Fig. 5.

Response to sildenafil intravenous infusion without iNO. Seven infants were enrolled before the need for iNO. Oxygenation index (OI) was improved by 1 h (24.6 ± 4.6 to 16.1 ± 9.9; ^*P = 0.0502), with significant and sustained improvement by 4 h after the initiation of sildenafil (14.7 ± 6.4, p = 0.0088). Of the seven infants who received sildenafil only, the majority (n = 5) were in cohorts 6–8, meaning that they received the highest maintenance infusion dose of 1.64 mg/kg/day, and differed only in the approach to the loading dose. Of these seven infants, only one infant required additional treatment with iNO, and that infant was in cohort 4, receiving loading and maintenance doses that were approximately 20% of the final dose tested in trial. Reprinted from Steinhorn et al. (2009) with permission from Elsevier