A system for controlling machine-induced expiratory airflow of a subject, the subject having an airway, the system comprising: a pressure generator (140) configured to generate a pressurized flow of breathable gas for delivery to the airway of the subject; and one or more processors (110) configured to execute computer program modules, the computer program modules comprising: a control module (170) configured to control the pressure generator a metric determination module (154) configured to determine a value of a flow metric during expiration by the subject, a flow analysis module (156) configured to compare the determined value of the flow metric with a target level of the flow metric; and an adjustment module (160) configured to adjust one or more of exsufflation pressure.