Clinical Reference Systems: Pediatric Advisor 10.0

DESCRIPTION

Premature infants, particularly those born more than 7 weeks early (before 32 weeks of pregnancy), have apnea. Having apnea means there are times when they stop breathing (apnea spells).

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 80 beats a minute and the baby becomes pale or bluish.

Babies normally breathe 20 to 60 times a minute. It is normal for babies to stop breathing for up to 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.

CAUSE

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 (a post-conceptional age of 34 to 36 weeks).

Premature infants have another kind of apnea spell called obstructive apnea. This kind of apnea occurs when their 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. Again, growth and strengthening of the tissues in the airway solve this problem.

Most premature babies have both kinds of apnea.

TREATMENT

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

1. Monitors

   Because premature and sick newborn babies are likely to have apnea, all babies admitted to the special care nursery (SCN) are attached to a monitor that continuously measures heart rate and respiratory (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 determine what is going on. The monitor is only a machine; a person needs to determine the meaning of the alarm.

   A record of the number of apnea spells is kept by the bed to keep track of how the baby is doing.

2. Stimulation

   When the monitor alarm sounds, the nurse goes to the baby and observes. 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.

3. Medications

   Several medications can stimulate the part of the brain that controls breathing and can reduce the number of apnea spells. Aminophylline and theophylline are the most commonly used drugs. They can be given directly into the veins (intravenously, or IV) or by mouth. Caffeine can also be very effective and is given by mouth.

   Side effects from the medication are usually mild. They include fast heart rate, throwing up, and irritability. The levels of medication in the blood can be measured and the dosage adjusted to get just the right level and avoid most side effects.

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

4. Respiratory support

   The more immature a baby is, the more frequent and severe the apnea can be. If the apnea spells are very frequent or very severe and the baby needs vigorous 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 device that fits into the baby's nose and blows oxygen under pressure into the baby's airway and lungs. CPAP can reduce the number of apnea spells and is often helpful for babies who have obstructive apnea. A baby on nasal CPAP does all the breathing herself.

   • 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 (extubate) to see if she is ready to breathe on her own. Sometimes it takes several tries before the baby is able 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.

5. Other causes of apnea

   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 such problems are corrected, the apnea will occur less often and be less severe. Your baby's physician may look for these problems if the apnea suddenly gets worse.

DISCHARGE FROM THE HOSPITAL

Most premature babies outgrow their apnea at a post-conceptional age of 34 to 36 weeks. If they are apnea free for a week--that is, they do not have an apnea spell for at least a week--they will probably not have apnea again.

The decisions for discharge from the hospital may be different for each baby, but here are some general guidelines:

• All families who have babies with apnea are encouraged to be trained in infant cardiopulmonary resuscitation (CPR) before the baby is discharged. Although it is unlikely that you will ever have to use CPR, it is best for you to be prepared.
• If a baby has never been given medication for apnea, he may be considered ready for discharge when he has not had apnea for 7 days.
• If a baby given medication for apnea does not have apnea for 7 days and is ready to go home, he may be sent home with a prescription for theophylline or caffeine. After he has grown and matured for about a month his medication may be stopped. Theophylline is given by mouth three times a day. Caffeine is given by mouth once a day.
• If a baby on medication is apnea free but not ready to go home for other reasons, the theophylline or caffeine may be stopped and the baby will be observed for apnea for 5 to 7 days. If the baby has apnea again, he may be given medication for it again.
• Sometimes a baby keeps having apnea spells despite treatment with theophylline or caffeine. In these cases your baby's physician may recommend home monitoring to allow earlier discharge from the hospital. Before your baby is sent home, your physician will probably want to see him go 5 to 7 days without apnea. Then the family may be taught how to use a monitor at home. 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. As with all monitors, many false alarms occur. Most babies do not need home monitors.

LONG-TERM OUTCOME

Apnea caused by prematurity is not a cause of SIDS (sudden infant death syndrome, or crib death). SIDS cannot be predicted. Usually babies who die of SIDS do not give any clues there is a problem before they die. There are no tests to predict which babies are at risk for SIDS. Babies who have had apnea of prematurity are not necessarily at a higher risk for SIDS. Your baby's physician makes decisions for home monitoring based on how the baby is outgrowing his apnea spells, not to protect him from SIDS.

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 (44 weeks post-conceptional age). 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 rest assured, they do outgrow it.