[When and how to start sedation in a neuro-intensive care patient?]. / Quand et comment débuter une sédation en neuroréanimation ?

Sedatives drugs are part of the everyday care in the neuro-ICU. Reasons to sedate patients in neuro-ICU are as usual to ensure the comfort and to secure the patients, to permit nursing as well as to permit adaptation to the ventilator. But some objectives are specific in neuro-ICU as optimisation of cerebral haemodynamics and oxygenation, and to avoid a convulsive state or a dysautonomic syndrome. Starting the sedation usually necessitate a tracheal intubation and mechanical ventilation. Patients presenting with intracranial hypertension are at risk of developing cerebral ischaemia in case of cerebral haemodynamics alteration associated with anaesthetic drugs injection. Morphinomimetics increase intracranial pressure (ICP), but cerebral perfusion pressure and oxygenation (CPP) remain usually unaltered. Injection of an intravenous bolus of thiopental or propofol lowers ICP and CPP, but also the cerebral tissular oxygen consumption: the cerebral oxygenation seems therefore protected. The succinylcholine used for emergency tracheal intubation has no effect on the cerebral haemodynamic. Some more studies are needed to better understand the cerebral oxygenation at the local level when sedative drugs are injected or perfused in patients with intracranial hypertension.

Difficult endotracheal intubation as a result of penetrating cranio-facial injury by an arrow.

UNLABELLED: Penetrating injury of the face and airway may make endotracheal intubation difficult or impossible. We report the case of a patient who attempted to commit suicide with a crossbow. Surgery under general anesthesia was required to remove the arrow. The oral intubation route was impossible, and a fiberoptic nasal intubation under local anesthesia was performed. IMPLICATIONS: We report a case of a 42-yr-old patient who underwent surgery for a penetrating craniofacial injury caused by an arrow. Because of the median vertical trajectory of the arrow (from the chin to the frontal skull), only the right nasal approach was accessible for endotracheal intubation. Fiberoptic nasal intubation and securing the airway under local anesthesia are described.

[Diagnosis of status epilepticus by continuous EEG monitoring in a neurointensive care unit]. / Le diagnostic des états de mal épileptique par le monitorage de l'EEG en neuroréanimation.

Continuous EEG monitoring use has documented a surprisingly high incidence of convulsive and non-convulsive status epilepticus in patients with acute brain injuries. Seizures are the cause of secondary insult. Many problems may be encountered during EEG recording, such as electrical interferences and artefacts arising from the patient. To minimise these problems, we suggest the following: train the bedside nurse, make a library of the artefacts, have the EEG technologist check electrodes and establish low impedance, have the electroencephalographer examine the EEG, correlate the activity and movements of the patient. In the diagnosis and the management of convulsive and non-convulsive status epilepticus, the value of continuous EEG monitoring appears to be established.

[Functional neurosurgery for epilepsy]. / La chirurgie fonctionnelle de l'épilepsie.

Introduced at the end of the last century, epilepsy surgery is indicated in patients with intractable partial seizures and based on the resection of the epileptogenic cerebral tissue from which ictal discharges originate. Palliative procedures include seizure spread pathways interruption (callosotomy, multiple subpial transections) and chronic stimulation of the vagus nerve. Complete preoperative investigations including seizure observation, clinical tests, video-EEG, MRI and functional MRI, and PET-scan are performed in order to identify the epileptogenic zone. In difficult cases, invasive seizure monitoring through depth electrode implantation (SEEG) is performed. Resections for temporal lobe seizures are associated with favorable outcome: 60 to 90% of patients will be seizure-free after surgery. A less favorable outcome is observed after extra-temporal resections: 40 to 60% seizure-free patients. A better outcome is observed after surgery for epilepsy associated with an image-defined lesion, most often a tumor, rather than for cryptogenic epilepsy. Tumors associated with chronic partial epilepsy are indolent, most of them are dysembryoplastic neuroepithelial tumors (DNET). Outcome after palliative procedures are more variable, depending on the etiology of epilepsy.

Continuous jugular bulb venous oxygen saturation validation and variations during intracranial aneurysm surgery.

PURPOSE: During intracranial aneurysm surgery, numerous factors may alter cerebral blood flow and oxygen supply-demand balance. Continuous monitoring of jugular bulb venous oxygen saturation (SvjO2) may help in the anesthetic management of such procedures. MATERIALS AND METHODS: Fiberoptic SvjO2 was continuously monitored in seven patients during intracranial aneurysm surgery. Fiberoptic SvjO2 measurement was compared with IL3 CO-OXIMETER determination from 85 paired samples. The occurrence of large SvjO2 variations (SvjO2 variation reaching 10% or more of stable preceding value) during aneurysm surgery was recorded and classified according to the association or not with systemic clinical or therapeutic changes. RESULTS: Fiberoptic SvjO2 showed a limited accuracy, with limits of agreement with IL3 CO-OXIMETER at -16.8% and +10.7% and a small bias (-3.1%). SvjO2 variations were frequent during aneurysm surgery, ranging from 3 to 22 per patient during procedures lasting 6 hours (range 4.5 to 7). Half of these variations occurred in the absence of any systemic clinical or therapeutic change, most often leading to an increased SvjO2. CONCLUSIONS: Although the accuracy of fiberoptic SvjO2 determination is limited, it allows the detection of cerebral blood flow and oxygen supply-demand imbalance during aneurysm surgery. The frequent occurrence of SvjO2 elevations is suggestive of reactive hyperemia mechanisms.

Intra-operative monitoring of the facial nerve with an air inflated balloon. Technical note.

A simple, reliable and cheap device for intra-operative monitoring of the facial nerve during surgery for cerebellopontine angle tumours is presented. It consists of a single use tracheostomy tube with a low pressure air inflatable cuff placed in the mouth of the patient on the side of the tumour, connected by a pressure transducer to a monitoring unit. It records any pressure changes in the patient's mouth induced by muscular contractions as a result of excitation of the inferior parts of the facial nerve.

MRI in multiple vascular lesions: identification of the ruptured malformation.

4 patients were recently admitted for subarachnoid haemorrhage with multiple vascular lesions. 3 of them presented with multiple aneurysms, and one with an aneurysm associated with an arteriovenous malformation. In these 4 cases identification of the ruptured lesion was difficult in spite of clinical examination, CT scan, and complete panangiography; on magnetic resonance imaging (MRI) was found a signal hyperintensity, mainly on T2 weighted views, corresponding to blood clots around the ruptured aneurysm. This signal hyperintensity was completely absent in the vicinity of the associated vascular lesion, which appeared only as a signal void corresponding to the blood flow inside the unruptured lesion. Therefore MRI can be used in such cases to identify the ruptured lesion, so permitting the choice of the best approach and strategy of treatment.

[Value of the measurement of cerebral blood flow before and after diamox injection in predicting clinical vasospasm and final outcome in aneurysmal subarachnoid hemorrhage]. / Intérêt de la mesure du débit sanguin cérébral avant et après injection de diamox dans la prédiction du vasospasme clinique et du résultat clinique final des hémorragies méningées anévrysmales.

The timing for surgery on ruptured intracranial aneurysms remains a difficult question and the choice of the day of operation depends greatly from the occurrence of a vasospasm. On a previous paper, the value of the cerebral blood flow (CBF) measurement by intravenous injection of Xenon 133 was demonstrated to be efficient for the prediction of vasospasm only when done between day 4 and day 8 after bleeding. Moreover the efficiency of the measurement was much greater if the evolution of the CBF values between D0 and D8 was considered, but this method was incompatible with early surgery. It suggested the interest of a dynamic study of the CBF by the same method. On a series of 43 patients, the comparison between basal CBF values and reactivity of CBF values to intravenous injection of 1 gram of acetazolamide for the prediction of clinical vasospasm is presented. The series comprises 32 early admitted patients (74%) and 31 operated patients (16 of them between D0 and D3 after bleeding, 15 others after D4). The efficiency of the CBF reactivity study for the prediction of the clinical vasospasm appears much greater than that of the basal CBF value, even during the first three days after bleeding, but not for the prediction of the final clinical outcome. The method is immediate and compatible with early surgery. What precisely is evaluated by this method on the physiopathology of the vasospasm remains disputable, but the operability of the patients seems to be explored.

[Evaluation of cerebral blood flow in severe brain injuries by SVO2 measurement in the internal jugular vein]. / Evaluation du débit sanguin cérébral des traumatisés crâniens graves à partir de la mesure de la SVO2 dans le golfe de la jugulaire interne.

The purpose of the present study was to assess the value of jugular oxyhemoglobin saturation percent (SvO2) in predicting cerebral blood flow (CBF). SvO2 and CBF were measured in 25 adults with acute brain trauma (Glasgow Coma Scale < 8). From the data a classification of CBS and SvO2 was developed: in the first group of patients the presence of cerebral ischemia could be identified in the presence of low CBF (< 40 ml/min/100g) and a low SvO2. In the second group he CBF is closely coupled to and regulated by the cerebral metabolic rate of oxygen (CMRO2) and values of SvO2 are intermediate. In the third group hyperaemia was defined as both an increase of SvO2 and CBF (> 60ml/min/100g) and a decrease of CMRO2. The SvO2 was measured in 18 of these 25 patients following 1) intravenous infusion of mannitol (1 g.kg-1) and hyperventilation (PCO2 = 3.4 kPa). The data suggest that there is no correlation between SvO2 and CBF, but a reliable estimates of CBF may be made from SvO2 measurement after mannitol and hyperventilation.

[Hemodynamic and metabolic effects of thiopental in patients with severe head injuries]. / Effets hémodynamiques et métaboliques du thiopental chez le traumatisé cranien grave.

The effect of pentobarbital was evaluated in 12 comatose brain injured patients (Glasgow coma scale < 7 at admission). Mean hemispheric cerebral blood flow (CBF) was studied following intravenous administration of 133Xenon. The results indicated a decrease in CBF, mean arterial pressure (MAP), intracranial pressure (ICP) and cerebral metabolic rate of oxygen (CMRO2). The increase in cerebral perfusion pressure (PP) was found only in patients with diffuse brain injury. The results supports the hypothesis that barbiturate therapy is more effective at reducing ICP while preserving CPP when the cause is a diffuse lesion.

[Calcium inhibitors: effects on cerebral blood flow and intracranial pressure]. / Anti-calciques: effets sur le débit sanguin cérébral et sur la pression intracrânienne.

Calcium entry blockers (CEB) have been a major advance in pharmacologic research in the last decade, especially in cardiovascular diseases. In neurology and intensive care, prescription of CEB seems to be more selective. CEB are potent cerebrovascular vasodilating drugs especially after KCL induced vasoconstriction. This property appears less evident when vasoconstriction is achieved by agonist substances. CEB act selectively on cerebral vessels, an effect which prevents the occurrence of systemic arterial hypotension. However they greatly modify the cerebrovascular response to arterial CO2. Concerning the cerebrovascular response to arterial CO2. Concerning their potential benefits in brain ischemia, it is now well admitted that CEB are useful in subarachnoid hemorrhage. Several controlled and uncontrolled human studies have demonstrated the CEB potency in vasospasm prevention and in cerebral ischemic consequences. Nonetheless when the vasospasm is installed, the benefit of the CEB appears less evident. In focal cerebral ischemia, data are few and unclear suggesting a cautious prescription of CEB. Finally CEB seem to increase intracranial pressure in humans, although this effect depends on the underlying neurologic pathology.

[Feasibility of calcium inhibitors in the treatment of brain disease following cardiac arrest]. / Possibilités des inhibiteurs calciques dans le traitement de l'encéphalopathie post-arrêt circulatoire.

One of the crucial factors affecting mortality and morbidity after circulatory arrest the ischemic neuronal damage following complete cessation of cerebral blood-flow. To date, no accepted pharmacologic neuroprotective therapy has emerged. Cerebral ischemia causes a rapid shift of Ca++ from the extracellular spaces into cells and it is assumed that this excessive entry of Ca++ is the final pathway of cell death. In addition, Ca++ is involved in the diffuse vasospasm which occurs after global cerebral ischemia. Therefore, calcium entry blockers such as dihydropyridines derivatives have sparked considerable interest especially because of their preferential cerebrovasodilating effects. In vivo studies have demonstrated protection from brain ischemia with calcium entry blockers. However no direct protective effect of these drugs has been shown on neurons. More recent results have underscored the importance of excitatory amino acid neurotransmitters and receptors (particularly N-Methyl-D-Aspartate receptors) in causing intracellular calcium overload and neuronal death after ischemia. Blockade of these receptors or their associated channels may be an interesting way to protect the brain against ischemic damage.

[Clinical tolerance of CY 216 (Fraxiparin) in the prevention of thromboembolic accidents after neurosurgery]. / Etude de la tolérance clinique du CY 216 (Fraxiparine) dans la prévention des accidents thrombo-emboliques au décours de la neuro-chirurgie.

Clinical tolerance of CY 216 was assessed on 97 patients in two neurosurgical departments (Hopital Lariboisière and Hopital Beaujon, Paris). All the 97 patients were operated on by different cranial approaches, but always including bone flap. No thrombo-embolic event could be detected in this series. Post-operative intracranial hemorrhage was observed in 19 cases on the basis of CT scan performed on the first and seventh post-operative day. Among these 19 patients, 8 presented an increase of the hemorrhagic aspect between the 2 CT scan. However, clinical state of these patients improved and no reoperation was necessary to treat these hemorrhages. From this study, we consider that CY 216 is an effective mean of thrombo-embolism prevention with little hemorrhagic side-effect. Therefore, it can be recommended in the aftermath of intracranial surgical procedures.

Vascular abnormalities in the neck associated with intracranial aneurysms.

In 102 cases of ruptured intracranial aneurysms, the cervical as well as the cranial areas were explored by angiography. Loops in the course of the cervical vessels were present in 28 patients; features of fibromuscular dysplasia were present in 31 patients; and in 50 patients, no abnormalities were observed. In 7 patients, both cervical anomalies were present. Loops were associated with single aneurysms (95%), located primarily on the anterior communicating artery (76%), predominantly in men (M/F = 1.6). Aneurysms with fibromuscular dysplasia affected women more than men (F/M = 7), were frequently multiple (58%), and were located mainly on the intracranial part of the internal carotid and vertebral arteries (51%). These data suggest new concepts of aneurysm formation from inherited diseases and should permit the detection of some aneurysms before rupture.

[Criteria for brain death: cessation of cerebral circulation demonstrated by Doppler ultrasonography of the carotid arteries]. / A propos des critères de la mort cérébrale: l'arrêt de la circulation cérébrale mis en évidence par le Döppler carotidien.

If human death is defined by brain death, its diagnosis needs medicolegal criteria based on clinical examination and EEG. However, this evaluation could be difficult because technical or physiological limitations might impair the interpretation, especially after barbiturates and/or hypothermia. Since brain death is characterized by an intracranial circulatory arrest, methods assessing this phenomenon are warranted. Among these methods, conventional or isotopic cerebral angiography appears the most promising, but it cannot be easily performed everywhere. Because superficial blood flow in arteries is now accurately measured by the pulsed Döppler technique, this prompted us to test the specificity and sensitivity of common carotid blood flow data for brain death diagnosis. Two series of age-matched patients (36 yrs in mean) were studied. Series 1 (n = 28) was used to define the discriminant parameters between 14 severe coma patients and 14 brain-dead patients diagnosed by the classical criteria. Then these parameters were prospectively tested in a blind manner on a second series of 28 patients suffering from severe coma. The parameters allowing us to classify patients as brain dead or not with a 100% specificity and sensitivity were: end diastolic blood flow (QED in ml/min), end diastolic blood flow velocity (VED), and cerebral metabolic index (CMI = QED x AV D 02). The most powerful discriminant parameter was QED, allowing a strictly non-invasive diagnosis of brain death.

[Value of the measurement of cerebral blood flow in choosing the operative time of ruptured intracranial aneurysm]. / Intérêt de la mesure du débit sanguin cérébral dans le choix de la date opératoire des anévrysmes intracrâniens rompus.

The authors report a series of 135 patients treated between 1984 and 1987, for a ruptured intracranial saccular aneurysm in the Department of Neurosurgery at the Lariboisiere Hospital. The value of C.T. scan and cerebral blood flow measurements (C.B.F.) in predicting the development of vasospasm was studied on 99 cases. The analysis confirmed that the C.T. Scan findings are closely related to vasospasm. A low C.B.F. between the fourth and the eight day following the bleeding was significantly associated with the development of delayed cerebral ischaemia. On the contrary, no relation was found between vasospasm and the C.B.F. measured during the three days following the bleeding. The authors propose to operate without delay on clinical grounds on patients referred during the first three days after the hemorrhage and to decide, on clinical and C.B.F. data, the timing of the intervention for patients admitted after this data, i.e. 35% of their patients.