Cardiovascular medicines in children — formative SAQs

SAQ 1 — A cyanotic neonate and prostaglandin E1 (10 marks, 15 minutes)

Stem: A two-day-old term neonate presents with central cyanosis, tachypnoea and a metabolic acidosis. There is strong clinical suspicion of a duct-dependent congenital heart lesion, and echocardiography is being arranged. Outline the immediate pharmacological management, the dose, the target, and the adverse effects you must prepare for. ^[10]

Model answer

Immediate action (2 marks). Do not wait for echocardiography. Start an intravenous prostaglandin E1 (alprostadil) infusion at once, because the circulation depends on a patent ductus arteriosus that is closing. Prostaglandin E1 reopens and keeps the duct patent while definitive anatomy-specific management is arranged. Secure intravenous access, give oxygen, and prepare for transfer to a cardiac centre. ^[10]

Dose and titration (3 marks). Start at 0.01 to 0.05 microgram per kilogram per minute intravenously and titrate upward toward a typical maximum of around 0.1 microgram per kilogram per minute, watching for the response: a rising oxygen saturation, a warming perfusion, and a falling lactate. The target saturation in most duct-dependent cyanotic disease is around 75 to 85 per cent, not a normal saturation, because excessive pulmonary flow steals from the systemic circulation. State that prostaglandin E1 is a bridge, not a treatment. ^[10]

Adverse effects and preparation (3 marks). Three adverse effects are expected and prepared for. Apnoea is common — have a plan for intubation and ventilation. Fever can mislead the team toward a septic work-up; recognise it as a drug effect. Hypotension is managed with volume and, where needed, a low-dose vasopressor. Recognise that the fever and apnoea are the drug, not the disease. ^[10]

Safety and disposition (2 marks). Treat the prostaglandin as a bridge to definitive anatomy repair or palliation. Communicate clearly with the family, organise retrieval to a cardiac centre, and document the dose, the titration and the airway plan. Do not allow suspicion of sepsis to delay the prostaglandin, but take appropriate cultures and consider antibiotics alongside. ^[10]