Medicolegal diagnosis of asphyxia--cerebral blood flow and brain oxygen tension.

Over the last several years, using rabbit models the authors analyzed cerebral blood flow (CBF), the brain oxygen tension (PtO2) and other physiological parameters during asphyxiation as means of achieving a practical diagnosis of asphyxiation. The author reports here on the effects of compression of the carotid arteries and obstruction of the airway leading to hypoxia, based on an analysis of CBF and PtO2 during hanging. Immediately after hanging, the CBF dropped but then rose suddenly. After several minutes, it dropped along with blood pressure. The PtO2 continued to decrease until the time of irreversible apnea. These findings suggest the effects of compression of the carotid arteries and the airway occlusion. After death, these results were confirmed with the injection-molded resin specimens of the airway and by the angiograph. But the closure of the vertebral arteries was not produced by the hanging.