A patient support apparatus includes a frame and a mattress positioned on the frame. A respiratory therapy device is coupled to the frame. The respiratory therapy device includes a blower having an inlet and an outlet, a patient interface, and a valve including a valve member that is rotatable through a first angular displacement in a first direction from a first position to a second position. The outlet of the blower is coupled to the patient interface so that positive pressure is provided to a patient's airway via the patient interface when the valve member is in the first position. The inlet of the blower is coupled to the patient interface so that negative pressure is provided to the patient's airway via the patient interface when the valve member is in the second position.