Abstract: A disposable inhalation spirometer apparatus for prophylactic respiratory maneuver is in expensively constructed and intended for single-patient use. The apparatus includes a tube with an interior respiratory passage communicating through a one-way valve structure to a nebulizer assembly and having a separate visual inhalation meter. The nebulizer assembly includes both a medicant mist dispensing nebulizer and an enlarged, enclosed, mist accumulation chamber which is positioned between the nebulizer and the tube passage. The visual inhalation meter includes a tube defining a chamber and having a transparent portion or window with a scale or indicia thereon and in which is mounted a floating piston movable in response to low differential pressure to indicate relative inspirational ability. A one-way check valve in an end of the tube passage opens to the atmosphere upon exhalation and permits the patient to maintain constant contact with a tube mouthpiece.