Evaluation of the Safety of Inhaled Sedation With Isoflurane in Head Trauma Patients

Inclusion Criteria: * Patient \> 18 years old * Hospitalized in surgical intensive care (CPR and RNC) for severe head trauma * On intravenous hypnotic therapy for at least 24 hours with at least 2 lines of IV hypnotics and requiring continued sedation for at least 24 hours, with a RASS of between -3 and -5 * Initial ICP \< 15 mmHg on introduction of isoflurane * Functional intracranial pressure sensor * Transcranial Doppler measurements performed within 24 hours * Written informed consent from a legal representative/relative/trusted person. In the absence of a legal representative, the patient may be included under the emergency procedure. Exclusion Criteria: * Patients who have had a decompressive craniectomy * Patients with a personal or family history of malignant hyperthermia * Patients with a history of long QT syndrome * Patients taking MAOI-type antidepressants (iproniazid (MARSILID) and moclobemide (MOCLAMIDE)) * Patients with known hypersensitivity to isoflurane or other volatile halogenated anaesthetic agents * Patients who have experienced liver damage, jaundice, unexplained fever, or eosinophilia after administration of a halogenated anaesthetic. * Patients expected to die within the next 24 hours * Subject in a period of exclusion from another clinical trial, * Technical unavailability of the inhaler * Persons covered by articles L1121-5 to L1121-8 of the CSP (corresponding to all protected persons: pregnant women, women in childbirth, nursing mothers, persons deprived of their liberty by judicial or administrative decision, persons subject to a legal protection measure). * No European social security