A 3-day-old male neonate born to non-consanguineous parents presents with severe cyanosis and respiratory distress. On examination, he is deeply cyanosed with a single loud S2. Chest X-ray shows an 'egg on string' appearance with decreased pulmonary vascular markings. Echocardiography confirms anterior aorta overriding a posteriorly located pulmonary artery with severe right ventricular outflow tract obstruction. The baby is started on prostaglandin E1 infusion and oxygen, but remains severely cyanosed. Which of the following is the most appropriate next step in management?

Explanation

## Clinical Diagnosis This is a case of **transposition of the great arteries (TGA)** with severe cyanosis unresponsive to medical management. **Key Point:** The clinical triad of TGA is: 1. Severe cyanosis within hours of birth 2. Single loud S2 (both arteries arise anteriorly from right ventricle) 3. 'Egg on string' appearance on CXR (narrow mediastinum, decreased pulmonary markings) ## Why Balloon Atrial Septostomy? **High-Yield:** In TGA, the right and left circulations are in parallel rather than in series. Survival depends on mixing of blood at the atrial level (PDA and foramen ovale). When PGE1 alone fails to maintain adequate oxygenation (SpO2 < 75% despite PGE1), balloon atrial septostomy (Rashkind procedure) is the **emergency bridge therapy**. **Clinical Pearl:** The Rashkind procedure: - Creates/enlarges an ASD by inflating a balloon catheter in the right atrium and pulling it back across the septum - Increases right-to-left shunting at the atrial level - Improves mixing of oxygenated and deoxygenated blood - Buys time (days to weeks) until definitive surgical repair can be performed - Success rate > 90% in experienced centers ## Definitive vs. Palliative Management | Intervention | Timing | Indication | Goal | |---|---|---|---| | **Prostaglandin E1** | Immediate | All TGA neonates | Keep PDA patent for mixing | | **Balloon atrial septostomy** | Emergency (if PGE1 inadequate) | Severe cyanosis (SpO2 < 75%) | Increase atrial-level mixing | | **Arterial switch (Jatene)** | Elective (within days) | All TGA | Anatomic correction | | **Blalock-Taussig shunt** | Rescue/palliative | Complex TGA + other lesions | Increase pulmonary blood flow | **Key Point:** The Jatene procedure (arterial switch) is the definitive surgical correction and is performed within the first week of life, but it requires urgent stabilization first. The Rashkind procedure is the immediate life-saving bridge. [cite:Park 26e Ch 11]