Effect of experimental blunt head injury on acute regional cerebral blood flow and edema

Acute edema occurs in cerebral hemispheres with contusion after a cranial impact-acceleration injury in the cat. In the present study, we asked whether changes in rCBF could contribute to this early pathophysiology. Cortical and white matter blood flow were measured with RMS before and at 10, 30, and 60 min after cranial impact. Specific gravity was tested peripheral to sample sites for rCBF. Head-injured animals with severe unilateral (grade 2) contusions had bilateral postinjury decreases in rCBF despite adequate cerebral perfusion pressure and carefully regulated PCO2 and PO2. Injured cats without cerebral contusion (grade 0) had substantial individual variation in rCBF after injury, with no group changes from preinjury values. Edema was measurable in the left cortex of grade 2 animals. Because of differences in sample sites, specific gravity data could not be reliably correlated with rCBF. Our findings suggest that acute oligemia can occur in the traumatized brain without systemic dysfunction.