Abstract: An airway circuit has two modes of operation, dependent upon the presence or absence of a nebulizer in a nebulizer port. When the nebulizer if absent, a patient port is in fluid communications with a ventilation circuit port through a heat and humidity exchange element. When the nebulizer is inserted into the nebulizer port, the nebulizer port (and nebulizer), patient port, and ventilation circuit port are in fluid communications with each other and the heat and humidity exchange element is isolated, thereby protecting the heat and humidity exchange element from medicines emanating from the nebulizer. After the nebulizer is removed from the nebulizer port, the patient port is again placed in fluid communications with the ventilation circuit port through a heat and humidity exchange element.

Abstract: An airway circuit has two modes of operation, dependent upon the presence or absence of a nebulizer in a nebulizer port. When the nebulizer if absent, a patient port is in fluid communications with a ventilation circuit port through a heat and humidity exchange element. When the nebulizer is inserted into the nebulizer port, the nebulizer port (and nebulizer), patient port, and ventilation circuit port are in fluid communications with each other and the heat and humidity exchange element is isolated, thereby protecting the heat and humidity exchange element from medicines emanating from the nebulizer. After the nebulizer is removed from the nebulizer port, the patient port is again placed in fluid communications with the ventilation circuit port through a heat and humidity exchange element.