Comparison of an Inhaled Sedation Strategy to an Intravenous Sedation Strategy in Intensive Care Unit Patients Treated With Invasive Mechanical Ventilation

The objective of the study is to determine the impact on the frequency of occurrence of delirium of an early inhaled sedation strategy (from induction in rapid sequence if intubation in intensive care, or from admission if intubated in pre -hospital) by Isoflurane using an ANACONDA ™ type system, compared to a conventional intravenous sedation strategy.

Inclusion Criteria: * Patient aged 18 and over * Patient requiring mechanical ventilation for at least 24 hours * The patient requires continuous and immediate sedation for more comfort, safety and to facilitate the administration of survival measures. * Consent obtained from patient or relative Exclusion Criteria: Patient hospitalized for the following reasons for admission: * Cardiac arrest * State of refractory epilepticus * Head trauma * Stroke * Hearing, visual or aphasia disorders before inclusion making it impossible to take the CAM-ICU * Sedation started more than 24 hours ago * Impairment of cognitive functions and / or dementia * Contraindication to halogenated gases (personal or family history of malignant hyperthermia, acute or chronic neuromuscular disease, hepatocellular insufficiency with PT \