PPHN Pharm Flashcards
What is the state of the fetus concerning pulmonary blood flow?
The fetus is in a state of pulmonary hypertension with low pulmonary blood flow.
What is PPHN?
PPHN is a condition where the normal circulatory transition of blood flow fails to occur, and pulmonary blood flow remains low.
What are the contributing factors to elevated pulmonary vascular resistance in PPHN?
Pulmonary vasoconstriction, vascular proliferation, and remodeling.
List some risk factors for PPHN.
- Maternal medications (NSAIDs, SSRIs)
- Chorioamnionitis
- Gestational Diabetes Mellitus (GDM)
- Smoking
- Hypoxemia
- Congenital heart disease
What are the causes of hypoxemia that can lead to PPHN?
- Asphyxia
- Lung parenchymal conditions (meconium aspiration, RDS, pneumonia)
- Congenital Diaphragmatic Hernia (CDH)
- Polycythemia
- Acidosis
- Hypercapnia
What are the three types of PPHN categorized by etiology?
- Idiopathic
- Maladaptation
- Underdeveloped vasculature
What is the pathology of PPHN?
PPHN typically begins with hypoxemia causing persistent pulmonary vasoconstriction, leading to right-to-left shunting through fetal shunts.
What metabolic consequence occurs due to deoxygenated blood bypassing the lungs in PPHN?
The body relies on anaerobic metabolism, producing lactate and causing metabolic acidosis.
What is the role of endothelium-derived mediators at birth?
They play an important role in cardiopulmonary transition.
What happens to the balance of vasoconstrictors and vasodilators in PPHN?
There is decreased production of vasodilators and increased vasoconstrictors.
What is Inhaled Nitric Oxide (iNO) used for?
iNO is used as a selective pulmonary vasodilator in the management of PPHN.
What is the recommended initial dose of iNO for term infants?
20 ppm, with improvement in oxygenation expected in less than 30 minutes.
True or False: iNO should be used in infants with ductal dependent blood flow.
False.
What is the half-life of iNO?
2-6 seconds.
What should be monitored when administering iNO?
Methemoglobinemia and platelet count.
What is the function of Sildenafil/Tadalafil in PPHN?
They are selective PDE-5 inhibitors that cause vasodilation in the pulmonary vascular system.
What effect does Bosentan have in PPHN?
Bosentan acts as an ET-1 receptor agonist, primarily affecting vasoconstriction.
What is the mechanism of action of prostacyclin analogues?
They activate adenylate cyclase to increase cAMP concentrations in vascular smooth muscle cells.
What are the side effects of Sildenafil?
- Hearing loss
- Hypotension
- Priapism
- Anterior ischemic neuropathy
What is the role of Milrinone in treating PPHN?
Milrinone acts as a PDE-3 inhibitor with inotropic and lusitropic effects, improving ventricular function.
What is Alprostadil used for?
To maintain ductus arteriosus patency as a bridge to operative correction or palliation.
What is the benefit of combination therapy in PPHN?
It may provide an additive effect or achieve the same effect at lower doses.
