A system configured to monitor pulmonary congestion in a subject, the system comprising: a pressure generator configured for generating a pressurized flow of breathable gas for delivery to the airway of the subject, said pressure generator comprising a gas support device configured to control one or more of the parameters of the pressurized flow of breathable gas in accordance with a predetermined algorithm; one or more sensors configured to monitor gas breathed by the subject; a user interface configured to enable a user to interact with the system; and one or more processors configured to implement a plurality of computer program modules, the computer program modules comprising: a parameter module configured to receive output signals from the one or more sensors and to determine one or more parameters of the breathing of the subject from the received output signals, a congestion monitor module configured to identify pulmonary congestion in the subject based on the one or more parameters of the breathing of the subject determined by the parameter module; and a notification module configured to control the user interface to provide a notification to the user of pulmonary congestion in the subject, if the congestion monitor module identifies pulmonary congestion in the subject; characterized in that the parameter module is further configured to cause the pressure support device to override the treatment algorithm to facilitate the determination of the one or more parameters of the breathing of the subject according to a predetermined testing regime. a pressure generator configured for generating a pressurized flow of breathable gas for delivery to the airway of the subject, said pressure generator comprising a gas support device configured to control one or more of the parameters of the pressurized flow of breathable gas in accordance with a predetermined algorithm; one or more sensors configured to monitor gas breathed by the subject; a user interface configured to enable a user to interact with the system; and one or more processors configured to implement a plurality of computer program modules, the computer program modules comprising: a parameter module configured to receive output signals from the one or more sensors and to determine one or more parameters of the breathing of the subject from the received output signals, a congestion monitor module configured to identify pulmonary congestion in the subject based on the one or more parameters of the breathing of the subject determined by the parameter module; and a notification module configured to control the user interface to provide a notification to the user of pulmonary congestion in the subject, if the congestion monitor module identifies pulmonary congestion in the subject; a parameter module configured to receive output signals from the one or more sensors and to determine one or more parameters of the breathing of the subject from the received output signals, a congestion monitor module configured to identify pulmonary congestion in the subject based on the one or more parameters of the breathing of the subject determined by the parameter module; and a notification module configured to control the user interface to provide a notification to the user of pulmonary congestion in the subject, if the congestion monitor module identifies pulmonary congestion in the subject;