Demystifying

Critical Congenital Heart Disease

Is it safe to give fluids?

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What O2 sat should I target?

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When do I give prostaglandin?

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Is it safe to give fluids? 〰️ What O2 sat should I target? 〰️ When do I give prostaglandin? 〰️

Let’s face it, trying to remember the specific structural abnormalities and whether oxygen or fluids are safe in the heat of the moment is hard. To simplify the management of congenital heart emergencies, we can categorize them into three primary processes based on their typical clinical presentation.

  • Right-sided obstructive lesions resulting in central cyanosis.

    Examples: Tricuspid atresia, pulmonary stenosis, Ebstein anomaly, TGA w/o VSD, Tetralogy of Fallot

    Obstructed pulmonary venous return resulting in cyanosis and heart failure.

    Examples: TAPVR, truncus arteriosus, double outlet right ventricle, TGA with VSD or PDA

  • Left to right shunting results in pulmonary overcirculation and heart failure.

    Examples: VSD, PDA, AVM, AV canal defect

  • Left-sided obstructive lesion results in decreased systemic blood flow and cardiogenic shock.

    Examples: Hypoplastic left heart syndrome, Coarctation of the aorta, Interrupted aortic arch, Aortic stenosis, ALCAPA

Decreased pulmonary blood flow

Lesions with right-sided obstructive lesions and/or right-to-left shunting result in a blue baby with central cyanosis. Typically present <1 month of age as patent ductus arteriosus (PDA) is closing. These right-sided obstructive lesions tend to be dependent on a PDA to supply the pulmonary blood flow. There are some exceptions that are non-PDA dependent such as Tetralogy of Fallot and TGA w/o VSD.

  • Cyanosis (SpO2 <80%)

  • Failed hyperoxia test

  • CXR: normal lungs, cardiomegaly

  • EKG: RVH

Management

  1. Give supplemental oxygen (goal 100%) +/- inhaled nitric oxide to decrease pulmonary vascular resistance (PVR) and facilitate pulmonary blood flow.

  2. Safe to give IV fluids (20 cc/kg)

  3. Administer prostaglandin (PGE-1) to maintain PDA

    If the patient fails to improve after the initial dose, then discontinue the infusion as this could signify pulmonary venous or left atrial obstruction as seen in TAPVR, an infant with TGA without VSD, or TOF.

Increased pulmonary blood flow

Left to right shunting causes increased pulmonary blood flow resulting in a pink baby with symptoms of heart failure. Typically presents between 1-6 months of age as pulmonary vascular resistance (PVR) falls causing increased shunting.

  • Feeding difficulty, sweating with feeds, failure to thrive

  • Tachypnea, respiratory distress, rales, hepatomegaly

  • Elevated BNP

  • CXR: wet lungs, cardiomegaly

  • EKG: RAD, AV block

Management

  1. Minimize O2 (goal 80-85%) as it can cause pulmonary vasodilation and worsen pulmonary overcirculation. Consider adding positive pressure ventilation or intubate to increase PVR and minimize shunting

  2. Judicious IVF (5-10 cc/kg bolus) to not worsen the left heart failure

  3. Diuretics

Decreased systemic blood flow

Left obstructive lesion causes inadequate systemic blood flow resulting in a gray baby with symptoms of cardiogenic shock. Typically presents <1 months of age as patent ductus arteriosus (PDA) is closing. These left-sided obstructive lesions tend to be dependent on a PDA to supply the systemic blood flow.

  • Pallor (“ashen gray”)

  • Tachycardia, hypotension, delayed capillary refill, altered mental status

  • Differential SpO2, BP, and pulse in RUE vs LLE

  • CXR: wet lungs, cardiomegaly

  • EKG: LVH

Management

  1. Minimize O2 (goal 80-85%) as decreased PVR can lead to systemic steal. Consider adding positive pressure ventilation or intubate to increase PVR and minimize shunting

  2. Judicious IVF (5-10 cc/kg bolus)

  3. Administer prostaglandin (PGE-1) to maintain PDA

  4. Epinephrine and dopamine for hemodynamic support

  5. Milrinone or dobutamine for afterload reduction and inotropy

Key points:

  1. Treating hypoxia with oxygen can worsen left-to-right shunting due to its potent pulmonary vasodilatory effects. If known, target the patient’s baseline oxygen saturation otherwise aim for 85%.

  2. Some CHD benefit from IV fluids, however, others can worsen underlying heart failure or cardiogenic shock. Give IV fluids in 5-10 cc/kg aliquots and reassess for a response.

  3. In general, prostaglandin should be administered for patients <2 weeks presenting with cyanosis or shock with suspected CHD. Be mindful as it may cause apnea so be prepared to intubate if needed.

  4. CHD can mimic common viral illnesses. Quiet tachypnea and worsening clinical condition with IV fluids should warn you of the possibility of heart failure.