Patent Ductus Arteriosus

Reviewed by David Knight

September
2007

Incidence	Diagnosis	Investigations
Management	References	Other Related Documents

Incidence

PDA is a problem in ventilated very low birth weight infants. About 40% of these will have a large PDA at 3 days of age.

Diagnosis

Early: Mostly silent, with no murmur. BP may be low (systolic, diastolic and mean) with normal pulse pressure.
Late: Murmur. Hyperactive precordium.
Increased pulses. Wide pulse pressure. These are not reliable signs in the first few days.
Congestive Heart Failure
- Cardiomegaly
- Hepatomegaly
- Pulmonary congestion/oedema/plethora
Clinical respiratory deterioration.
Rising PaCO₂.

Usually diagnosed late. Most babies treated before this stage.

Investigations

Echocardiogram	Usually done at 3 days in infants <28 weeks' gestation or <1000g. Other babies are investigated on clinical suspicion. Rules out (most) congenital heart disease. It is important to rule out duct dependent lesions, especially coarctation. Pulmonary stenosis may be masked by a large PDA. Establishes ductal patency and size. Indicates the size of the shunt (ductus shunt is best assessed by its physical size, then by descending aortic flow pattern). A ductal lumen >1.5mm and a reversed descending aortic diastolic flow suggest a significant PDA. Left pulmonary artery flow may be useful. Left atrial:Aortic root ratios and LV size are less helpful. Assesses atrial shunt and size.
Chest X-ray	To look at heart size and lung fields.
ECG	The ECG is usually normal. It is rarely done in preterm infants.

Management

Indications for treatment	Significant shunt in a small baby with ongoing lung disease. Closure of the ductus is aimed mainly at improving lung function.
<28 weeks or <1000gms, and on IPPV or CPAP	Echocardiogram at 3 days. Significant PDA: Consider indomethacin.
Other babies on IPPV	Investigate if clinical suspicion.
Indomethacin	See drug protocol. Monitor creatinine, electrolytes, urine output & platelets before and at least daily initially. If these parameters remain normal, then they do not need to be routinely checked after the 3^rd dose. Review baby and results before each dose. Contraindications: Thrombocytopenia NEC Bleeding diathesis Poor renal function Pulmonary haemorrhage (note: may occur because there is a PDA)
Fluid restriction	While on indomethacin, reduce by 20-40ml/kg/day. There is no evidence that fluid restriction per se results in closure of the duct but there are studies suggesting that early, liberal fluid intakes are associated with a higher incidence of PDA.
Surgery	If PDA is still clinically significant after indomethacin, or if indomethacin is contraindicated. Surgery will usually be performed on NICU. Note that a increase in respiratory support is often required immediately after surgery.

References

1	Knight DB. The treatment of patent ductus arteriosus in preterm infants. A review and overview of randomized trials. Seminars in Neonatology. 2001; 6: 63-73.
2	Cooke L, Steer P, Woodgate P. Indomethacin for asymptomatic patent ductus arteriosus in preterm infants. Cochrane Database of Systematic Reviews 2003, Issue 1.
3	Herrera C, Holberton J, Davis P. Prolonged versus short course of indomethacin for the treatment of patent ductus arteriosus in preterm infants. Cochrane Database of Systematic Reviews 2001, Issue 4.
4	Brooks JM, Travadi JN et al. Is surgical ligation of patent ductus Arteriosus necessary? The Western Australian experience of conservative management. Arch Dis Childh. 2005; 90: F235-F239.
5	Evans N. Current controversies in the diagnosis and treatment of patent ductus arteriosus in preterm infants. Advances in Neonatal Care. 2003; 3: 168-177.

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