Use of Ketamine Associate With an Opioid for Sedation in ICU

All consecutive mechanically ventilated patients admitted in the ICU will be randomized to receive an infusion of 0.15 mg/kg/h of kétamine or placebo. Nurses and physicians will be blinded of the allocation arm. The infusion of ketamine will be stopped as soon as remifentanil will be discontinued by the physician.

to evaluate the impact of ketamine associated to an opioid for sedation of mechanically ventilated critically ill patients versus placebo. Sedation will be drive by nurses according to an algorithm. The investigators will evaluate the quantity of opioates used in each arm and the safety of ketamine.