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Biomedical subjects

B Roquefeuil

Publications and source records attributed to B Roquefeuil.

101 records · Page 6Linked to original sources
PubMedDate not supplied

[The effect of gamma-OH on cerebral metabolism and blood flow in human patients (author's transl)].

The effects of gamma-OH on cerebral blood flow (CBF) and metabolism were analysed in 10 neurosurgical patients, 15 min after a 60 mg/kg injection, both blood flow and oxygen consumption demonstrates a disconnection between blood flow and metabolism which appears an advantage and hence the interest in using this agent in anaesthesia and neurosurgical intensive care. 1 h40 min later no rebound effect was found; the metabolic reduction persisted whereas the CBF had returned to its resting level. Under gamma-OH CO2 production does not parallel O2 consumption and this could be interpreted as a sign that glucose-6-phosphate is metabolising via pentose.

Adolescent↗
PubMedDate not supplied

[A polygraphic, haemodynamic and metabolic study of 2 cases of the "locked-in" syndrome (author's transl)].

The sleep-waking pattern, cerebral blood flow (CBF) and cerebral metabolism have been studied in 2 cases of the "locked-in" syndrome, one traumatic, the other vascular in origin. Studies were performed in the third week in the first case and the seventh in the second. A lesion of the ventral pons was suggested clinically and neuroradiologically. The waking EEG was composed of alpha and theta activity. Different stages of slow wave sleep were diminished in quantity (NREM) as was paradoxical sleep (REM). The basal cerebral blood flow (CBF) was increased by 30 p. 100 compared to normals. Cerebral oxygen consumption was normal. The cerebral hyperaemia was evenly distributed and was associated with a failure of autoregulation. The vascular response to CO2 was normal, however. The E.E.G. findings, haemodynamic and metabolic studies confirmed a pontine lesion as the cause of the "locked-in" syndrome in contrast to akinetic mutism where the lesion is in the mid-brain.

Adolescent↗
PubMedDate not supplied

[Sleep organization by subjects in chronical post-traumatic inconscience (author's transl)].

Nine subjects who underwent a severe head traumatism with a brainstem dysfunction at the acute stage, were polygraphically recorded at the chronic stage under strict conditions of drug withdrawal and light-dark periods. Two groups of subjects were identified. The first one (5 subjects) showed normal NREM sleep and REM sleep morphologic patterns as well as a partly preserved architecture of sleep. The synchronisation of sleep with dark periods was lost in 4 out of 5 cases. In the second (4 subjects) NREM sleep morphologic patterns were lost and REM sleep was either uncertain or absent in 3 subjects. The synchronisation of sleep with dark periods was lost in 3 out of 4 cases. The morphologic alterations of sleep are connected with different types of encephalic lesions whereas the anomalies of the architecture of sleep and of its synchronisation with dark periods are referred to the numerous endogennous and exogenous stimuli undergone by these subjects. At the chronic stage of post-traumatic comas a 24-hour polygraphic recording supplies no definite information with regards to the prognosis.

Adult↗
PubMedDate not supplied

[Hemodynamic and metabolic changes at various levels of cerebral dysfunction during severe traumatic coma (author's transl)].

Cerebral blood flow (DSC) and oxygen consumption were measured in a series of patients in the acute phase of severe brain injury, and the results analyzed as a function of the level of cerebral dysfunction determined clinically. The most frequent modifications were increased cerebral blood flow and reduced oxygen consumption, whatever the degree of dysfunction. Hemodynamic data has no prognostic value whereas oxygen consumption results are more valid. Increased cerebral blood flow is noted constantly in patients at a level of mesencephalic dysfunction. Reduced O2 consumption associated with increased blood flow is the result of a disturbance in the blood flow-metabolism ratio and could be due to cerebral vasodilatation. This great increase in cerebral vasodilatation observed in cerebral dysfunction syndromes is in favour of the existence of a central neurogenic system in the brain stem regulating cerebral blood circulation.

Brain↗
PubMedDate not supplied

[Measurement of differences in oxygen between arteries and veins. Application to the study of cerebral metabolism].

The cerebral metabolic exploration requires a precises measurement of the arterio-venous differences and this, for each metabolite. As far as oxygen is concerned, there are many techniques to measure the blood contents (CaO2 - CvO2). Direct methods give accurate results but their high technicality makes it difficult to adapt them to the increasing medical demand. The authors report the principle and the technique of the indirect method based upon the measurement of the total hemoglobin concentration and the saturation in oxygen. They recall the possible causes of errors, the main of which - induced by an insufficient homogenization of the sample - is (by the way) to be found in both groups of methods although to a lesser degree in the indirect method. Therefore, the latter, that all normally equipped laboratories can carry into practice, seems quite adapted to the "hospital demand" and its validity confirmed by an experience that now belongs to the past.

Arteries↗
PubMedDate not supplied

[The MA 1 B respirator. Apropos of an experiment involving 91,300 hours of function].

Description of the working principle and the characteristics of the Bennet MA 1 B respirator, which is of the release of volume type with electro-mechanical functioning. Study of the advantages and drawbacks. During an experiment involving 91,300 hours of utilization of 21 sets of apparatus, 12 breakdowns concerning a mechanical or electrical component were recorded. No incident in the functioning of the electronic part of the system of control or of surveillance was noted. The reliability of the apparatus appears on the whole to be satisfactory, taking into account its remarkable working posibilities.

Evaluation Studies as Topic↗