Patent (open) ductus Arteriosus (PDA)
Ductus arteriosus is normal pathway in fetal circulatory system.
Connection left pulmonary artery with descending aorta.
Blood flow is shunted away from lungs through ductus arteriosus directly into systematic circulation.
Functional closure of ductus arteriosus, first 10-15 hours after birth and permanent closure within 5-7 days.
If closure of arteriosus doesnot occur even by 2-3 week of age, then known as patent (open) ductus arteriosus.
Pathophysiology
Failure of closure of ductus arteriosus leads to shunting of blood from high pressure aorta to low pressure pulmonary artery (left to right shunt).
Result increased blood flow to pulmonary tree and increased blood return to left side of heart causing volume loaded left ventricles.
Clinical features
Depend on size of PDA and age of infant.
In preterm infant
Symptoms appear earlier.
In preterm infants pulmonary vascular resistance falls more rapidly. Allowing more left to right shunting, their myocardium is immature and less stable to handle and extra load occur and go into congestive heart failure.
In term infants
Depend on size of ductus.
Small PDA- Asymptomatic
Large PDA- Congestive heart failure
Condition cause growth retardation and easy fatigability.
Diagnostic Evaluation
1. Cardiac Examination
Systolic murmur or continuous murmur present. Best heard 2nd to 3rd left intercostal space. Diastolic rumble and gallop.
2. Electrocardiogram
ECG usually normal, may show left ventricular hypertrophy and left atrial dilatation in older children.
3. Chest radiograph
Shows increased pulmonary vascularity with normal or increased heart size.
4. Echocardiogram
Colour flow 2D echo helps in visualization of patent ductus arteriosus.
With Doppler amount of blood flow cross PDA estmated.
Therapeutic Management
Ventilator support
Oxygen Therapy
Medical intervention
Surgical intervention
1. Administration of Indomethacin; (NSAIDs); Prostaglandin inhibitor.
By inhibiting prostaglandin, indomethacin allows PDA to close.
More effective in preterm and term infant.
Administer before age of 10 days.
Orally /IV dose 0.2 mg/kg three, times
Surgical management
Lateral thoracotomy, closed heart surgery
Ductus ligated with sutures or ligated and divided completely.
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