Duct-dependent congenital heart disease: SAQ

This baby has duct-dependent systemic circulation, most likely critical coarctation of the aorta or interrupted aortic arch. The history of a well baby discharged on day 1 who collapses on day 3 is the classic duct-dependent presentation: the ductus arteriosus was perfusing the lower body, and it has now closed. The weak femoral pulses, the large arm-to-leg blood pressure differential of 30 millimetres of mercury, the severe metabolic acidosis, and the hypoglycaemia together confirm a left-sided obstructive lesion in cardiogenic shock. The immediate priority is to start prostaglandin E1 to reopen the duct, correct the hypoglycaemia, and cover sepsis while arranging echocardiography and transfer. [1] [3]

Question 1 (10 marks)

Outline your immediate assessment and resuscitation plan for this baby, including the specific drug therapy you would start and why. [1]

Begin with an airway, breathing, and circulation assessment and recognise that this baby is in critical condition. He is in cardiogenic shock with severe metabolic acidosis, prolonged capillary refill, tachycardia, grunting, and hypoglycaemia. The first interventions run in parallel: gain intravenous access, check and correct the glucose, and send a venous gas, blood culture, full blood count, and electrolytes. Give a bolus of 2 millilitres per kilogram of 10 percent dextrose for the hypoglycaemia and a cautious 10 millilitres per kilogram of isotonic saline only if shock is profound, because the underlying problem is obstructed blood flow rather than volume depletion. [1]

Start prostaglandin E1 (alprostadil) immediately at 0.01 micrograms per kilogram per minute intravenously and titrate up to 0.05 micrograms per kilogram per minute. The rationale is that this baby has a left-sided duct-dependent lesion where the closed ductus arteriosus was the only route for systemic blood flow to the lower body. Reopening the duct restores perfusion, improves the acidosis, and buys time for definitive surgery. Do not wait for the echocardiogram to start the infusion. [1]

Anticipate the side effects of prostaglandin E1, which include apnoea in approximately 10 percent of treated neonates, hypotension, fever, and flushing. Have intubation equipment ready and be prepared to electively intubate, especially if the baby needs transfer. Cover sepsis with empiric antibiotics because sepsis mimics and coexists with duct-dependent congenital heart disease, and confirm the anatomy with echocardiography as soon as the baby is stabilised. [2]