Tetralogy of Fallot — branching viva

Examiner opening (Examiner)

You are the general paediatric registrar in the emergency department. A four-month-old girl is brought in cyanotic and agitated after a feed, with a systolic ejection murmur at the left upper sternal border and a single second heart sound. As you assess her she gets bluer and the murmur gets quieter. Talk me through your immediate assessment and management. ^[1]

Exemplar opening (Candidate)

This infant is having a hypercyanotic tet spell on the background of what is almost certainly tetralogy of Fallot, and I will treat it as an emergency now rather than observe. First, the airway, breathing and circulation: give 100 per cent oxygen and place her in the knee–chest position, which raises systemic vascular resistance and reduces the right-to-left shunt. I need intravenous access to give morphine 0.1 mg/kg to calm her and blunt the infundibular spasm, a 10 mL/kg isotonic saline bolus for preload, and phenylephrine 5 micrograms/kg intravenously to raise systemic vascular resistance if the spell continues. I will correct any acidosis with sodium bicarbonate. The softening murmur with deepening cyanosis is the paradox of a severe spell — the outflow is so narrowed that little blood reaches the lungs, so the murmur fades. ^[1]