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Biomedical subjects

R Deleuze

Publications and source records attributed to R Deleuze.

At least 19 recordsLinked to original sources

[Use of intravenous lidocaine in neuro-anesthesia and neuro-resuscitation].

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.

Anesthesia, Intravenous↗

[Treatment of ischemic cerebral edema with intracranial hypertension after neurosurgery of intracranial aneurysms].

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.

Blood Pressure↗

A controlled study of Dextran 40: effect on cerebral blood flow and metabolic rates in acute head trauma.

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.

Adolescent↗

[Complications related to the seated position of the aged patient in neurosurgery].

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.

Aged↗