Transient tachypnea of the newborn
Respiratory distress syndrome
Congenital lung malformations
Birth is a transition from a fluid environment to one where we breathe air. Breathing difficulties are common immediately after birth and during the first few hours of life. In rare cases, a newborn baby may have no or very poor breathing because he has received little or no oxygen due to a problem during labour, delivery, or immediately after birth.
Initially, when a newborn baby is deprived of oxygen, his breaths will become fast and shallow. If the situation continues, he will stop breathing entirely, his heart rate will fall, and he will lose muscle tone. It is possible to revive the newborn baby at this point with simple stimulation and exposure to oxygen. However, if the newborn baby continues to be deprived of oxygen, he will start to gasp deeply, and then he will stop breathing again. His heart rate, blood pressure, and muscle tone will continue to drop, and he will die unless he is promptly resuscitated. There is also the risk of brain damage if not enough oxygen reaches the brain. If a newborn baby is not breathing, or has very poor breathing, he must be resuscitated immediately.
Doctors, nurses, midwives, and respiratory therapists are trained to rapidly recognize when a newborn baby needs to be resuscitated. If the newborn baby is born at home, the midwife needs to immediately recognize the problem, resuscitate the baby and transport him to the hospital, where continuing care will be provided by the health care team. In order for resuscitation to be successful, the doctors and nurses at the hospital need to have resources, such as oxygen equipment and other devices, ready at their fingertips.
If a newborn baby needs resuscitation at or after birth, here are a few things that the doctors and nurses will do:
- Reduce heat loss: The newborn baby will be placed on his back in a warmer to prevent heat loss, and any amniotic fluid will be dried off.
- Suction the mouth and nose: The health care providers will suction the newborn baby’s mouth and nose. If there is meconium present in the mouth or nose, it will be removed by suctioning. If the newborn baby is inactive and not breathing, his windpipe may also be suctioned.
- Examination: The newborn baby will be examined for breathing, heart rate, and colour. This examination will be done very rapidly, in less than 20 seconds.
- Ventilation: If the newborn baby is not breathing, or if his heart rate is less than 100 beats per minute, the doctor will start giving him ventilation with a bag and mask. The doctor will check his heart rate again after a few seconds, and if it is still low and not increasing, the newborn baby will continue to be given ventilation. The doctor may also need to start giving the baby chest compressions.
- Intubation: In some cases when ventilation with a bag and mask is not working, a newborn baby may need to be intubated with a tube that is placed into his windpipe. This tube can deliver gentle puffs of air to the newborn baby’s lungs at a rate of one breath every one or two seconds. Intubation is very helpful if a newborn baby is having a lot of trouble breathing.
- Chest compressions: If the newborn baby needs chest compressions, the doctor will press on his chest three times every two seconds. The doctor will also give him ventilation with a bag and mask every two seconds. After half a minute of chest compressions, the doctor will check the newborn baby’s heart rate. If it is still too low, the doctor may need to give the newborn baby chemical resuscitation.
- Drugs: If ongoing resuscitation is needed, epinephrine and other drugs will be given to the newborn baby, either using an IV or through the windpipe tube if he has one. These drugs will increase the baby’s heart rate and improve the flow of blood around the baby’s body. They are given rapidly and sometimes in repeated doses.
Transient tachypnea of the newborn
Transient tachypnea of the newborn (TTN) is a condition where breathing is rapid for a short period of time immediately after birth. Newborn babies with TTN, which is also known as "wet lung," may have the following features in addition to rapid breathing:
- retractions, also called indrawing: the inward movement of the muscles under the rib cage, between the ribs and in the base of the neck
- cyanosis: a bluish discolouration of the gums, lips, and skin
During pregnancy, the unborn baby’s lungs are expanded with fluid. At birth, this fluid must be rapidly removed and replaced with air. When a baby is born vaginally, the birthing process may help to remove some of this fluid from the lungs. The rest of the fluid is removed by the lymph system and blood vessels. TTN occurs if the liquid in the lung is not removed quickly enough. About 1% of newborn babies experience TTN after birth. There is a higher risk of TTN in babies who are born by caesarean section.
TTN is diagnosed by an assessment of the newborn baby’s symptoms, signs, and X-rays. At first, it may be difficult to distinguish TTN from other causes of respiratory distress. Timing is a key factor, as TTN appears at birth or immediately after birth.
Usually the symptoms can be treated with a little extra oxygen. The newborn baby is monitored for improvement, and sometimes antibiotics are given for the first two days or so. Most newborn babies recover from TTN within three days. If the symptoms last longer, or the newborn baby needs a lot of oxygen, he should be evaluated for an alternative diagnosis.
Respiratory distress syndrome
Normally, when the lungs initially expand with the newborn baby’s first breath, the air sacs fill and remain open. Because the sacs remain open, the surface area within the lungs becomes quite large. Imagine the difference between a straight skirt and a heavily pleated skirt. The skirt with the pleats has much more material in it and therefore a larger area that is exposed to the air. In the lungs, the air sacs or alveoli, though more like bubbles than pleats, increase the surface area of the inside of the lungs and therefore make gas exchange easier. The larger the surface exposed to the air coming into the lungs, the more opportunity oxygen has to pass into the alveoli and the blood.
A substance called surfactant has an essential role in keeping the alveoli open. Surfactant is a kind of foamy, fatty liquid that acts like grease. Without it, the air sacs open but have difficulty remaining open because they stick together. Surfactant allows the sacs to remain open.
Surfactant usually appears in the fetus’ lungs at about the 24th week of pregnancy and gradually builds up to its full level by about the 35th week. Additionally, when labour begins, the mother’s body produces a type of natural steroid that makes its way to the baby through the placenta and umbilical cord. This steroid initiates or speeds up production of surfactant in the lungs in preparation for a newborn baby’s first breath. Newborn babies born without enough surfactant are said to have respiratory distress syndrome or RDS. Premature babies are most at risk for RDS.
Sometimes, a premature birth is not a completely unexpected event. Perhaps due to some kind of distress, a decision is made to initiate labour or perform a caesarean section before term. In these cases, the mother will likely be given steroids to help the baby speed up production of surfactant in the lung and reduce the chances of RDS. At other times, a premature birth is completely unexpected and the administration of steroids either is not possible or will not have time to have an effect on the baby’s lungs by the time of birth. In this case, the newborn baby may be given artificial surfactant to take the place of what her lungs would normally produce. In either case, the newborn baby’s breathing will usually need to be stabilized, either with the help of supplemental oxygen or a ventilator.
Once these measures have been taken, RDS needs time to resolve. The overwhelming majority of newborn babies recover from RDS without major complications or negative implications as the child grows older. However, newborn babies with severe RDS, usually the smallest and most premature babies, are at risk for breathing difficulties, including chronic lung disease and respiratory infections.
Meconium is the build up of waste products in the unborn baby’s intestines before birth. It starts to accumulate in the intestines at around 34 weeks gestation. Usually the newborn baby passes the meconium in a series of bowel movements in the first few days after birth.
Sometimes, if the gastrointestinal system has matured to a certain point, the unborn baby might pass some meconium into the amniotic fluid while he is still in the womb. This is most common when the baby is post-term. The passage of meconium into the amniotic fluid might also happen if the unborn baby experiences a problem such as a lack of oxygen during labour. When meconium mixes with the amniotic fluid, it forms a greenish-black fluid of variable thickness.
If meconium gets into the amniotic fluid, there is a chance that the unborn baby will inhale it. This is called meconium aspiration. When this happens, the newborn baby’s air passages can become blocked, and his lungs can become inflamed. Meconium aspiration is a frequent problem in newborn babies, and affects 10% to 15% of deliveries. About 5% to 10% of babies who are born with meconium aspiration develop respiratory distress, which is a condition where the baby has difficulty breathing. Some of these newborn babies require extra oxygen and ventilation.
The treatment for meconium aspiration depends on how severe the problem is. During and after birth, the newborn baby’s mouth and nose are suctioned. In newborn babies who have weak or no breathing signs, a tube may be placed immediately into the windpipe, to suction meconium from beneath the vocal cords. The newborn baby may need ventilation. Antibiotics may be started to prevent infection and pneumonia.
Meconium in the lungs tends to deactivate the fatty substance called surfactant which is necessary for the air sacs to fill properly with air. Newborn babies with meconium aspiration may need to receive a dose of surfactant to overcome this problem.
In mild cases of meconium aspiration, the condition subsides in two to four days. The newborn baby may have episodes of rapid breathing for a few extra days. Most newborn babies recover fully from this condition, and there usually is no lung damage. Some newborn babies with severe meconium aspiration requiring ventilation may have a more difficult recovery and outcome. Some babies have an increased risk of pneumonia and chronic lung disease as they get older.
A pneumothorax is a rupture of the air sacs, called alveoli, in the lung. As the newborn baby breathes air into the lungs, some of that air goes through the rupture and into the cavity that surrounds the lung. The air that enters the chest cavity puts pressure on the lung from the outside, squeezing and squashing the lung and making breathing more difficult. The positive pressure in the chest cavity can interfere with blood flow through the lungs. If severe, this pressure may prevent blood flow to the heart from the lungs or the body.
Pneumothorax can occur for several reasons. In general, a newborn baby’s lung tissues are vulnerable to rupture if they are under too much pressure. Sometimes the newborn baby’s first breath, opening and expanding the lungs for the first time, is enough to cause a rupture. Other times, pneumothorax occurs during mechanical ventilation. Because mechanical ventilation is only used when necessary, removal from the ventilator may not be possible. If your newborn baby is on a ventilator, his health care providers will pay particular attention to pressure levels and other settings on the ventilator to minimize the chance of lung damage.
Signs of a pneumothorax, which can come on quickly, include:
- a drop in oxygen levels in the blood
- a drop in blood pressure and heart rate
Sometimes a pneumothorax can be seen by shining a very bright light on the newborn baby’s chest. Depending on the size and maturity of the newborn baby, the light will penetrate through the chest wall and patches of air outside the lungs will appear luminous through the skin. Generally, however, a pneumothorax is diagnosed or confirmed with a chest X-ray.
If the hole caused by pneumothorax is small, it may not be noticed and will likely seal itself up. If the hole is large, it will likely interfere with breathing, at times suddenly and dramatically.
If a newborn baby with pneumothorax has no symptoms, or only mild symptoms, no treatment may be required. On the other hand, if the newborn baby is having significant difficulty breathing, or if the blood circulation is slowed, the air in the cavity surrounding the lungs must be removed rapidly. This can be done using a needle and syringe. If the newborn baby is already on mechanical ventilation, the doctor may insert a chest tube and remove the air through it. The tube can be removed a few days later.
Pneumonia is when a micro-organism enters the lung and causes its airways to become infected and inflamed. The lung may produce excess fluid that can accumulate in the airways. In general, pneumonia is first suspected when the newborn baby shows unexplained signs of respiratory distress. Certain events during delivery, the condition of the mother during delivery, and indeed the type of delivery can put a newborn at risk for infection.
The first symptoms of pneumonia are:
Other signs of pneumonia, such as a build up of fluid in the lungs, may have other causes. This can make diagnosis difficult.
X-rays are not always helpful when diagnosing pneumonia. X-rays may turn up patchy areas of the lung, which can cover a large area or be localized. Air bronchograms, or abnormal pockets of air sealed off from the rest of the lung, may also appear on X-ray. However, these signs are also present in other conditions such as TTN and RDS.
If a lung infection is suspected, doctors will probably not wait for the results of a laboratory test before beginning treatment. Broad-spectrum antibiotics, which can fight a wide range of possible infections, are prescribed. These antibiotics are used to clear the infection and to prevent it from spreading to other parts of the body. Most newborn babies require extra oxygen to help them breathe while the infection clears. Premature babies may need a fatty substance called surfactant to help the air sacs to fill and stay open properly. Sometimes a newborn baby requires mechanical ventilation.
Congenital lung malformations
Although rare, some newborn babies are born with a congenital malformation of the lungs. These types of malformation may be suspected if the newborn baby has an increased breathing rate, grunting, or a bluish tint to the skin, and there is no other explanation. In other words, if lung function remains poor and the conditions listed above are ruled out, a malformation will be suspected.
Generally speaking, X-rays and other imaging techniques are used to confirm a diagnosis of malformation. In most cases, the malformation is corrected with surgery. Until the surgery can be performed, breathing is stabilized and supported.
There are many types of congenital lung malformations. The most common of these are:
- Congenital diaphragmatic hernia: This is a malformation of the diaphragm, which separates the chest from the abdomen. Usually with this condition, the diaphragm either is missing or has a hole in it. As a result, the organs in the abdomen – the stomach, liver, and so on – can drift into the chest cavity, leaving little room for the lungs to develop during fetal life. The lungs are smaller than usual, especially the lung on the same side as the diaphragmatic hernia. Repair is accomplished with surgery.
- Cystic adenomatous malformations: These are cysts at the end of the small airways within the lung. There may be many small cysts, giving the lung a honeycomb appearance on X-ray, or there may be one or two large cysts. Cysts in the lung usually drain poorly and cause chronic infections. Most newborn babies with these cysts have respiratory distress. Surgical removal of the affected lobe is the treatment. The surgeon will try to remove as little of the remaining healthy lung tissue as possible.
- Congenital lobar emphysema: This is a malformation that causes overinflation of one of the lobes of the lungs. Congenital lobar emphysema becomes a problem because the overinflated lung takes up more space than it should and therefore interferes with the regular inflation of the rest of the lung. Surgery is the treatment for this condition.
- Pulmonary sequestration: This is an area of lung tissue that is not connected to the airways of the lung. The extra lung tissue has no function. The abnormality may be within or outside the lung. A pulmonary sequestration may cause breathing problems, or there may not be any symptoms at all. Surgery is recommended to remove a pulmonary sequestration.