Non-invasive Ventilation and High-speed Oxygen Therapy Effects on Heart Function - HiFlow-Heart Study

Inclusion criteria

• Major patient
• Patient who has undergone cardiac surgery with extracorporeal circulation for more than 24 hours and has been extubated for at least 6 hours.
• Pre-operative heart failure with left ventricular ejection fraction \< 40%.
• Invasive monitoring by pulmonary arterial catheter (Swan-Ganz) with transpulmonary thermodilution and by radial arterial catheter intended for use in the intra- and post-operative monitoring of the patient.
• Treatment with conventional oxygen therapy (O2C) without an increase in O2 flow for more than 30 minuts, without signs of hypoxemia (SpO292%)
• Stable hemodynamic parameters: no changes in hemodynamic parameters (arterial pressures and pulmonary and cardiac index) by more than 10% over the 30 minutes prior to inclusion and no increase in cardiotropic medication for at least 30 minutes.
• Patient with an oxygenation rate ≤ 6L
• For women of child-bearing age: negative pregnancy test at inclusion
• Person who has read and understood the information letter and signed the consent form
• Affiliation to a social security scheme

Exclusion criteria

• Contraindication to the use of NIV or HFO
• Patient with orotracheal intubation or tracheotomy
• Renal failure with hemodialysis or hemofiltration
• Uncontrolled state of shock (PAS\<90 mmHg and/or cardiac index\<1.8 L/min/m² and/or norepinephrine\>0.2 μg/kg/min and/or dobutamine\>10 μg/kg/min)
• Acute respiratory failure as defined by :
• clinical signs: respiratory rate \>35/min, signs of struggle, SpO2\<92% on O2C
• indication for treatment with NIV or HFO at the discretion of the clinician
• oxygen dependency requiring O2C\>6L/min O2C flow at the oxygen mask
• Chronic advanced respiratory disease
• Chronic treatment with NIV or CPAP at home
• Non-operated aortic or mitral insufficiency ≥ II/IV
• Administration of loop diuretics within 3 hours prior to inclusion for intravenous forms and within 6 hours for oral forms.
• Presence of altered consciousness defined by a Glasgow score \< 15/15 or cognitive dysfunction defined by a CAM-ICU score \> 0/4
• Pregnant or parturient or nursing woman or proven lack of effective contraception
• Person deprived of liberty by an administrative or judicial decision or person placed under judicial protection / subtutorship or guardianship
• Person participating in another trial / having participated in another trial that may interfere with the procedures that are the subject of the research within a 4-week time frame