PDA Flashcards
(28 cards)
What is the function of the ductus arteriosus (DA) in fetal circulation?
The DA connects the pulmonary artery to the descending aorta, allowing blood to bypass non-ventilated fetal lungs.
What percentage of right ventricular output flows through the DA in utero?
~90%
What maintains DA patency during fetal life?
Low oxygen tension (PaO2) and high levels of prostaglandin E2 (PGE2).
What triggers the closure of the ductus arteriosus after birth?
Increase in PaO2 and decrease in PGE2.
When does functional closure of the DA typically occur?
Within 72 hours postnatally.
What completes anatomical closure of the DA?
Intimal thickening and fibrosis, generally by 4 months of age.
What is the effect of umbilical cord clamping on the DA?
Increases systemic vascular resistance (SVR).
How does lung expansion affect the ductus arteriosus?
Decreases pulmonary vascular resistance (PVR) and increases pulmonary blood flow.
What role does oxygenation play in the closure of the DA?
Increases reduce PGE2 production and enhance its metabolism.
What factors prevent closure of the DA in preterm infants?
- Immature pulmonary and renal metabolism
- Increased nitric oxide (NO) from oxygen therapy
- Immature ductal muscle structure
- Sepsis, RDS, and other comorbidities
What are clinical manifestations of hemodynamically significant PDA (hsPDA)?
- Systolic murmur
- Bounding peripheral pulses
- Widened pulse pressure (>20 mmHg)
- Tachycardia
- Escalating oxygen needs
- Decreased urine output
What is the gold standard for diagnosing PDA?
Echocardiography.
What do elevated levels of BNP or NT-proBNP indicate?
Ventricular stress from volume overload.
What is a common outcome for ELBW infants with PDA within the first 8 days?
Spontaneous closure.
What is a conservative treatment strategy for PDA?
- Optimize fluid balance
- Diuretics may improve symptoms
- Ensure adequate oxygenation
What is the mechanism of action of indomethacin?
Non-selective inhibition of COX-1 and COX-2, reducing PGE2 synthesis.
When is indomethacin most effective?
When given within the first 3 days of life.
What are the adverse effects of indomethacin?
- ↓ cerebral perfusion
- ↓ urine output
- Risk for spontaneous intestinal perforation (SIP)
What is the standard dosing for ibuprofen in PDA management?
10 mg/kg IV or PO initially, followed by 5 mg/kg at 24 and 48 hours.
What are the advantages of using ibuprofen compared to indomethacin?
May be safer in terms of renal, GI, and cerebral perfusion.
What is the dosing for acetaminophen in PDA management?
7.5–15 mg/kg q6h for 3–7 days IV or PO.
What are the potential adverse effects of acetaminophen?
- Hepatotoxicity
- Transient elevations in AST, ALT, GGT
What is indicated when pharmacologic therapy for PDA fails?
Surgical management.
What are some risks associated with surgical management of PDA?
- Vocal cord paralysis
- Chylothorax
- Pneumothorax
- Ductal tear
