Inclusion Criteria:  Circulatory support by veno-arterial ECMO for cardiogenic shock; Presence of severe respiratory distress; Presence of dyspnea ≥ 40 mm on a visual analogue scale of dyspnea (VAS-dyspnea) Decision by the clinician in charge of the patient to either modify the ECMO parameters or to administer non-invasive ventilation in order to decrease the intensity of the dyspnea; presence of an arterial catheter; : RASS score between 0 and +1 ; Absence of delirium on the CAM-ICU score; being socially insured.  Exclusion Criteria:  patient unable to express opposition; protected minor or adult patient; pregnant woman; double veno-arterial ECMO; central ECMO; left ventricular assist or long-term bi-ventricular assist