The device (1) has a tube (4) forming a main channel (5) connected to an airway of a patient via a distal orifice (7) such that the main channel connects a respiratory system of the patient to outside. An auxiliary channel (8) is connected with a respiratory gas source to insufflate a jet of respiratory gas into the system, and opens via its distal end (8A), into the main channel in the vicinity of the distal orifice of the main channel. A removal channel (22) removes vitiated gas exhaled by the patient between the distal end of the auxiliary channel and the orifice of the main channel. An independent claim is also included for a system for measuring a parameter of vitiated gas exhaled through an airway of a patient.
