A dose of 10-20 ppm measured within the delivery device is sufficient to maintain nasopharyngeal concentrations within a range of 1-10 ppm. My co-authors and I have also reported a series of eleven infants with pulmonary hypertension treated with low dose iNO delivered via nasal cannula after extubation at the 14th Annual CNMC Symposium on ECMO & Advanced Therapies for Respiratory Failure, Keystone, CO, 1998.