Apnea of Prematurity

What is apnea?

Apnea means there are times when breathing stops. These are called apnea spells. Babies who are born early, particularly those born more than 7 weeks early (before 32 weeks of pregnancy), often have apnea.

A baby with apnea:

• suddenly stops breathing for more than 10 seconds
• has a drop in heart rate below 90 beats a minute when the apnea occurs
• becomes pale or bluish around the mouth and face during an apnea spell
• starts breathing again by himself or needs help to restart breathing.

Apnea may happen once a day or many times a day. The more immature the baby is, the more frequent the apnea spells are. As the baby matures, he outgrows the apnea.

It is normal for babies to have pauses in their heart and breathing rates. The normal heart rate for babies is between 120 and 160 beats a minute. Many babies have brief drops in the heart rate. The drop in heart rate is considered normal if the heart rate returns to normal by itself and there is no breathing pause or change in the baby's skin color when the drop occurs. It is not normal if the baby's heart rate drops below 90 beats a minute and the baby becomes pale or bluish.

Babies normally breathe 20 to 60 times a minute and sometimes stop breathing for 10 to 12 seconds. These breathing pauses are considered to be normal if the baby begins breathing again by himself and there is no change in the baby's skin color and no drop in heart rate. Babies may also have a breathing pattern in which they have a breathing pause and then breathe several rapid shallow breaths. This is called periodic breathing and is also considered to be normal. Pauses between breaths that are longer than 15 seconds or pauses that occur with a change in the baby's skin color and a drop in heart rate are not normal.

What causes apnea?

A baby does not need to breathe before she is born because she gets oxygen from the placenta. Once born, the baby needs to breathe continuously to get oxygen. The brain controls the breathing rate and rhythm. The premature baby's brain is not yet programmed for nonstop breathing and so the baby sometimes stops breathing. Apnea caused by an immature brain is called central apnea. The premature baby outgrows central apnea as the brain matures. Often babies outgrow central apnea by 34 to 36 weeks after conception.

Premature infants have another kind of apnea spell called obstructive apnea. This kind of apnea occurs when the baby's fragile airway is blocked. The block may be caused by mucous, or the baby may be in a position that kinks the airway. The baby tries to breathe but can't move air because of the blockage. Suctioning the airway or changing the baby's position usually relieves the problem. Normal growth and strengthening of the tissues in the airway solve this problem.

Most premature babies have both kinds of apnea.

What is the treatment?

The treatment for apnea is designed to protect the baby from stopping breathing while we wait for the baby to outgrow the problem.

Monitoring

Because premature and sick newborn babies are likely to have apnea, all babies admitted to the special care nursery are attached to a monitor that continuously measures heart rate and breathing rate. This type of monitor is called a cardiorespiratory monitor. If the baby stops breathing for too long or his heart rate drops too low, the monitor sounds an alarm to alert the staff. A nurse then immediately checks the baby to see if he needs any help.

Many alarms are false alarms because the monitor did not measure the breathing or heart rate correctly. Sometimes the monitor leads come off the skin, causing an alarm to sound. Someone must look at the baby and see what is going on.

Stimulation

When the monitor alarm sounds, the nurse checks the baby. She determines whether the baby is breathing, what the heart rate is, and whether there is any change in the color of the baby's skin. Many times the baby starts breathing again by herself and does not need any help.

If the baby is not breathing, her back, arms, or legs are rubbed. The baby's head may be turned to a different side or she may be turned over. This kind of stimulation is continued until the baby is clearly trying to breathe again. If the baby remains pale or bluish, oxygen may be given to her. Occasionally the baby may be given some breaths with a bag filled with oxygen to help her start breathing again. This is called bag-and-mask breathing.

Medications

Medicine can cause part of the brain that controls breathing to be more active which can reduce the number of apnea spells. Caffeine is the drug most often used. It can be given directly into the vein (IV) or mixed in with milk during feedings.

Side effects from the medicine are usually mild. They include fast heart rate, throwing up, and irritability. The levels of medicine in the blood can be measured to be sure the baby's getting enough but not too much. This helps avoid most side effects.

The baby keeps getting medicine until he has outgrown the apnea.

Respiratory support

The more immature a baby is, the worse the apnea can be. If the apnea spells happen a lot or last a long time and the baby needs a lot stimulation or mask-and-bag breathing to start breathing again, the baby may need help with her breathing so she can rest. Nasal CPAP and a ventilator are two ways to help the baby breathe.

• Nasal CPAP

  Nasal CPAP is a system that blows oxygen under pressure into the baby's airway and lungs through the nose. CPAP can reduce the number of apnea spells and is often helpful for babies who have obstructive apnea. The baby doesn't work as hard to breathe, because the pressure from the CPAP machine helps keep the airway open.

• Ventilator

  Babies who are very small or who have very frequent, severe spells of apnea often need to be put on a ventilator to help their breathing. A tube is put through the mouth and into the windpipe (trachea). Tape across the baby's upper lip holds the tube in place. The ventilator blows air and oxygen under pressure through the tube and into the lungs to give the baby extra breaths. The baby is left on the ventilator for a while to give time for growth and maturation.

  After a few days or weeks the baby is taken off the ventilator to see if she is ready to breathe on her own. Sometimes it takes several tries before the baby is able to breathe well enough to stay off the ventilator. Using the ventilator does not cause the baby to get lazy or forget how to breathe. The baby is being given time to mature and grow.

Treating other problems

A premature baby's apnea may be worsened by other problems the baby may have. Infection, anemia (low red blood cell count), and an imbalance of minerals in the blood can all cause a baby's apnea to worsen. If problems are found and corrected, the apnea will occur less often and be less severe. Your baby's doctor may look for these problems if the apnea suddenly gets worse.

When can my baby go home?

Babies need to be free from apnea spells for 5 to 7 days before they can be considered ready to go home. The baby may be sent home while still taking medicines. If medicines are being used and the baby is still having breathing problems, your baby's health care provider may recommend home monitoring. These monitors are similar to the monitors used in the hospital and will sound an alarm if the baby's breathing or heart rate changes. You will be taught how to use the monitor if one is sent home with you.

All families who have babies with apnea are encouraged to be trained in infant cardiopulmonary resuscitation (CPR) before the baby goes home. Although it is unlikely that you will ever have to use CPR, it is best for you to be prepared.

How long will it last?

All babies outgrow apnea caused by prematurity, although some may take longer than others. Almost all babies stop having apnea by 1 month after their due date. Apnea does not cause long-term brain damage, and babies whose apnea lasts a long time do not have more problems than other babies. Apnea is one of the more frightening problems premature babies can have, but they do outgrow it.

Apnea caused by prematurity is not a cause of SIDS (sudden infant death syndrome, or crib death). Babies who have had apnea of prematurity are not necessarily at a higher risk for SIDS.