Cerebral Blood Flow Reduction After Severe Head Injury and Its Relationship to the Extent of Brain Damage in Apallic Syndrome

Abstract

In most types of coma, cerebral blood flow (CBF) is reduced (Kety, 1949). This reduction is usually accompanied and probably induced by a decrease in oxygen consumption (Lassen, 1959). Following severe head injury, cerebral circulation time (Taylor and Bell, 1966), CBF, and cerebral metabolic rate for oxygen (CMRO₂) are decreased (Ingvar et al., 1964; Baldy-Moulinier and Frèrebeau, 1969; Shalit et al., 1970; Meyer et al., 1970); however, an increased CBF was sometimes observed shortly after the head trauma in animal experiments (German et al., 1947; Brown and Brown, 1954) and in patients (Shalit et al., 1970). This intensified cerebral perfusion, which was not paralleld by an equally increased CMRO₂, suggests the presence of a luxury perfusion syndrome (Lassen, 1966). After this initial phase CBF is reduced. The present study has attempted to establish whether or not the reduction of CBF is proportional to the brain damage in patients with the apallic syndrome and whether or not the measured CBF value furnishes prognostic information.