Inhaled nitric oxide in infants with developing or established chronic lung disease.

The effect on gas exchange of increasing concentrations of nitric oxide (0-60 parts per million) added to the inspired gases of nine ventilator-dependent infants (median postnatal age = 4 weeks; range 2-16 weeks) with chronic lung disease and pathological oxygenation index values was studied by means of arterial or transcutaneous PO2/PCO2. A significant improvement of oxygenation, indicated by a reduction of oxygenation index, was found (p < 0.014). The optimal nitric oxide concentration and the individual response varied between patients. PO2 returned to baseline values after the discontinuation of nitric oxide in all patients except one. No effect on PCO2 could be identified. Methaemoglobin values only increased marginally during the nitrous oxide exposition (pre-nitric oxide: 0.56% +/- 0.27; post-nitric oxide: 0.78 +/- 0.08; p = ns). Systemic blood pressure and heart rate were unaffected in all patients. Before inhaled nitric oxide can be considered for prolonged use in this patient category further studies regarding long-term efficacy and safety are needed.