Approach to a Child with Cyanotic Heart Disease

Anita Khalil

Central cyanosis in an infant is a diagnostic emergency. Cyanosis be associated with diseases of central nervous system, blood lungs and cardiovascular system. Central cyanosis may be due to inadequately oxygenerated pulmonary venous blood, in which case inhalation of 100% oxygen for 10 minutes may diminish or clear the discolouration.

When PaO₂ of arterial sample:

• 250 mm Hg - excludes congenital heart disease.
• >160 mm Hg - unlikely
• <150 mm Hg - suggestive of cyanotic CHD, RDS and persistent foetal circulation .

As a single determinant, if radial artery O₂ saturation > 80% after 100% O₂ inhalation, it excludes cyanotic heart disease.

Management Of Cyanotic Infants

• Avoid Iron deficiency - avoid late weaning and ensure adequate iron uptake.
• Avoid dehydration - polycythemia predisposes to dehydration even when well hydrated.
• Ensure good weight gain - avoid failure to thrive.
• Endocarditis risk - counsel family members about prevention.
• Influenza risk - immunize.
• Recurrence risk - will increase - so counseling of family.
• Hypercyanotic spells - tetralogy of fallot.
• If frequent - surgery advised.

Non Surgical Management Of Cyanotic CHD

When a cyanotic infant presents with deep cyanosis, congestive cardiac failure or rhythm disturbance, the patient is usually hypoxic and acidotic. The circulation depends on the potency of ductus arteriosus and foramen ovale. Congestive cardiac failure is due to increased pulmonary blood flow which has to be managed by decongestive measures.

Maintenance Of Ductal Patency

Various ductus dependent lesions are:-

1. Those with severe RVOT obstruction pulmonary atresia, TOF, Severe pulmonary stenosis.
2. Transposition of great arteries with intact ventricular septum.
3. Tricuspid atresia with pulmonary stenosis.
4. Hypoplastic left heart syndrome.

Various interventions to maintain ductal patency are:-

• Prostaglandin infusion to maintainductal patency. PGE1 - 0.1 ngm/kg/min parenterally to tide over till ready for surgery
• transcatheter intervention
• Endo vascular stents

Transcatheter Atrial Septostomy:

1. Better inter - atrial mixing.
   • Transposition of great arteries
   • Taussig bing anomaly
2. Augmentation of L-R shunt
   • Mitral atresia
   • DORV with restrictive left A-V valve,
   • Univentricular heart with restrictive left A-V valve,
   • Post Fontan surgery requiring fenestration.
3. Augmentation of R-L shunt
   • TAPVC
   • Pulmonary atresia, tricuspid atresia
   • Ebstein's anomaly

Hypoplastic left heart syndrome with interatrial obstruction and severe pulmonary vascular disease are examples in which enlarging an ASD as a bridge to cardiac transplantation is beneficial.

Specific Management

Transposition of great arteries (TGA) with VSD In TGA with VSD, surgical treatment is advised within first 2-4 months of life as congestive heart failure and growth failure are difficult to manage. Arterial switch operation is needed at the earliest, without which prognosis is poor and infants succumb within 1st year of life.

Tetralogy of Fallot

The treatment depends on the severity of right ventricular outflow tract (RVOT) obstruction. If it is severe, then ductus arteriosus is to be kept open with PGE1 infusion. In less severe cases, while waiting for surgery dehydration is to be prevented, iron deficiency anemia is to be prevented by oral iron therapy. Oral propranolol (1mg/kg/6 hourly) decreases the frequency and severity of hypercyanotic spells.

Palliative surgery (Blalock - Taussig shunt) may be performed to decrease the severity of hypoxia and provide linear growth. Full correction may be done later.

Hypercyanotic Spell - Stepwise Treatment:

1. Place the child in a knee - chest position
2. Humidified O2 by mask
3. Sedation - Morphine 0.01 - 0.1 mg/kg subcutaneously.
4. I/V fluids - to combat dehydration and acidosis with sodium bicarbonate
5. I/V propranolol 0.1 mg/kg intravenously.
6. Administer general anaesthesia if the spell does not subside by 30 minutes.
7. If the hypercyanotic spell does not respond to the above mentioned measures, then emergency palliative shunt surgery or corrective surgery should be performed.