Persistent Pulmonary Hypertension of the Newborn
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This disorder causes severe trouble breathing (respiratory distress) in full-term or postterm newborns.
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Breathing is rapid, and the skin and/or lips may be bluish or may be pale and grayish.
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The diagnosis is confirmed by an echocardiogram.
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Treatment involves opening (dilating) the arteries to the lungs by giving high concentrations of oxygen, often while supporting the newborn’s breathing with a ventilator.
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To help dilate the arteries in the lungs, sometimes nitric oxide is added to the gas that the newborn is breathing.
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Extracorporeal membrane oxygenation is sometimes used in the most severe cases.
(See also Overview of General Problems in Newborns.)
Normally, the blood vessels to the fetus's lungs are tightly constricted before birth. The lungs do not need much blood flow before birth because the placenta rather than the lungs eliminates carbon dioxide and transports oxygen to the fetus. Immediately after birth, the umbilical cord is cut and the newborn’s lungs must take over the role of oxygenating the blood and removing carbon dioxide. To achieve this process, it is necessary for the fluid filling the air sacs (alveoli) in the lungs to be replaced by air and for the pulmonary arteries, which bring blood to the lungs, to widen (dilate) so that an adequate amount of blood flows through the lungs to be oxygenated.
Causes
Sometimes the blood vessels to the lungs do not dilate after birth as they normally should. When the blood vessels to the lungs do not dilate, blood pressure in the pulmonary arteries is too high (pulmonary hypertension), and blood flow to the lungs is insufficient. Because of this insufficient blood flow, not enough oxygen reaches the blood.
There are many reasons the blood vessels may not dilate, including
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Severe distress during delivery (such as from meconium aspiration syndrome)
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Any other circumstance that causes a low level of oxygen in the fetus before, during, or after delivery (such as infection in the mother or the fetus [sepsis in the newborn], problems with the placenta, diaphragmatic hernia, collapsed lung, underdeveloped lungs, or pneumonia)
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Certain drugs taken during pregnancy (such as large doses of aspirin or other nonsteroidal anti-inflammatory drugs such as ibuprofen)
Symptoms
Sometimes persistent pulmonary hypertension is present from birth. Other times, it develops over the first day or two.
Breathing is usually rapid, and there may be severe respiratory distress if the newborn has an underlying lung disorder (such as respiratory distress syndrome). The skin and/or lips may have a bluish discoloration (cyanosis) due to low blood oxygen levels. Sometimes newborns with persistent pulmonary hypertension have low blood pressure (hypotension) that causes weak pulses and a pale, grayish hue to the skin.
Diagnosis
Doctors may suspect persistent pulmonary hypertension if the mother took high doses of aspirin or indomethacin during pregnancy or had a stressful delivery. They also suspect persistent pulmonary hypertension if the newborn has severe respiratory distress, cyanosis that does not go away when high concentrations of supplemental oxygen are given, and unexpectedly low oxygen levels in the blood. Doctors may also suspect persistent pulmonary hypertension in newborns who have meconium aspiration syndrome, who may have an infection, or who need more oxygen or breathing support than expected.
To confirm the diagnosis of persistent pulmonary hypertension of the newborn, doctors do an echocardiogram to see how blood flows through the heart and to the lungs.
A chest x-ray may be entirely normal if there is no underlying lung disorder or may show changes caused by an underlying disorder (such as diaphragmatic hernia or meconium aspiration syndrome).
Cultures of the blood may be done to look for certain kinds of bacteria.
Prognosis
Treatment
Treatment of persistent pulmonary hypertension of the newborn involves placing newborns in an environment with 100% oxygen. In severe cases, a ventilator (a machine that helps air get in and out of the lungs) providing 100% oxygen may be needed. A high percentage of oxygen in the blood helps open the arteries going to the lungs.
A very small concentration of the gas nitric oxide may be added to the oxygen that the newborn is breathing. Inhaled nitric oxide opens the arteries in the newborn’s lungs and reduces pulmonary hypertension. This treatment may be needed for several days.
Rarely, if all other treatments do not work, extracorporeal membrane oxygenation (ECMO) can be used. In this procedure, blood from the newborn is circulated through a machine that adds oxygen and removes carbon dioxide and then returns the blood to the newborn. The machine acts as an artificial set of lungs for the newborn. As the machine does the work of getting oxygen into the newborn's body, the newborn's lungs have time to rest and the blood vessels slowly open up. ECMO has been lifesaving, allowing some newborns with pulmonary hypertension who do not respond to other treatments to survive until the pulmonary hypertension resolves.
Fluids and other treatments, such as antibiotics for an infection, are given as needed.
