Heat and moisture filter exchanger and method

A heat and moisture exchanger for selectively conducting a stream of air produced by a ventilator through a moisturizing medium or causing the stream of air to bypass the moisturizing medium, the heat and moisture exchanger comprising:

• (a) a housing having a ventilator-side port configured to be coupled to an outlet of a ventilator and a source of aerosolized medication, the housing also having a patient-side port configured to be coupled to a patient to provide ventilation to the patient;
• (b) a structure within the housing forming a first path within the housing for conducting non-aerosolized air from the ventilator-side port through the moisturizing medium to the patient-side port and a second path within the housing for conducting air carrying aerosolized medication from the ventilator-side port to the patient-side port by bypassing the moisturizing medium, wherein said structure includes a tube located within the housing between the ventilator-side port and the patient-side port, the second path extending entirely through the tube;
• (c) a two-way valve mechanism in the housing for selectively coupling the ventilator-side port into fluid communication with one or the other of the first and second paths;
• said two-way valve mechanism including a valve post having an upper end portion extending through the housing and attached to the external valve control and a lower end portion extending through a wall of the tube, and wherein the two-way valve mechanism also includes a butterfly valve vane located in the tube and attached to the lower end portion of the valve post;
• (d) an external valve control extending through the housing for controlling the two-way valve mechanism, wherein said two-way valve mechanism selectively blocks or opens a portion of the second path extending through the tube in response to the external valve control, the moisturizing medium being disposed between an outer surface of the tube and an inner surface of the housing, the first path extending around the tube and through the moisturizing medium;
• and
• (e) a gap between a first end of the tube and the ventilator-side port. the gap forming part of the first path.