An adaptive gas mixture controller system. A pulse oximeter interface receives pulse oximeter data. A gas blender interface communicates with a separate externally connected gas blender. A processor receives pulse oximeter data via the pulse oximeter interface and outputs data to the gas blender interface for adaptive feedback control of the gas mixture based upon the SpO2 level signals from the pulse oximeter interface. When the processor receives data from the gas blender indicating that the gas mixture has been manually changed, enters a manual override mode and halts sending adaptive feedback control signals to the gas blender. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.