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]

SAQ 2 — Stepwise pharmacological management of paediatric heart failure (10 marks, 15 minutes)

Stem: A six-month-old with a dilated cardiomyopathy has chronic heart failure with oedema, tachypnoea and poor weight gain. Outline the stepwise pharmacological management, the doses of each drug, and the trial evidence that shapes paediatric heart failure prescribing. [2] [3] [4]

Model answer

Step 1 — Symptom relief with a diuretic (2 marks). Begin with a diuretic to relieve congestion: furosemide at 0.5 to 2 milligrams per kilogram per dose, orally or intravenously, one to four times daily, with spironolactone at 1 to 3 milligrams per kilogram per day for potassium-sparing and aldosterone antagonism. Monitor the sodium, potassium and volume, and recheck the weight. [4]

Step 2 — Afterload reduction with an ACE inhibitor (3 marks). Add an ACE inhibitor to reduce afterload and the neurohormonal burden. Captopril is given in the infant at an initial 0.15 to 0.3 milligram per kilogram per dose every eight hours, or enalapril at 0.1 milligram per kilogram once daily, titrated upward. Check the blood pressure at first dose, and recheck urea, electrolytes and creatinine within one to two weeks and after each dose change, because the harm is hyperkalaemia and a rising creatinine. [4]

Step 3 — Neurohormonal modulation with a beta-blocker (3 marks). Once the child is stable, add carvedilol started at 0.05 to 0.1 milligram per kilogram twice daily and titrated over weeks toward 0.3 to 0.5 milligram per kilogram twice daily, watching the heart rate and blood pressure. Symptomatic digoxin may be added at an oral maintenance dose of 5 to 10 micrograms per kilogram per day in divided doses. [2] [4]

Trial evidence and honest communication (2 marks). The carvedilol randomised trial of Shaddy and colleagues did not show a significant benefit on its primary composite outcome in children, and the single-ventricle enalapril trial of Hsu and colleagues likewise showed no benefit on the primary outcomes for infants after stage-one palliation. These trials explain why paediatric heart failure prescribing is extrapolated from adult evidence and physiology and is specialist-supervised rather than evidence-rigid. Communicate that uncertainty honestly to the family while building a structured, monitored plan. [2] [3]