The present invention is a method, system, and apparatus for providing automated closed-loop control of oxygen-hemoglobin saturation, SpO2, levels that adapts to the specific, unique, and variable needs of the individual patient in real-time. A method, system, and standalone breathable gas blending apparatus for controlling SpO2 levels in human patients requiring supplemental oxygen therapy, inclusive of adults, pediatrics, and neonates, are described.
