A heat and moisture exchanger for both conducting a stream of air produced by a ventilator to a moisturizing medium and internally bypassing the moisturizing medium if aerosolized medication is introduced into the stream includes a housing having a ventilator-side port coupled to an outlet of a ventilator...http://www.google.es/patents/US7921846?utm_source=gb-gplus-sharePatente US7921846 - Heat and moisture filter exchanger and method
