This is a randomiized, placebo controlled trail that will evaluate the influence of inhaled NO (INO) on the saturation and exercise capacity of patients with COPD and IPF. All patients will sign a consent form before enrolment. Each patient will undergo two six-minute walk tests. Whether the INO will be used in the first or the second trial will be determined by computer generated randomization with random numbers sealed in opaque envelops. For the placebo 6-minute test we will use placebo cartridges in the INO generator, for INO 6-minute test we will use NO cartridges. The treatment with INO or placebo will start 20 minutes before the 6-minute walk test and will end at the end of the 6-minute walk test. Between tests a time interval of at least 60 minutes will be kept. During the test, the patients' pulse and saturation level will be monitored with a pulse oximetry. The data will be recorded continuously from baseline to 5 minutes after the test is over. The distance the patient walked will also be recorded. Patients that require supplemental oxygen will perform the tests with oxygen supplementation.~Dosing The NO dosing will be fixed. The first 10 patients will be treated with INO at a dose of 45 parts per million (ppm) per kilogram (kg). from patient 10 to 20 a dose of 75 ppm per kg will be given and from patient 20-100 a dose of 115 ppm per kg will be given.
Our objective is to evaluate the influence of inhaled NO on the saturation and exercise capacity of patients with COPD and IPF. each participant will undergo two six minute walk tests, one with inhaled NO and the other with placebo.