Continuous and intermittent administration of intravenous sildenafil in critically ill infants with pulmonary hypertension.

Intravenous (IV) sildenafil may be administered as a continuous infusion or intermittent bolus dosing in infants with pulmonary hypertension (PH). We aimed to compare these delivery methods. Methods We retrospectively evaluated subjects less than 12 months old treated with IV sildenafil for PH. Vital signs, oxygen requirement, vasoactive-inotropic score (VIS), and echocardiogram results before and after sildenafil initiation, and the need for discontinuation due to side effects, were noted. Results Forty-three subjects were identified (23 continuous, 20 intermittent). There were clinically significant differences in PH classifications between groups. The continuous group was significantly younger (p = 0.010) with higher baseline severity of illness suggested by higher inspired oxygen (FiO2 ) and VIS (p = 0.012). After sildenafil initiation, there were no significant differences in changes in blood pressure, oxygen saturation, FiO2 , or VIS between groups, and no difference in the number of subjects requiring discontinuation due to side effects (4 continuous, 1 intermittent, p = 0.351). Eight continuous group subjects (34.8%) and 3 intermittent group subjects (15.0%) died (p = 0.024), but echocardiographic improvement in PH degree was more common in the continuous group (77.8% vs. 33.3%, p = 0.007). Conclusion In this small cohort of infants treated with continuous or intermittent IV sildenafil, in the setting of different baseline characteristics between groups, there were no significant differences in changes in vital signs, VIS, FiO2 , or need for discontinuation of therapy due to side effects. Higher continuous group mortality may be explained by greater baseline illness severity, but larger prospective, randomized studies are required to investigate these different delivery methods.