Persistent pulmonary hypertension of the newborn: clinical course, outcomes, and use of sildenafil at Port Moresby General Hospital

Introduction Persistent pulmonary hypertension of the newborn (PPHN) is characterized by high pulmonary vascular resistance during the transition phase from intra- to extra-uterine life. It can complicate birth asphyxia, meconium aspiration, sepsis, pneumonia and other perinatal insults. PPHN can be difficult for health care workers to diagnose and treat, particularly where echocardiography is unavailable. In a prospective study of neonates at the Port Moresby General Hospital in Papua New Guinea, we examined the diagnosis of PPHN, using clinical signs and pre- and post-ductal oxygen saturation (SpO2) gradient (delta saturation) measured by pulse oximetry. We describe the course, outcomes, and the use of sildenafil, a phosphodiesterase inhibitor that can reduce pulmonary vascular resistance. Methodology Neonates > 35.5 weeks gestation with respiratory distress, hypoxemia (SpO2 < 90%) and a pulse oximetry oxygen saturation pre- and post-ductal gradient of > 5% were followed prospectively. Pre- and post-ductal saturation and clinical features were recorded, and a respiratory distress score (RDS) was calculated. Affected neonates received oxygen therapy, supportive care, and sildenafil (1–2 mg kg−1 every 6 hours). We recorded the delta saturation and RDS for the first 5 days and compared neonates who survived and those who died. Results Forty-two neonates with PPHN were evaluated over 6 months, representing 5% of all admissions to the Special Care Nursery and 20% of all newborns with respiratory distress. Twelve newborns died (29% mortality rate), with the highest mortality among newborns with severe birth asphyxia (encephalopathy) and meconium aspiration syndrome. Following the initiation of sildenafil and nasal prong oxygen, 55% of neonates improved within 24 hours, with no apparent side effects. Mean ± s.d. duration of oxygen therapy and hospital stay were 5.6 ± 4.4 days and 7.7 ± 6.5 days, respectively. Conclusion Sildenafil with oxygen and supportive care was associated with a positive outcome for a percentage of newborns affected by PPHN when intensive care and echocardiography were unavailable. Pre- and post-ductal oxygen saturations together with other clinical features can support the diagnosis of PPHN in resource-limited clinical settings. Standard protocols and improved access to echocardiography could enhance PPHN detection and management. Prevention measures will be necessary to reduce the morbidity and mortality of perinatal asphyxia and PPHN.