A substance delivery apparatus for use with a system for supplying breathable gas to a human or animal includes a sensor to measure the pressure of the supplied breathable gas and to detect inhalation by the human or animal; and a reservoir, a conduit, a pump, and a diaphragm to deliver the substance...http://www.google.com.au/patents/US20100282251?utm_source=gb-gplus-sharePatent US20100282251 - METHOD AND APPARATUS FOR SUBSTANCE DELIVERY IN SYSTEM FOR SUPPLYING BREATHABLE GAS
