Patent ductus arteriosus

Overview

• a form of congenital heart defect
• generally classed as 'acyanotic'. However, uncorrected can eventually result in late cyanosis in the lower extremities, termed differential cyanosis
• connection between the pulmonary trunk and descending aorta
• usually, the ductus arteriosus closes with the first breaths due to increased pulmonary flow which enhances prostaglandins clearance
• more common in premature babies, born at high altitude or maternal rubella infection in the first trimester

Features

• left subclavicular thrill
• continuous 'machinery' murmur
• large volume, bounding, collapsing pulse
• wide pulse pressure
• heaving apex beat

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Management

Preterm infants

• most centres now recommend initial expectant supportive care rather than early pharmacologic therapy as spontaneous closure often occurs
• if hemodynamically significant ΡDA remains or the infant remains ventilator dependent after one week of age then pharmacological closure is generally recommended:
  • ibuprofen, indomethacin or paracetamol
  • inhibits prostaglandin synthesis
  • given to the infant, not to the mother in the antenatal period
  • closes the connection in the majority of cases
  • indomethacin use is declining due to increased side-effect profile compared to other drugs