A system for controlling oxygen supply for a subject having an airway, the system comprising: a pressure generator configured to generate a pressurized flow of breathable gas for delivery to the airway of the subject, wherein the pressurized flow of breathable gas is delivered through a subject interface appliance; a plurality of physiological sensors configured to generate output signals conveying physiological information related to one or more physiological parameters of the subject; one or more position sensors configured to generate output signals conveying position information related to one or more of the physiological sensors with respect to the subject, the subject interface appliance, and/or to other ones of the physiological sensors; one or more processors configured to execute computer program modules, the computer program modules comprising: a parameter determination module configured to determine a level of arterial oxygen saturation of the subject based on the output signals generated by the physiological sensors; an artifact module configured to detect displacement of the physiological sensors that could result in artifacts in determinations of the level of arterial oxygen saturation by the parameter determination module, wherein the artifact module is configured to detect such displacement based on the output signals generated by the one or more position sensors; and an oxygen control module configured to adjust one or more of the pressurized flow of breathable gas and/or a fraction of oxygen in the pressurized flow of breathable gas based on the determined level of arterial oxygen saturation and detections of displacement by the artifact module. a pressure generator configured to generate a pressurized flow of breathable gas for delivery to the airway of the subject, wherein the pressurized flow of breathable gas is delivered through a subject interface appliance; a plurality of physiological sensors configured to generate output signals conveying physiological information related to one or more physiological parameters of the subject; one or more position sensors configured to generate output signals conveying position information related to one or more of the physiological sensors with respect to the subject, the subject interface appliance, and/or to other ones of the physiological sensors; one or more processors configured to execute computer program modules, the computer program modules comprising: a parameter determination module configured to determine a level of arterial oxygen saturation of the subject based on the output signals generated by the physiological sensors; an artifact module configured to detect displacement of the physiological sensors that could result in artifacts in determinations of the level of arterial oxygen saturation by the parameter determination module, wherein the artifact module is configured to detect such displacement based on the output signals generated by the one or more position sensors; and an oxygen control module configured to adjust one or more of the pressurized flow of breathable gas and/or a fraction of oxygen in the pressurized flow of breathable gas based on the determined level of arterial oxygen saturation and detections of displacement by the artifact module. a parameter determination module configured to determine a level of arterial oxygen saturation of the subject based on the output signals generated by the physiological sensors; an artifact module configured to detect displacement of the physiological sensors that could result in artifacts in determinations of the level of arterial oxygen saturation by the parameter determination module, wherein the artifact module is configured to detect such displacement based on the output signals generated by the one or more position sensors; and an oxygen control module configured to adjust one or more of the pressurized flow of breathable gas and/or a fraction of oxygen in the pressurized flow of breathable gas based on the determined level of arterial oxygen saturation and detections of displacement by the artifact module.