Control device for supplying supplemental respiratory oxygen

The present invention relates to a system for delivering supplemental respiratory oxygen to a patient. The system comprises a blood oxygen content level sensor (14), a supplemental oxygen source (20), a valve (26) in fluid communication with the supplemental oxygen source. The system furthermore comprises a controller (10) capable of operating the valve, wherein the controller controls supplemental oxygen flow through the valve to deliver a variable dose of supplemental oxygen from the supplemental oxygen source to the patient. The variable dose of supplemental oxygen is at least partially determined based on the measured blood oxygen content. Furthermore, the system comprises means for determining when the blood oxygen content level measured by the blood oxygen content level sensor is invalid resulting in that the controller operates the valve to deliver a default amount of supplemental oxygen to the patient when the measured blood oxygen content is invalid, and means for determining when the blood oxygen content level measured by the blood oxygen content level sensor is valid after being invalid resulting in that the controller variably restricts supplemental oxygen flow through the valve to deliver a variable dose of supplemental oxygen from the supplemental oxygen source to the patient, wherein the variable dose of supplemental oxygen is at least partially determined based on the measured blood oxygen content.