor. Because interventions are available to combat vasospasm, including medications (e.g., nimodipine), volume expansion, and elevation of blood pressure, the authors believe that identification and treatment of this potentially damaging condition are compelling, especially in patients whose CT scans demonstrate SAH.