Study objective: Data concerning inhaled nitric oxide (iNO) on pediatric ARDS is rare. We investigated the effects of iNO on pediatric ARDS in order to examine the ability to predict a response to iNO, the optimal concentration of iNO, the effects of ≤1 ppm nitric oxide (NO), and the effect of iNO on PaCO2.
Setting: ICU at Kumamoto (Japan) University Hospital.
Patients and interventions: Seven children with ARDS. The initial responses to 16 ppm NO and the dose-response effects of 0.13 to 16 ppm NO were assessed.
Measurements and results: Sixteen ppm of iNO improved oxygenation in all seven children. The use of iNO significantly increased the ratio of arterial oxygen tension to the fraction of inspired oxygen (PaO2/FIO2). A correlation between the NO-induced increase in PaO2/FIO2 and the baseline PaO2/FIO2 was observed (r=0.93, p<0.01). Dose-response tests showed that the optimal concentration of iNO was ≤4 ppm, improvements in PaO2/FIO2 could be observed with concentrations of ≤1 ppm NO, and iNO induced a slight decrease in PaCO2.
Conclusions: In children with ARDS, iNO frequently improves oxygenation and induces a slight decrease in PaCO2, with the baseline PaO2/FIO2 functioning as a predictor of all NO response. Improvements of PaO2 and PaCO2 were observed with concentrations of iNO of ≤1 ppm, a level in which the risk of a toxic reaction in children is minimal. Effects on outcome need verification in larger controlled trials.