[Value of cerebral metabolic exploration in post-traumatic coma states in the acute phase]

Abstract

The authors report the values of mean hemispheric blood-flow and cerebral arterial consumption they found in 34 neurosurgical comatous cases in acute state. In basal conditions, mean values of mean hemispheric bloodflow and oxygen consumption are lowered. There seems to be a relation between the values found and the comatous stage on one hand, the prognosis on the other hand. The cerebral response to hypercapnia (16 assays) allows to separate 2 groups, one with a noticeable improvement of cerebral bloodflow, the other with only a minimal response. There was no significant variation of cerebral oxygen consumption in both group. Cerebral response to CO2 seems to be clearly related to the stage of coma (low in the most severe cases) but pronostic incidence remained uncertain. A hypertensive test by means of Aramine (18 assays) allows to separate 3 groups : 1 group (8 cases) where the mean hemispheric bloodflow remained stable during hypertension as did the cerebral oxygen consumption -(autoregulation remained unchanged), 1 group (4 cases) where mean hemispheric bloodflow and cerebral oxygen consumption were lowered (excessive autoregulation), 1 group (6 cases) where mean hemispheric bloodflow increases clearly while under Aramine perfusion (loss of autoregulation). Those dynamic tests, either hypercapnic or hypertensive, allow, in comparing oxygen consumption variations with cerebral bloodflow variations, the distinction between : patients where metabolic autoregulation seems maintained (good prognosis) - (10 cases), patients where metabolic regulation is lost with either "luxury perfusion" (14 cases) - poor prognosis, or "insufficient perfusion" (10 cases). The authors are discussing the treatment concerning those last mentioned patients.