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

This study is comparing two oxygen delivery methods — non-invasive ventilation (NIV, a breathing mask) and high-flow oxygen therapy — in patients who have just had heart surgery and have reduced heart function. Researchers want to know which method best supports heart and lung recovery in the period just after being removed from a breathing tube. **You may be eligible if:** - You are an adult who has had heart surgery involving a heart-lung bypass machine for more than 24 hours - You have been extubated (breathing tube removed) for at least 6 hours - You have pre-existing reduced heart function (ejection fraction below 40%) - Your vital signs and blood oxygen levels are currently stable on low-flow oxygen - You have the required invasive monitors already in place as part of your standard care **You may NOT be eligible if:** - You require re-intubation or tracheotomy - You are in active shock or hemodynamically unstable - You have kidney failure requiring dialysis - You have a contraindication to the breathing mask (NIV) or high-flow oxygen - You have signs of acute respiratory failure - You are pregnant Talk to your doctor to see if this trial is right for you.