Persistent Pulmonary Hypertension of the Newborn (PPHN) is a condition affecting the flow of blood to a newborn's lungs just after birth. As a part of the normal birthing process, the child's blood pressure in the lungs will drop to provide normal blood flow circulation when the baby breathes on its own. Alternatively, persistent pulmonary hypertension of the newborn causes a return to fetal circulation for the flow of blood bypasses the lungs and the baby is unable to breathe.
Approximately one out of 700 newborns are born with persistent pulmonary hypertension. The serious breathing problem usually affects premature babies at 34 weeks or more. Full-term babies will usually have some other form of breathing issue.
The neonatal pulmonary hypertension problem often results in hypoxemia where the flow of blood is diminished, providing an abnormally low level of oxygen to the body. Without treatment, the disorder can lead to severe respiratory distress where the skin becomes bluish in color and the child's breathing becomes rapid.
- Who Is at Risk for Persistent Pulmonary Hypertension of The Newborn?
- Common Symptoms
- Diagnosing Persistent Pulmonary Hypertension Of The Newborn
- Treating the Condition
- Prognosis (Outlook)
Who Is at Risk for Persistent Pulmonary Hypertension of The Newborn?
Persistent pulmonary hypertension of the newborn is a congenital defect that usually affects near full-term and full-term babies. The condition is typically recognized within the first 72 hours after delivery. While any child was susceptible to developing PPHN at birth, there are specific risk factors that are known to increase the potential risk. These include:
- Congenital disorders including congenital heart disease and underdeveloped lungs
- Low body temperature
- Insufficient oxygen levels before and after the baby's delivery
- Respiratory Distress Syndrome where the child has difficulty in breathing because the lungs have not fully developed
- Meconium aspiration where the fetus inhales their bowel movement into their lungs prior to birth
Meconium Aspiration Complications
Some births are complicated due to meconium stained amniotic fluid that can cause fetal distress, an awkwardly positioned fetus (dystocia), the need for a cesarean section birth when the cervix and uterus fail to contract and expand. These complications are often the result of certain risk factors that include:
- Women delivering babies at a risky age
- Cocaine abuse
- Placental insufficiency
- Maternal hypertension
Meconium aspiration can be a serious problem if it leads to certain complications including meconium aspiration syndrome, birth asphyxia, and the need to place the child in the neonatal intensive care unit after birth. If the child was healthy at birth, no suction is required, especially if there are no detectable signs of fetal distress within an hour or two after birth.
However, if the child is sick during delivery, the birthing team will likely suction the newborn's airways after the child's shoulders have been delivered through the vaginal canal. In addition, the child might require ventilatory/oxygen support or prophylactic antibiotics immediately after being born.
The most common signs and symptoms associated with persistent pulmonary hypertension of the newborn involve prenatal stress including:
- Systemic hypotension (abnormally low blood pressure)
- Meconium staining that mixes with amniotic fluid prior to the baby's birth
- Harsh systolic heart murmur involving tricuspid regurgitation
- Respiratory distress including tachypnea
- Cyanosis caused by perfusion or poor cardiac function
Some newborns experience idiopathic PPHN and never display any symptom of acute distress.
Diagnosing Persistent Pulmonary Hypertension Of The Newborn
Many times, persistent pulmonary hypertension of the newborn is obvious at birth. However, some children developed the condition in a day or two following their delivery. The doctor will usually detect noticeable signs of rapid breathing or severe respiratory distress. Other times, the newborn's skin will take on a bluish discoloration as a result of cyanosis when oxygen levels in the bloodstream are extremely low. If the child was suffering from hypotension (low blood pressure), they often display a grace, blue hue to their skin and present a weakened pulse.
The obstetrician may be suspicious the child is suffering from persistent pulmonary hypertension if the mother had a stressful delivery or took high dosages of indomethacin or aspirin for an extended period of time while they were pregnant. Other times, the child will suffer severe respiratory distress or other noticeable signs associated with PPHN. Diagnosing the condition may be difficult because chest x-rays could show the child's internal organs are normal without presenting any underlying disorder of the lungs. Usually, an accurate diagnosis will require extensive tests including echocardiograms that provide a better understanding of the newborn's pulmonary arteries.
The doctor may also want to perform a cardiac ultrasound test to evaluate the child's blood flow circulation. This information will provide the data required to develop an effective treatment plan to improve blood flow oxygen levels, maintain typical blood pressure, and relax the lungs blood vessels. The doctor may determine there is an underlying disorder that is exacerbating the condition including neonatal pneumonia, meconium aspiration syndrome or a congenital diaphragmatic hernia.
Other test used to validate a diagnosis of persistent pulmonary hypertension of the newborn include:
- Arterial Blood Gas (ABG) Test to evaluate oxygen that is delivered throughout the body
- Serum Electrolyte Tests can provide valuable information on blood-associated mineral balances
- Ultrasound technology using sound waves can identify any bleeding in the brain that might be associated with the condition
- Pulse Oximetry measurements that identify the level of oxygen in the bloodstream to ensure that the tissue in the baby's body is receiving sufficient oxygen
- Lumbar Puncture (Spinal Tap) to rule out or verify an infection
Treating the Condition
Treating the condition usually requires ensuring that the baby is receiving 100% of the necessary oxygen to survive. In addition, the doctor may also recommend nitric oxide that helps the body utilize the available oxygen or the use of a special ventilator to allow the baby to breathe at a normal rate. In severe cases, the doctor may recommend a temporary heart-lung bypass to allow the child ample time to recover from the condition.
The most common methods associated with treating persistent pulmonary hypertension of the newborn include:
- Continuous monitoring of the baby's blood pressure and oxygenation levels
- Nutritional support
- Correcting the child's electrolyte and glucose abnormalities caused by the defect
- Routinely maintaining the child's blood pressure
- Minimal handling of the child during the recovery process
- Avoidance of invasive procedures when noninvasive procedures can provide the same results
The medical team will usually provide a variety of therapeutic methods if one or more of the following treatments listed above are utilized. This includes:
- Assisted ventilation
- Inotropic (normal muscle contraction) support
- The use of nitric oxide
- Surfactant administration
- Correction of alkalosis and acidosis
- Endotracheal intubation
- Extracorporeal membrane oxygenation (ECMO) to provide respiratory oxygen support
- High-frequency oscillatory ventilation
The medical team will usually involve a developmental pediatrician and/or neurologist to perform a neurological evaluation after the child is discharged from the hospital.
Only the most severe cases of meconium aspiration are fatal. However, suctioning the baby's lungs, providing prophylactic antibiotics, and ventilatory support has proven highly effective at decreasing the number of cases where the child dies from complications associated with persistent pulmonary hypertension of the newborn.