Transposition of the Great Arteries (TGA)

Presentation

• Severe cyanosis immediately after birth (not responsive to supplemental oxygen)
• Reverse differential cyanosis (post-ductal SpO2 higher than pre-ductal) if PPHN/PDA present
• Single, loud second heart sound (S2)
• Classic chest X-ray: 'Egg on a string' appearance (narrow mediastinum)

Workup

• Hyperoxia test (fails to increase PaO2 above 100 mmHg, indicating cyanotic CHD)
• Echocardiogram (confirms ventriculoarterial discordance)
• Assess adequacy of interatrial mixing (size of PFO/ASD)

Management

• Immediate Prostaglandin E1 (PGE1) to keep PDA open and improve mixing
• Urgent Balloon Atrial Septostomy (BAS) if restrictive atrial communication and severe hypoxemia
• Intubation and mechanical ventilation for stabilization if clinically indicated
• Surgical Arterial Switch Operation (ASO) typically within first 1-2 weeks of life

Extended Pharmacology & Critical Care

• Alprostadil (PGE1) continuous infusion: Start at 0.05 to 0.1 mcg/kg/min; monitor strictly for apnea, hyperthermia, and extreme vasodilation.
• Milrinone loading dose 50 mcg/kg over 15 mins (only if stable blood pressure), followed by 0.33 to 0.75 mcg/kg/min infusion.
• Strict I&O monitoring; maintain urine output > 1-2 mL/kg/hr using indwelling catheter if necessary.
• Maintain hematocrit > 35-40% via PRBC administration to optimize oxygen delivery in cyanotic lesions.
• Nursing: Q1 hour blood pressure monitoring (arterial line preferred), monitor for feeding intolerance indicating gut hypoperfusion.

Standardized Discharge & Follow-Up Criteria

• Adequate weight gain explicitly > 15-30g/day over a continuous 3-5 day period.
• Maintenance of temperature in an open crib with standard clothing for 48 hours.
• Successful completion of the 90-120 minute Infant Car Seat Challenge.
• Caregiver successfully completed CPR training, rooming-in, and independent medication administration.
• Referrals placed for High-Risk Infant Follow-Up Clinic, Early Intervention (PT/OT), and appropriate sub-specialists.

Diagnostic & Management Algorithm

• TGA Mixing Preservation: [START] Extreme Cyanosis + Echo CONFIRMS TGA -> [ACTION] Start PGE1 continuous infusion -> [EVALUATE] Restrictive Atrial Septum? -> [YES] Emergency Balloon Atrial Septostomy -> [GOAL] Arterial Switch Operation

References

1. Villafañe J, Lantin-Hermoso MR, Bhatt AB, et al. D-transposition of the great arteries: the current era of the arterial switch operation. J Am Coll Cardiol.