Evaluation of the Inhibitory Effect of Phosphodisterase Inhibitors Type 5 on the Development of Retinopathy of Prematurity in Preterm Infants

Retinopathy of Prematurity (ROP) is a proliferative retinopathy, which involve the retina of premature infants. ROP is continues as a significant cause of blindness in premature infants. Low gestational age and exposure of premature newborns to high concentration of oxygen are the most significant risk factors in development of ROP. Exposure of immature retina to hyperoxia down regulates retinal vascular endothelial growth factor (VEGF). Retinal blood vessels constrict and may be obliterated, resulting in phase 1 ROP. In this randomized double blind clinical trial study we assess the effect of phoshodiesterase inhibitors type 5 via increasing of VEGF on development of phase 1 ROP as primary outcome and phase 2- 5 ROP; duration of Nasal Continuous Positive Airway Pressure (NCPAP), Mechanical Ventilation (MV)and oxygen therapy as secondary outcome in premature infants with gestational age of less than 32 weeks. Inclusion criteria: newborns with gestational age less than 32 weeks; need to oxygen therapy. Exclusion criteria: blood sugar≥ 150mg% more than 7 days; metabolic acidosis (pH< 7.2) more than 24h; blood transfusion greater than 10ml/kg in first 4 weeks of life; sepsis with fungi. NCPAP therapy with 4-6 cm H2o begin as soon as possible in included cases. Infants who require Fio2≥ 40% to maintain o2 saturation≥ 90% will be intubated and treated with intratracheal surfactant according to Intubation- Surfactant- Raid Extubation(INSURE) method. Mechanical ventilation was considered in babies with INSURE failure. Sildenafil or placebo will be administered to eligible cases till discontinue of supplemental oxygen. Development of Retinopathy was assessed .

Vice chancellor for research, Ahvaz Jundishapur University of Medical Sciences