A delivery system utilizing a diffusion membrane that regulates the concentration of medical gases that are administered to a patient. A storage vessel contains a neat or pure medical gas under pressure that is in fluid communication with a diffusion membrane. The medical gas is then dispensed at a specified rate by diffusion across a membrane into a carrier gas. The concentration is kept constant by regulating the pressure and carrier gas flow. Typical applications are for inhaled gases that are used in patient treatment and care.
