[Anaesthesia for patients with intracranial hypertension due to cerebral oedema]

The role of nitrous oxide in stroke

Stroke that is caused by poor blood flow into the brain results in cell death, including ischemia stroke due to lack of blood into brain tissue, and hemorrhage due to bleeding. Both of them will give rise to the dysfunction of brain. In general, the signs and symptoms of stroke are the inability of feeling or moving on one side of body, sometimes loss of vision to one side. Above symptoms will appear soon after the stroke has happened. If the symptoms and signs happen in 1 or 2 hours, we often call them as transient ischemic attack. Moreover, hemorrhagic stroke often leads to severe headache. It is known that neuronal death can happen after stroke, and it depends upon the activation of N-methyl-D-aspartate (NMDA) excitatory glutamate receptor which is the goal for a lot of neuroprotective agents. Nitrous oxide was discovered by Joseph Priestley in 1772, and then he and his friends, including the poet Coleridge and Robert Sauce, experimented with the gas. They found this gas could make patients loss the sense of pain and still maintain consciousness after inhalation. Shortly the gas was used as an anesthetic, especially in the field of dentists. Now, accroding to theme of Helene N. David and other scientists, both of nitrous oxide at 75 vol% and xenon at 50 vol% could reduce ischemic neuronal death in the cortex by 70% and decrease NMDA-induced Ca²⁺ influx by 30%. Therefore, more clinical and experimental studies are important to illuminate the mechanisms of how nitrous oxide protects brain tissue and to explore the best protocol of this gas in stroke treatment.

[Anesthesiological aspects and complications of intracranial meningiomas operated at the Sylvanus Olympio University Hospital Center, Lomé: about 21 cases]

This study aimed to point to both the anesthesiological aspects and the perioperative complications of intracranial meningiomas operated at the Sylvanus Olympio University Hospital Center, Lomé. We conducted a retrospective study by reviewing the medical records of patients with intracranial meningiomas undergoing surgery over the period December 2010-December 2015 (5 years) at the Sylvanus Olympio University Hospital Center, Lomé. Out of 46 patients operated fo brain tumors, 21 (45.6%) had meningioma. The average age was 49 ±20 years, with a male predominance (52.4%) and a sex ratio (M/F) of 1.1. Patients were classified according to ASA classification: 16 patients were classified as ASA II, 4 patients as ASA III and 1 patient as ASA IV. Patients underwent total intravenous anesthesia using hypnotic agent such as propofol (100%) and fentanyl (76.2%), which was the most available opioid. Perioperative complications were: bleeding, (mean blood loss: 1750 ±584 ml), hypotension (mean arterial pressure (MAP) < 60 mmHg) in 10 (47.6%) patients; hemorrhagic shock in 2 (9.5%) patients, cardiovascular arrest: 01 (4.7%) patient successfully resuscitated. Postoperative complications were: convulsions in 5 (23.8%) cases, hyperthermia in 4 (19%) cases, hemorrhagic shock in 2 (9.5%) cases, death in 2 (9.5%) cases. Perioperative morbidity and mortality associated with intracranial meningioma surgery at the Sylvanus Olympio University Hospital Center, Lomé remains high. Improvement of technical equipment and early consultation should reduce these complications.

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.

Le propofol et l'AIVOC en neuro-anesthésie

Propofol is an intravenous anaesthetic agent, which presents interesting features for its use in neuro-anaesthesia: it is a powerful hypnotic that does not increase the intracranial pressure. The delay of recovery is short even after several hours of continuous infusion. This is essential for a fast neurologic examination. Continuous infusion should be preferred to bolus in order to prevent hypotension and decrease of the cerebral perfusion pressure. Target-controlled infusion models based on effect site concentrations are now available through several softwares. This technique appears especially useful for awake craniotomy and functional neurosurgery. The level of consciousness is easily fixed between deep anaesthesia and light sedation permitting to ask the patient to move following orders. A sedation controlled by the patient himself is even possible.