The purpose of this study is to test the association between ICU acquired weakness as evaluated by dominant handheld dynamometry (handgrip) and the mechanical ventilation weaning outcome

Previous studies have evidenced that Intensive Care Unit acquired peripheral muscle weakness may lead to delayed mechanical ventilation weaning (i.e difficult or prolonged weaning according to guidelines). Nevertheless, no study has ever tested the association between handgrip strength and extubation outcome. The investigators have generated the hypothesis that ICU acquired weakness, as tested by handgrip strength might be associated with extubation outcome. The investigators have planned to include 240 patients. Handgrip strength will be monitored, along with a full muscular assessment through Medical Research Council score by the attending physiotherapist. Physicians in charge of the patients will be blinded to these values and the weaning protocol will continue according to guidelines.

Inclusion Criteria:

• adult patients
• under mechanical ventilation for at least 48 hours
• meeting readiness to wean criteria according to international guidelines
• with social security
• informed consent given by the patient or a proxy

Exclusion Criteria:

• baseline pre existing rheumatologic or neurologic condition preventing the patient to use the tested device
• confusion (as assessed by Confusion Assessment Method for the Intensive Care Unit )
• Patients whose extubation is a terminal extubation, or with prior decision not to resort a reintubation in case of post-extubation respiratory distress.
• known pregnancy
• Inability to deliver clear patient information (language barrier without an interpreter, for example)
• Participation in another intervention research