Clinical scenario: Respiratory distress | Femoral pulses not palpable
4-day-old term male neonate is brought to the emergency department because of poor feeding, lethargy, and progressive respiratory distress for the past 12 hours. Pregnancy and delivery were uneventful, and he was discharged home on day 2 of life.
On examination, he is pale, irritable, and tachypneic (RR 72/min). Heart rate is 186/min, blood pressure is 58/34 mmHg in both upper limbs, capillary refill time is 5 seconds, and oxygen saturation is 94% in the right hand and 92% in the foot while breathing room air. Femoral pulses are barely palpable, whereas brachial pulses are normal. The liver is enlarged 4 cm below the right costal margin. Cardiac auscultation reveals no significant murmur.
Arterial blood gas demonstrates:
- pH: 7.18
- Lactate: 8.2 mmol/L
- Base deficit: –12 mmol/L
Chest radiograph shows mild cardiomegaly with pulmonary venous congestion.
What is the most appropriate immediate management?
A. Administer intravenous prostaglandin E₁ infusion
B. Administer intravenous furosemide
C. Begin inhaled nitric oxide
D. Perform urgent balloon atrial septostomy
E. Start intravenous milrinone
Correct answer & Explanation:
Answer: A. Administer intravenous prostaglandin E₁ infusion
Explanation
This neonate has duct-dependent systemic circulation, most likely due to critical coarctation of the aorta or interrupted aortic arch.
Key clues
- Well for the first 2–3 days of life.
- Sudden deterioration after physiological closure of the ductus arteriosus.
- Shock with metabolic acidosis and elevated lactate.
- Weak femoral pulses but preserved upper limb pulses.
- Minimal pre/post-ductal oxygen saturation difference.
- Hepatomegaly indicating heart failure.
- No murmur (important—critical coarctation may have no audible murmur).
The priority is to reopen the ductus arteriosus with prostaglandin E₁ (alprostadil) to restore systemic perfusion while arranging definitive cardiac intervention.
Why the other options are incorrect
B. Intravenous furosemide
May reduce pulmonary congestion but does not correct the life-threatening systemic hypoperfusion. It may worsen hypotension.
C. Inhaled nitric oxide
Indicated for persistent pulmonary hypertension of the newborn, not left-sided obstructive lesions causing duct-dependent systemic blood flow.
D. Urgent balloon atrial septostomy
Performed for transposition of the great arteries with restrictive atrial communication, not critical coarctation or interrupted aortic arch.
E. Intravenous milrinone
May support myocardial function but is not the initial life-saving therapy. Without restoring ductal flow, systemic circulation remains critically compromised.
CPSP Pearls
- A neonate who collapses between days 3 and 7 of life should always prompt consideration of a duct-dependent congenital heart disease.
- Absent or weak femoral pulses with metabolic acidosis strongly suggest critical coarctation of the aorta until proven otherwise.
- Do not wait for echocardiography before starting prostaglandin E₁ when a duct-dependent lesion is suspected.
- A normal oxygen saturation does not exclude critical congenital heart disease, particularly lesions causing systemic outflow obstruction.
