A term neonate develops hypoxemic respiratory failure unresponsive to 100% oxygen, with pre-ductal SpO2 of 95% and post-ductal SpO2 of 78%. Echocardiography shows right-to-left shunting across the ductus arteriosus and foramen ovale. Which intervention is MOST LIKELY to provide the most immediate hemodynamic benefit?
- A Inhaled nitric oxide to selectively reduce pulmonary vascular resistance ✓
- B Surfactant administration to improve lung compliance
- C Systemic vasopressors to increase systemic vascular resistance and reverse shunting
- D Sodium bicarbonate infusion to correct metabolic acidosis
Explanation
In persistent pulmonary hypertension of the newborn (PPHN), right-to-left shunting occurs because pulmonary vascular resistance (PVR) exceeds systemic vascular resistance. Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator that reduces PVR by activating guanylate cyclase in pulmonary vascular smooth muscle, thereby reversing the shunt. Surfactant helps if there is underlying parenchymal disease but does not directly lower PVR. Systemic vasopressors raise SVR but may worsen right ventricular afterload if given without addressing PVR. Bicarbonate may help alkalosis-induced pulmonary vasodilation but is not the primary targeted therapy.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.