Opioid-free Analgesia in Intensive Care Unit

Inclusion Criteria: * Patient hospitalized in ICU and requiring sedation-analgesia for mechanical ventilation. * Patient undergoing mechanical ventilation for more than 2 hours and less than 24 hours. * Informed consent signed by the patient or his trusted person, legal representative, family member, curator or tutor, or emergency consent procedure. * Patient affiliated to the French Government Public Health Insurance. * Patient over 18 years old. Exclusion Criteria: * Patient already involved in a trial that might influence our primary endpoint. * Patient in exclusion-period determined by another trial or study. * Patient who is likely to be requiring less than 48 hours of mechanical ventilation. * Patient with contraindication or allergies to at least one of the following medication : paracetamol, nefopam, tramadol, ketamine, remifentanil. * Patient with hepatic insufficiency (defined as PT \< 50%). * Parturient or breast-feeding patient. * Patient suffering from moderate to severe Acute Respiratory Distress Syndrome (ARDS), with decreased PaO2/FiO2 ratio under 150mmHg after respiratory optimization (courant volume 6mL/kg and PEEP \> 5mbar). * Patient requiring curare treatment. * Patients with an indication for locoregional analgesia prior to extubation (perineural sealing, epidural analgesia).