RESUMEN
Bolus injections of lidocaine are commonly used during neuroanesthesia to prevent or treat ICP elevations caused by tracheal or painful stimuli. Lidocaine can also be employed in case of hard intracranial hypertension, when the usual therapy fails. With continuous perfusion, at high doses, of this agent, a state of lidocaine anesthesia can be induced which is more readily reversible than barbiturate anesthesia. A simultaneous anticonvulsant therapy is mandatory because of the well-known epileptogenicity of lidocaine. Closed cardiovascular monitoring is also needed to detect early signs of cardiotoxicity. Experimental works point to the effectiveness of i.v. lidocaine to prevent ischemic lesions secondary to a cerebral artery occlusion. This protective effect may result from some properties exhibited by lidocaine and not by thiopental: stabilisation of transmembrane ionic fluxes, inhibition of leucocytes intravascular sticking and tissular migration. So, i.v. lidocaine seems help to preserve or improve cerebral perfusion pressure and in cases when the latter decrease below the critical threshold, to protect against cerebral ischemia.
Asunto(s)
Anestesia Intravenosa/métodos , Isquemia Encefálica/tratamiento farmacológico , Lidocaína/uso terapéutico , Neurocirugia , Seudotumor Cerebral/tratamiento farmacológico , Resucitación , Humanos , Presión Intracraneal/efectos de los fármacos , Lidocaína/farmacologíaRESUMEN
Ischemic cerebral edema frequently develops after aneurysm surgery and may lead to severe intracranial hypertension. Of prime importance are reducing the level of ICP and preserving oligemic areas from becoming infarcted. Besides correction of factors known to worsen intracranial hypertension, several therapeutics may be of value: external CSF drainage, perfusion of mannitol, induced arterial hypertension and use of anesthetic agents with cerebral vasoconstricting capability. Hyperventilation is not recommended. Arterial hypotension and hypovolemia certainly contribute to aggravate cerebral ischemia and must be corrected. Cerebral ischemia may be reduced by two specific approaches: by improving cerebral oxygen transport in ischemic areas using arterial hypertension and calcium blockers rather than hemodilution or hypervolemia; by reducing cerebral metabolic rates with heavy anesthesia under the cover of a complete cardiovascular monitoring. In view of the large heterogenicity in cerebral lesions and physiopathological stages, a therapeutical trial appears suitable in each individual case. Criteria allowing to know if any therapeutic, used alone or in association, is beneficial include increase in blood flow in ischemic areas, reduction of ICP level and normalizing of indices like CSF or venous jugular blood lactate.
Asunto(s)
Edema Encefálico/terapia , Aneurisma Intracraneal/cirugía , Seudotumor Cerebral/terapia , Presión Sanguínea , Edema Encefálico/etiología , Isquemia Encefálica/prevención & control , Derivaciones del Líquido Cefalorraquídeo , Humanos , Presión Intracraneal , Manitol/uso terapéutico , Monitoreo Fisiológico , Complicaciones Posoperatorias , Seudotumor Cerebral/etiologíaRESUMEN
A controlled double-blind evaluation of the effects of Dextran 40 at different concentrations on cerebral blood flow (CBF), cerebral oxygen consumption (CMRO2) and cerebral lactate production (CMRLact) was carried out. We studied 40 patients in coma due to recent head injury. Concentrations of Dextran solution were not significantly related to variations in CBF and metabolic rate over the period of infusion. The lack of effect of the Dextran infusion may be explained by the absence of global brain ischemia in these patients at the time of the study. The very low initial CBF values were a consequence of brain metabolic depression and not a sign of global ischaemia. The rheological benefits of treatment with Dextran 40 in head injured patients should preferably be investigated using techniques which permit detection of local changes in CBF and metabolism.
Asunto(s)
Lesiones Encefálicas/tratamiento farmacológico , Circulación Cerebrovascular/efectos de los fármacos , Dextranos/uso terapéutico , Adolescente , Adulto , Anciano , Isquemia Encefálica/tratamiento farmacológico , Ensayos Clínicos como Asunto , Dextranos/sangre , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Humanos , Lactatos/biosíntesis , Persona de Mediana Edad , Consumo de Oxígeno/efectos de los fármacosAsunto(s)
Hematoma Epidural Craneal/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Adulto , Angiografía Cerebral , Femenino , Estudios de Seguimiento , Hematoma Epidural Craneal/mortalidad , Hematoma Epidural Craneal/cirugía , Humanos , Masculino , Índice de Severidad de la Enfermedad , Factores de TiempoAsunto(s)
Lesiones Encefálicas/diagnóstico por imagen , Presión Intracraneal , Espacio Subaracnoideo/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Edema Encefálico/diagnóstico por imagen , Lesiones Encefálicas/fisiopatología , Hemorragia Cerebral/diagnóstico por imagen , Hemorragia Cerebral/fisiopatología , Humanos , Monitoreo FisiológicoAsunto(s)
Isquemia Encefálica/etiología , Enfermedades de las Arterias Carótidas/cirugía , Circulación Cerebrovascular , Endarterectomía/efectos adversos , Homeostasis , Presión Intracraneal , Monitoreo Fisiológico , Enfermedades de las Arterias Carótidas/complicaciones , Constricción Patológica , Humanos , Estudios Retrospectivos , RiesgoRESUMEN
The advantages of the sitting position for neurosurgery of the posterior fossa are evident and universally admitted. However, respiratory and haemodynamic consequences make this position uncommon and even exceptional for the old patient whose existing physiological cardiovascular and pulmonary disturbances may result in greater risks. In this study, the complications observed during and after surgery in twenty-two patients over 65 years are analysed. These patients underwent functional neurosurgical procedures in sitting position. According to the results, old age does not appear to be an absolute contra-indication of the sitting position for this type of surgery.