BEDSIDE MEASUREMENT OF THE 3RD VENTRICLES DIAMETER DURING EPISODES OFARISING INTRACRANIAL-PRESSURE AFTER HEAD TRAUMA - USING TRANSCRANIAL REAL-TIME SONOGRAPHY FOR A NONINVASIVE EXAMINATION OF INTRACRANIAL COMPENSATION MECHANISMS

Using transcranial real-time sonography, changes in the axial diameter of the third ventricle during manoeuvres, which increased intracrania l pressure (ICP), were measured in 28 patients with moderate to severe head injury. The measurements were correlated with ICP measured by ep idural pressure monitoring. We observed reductions in diameter ranging from 0.3 to 1.1 mm with rises in intracranial pressure of at least 5 mm in 22 patients of whom only one died. In 6 additional patients, no changes in diameter were seen, and 5 of the 6 died. We interprete that poor outcome as a measurable inability for the brain to expel cerebro spinal fluid into extracerebral compartments during increased ICP. Tra nscranial real-time sonography may provide additional information abou t intracranial cerebral fluid dynamics and compliance.