Inclusion Criteria:  Mechanical ventilation : invasive for at least 48 hours or non-invasive for at least 24 hours, sequential or continuous Dyspnea ≥ 4 on a visual analogic scale (VAS) from 0 to 10 Absence of delirium (evaluated by the CAM-ICU score) ; Communicative patient  Exclusion Criteria:  Patients on ECMO or decarboxylation ; Patients on long-term left ventricular support; Patients postoperatively following any surgery (pain from the procedure may interfere with dyspnea); Protected minors and adults; Pregnant women.