An auto-titration pressure support system (30) comprising a pressure generating system (32) adapted to generate a flow of breathing gas at a selectable pressure level a patient circuit (36) having a first end adapted to be coupled to the pressure generating system and a second end adapted to be coupled to an airway of a patient a monitoring system (44) associated with the patient circuit or the pressure generating system and adapted to measure a parameter indicative of a flow of gas in such a patients airway and to output a flow signal indicative thereof and a controller (50) coupled to the monitoring system and the pressure generating system, for controlling the pressure generating system based on the output of the monitoring system, wherein the controller determines a breathing parameter from the flow signal, and wherein the controller analyzes a variability of the breathing parameter and controls the pressure generating system based on a result of the variability analysis.
