par Ewalenko, Patricia 
Référence Acta Anaesthesiologica Belgica, 29, 3, page (239-252)
Publication Publié, 1978
Référence Acta Anaesthesiologica Belgica, 29, 3, page (239-252)
Publication Publié, 1978
Article révisé par les pairs
| Résumé : | The management of neurosurgical patients has changed since a few years with the development of intracranial pressure (ICP) monitoring, the value of which having now become widely recognized. An understanding of pathophysiological mechanisms of increased ICP is mandatory for its management. In the normal state, a variation of volume of any of the intacranial constituants [brain substance, cerebrospinal fluid (CSF), arterial and venous blood] is accompanied by an inverse change of the others, so that the total volume and the pressure remain constant. As soon as the compensation mechanisms are outrun, the ICP measured as the ventricular fluid pressure will increase. The relationship between volume and pressure increases is represented by the compliance curve of the intracranial contents. Continuous measurement of ICP is mainly done by two methods : catheterization of a ventricle which allows CSF removal for drainage or analysis and testing of the cerebral compliance (by addition or subtraction of one ml of fluid and noting the change in pressure); recording the extradural pressure, which entails less risk of infection, but does not allow CSF removal and may over-read the intraventricular pressure. The nomrla ICP lies between 10-15 mm Hg (15-20 cm H2O). The recognition of abnormal ICP waves is important : Lundberg first described the large A or plateau waves (50-100 mm Hg), accompanied by clinical signs of cerebral hypertension; there are also B waves (up to 50 mm Hg), less significant, usually accompanying a decrease of wakefulness, and C waves seemingly correlated with Traube-Hering-Mayer waves of the blood pressure. ICP may be increased due to disease (tumor, hematoma, edema, CSF blockage or benign cerebral hypertension) or iatrogenic (increased cerebral blood flow with vasodilatation during hypoxia, hypercarbia and anesthesia with most halogenated anesthetics; impaired venous drainage : coughing, straining, positive pressure ventilation with PEEP, etc.). In conclusion, ICP monitoring is a useful tool in neuroanesthesia and in neurological intensive care and in association with other methods of investigation like cerebral blood flow and metabolic rate measurement, CAT scanning, will be contributive in evaluating new treatments. |
