Testing of the airways and pulmonary tract of a patient, particularly for sensitivity to aerosols

Method of introducing two different additive aerosols into the airways and pulmonary tract of a patient (10) breathing a breathable gas through a breathing tube (12) having a mouthpiece, for testing sensitivity to specific substances administered in one of the aerosols comprising

• sensing initiation of the inhalation phase of a breathing cycle of the patient;
• establishing a timing interval after initiation of the breathing phase;
• introducing a first one of the aerosols into the inhaling gas immediately in advance of the mouthpiece after elapse of the timing interval and for a time duration which is less than the remaining time of a normal inhalation phase of the breathing cycle;
• essentially continuously determining airways resistance;
• introducing a second one of the aerosols into the inhaling air immediately in advance of the mouthpiece during a time when the first one of the aerosols is not being introduced,
• and wherein said aerosol introduction steps consist of vaporizing the selected one of the aerosols for the time duration that said aerosol is being introduced into the inhaling gas while maintaining continuous communication between the breathing tube and both aerosols.

Apparatus for testing the airways and pulmonary tract of a patient (10) for sensitivity to different specific substances administered in respective ones of two aerosols comprising

• a mouthpiece (14) adapted for breathing connection with the mouth of a patient;
• a single breathing tube duct means (12) having a first end coupled to the mouthpiece;
• and a second end communicating with a breathing gas;
• air flow analyzing and signal producing means (16, 18, 22, 24) for analyzing air flow through the breathing tube means to determine the beginning and end of inhalation (IN) and exhalation (EX) phases of the breathing cycles of the patient and for measuring the airways resistance of the pulmonary tract, coupled to the duct means, said analyzing means producing a signal corresponding to the gas flow in said duct means and including controllable flow resisting means (16, 18) in said duct means, and pressure sensor means (24) having an inlet (22) coupled to said duct means;
• first atomizing means (34) including a first one of the aerosols, and having an outlet (34a) continuously open and coupled to the breathing tube duct means;
• second atomizing means (32) including a second one of the aerosols, and having an outlet (32a) continuously open and coupled to the breathing duct means;
• and control means (38, 40, 42) coupled and responsive to said flow analyzing means (16, 18, 22, 24) for selectively controlling application of atomizing energy to said first and second atomizing means as a function of inhaling (IN) and exhaling (EX) breathing phases of the breathing cycle of the patient,
• said control means controlling said atomizing means (34) to selectively introduce aerosols into the breathing tube duct means only during selected portions of the inhaling phase (IN) of at least one breathing cycle;
• time delay means (54) responsive to said control means and providing a predetermined period of time (.DELTA.t) subsequent to commencement of the inhalation phase (IN) of the breathing cycle of a patient as determined by said analyzing means, and controlling one (34) of the atomizing means to supply atomizing particles to the breathing tube upon expiration of said predetermined period of time;
• and wherein the outlet (34a) from the first atomizing means is directly coupled to the mouthpiece (14) and located closely adjacent the mouthpiece;
• the pressure sensor inlet (22) is coupled to the duct means between the outlet from the atomizing means (34) and the controllable flow resistance means (16, 18);
• and the pressure sensor (24) is coupled to the control means for determination of airways resistance.