Primary Pulmonary Hypertension in Newborns
- Prior to birth, the baby's body is oxygenated by the mother's placenta. He has no immediate need for the lungs or the arteries leading to the lungs. After birth, the baby takes a deep breath of oxygen which expands the lungs and expands the arteries, bringing blood flow to the lungs. In pulmonary hypertension, the lungs and vessels leading to the lungs do not expand, causing decreased flow to the lungs and increased pressure on the heart.
- Imagine a faucet (heart), water (blood), a hose (pulmonary artery) and a garden (lungs). If the opening of the hose (pulmonary artery) is wide, the water (blood) flows easily to the garden (lungs). If the opening is narrow, less water (blood) flows to the plants (lungs) and is under greater pressure (pulmonary hypertension). That increased pressure backs up to the faucet (heart) and weakens the heart.
- According to the "Merck Medical Manual," the symptoms of pulmonary hypertension in newborns include rapid breathing, retractions (sinking around ribs visible when breathing), low oxygenation, bluish or grayish color, low blood pressure and weak pulse. Other symptoms may include decreased urine output and extreme lethargy.
- According to Robin H. Steinhorn, M.D., PPHN in newborns can be caused by hyaline membrane disease (immature lungs in premature babies), meconium aspiration (baby inhales his first stool prior to birth) and congenital diaphragmatic hernia (diaphragm is not completely formed) (see link in References). Other causes include maternal infection, maternal smoking, excessive aspirin, non-steroidal anti-inflammatories (acetaminophen, ibuprofen) and certain anti-depressants (SSRIs) taken by the mother prior to birth. In some, the cause is idiopathic, meaning the cause is unknown.
- The newborn with PPHN is critically ill. Treatment includes placement on a ventilator with inhaled nitric oxide, HFOV (High Frequency Oscillating Ventilator), ECMO (lung bypass), surgery to correct an underlying condition such as a diaphragmatic hernia, or a heart defect; medicines such as sildenafil to dilate the pulmonary artery and supportive therapy to support blood pressure, temperature, nutrition and sedation. Emotional support should be provided to the family.