Persistent Pulmonary Hypertension of the Newborn (PPHN) – Causes, Symptoms & Treatment

In the case of babies, persistent pulmonary hypertension is a situation where the newborn is unable to breathe properly outside the womb of the mother. Babies born with this disease show symptoms like fast breathing, difficulty in breathing, and have insufficient blood oxygen levels, after their first few breaths. This potentially fatal condition is known as persistent pulmonary hypertension newborn (PPHN) and requires quick diagnosis and timely treatment.

What Is Persistent Pulmonary Hypertension of the Newborn (PPHN)?

While in the womb, babies usually get oxygen from the placenta. After birth, however, their lungs must start bringing in oxygen and remove waste gases from the body. This process of respiration or gas exchange allows life-sustaining oxygen to come into the body. After delivery, the blood vessels in the baby’s lungs open up as soon as they try to take the first breath. Sometimes, children are either born with narrowing in the lung arteries or the arteries get thicker and narrower in due course of time. The narrowing of arteries increases blood pressure and causes acute breathing problems or Pulmonary hypertension. Less than 0.1% of 1million babies get PPHN. The condition appears most often in post-term or full-term babies, those born under difficult situations during birth, or have other breathing disorders. If not treated or diagnosed timely, the condition leads to problems with the heart and other vital organs.

Reduced oxygen flow to the brain and other organs endangers the baby’s life. Its occurrence is as frequent as 1.9 per 1,000 live births in the United States, with mortality rates ranging from 4% to 33%.

How Does PPHN Occur?

Inside the womb, the placenta provides oxygenated blood to the baby. This allows the baby’s lungs to remain non-functional and with closed blood vessels. During this time the baby’s blood generally flows over its lungs. After the birth, the baby needs to start breathing on its own to get oxygenated blood.  The pulmonary blood vessels open up allowing blood to flow through the lungs and receive oxygen and give off carbon dioxide. The oxygen-rich blood goes to the heart and is pumped to the rest of the body.

Sometimes the blood vessel called Ductus Arteriosusis constricts or permanently closes after the baby’s birth. This takes the blood away from the lungs to other organs, but without the much-needed oxygen. The excessive pressure in the ductus arteriosus as the lungs push the blood through can potentially hurt the baby’s heart, lungs.

Causes of PPHN

Underdeveloped or abnormally developed blood vessels present in the lungs are one of the primary causes of PPHN.  It is also possible that the pulmonary blood vessels of a baby can face a problem adjusting to the outside air right after birth. While it can be rather difficult to ascertain the exact reason for this condition in a baby, here are some of the most common reasons:

1. Meconium aspiration

Almost 90% of PPHN comes from meconium aspiration or ingestion of fecal matter into the lungs while breathing. When a baby passes feces in the womb, it gets mixed with the amniotic fluid. Sometimes this fluid gets into the lung as the baby takes its first breath.

2. Infection

Pneumonia or other lung or chest infections and bloodstream infections before or during birth reduces the supply of oxygen and increases the risk of PPHN. If, for example, the water breaks long before childbirth reducing oxygen supply or there was group B strep infection present, then there is an increased chance of PPHN.

3. Structural or functional anomalies of the heart and lungs

Babies born with abnormal heart or lung conditions such as a hole in the diaphragm, aortic stenosis, or abnormally small lungs, have a higher likelihood of getting PPHN.

4. Uncontrolled or unstable blood pressure during pregnancy

A healthy human body requires a blood pressure of 120/80 or less. If the mother’s blood pressure shoots up beyond the desired level, then it leads to Preeclampsia, which can be a possible reason for PPHN. Careful monitoring of blood pressure during pregnancy helps in the prevention of unwanted complications.

5. Babies born post membrane rupture

Preterm infants are generally born small and suffer from complications linked to placental insufficiency and reduced fetal growth. These babies have a heightened risk of developing PPHN. It is the same for those born long after the membrane rupture with varying degrees of pulmonary hypoplasia.

6. Inhaling or ingesting nicotine during pregnancy

Nicotine adversely impacts the fetus when used during pregnancy. It causes vasoconstriction by reducing lung function and the development of pulmonary veins of the unborn child. Cigarette smoking or using or inhaling any other substance containing nicotine increases the risk of PPHN for the baby.

7. Anti-Inflammatory drugs during pregnancy

Mothers who have taken non-steroidal anti-inflammatory drugs (NSAIDs) and selective serotonin receptor inhibitors during the third trimester are most likely to give birth to babies with persistent pulmonary hypertension. These medicines may constrict the fetal ductus arteriosus in utero, increasing the chances of idiopathic PPHN.

Symptoms of PPHN

Symptoms of a PPHN can be detected as early as 72 hours of birth. Doctors can usually detect the seriousness of PPHN from the symptoms shown by the newborns. The baby’s inability to breathe normally can sometimes lead to death. Here are some symptoms of PPHN:

1. Less amount of urination
2. Fast Breathing
3. The blue color of skin and lips (cyanosis)
4. Reduced oxygen levels in the blood or poor saturation of oxygen even after oxygen is administered upto 100 percent.
5. Fast Heart rate

Risk Factors for PPHN

Birth asphyxia in babies is a condition caused by a reduced amount of oxygen. This mostly happens for newborns with birth asphyxia or who are born with a lot of difficulties. Although the real reasons are unknown to us, certain factors increase the risk of developing PPHN in infants. Let us look into the possible risk factors of this illness :

1. Babies have abnormal development of the heart or lungs.
2. Meconium aspiration happens when the baby breathes in its feces.
3. Infections, such as heart issues, pneumonia, and lung problems in babies, are also more likely to lead to PPHN.
4. Infants with underdeveloped lungs have problems in breathing. This condition is known as Respiratory distress syndrome.
5. Insufficient or a total lack of oxygen before or during birth.
6. Diaphragmatic hernia is a condition caused by a hole in the diaphragm. The diaphragm is the muscle separating the chest from the abdomen. If a baby has PPHN, their organs from one side intrude on the chest by pushing through the hole.
7. Statistics suggest that babies delivered through C-section have more chances of developing PPHN than normal vaginal delivery. During a natural delivery, fluid is expelled out of the lungs forcing the fetal lungs to compress. This is not possible with C-Section delivery.
8. African-American ethnicity
9. Both term or pre-term infants on the later stage of pregnancy who are less than 34 weeks.
10. Gestational diabetes and obesity in mothers can contribute to the size of the newborn baby. This includes both babies that are too big or too small for their developmental age at birth.

Diagnosis of PPHN Baby

A healthcare provider would check your baby’s health and delivery history before conducting the following tests to diagnose PPHN:

1. Echocardiogram (ECG)

Sound waves or standard ultrasound create medical images of the blood vessels and the heart to determine how the blood flows through the body.

2. X-Rays

Pictures of the lungs are taken to see if the heart is too large.

3. Serum Electrolyte Test and Blood Test

Doctors can conduct a complete blood count test to evaluate the variations of platelet count RBC (red blood cells) and WBC (white blood cells) that are present in the blood. This detects different types of conditions or diseases in the body. Serum electrolyte tests on the other hand measure the level of the main chemicals in the body. This test ascertains how perfectly an infant with infection can utilize the oxygen to its optimum level.

4. Pulse Oximeter

A pulse oximeter is a non-invasive way of measuring oxygen levels in the blood helping to identify oxygen saturation levels in the baby’s tissues. It also evaluates heart rate.

5. Electrocardiogram

This procedure traces the electrical activity in the heart.

6. Lumber Puncture

Also known as a spinal tap, blood tests are performed in the lower back to draw the cerebrospinal fluid that is tested to determine the presence of any infection in the baby.

Treatment for PPHN

Initial treatment of PPHN includes simple measures, such as keeping the baby in an incubator or keeping it warm and giving oxygen through small prongs in the nostrils. If these don’t work, the baby needs to be shifted to a neonatal intensive care unit to raise oxygen levels. Identification of the underlying problem causing PPHN is mandatory for deciding the course of complete treatment. Different types of mechanical ventilation and respiratory therapy options are done as a part of the treatment of PPHN NICU to boost the flow of oxygen to the baby’s organs. Here are some of them that will prevent serious health problems:

1. Oxygen

Supplemental oxygen-containing air may be given to your baby through a nasal cannula, plastic hood, face mask, or nasopharyngeal catheter. The high pressure of oxygen helps to open up the airways and lungs.

2. Assisted ventilation

This method of assisted mechanical ventilation allows spontaneous breathing to restore any physiological irregularities in the diaphragm. An inserted windpipe or tube carrying oxygen supports your baby’s breathing during this procedure.

3. Nitric oxide

Nitic oxide administered through a ventilator effectively treats PPHN because it relaxes contracted lung blood vessels and improves oxygen saturation by controlling the amount of blood flowing into the lungs. Being a small gas molecule, it avidly binds with the hemoglobin once entering the bloodstream. This process helps to limit systemic vascular activity and delivers oxygen to the baby’s brain directly.

4. High-frequency oscillatory ventilation

When conventional mechanical ventilation fails, this lung-protective strategy is utilized for the beneficial effects of oxygenation and ventilation in babies.

5. Medication

When there is excessive pressure in the blood vessels of the lungs, medications will help neonatal patients suffering from pulmonary hypertension. A cannula or drip is inserted into the baby’s hand or foot to administer some antibiotics. Digoxin, Warfarin (Coumadin), and vasodilators like nifedipine or intravenous medicine such as prostacyclin are given to babies. Oral medications, drugs inhaled into the lungs, or medicines given directly into the bloodstream through an intravenous injection can help a baby fight this condition.

6. ECMO

Extracorporeal membrane oxygenation (ECMO) is done as rescue therapy to provide an adequate amount of gaseous exchange to support life.

Complications of PPHN

PPHN can develop into a severe condition that can sometimes take more than a week or even a few months to recover the baby’s lungs. All of your baby’s organs need a regular supply of oxygen-rich blood. Babies detected with PPHN have low blood oxygen saturation levels even when they breathe air with 100% oxygen.

This deprivation of oxygen deprivation can lead to higher possibilities of physical and mental disabilities and long-term health problems that may not be seen until later in a child’s life. Serious complications include organ damage, major brain injuries, hearing deficits, stroke, heart failure, kidney failure, brain hemorrhage, seizures, cerebral palsy, and oxygen dependence.

PPHN can also cause death. Although PPHN in babies is detected within 72 hours of birth the chances of survival in this respiratory distress syndrome can be between 10-50%.

Every child’s condition or response to treatment differ. So, consult your child’s pediatrician to understand the line of treatment. It’s your confidence and hopes that your baby’s care is in the right hands of the best doctors and professionally trained staff that can make your baby overcome this condition.

Also Read:

Jaundice in Newborn Babies

Hypoglycaemia in Newborns

Salmon Patches in Newborns