PDA Pharm Flashcards
What does PDA stand for in neonatal care?
Patent Ductus Arteriosus
PDA is a persistence of a conduit between the aorta and pulmonary artery, necessary for fetal circulation.
What is the most significant risk factor for developing a PDA?
Preterm birth
The incidence of PDA is inversely related to gestational age, with 80% of infants born at 25-28 weeks experiencing a PDA.
What are common risk factors associated with PDA?
- Excessive fluid administration
- Respiratory distress
- Septicemia
- Phototherapy
- Furosemide therapy
What is the role of PDA in fetal circulation?
Necessary to bypass the high resistance pulmonary circulation and oxygenate the lower limbs.
What happens during the transition from fetal to neonatal circulation at birth?
- Loss of placental circuit function
- Decreased blood flow through the inferior vena cava
- Inflation of lungs with first breath
- Drop in pulmonary vascular pressure
What is the functional closure of the ductus arteriosus primarily due to?
Smooth muscle contraction.
What causes the anatomical closure of the ductus arteriosus?
Extensive neointimal thickening and loss of smooth muscle cells.
What is the significance of pulmonary vascular resistance and systemic vascular resistance in PDA?
Increases in systemic vascular resistance and decreases in pulmonary vascular resistance favor left-right shunting.
What are the cardiovascular clinical presentations of PDA?
- Wide pulse pressure
- Coarse systolic murmur at the left sternal border
- Active precordium
- Hypotension
What complications can arise from renal hypoperfusion due to PDA?
- Fluid retention within cardiopulmonary circuit
- Metabolic acidosis
- Oliguria
- Hyponatremia
- Increased creatinine
What diagnostic tool is definitive for diagnosing a PDA?
Doppler echocardiogram.
What is the best early predictor of hemodynamic significance in babies less than 29 weeks?
A ductal diameter greater than 1.5 mm measured in the first 31 hours of life.
What are conservative management strategies for PDA?
- Decreasing preload
- Optimizing gas exchange
- Mitigating excessive pulmonary blood flow
What is indomethacin used for in the context of PDA?
To promote closure of the ductus arteriosus.
What are the adverse effects of indomethacin?
- Rapid decrease in renal and mesenteric blood flow
- Decreased cerebral blood flow
- Impaired platelet aggregation
What is the mechanism of action of ibuprofen in treating PDA?
Non-selective COX inhibitor.
What is the significance of PGE2 in relation to PDA?
PGE2 is a vasodilator that maintains patency of the duct during fetal life and may persist after birth in cases of delayed transition.
What is the primary mechanism of action of acetaminophen on PDA?
Peroxidase-mediated inhibition of conversion of prostaglandin G2 to H2.
What are the potential long-term effects of acetaminophen use in neonates?
Unknown.
What are the implications of ductal steal in a PDA?
Reversal of flow leads to pulmonary overcirculation and systemic hypoperfusion.
What is the typical timeline for prophylactic treatment of PDA?
Up until 24 hours after birth.
What are the two phases of ductal closure?
- Functional closure
- Anatomical closure
What is the impact of blood viscosity on PDA hemodynamics?
Anemic infants will experience increased left-to-right shunting.
What is the effect of oxygen on the ductus arteriosus in term infants compared to preterm infants?
In term infants, oxygen acts as a vasoconstrictor, while in preterm infants, the ductus is less sensitive to oxygen, promoting patency.
