pediatrics
Persistent Pulmonary Hypertension of the Newborn
Etiology of PPHN
In Normal Fetal Circulation , blood entering the right side of the heart has already been oxygenated via the placenta. Because the lungs are not ventilated, only a small amount of blood needs to go through the pulmonary artery. Most blood from the right side of the heart bypasses the lungs through the foramen ovale and ductus arteriosus. Normally, these two structures close shortly after birth. (See also In PPHN (previously known as persistent fetal circulation), prenatal stress, postnatal stress, and anatomical differences may result in the persistence of elevated pulmonary vascular resistance after birth. Hypoxemia and acidosis cause the pulmonary arterioles to constrict and the ductus arteriosus to dilate, reversing the usual processes establishing newborn circulation at delivery and resulting in right-to-left shunting through the ductus arteriosus, foramen ovale, or both. This right-to-left shunting bypasses the lungs and causes nonoxygenated or poorly oxygenated blood to be delivered systemically. Themost common causesof persistent pulmonary hypertension of the newborn involve Perinatal asphyxia or hypoxia A history of meconium staining of amniotic fluid or meconium in the trachea is common. Hypoxia triggers reversion to or persistence of elevated pulmonary vascular resistance, a normal state in the fetus. Additional causes include Respiratory Distress Syndrome in Neonates None Premature ductus arteriosus or foramen ovale closure, which increases fetal pulmonary blood flow and may be triggered by maternal nonsteroidal anti-inflammatory drug (NSAID) use ( Etiology references ) Pulmonary hypoplasia with associated pulmonary vasculature hypoplasia leading to PPHN ( Etiology references ) Diaphragmatic Hernia , in which one lung is severely hypoplastic, also leading to pulmonary vasculature hypoplasia and PPHN Neonatal Sepsis or 1.Van Marter LJ, Hernandez-Diaz S, Werler MM, et al: Nonsteroidal anti-inflammatory drugs in late pregnancy and persistent pulmonary hypertension of the newborn.Pediatrics131(1):79–87, 2013. doi: 10.1542/peds.2012-0496 2.Chandrasekharan PK, Rawat M, Madappa R, et al: Congenital diaphragmatic hernia—A review.Matern Health Neonatol Perinatol3:6, 2017. doi: 10.1186/s40748-017-0045-1 