Pneumothorax, Pneumomediastinum and Pulmonary Interstitial Emphysema
What are Pneumothorax, Pneumomediastinum and Pulmonary Interstitial Emphysema (PIE)?
Normally the air that we breathe goes down the trachea (windpipe) to a series of branches of the windpipe called bronchi. The air then goes to the air sacs where oxygen is delivered to the blood and carbon dioxide is released. If the air sacs become overfilled with air, the air can break out of the air sacs and get into spaces where it should not be. This condition is sometimes referred to as air leak and includes the following:
Pneumothorax where the air is trapped inside the chest between the chest wall and the lung, causing the lung to collapse.
Pneumomediastinum where air is trapped in the middle part of the chest.
Pulmonary Interstitial Emphysema (PIE) where air is trapped between the tiny air sacs, encircling the smallest blood vessels and bronchi.
Less commonly, air can encircle the heart, (Pneumopericardium), get under the skin, (Subcutaneous Emphysema), leak into the abdomen (Pneumoperitoneum) or surround the kidneys (Pneumoretroperitoneum). A baby often has more than one form of air leak. For example, PIE can progress to pneumomediastinum and/or pneumothorax.
Which babies get air leak? Although air leak can happen in any baby, it is more common if:
the baby has underlying lung disease, the more severe the disease, the higher the risk for air leak.
the baby needs CPAP or mechanical ventilation for treatment of lung disease
Why do preemies get air leak? The lungs are not yet fully developed and the air sacs are more susceptible to rupture.
If the baby has lung disease, some air sacs are open and others are closed. Like blowing up balloons, it is easier to put lots of air into an air sac that has been opened previously than it is to put a small amount of air into an air sac that has never been opened.
There is more space between air sacs where leaking air can collect as interstitial emphysema.
What can be done to treat air leak? Some forms of air leak are more easily treated than others. Approaches to treatment include:
If the air leak is small, not increasing, and not causing significant problems, it may not need to be treated. The air gradually reabsorbs into the body.
Occasionally a pneumothorax can be treated by inserting a needle into the chest and sucking out the air with a syringe. Often, however, the air will recollect.
If a tube can be placed in the area where air is collecting, continuous suction on the tube can remove the air until the leak seals over. This is the most common treatment.
In a pneumothorax a chest tube is placed between two ribs and into the chest cavity between the lungs and the chest wall.
In a pneumopericardium a tube is placed between the heart and its covering, called a pericardial tube.
In interstitial emphysema and in pneumomediastinum, the spaces containing the air are sponge-like and cannot be treated with tubes.
If your baby has interstitial emphysema and is on a ventilator (breathing machine), your baby's doctor may change to a different pattern of ventilation (breathing). This may mean giving more rapid, but smaller breaths or changing to a form of ventilation called high frequency ventilation.
Is air leak serious? Depending on the amount of air and the space where it is located, the symptoms and seriousness of air leak may vary from mild to catastrophic. A large pneumothorax or a pneumopericardium usually causes sudden and rapid deterioration. Interstitial emphysema usually occurs more gradually.
When will it get better? As your baby's underlying lung disease improves, the air leak also improves. However, babies who have had air leak often improve more slowly than babies who have not. When the tubes no longer drain air, they will be removed. Once the tubes are out for more than a day and the baby is off the breathing machine or CPAP, airleak usually does not recur.