In a neonate with suspected persistent pulmonary hypertension (PPHN), pre- and post-ductal oxygen saturation monitoring is being performed. Pre-ductal SpO2 is 95% and post-ductal SpO2 is 82%. The most appropriate first-line intervention is:
- A Hyperventilation to achieve PaCO2 25–30 mmHg
- B Inhaled nitric oxide (iNO) at 20 ppm ✓
- C Sildenafil orally 1 mg/kg/dose
- D Tolazoline infusion
Correct answer: B. Inhaled nitric oxide (iNO) at 20 ppm
Explanation
Inhaled nitric oxide (iNO) at 20 ppm is the first-line selective pulmonary vasodilator for PPHN in term and near-term neonates, acting via guanylate cyclase to reduce pulmonary vascular resistance without systemic hypotension. The pre/post-ductal saturation difference >5% confirms right-to-left ductal shunting (PPHN). Hyperventilation causing hypocapnia is no longer recommended as it causes cerebral vasoconstriction and alkalosis-related complications. Tolazoline is outdated. Sildenafil is a second-line agent.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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