Interface apparatus for use by a patient having a patient airway and for use with a mechanical ventilator having inspiratory and expiratory tubing. An intrapulmonary percussive ventilator having an output and an injection device coupled to the output of the intrapulmonary percussive ventilator and having an output. The interface apparatus comprises a mixing device having a mixing chamber therein and having an outlet adapted to be connected to the patient airway. The body has fittings in communication with the mixing chamber adapted to be connected to the inspiratory tubing and to the expiratory tubing of the mechanical ventilator. The body also has an injection port in communication with the mixing chamber adapted to be connected to the output of the injection device.
