Correlations between brain oedema volume on CT and CSF dynamics in severely head injured patients.

The CSF dynamics were studied in 18 patients with severe head injury who remained comatose over 6 hours after trauma (GCS less than 8). Amount of brain oedema was estimated by CT tomodensitometry. In addition, CSF parameters of PVI. Elastance (E), compliance (C) and resorption resistance (R) were calculated from serial bolus infusion tests. We observed a decrease in viscoelastic parameters as indexed by PVI, however, no increase in resistance to CSF outflow. It was noted that patients with lower PVI developed more severe brain oedema during the 3-5 day post traumatic period. From these data, we conclude that buffering capacity in severe head injury is mainly affected by the volume of brain oedema and not by the haematoma volume.