Persistent pulmonary hypertension of the newborn

Clinical Case

A 40-week, 3.6 kg male infant is born via spontaneous vaginal delivery through thick meconium-stained liquor. Apgar scores are 3 at 1 minute and 5 at 5 minutes. He is intubated and suctioned under direct laryngoscopy in the delivery room for poor respiratory effort and cyanosis. At 1 hour of age in the NICU, pre-ductal SpO₂ is 82% on 100% FiO₂ and post-ductal SpO₂ is 60%. Blood pressure is 45/22 (mean 30). Capillary refill is 4 seconds. [1]

Discussion

The 22% pre–post ductal gradient in the setting of severe hypoxaemia despite 100% FiO₂, combined with meconium aspiration, establishes a working diagnosis of PPHN secondary to meconium aspiration syndrome. The mean BP of 30 is concerning — it falls below the gestational age (40), suggesting systemic hypotension that will worsen the right-to-left shunt. [1]

The immediate priority is to stabilise the infant before further decompensation. Intubation and ventilation are already in progress; I would apply gentle ventilation with permissive hypercapnia targeting pH 7.35–7.50, avoiding aggressive hyperventilation. I would send blood gas, glucose, calcium, and lactate, and correct any metabolic derangement promptly. [5]

An echocardiogram must be obtained urgently to confirm PPHN, assess right ventricular function, and exclude structural congenital heart disease before starting iNO. Meanwhile, I would treat the systemic hypotension with cautious volume and inotropes to raise mean BP above 40. [7]

Management Plan

Once the echocardiogram confirms PPHN and excludes structural heart disease, I would start inhaled nitric oxide at 20 ppm. The combination of meconium aspiration and PPHN suggests a maladaptation subtype that typically responds to iNO, though the response may be slower than in idiopathic disease. [4]

If iNO alone is insufficient, I would add sildenafil and milrinone as adjunctive vasodilators. If the OI exceeds 25–40 despite maximal therapy, I would urgently refer for veno-arterial ECMO. Given the meconium aspiration, surfactant administration may improve lung compliance and reduce the ventilation pressures needed. [3]

Long-term Follow-up

Survivors of PPHN require neurodevelopmental assessment at 6, 12, and 24 months and audiology testing before discharge and at 6 months, given the elevated risk of sensorineural hearing loss and cognitive impairment. The family should be counselled about the potential for chronic lung disease and the importance of comprehensive follow-up. [4]