Sleep Quality in Intensive Care Unit Patients at High Risk of Extubation Failure

Inclusion Criteria: * Intensive care units patients intubated for at least 24 hours with at least on of the four following risk factor : aged of 65 years or more, any underlying chronic cardiac or lung disease, mechanical ventilation for more than 7 days. * aged of 18 years or more Exclusion Criteria: * peripheral or central nervous system pathology * known psychiatric pathology or agitation * patient with decision of no reintubation * patient refusal * clinical worsening before polysomnography ( shock with vasopressors drugs, coma, PaO2/FiO2 ratio \< 150 with respiratory distress signs, coma with Glasgow scale \<8) * pregnant or breastfeeding women * patient under legal guardianship or protection * patient with no health insurance coverage * aged \< 18 years