[Value of brain metabolic studies in post-traumatic coma]. / Intérêt de l'exploration métabolique cérébrale dans les états de coma post-traumatique.

In 34 comatose patients in the acute phase, the mean hemispheric CBF is lowered as well as the CMRO2, with a quite good relation between these values and the coma level and prognostic so. The cerebral response to a PaCO2 range indicates a quite good relation with the coma level (the lowest value in the most severe comas). The cerebral autoregulation study, using Aramine induced hypertension, can separate the cases with a present autoregulation and the cases with a loss of autoregulation (the most severe and the poorest prognosis). In dynamic conditions (variation of the PaCO2 or Aramine induced hypertension), the change in CMRO2 is interesting : rather good prognosis among the patients with a normal metabolic autoregulation - poor prognosis among those whose metabolic autoregulation is lost.

[Value of cerebral metabolic exploration in post-traumatic coma states in the acute phase]. / Intérêt de l'exploration métabolique cérébrale dans les états de coma post-traumatiques en phase aigüe

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.

[Study of carbohydrate tolerance without and with corticotherapy]. / Etude de la tolérance hydrocarbonée hors et sous corticothérapie

Using the glucose tolerance test by the intravenous route, from which the coefficients K (CONARD) of carbohydrate assimilation and (BERNIER) of fasting glycogenolysis, are deduced, the authors study the carbohydrate tolerance of neuro-surgical patients in acute and chronic phases, under corticosteroid therapy and without corticosteroid therapy. The role of corticosteroid therapy in the decrease in carbohydrate tolerance reported is discussed ; for comparative purposes, the authors present the study of carbohydrate assimilation in irreversible coma and in patients with advanced neuroplegia.

[Plasma cortisol in neurosurgical resuscitation]. / Le cortisol plasmatique en réanimation neuró-chirurgicale

The authors study the values of spontaneous cortisonemia in neuro-surgical patients. They analysed the correlations between this parameter and certain clinical criteria (age, etiology, level of consciousness), the duration and nyctohemeral changes in spontaneous hypercortisonism. Furthermore, they presented the values of iatrogenic cortisonemias as a function of increasing doses of hydrocortisone and discussed the possible mechanisms for the disapperance of injected cortisone.

[Effects of intrathoracic pressure on cerebral circulation in the monkey as a function of body posture, sitting or standing]. / Effets de l'hyperpression thoracique sur la circulation cérébrale du singe en fonction de la position du corps, couchée ou debout.

Sixty-four measurements of CBF were performed in 8 monkeys in supine and in sitting position under various conditions of ventilation. The position of the body does not normally influence the response of brain circulation to CO2. The response is not different from normal with high insufflation pressure in supine position and the capacities to autoregulation seem to be maintained. In vertical position however there are no longer any significant relations between CBF and PaCO2, and the loss of autoregulation seems to occur earlier and to be more marked. Correlation of these findings to neuroradiologic data indicates that the cerebral venous drainage through the meningospinal plexus is enhanced in vertical position and that during intrathoracic hyperpressure the cerebral venous blood is retained in the jugular vein and meningospinal plexus, thus decreasing the cerebral venous pressure increase and maintaining a perfusion of brain tissue compatible with the survival of the animal.