Persistent Pulmonary Hypertension:  A Very Serious Condition in the Newborn

Persistent Pulmonary Hypertension

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We all hope for our newborn to have a healthy start, and those first few minutes and hours are critical.  Fortunately, the great majority of neonates have a relatively smooth beginning:  90% need only routine care right at birth, and an additional 9% need relatively minimal measures to jump-start their lives.

But let’s talk about that remaining one percent.  That group can need quite a bit of help to become stable, thriving infants, and most of these newborns will have problems with respiration—breathing in enough oxygen and expelling enough carbon dioxide to satisfy the body’s requirements.

Even among this group, there are a number of conditions that are usually straightforward for physicians to treat.  However, about 1.9 infants in 1000 will have a particularly serious condition known as persistent pulmonary hypertension of the newborn, or PPHN.  But what is PPHN?  And what can a parent expect when this is the diagnosis?

PPHN Explained

Hypertension, as we know, means high blood pressure, and refers to an issue with blood vessels (arteries and veins) that carry blood.  Pulmonary has to do with the lungs:  like the body’s other organs, the lungs contain blood vessels.  Thus, pulmonary hypertension refers to elevated pressure in the lung’s blood vessels.

In order to explain why this is an important problem, it’s worth looking what happens to blood flow in a fetus and how that changes once a baby is born.  Inside Mom, an unborn baby receives all oxygen and nutrients from the placenta; there is, in fact, little blood flow going through the lungs.

This blood flow pattern changes at birth.  As the baby takes his first few breaths, the lungs expand.  As this is happening, the flow to and from the placenta shuts down and is largely replaced by blood flow through the lungs’ blood vessels, which have responded to the changes by getting bigger.

That is, that’s how it happens in the great majority of babies.  But in rare cases, this doesn’t happen as it should:  the pressure in the lungs’ vessels stays sufficiently high that blood can’t get through.  Blood still flows through the body, but what was supposed to move through the lungs is diverted through the heart and major blood vessels, bypassing the lungs.  The newborn is thus deprived of oxygen and can’t get rid of carbon dioxide.

Why might this happen?  What prevents babies from making this necessary change?  Some reasons:

  • The baby may have an infection, particularly pneumonia.
  • There may be a birth defect in the lung that hinders the transition.
  • The lungs may not be properly developed.
  • The baby may have something known as meconium aspiration syndrome. In this illness, material from a bowel movement gets into the lung while inside Mom.
  • Recent research suggest that some medications taken by pregnant women may increase the risk of PPHN.

Certainly not every infant who develops these problems will get PPHN.  But any of them can increase the risk of contracting the illness.

If My Baby Has PPHN, What Will Happen?

Babies with PPHN are generally quite ill.  The first signs of illness are usually trouble breathing and a bluish color.  These signs may occur after delivery, when the newborn doesn’t transition well to breathing room air, or the problem may show up several hours later (though almost all newborns ultimately diagnosed with PPHN needed some help to breathe in the delivery room).  Many will have evidence of a bowel movement (meconium) prior to birth, which is a sign of stress.

Initial testing is similar for any newborn who has trouble breathing.  Usually, a blood sample is taken to measure the amount of oxygen and carbon dioxide in the blood.  Also, a quicker test known as pulse oximetry is performed.  This test uses infrared light to estimate the blood’s oxygen.  It’s not as specific as measuring through a blood draw, but it is quick and straightforward enough so that the baby’s oxygen can be monitored continuously.

A chest x-ray will be done to look for causes of PPHN, and generally the baby will receive test for infection.  In addition, an echocardiogram is done to get a picture of the heart and blood vessels.  This helps rule out other heart disease and gives physicians an idea of the amount of flow through the lung’s blood vessels.

Because of the severity of the illness, a newborn with PPHN are managed in a neonatal intensive care unit (NICU).  She will generally need extra oxygen, and many infants will need a tube and breathing machine (ventilator) to get all they need.  Sometimes oxygen levels are improved when infants are given a sedative, which decreases the effort needed to breathe.

In addition, the NICU’s medical team will treat any causes of PPHN that they suspect might be happening.  One example of this treatment is giving antibiotics for infection.

Medication is also frequently used to alter the baby’s blood flow so that blood goes through the lungs.  The goal is to relax the blood vessels in the lungs so that oxygen can enter.  Extremely ill babies may be candidates for extracorporeal membrane oxygenation (ECMO), a procedure where blood is circulated away from the body into a machine that adds oxygen before the blood is returned to the patient.

Although PPHN can be fatal, 90% do survive the illness.  Pediatric providers monitor graduates of PPHN treatment closely to make sure they are developing on target.

Fortunately, most babies who need help to breathe during those first few minutes of life will not end up with PPHN.  Those that do are monitored closely and, thanks to modern medical research, physicians have an increasing amount of treatment choices to hopefully improve the chances of a good recovery.

Stan Sack
Dr. Stan Sack has 29 years’ experience as a primary care pediatrician in Massachusetts and Florida. A medical writer since 2015, he enjoys blogging on topics that are on parents’ minds but are covered less often in books and on websites. He lives in the Florida Keys with his family and enjoys healthy cooking, fitness activities and singing in his spare time.

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