Inhaled Sedation in Critically Ill Patients

Who can take part

• Adult patients receiving mechanical ventilation, with an anticipated duration >48 hours after randomization, and requiring deep sedation (target RASS between -3 and -5)

Who cannot take part

• Patients expected to require repeated surgical interventions during their ICU stay
• Allergy to isoflurane or propofol
• Acute neurological condition
• Neuromuscular disease or high spinal cord injury likely to prevent discontinuation of mechanical ventilation due to baseline condition
• Any condition (e.g., blindness, deafness, dementia) or language barrier that prevents the administration of delirium or cognitive assessment scales
• History of ventricular tachycardia or long QT syndrome
• Contraindication to isoflurane or propofol
• Patients with maternal ancestry from Venezuela, due to the potential presence of an mt-ND4 gene mutation associated with neurological injury after exposure to certain volatile anaesthetic agents
• Significant air leak, defined as a leak exceeding 30% of the delivered minute ventilation
• Cardiopulmonary arrest
• Tidal volume < 300 mL or PaCO₂ > 50 mmHg at the time of randomization
• Invasive mechanical ventilation for more than 48 hours at the time of randomization
• Pregnancy
• Breast feeding
• ECMO
• ECCO2R
• Active humidification strictly required
• Requirement for benzodiazepine use for a specific indication
• Burns
• Life expectancy less than 48 hours, or patients with such a level of severity that death during the ICU stay is considered highly likely
• Lack of informed consent