The goal of this clinical trial is to evaluate a minimum viable prototype for automated closed-loop administration of propofol in deep sedated patients under invasive mechanical ventilation in the ICU. The main question it aims to answer is:

• whether the minimum viable prototype for automated closed-loop administration of propofol is effective in keeping patients in deep sedation using the lowest possible dose of propofol Participants will undergo deep sedation using the minimum viable prototype for automated closed-loop propofol administration.

The usual practice of sedation will be compared with the practice of sedating with the minimum viable prototype to see if the infusion rate of propofol is decreased

The design of the study will consist of each patient being exposed to both forms of administration (matched pair study) during a 12-hour day (8:00 a.m. to 8:00 p.m.) in a randomized manner. Specifically, a patient will be given propofol infusion in open-loop mode in the first 5 hours (8:00 a.m. to 1:00 p.m.) and the next 5 hours in closed-loop mode (3:00 p.m. to 8:00 p.m.) with a wash-out period of 2 hours. The order will be randomly determined for each patient. This design will allow the use of the prototype to be evaluated under highly controlled conditions by a trained operator dedicated exclusively to this function.

Inclusion Criteria:

• Indication of deep sedation for more than 48 hours

Exclusion Criteria:

• Dementia
• Cranial surgery
• Hypoxic-ischemic encephalopathy
• Chronic liver damage Child C
• History of substance and drug abuse that can alter EEG recordings or the metabolization of drugs (antipsychotics, cocaine, benzodiazepines, opioids)
• Pregnant women
• allergic to propofol
• EEG sensor of the BIS® Covidien cannot be installed