Described are methods of administering therapeutic gases comprising high concentrations of nitric oxide, particularly concentrations above 2,000 ppm. The therapeutic gas may be administered at a certain dosing rate, such as less than 166 micrograms of nitric oxide per second. Also described are methods of administering a therapeutic gas comprising nitric oxide to a patient, wherein a dose of nitric oxide is administered from a portable device that includes a delivery system and a mini-cylinder. Methods of intermittent administration of nitric oxide pulses are also described.
