An electrically-powered device designed to interface between a pulse oximeter probe and an electronic medical gas regulating unit during oxygen (O2) therapy, to continuously monitor haemoglobin oxygen saturation (SpO2), calculate the appropriate volume of O2 needed to be delivered to the patient based on SpO2 values, and transmit an electronic signal to the electronic O2 regulating unit. It includes a display, alarm(s), and integrated software; it does not come into direct contact with medical gases (i.e., does not include a gas regulator or tubing).