BACKGROUND: A significant number of infants who respond favorably to inhaled nitric oxide (INO) therapy prove difficult to wean off INO. This INO dependence necessitates prolonged use of INO or, on occasion, the use of alternative treatments, such as extracorporeal membrane oxygenation (ECMO). We observed that infants who appeared to be INO dependent could, in fact, be successfully weaned if the FIO2 was increased briefly during the withdrawal of INO therapy.

METHOD: Sixteen infants admitted to our neonatal intensive care unit for conditions associated with increased pulmonary vascular resistance responded well to INO therapy with a significant increase in PaO2(maximum INO given = 25 ppm). Weaning from INO in 5 ppm decrements was initiated once the FIO2 requirement reached below 0.5. When patients were stable on 5 ppm of INO, the gas was then discontinued. If a patient showed INO dependence, i.e. oxygen saturation fell by more than 10% or below 85%, INO was reinstituted at 5 ppm and the patient allowed to stabilize for 30 minutes. At this time, FIO2 was increased by 0.40 and weaning from INO was attempted again.

RESULTS: Nine infants were successfully weaned on the first attempt. The seven infants who failed the initial trial were all successfully weaned following the increase in FIO2. After successful weaning, FIO2 was returned to the pre-weaning level (mean time = 148 ± 51 mins) and INO was never reinstituted.

CONCLUSION: Infants showing INO dependency can be successfully weaned by increasing FIO2 transiently.