Apnea of Prematurity
Apnea of prematurity is a pause in breathing that lasts for more than 20 seconds.
Apnea of prematurity commonly occurs in newborns who are born before 34 weeks of pregnancy, increasing in frequency and severity among the most prematurely born. In these newborns, the part of the brain that controls breathing (respiratory center) has not matured fully. As a result, the newborns may have repeated episodes of normal breathing alternating with brief pauses in breathing. In very tiny premature newborns, apnea can be caused by temporary obstruction of the pharynx due to low muscle tone or a bending forward of the neck; this is called obstructive apnea. Over time, as the respiratory center matures, episodes of apnea become less frequent, and by the time the newborn approaches term, they no longer occur.
Symptoms and Diagnosis
Premature newborns are routinely attached to a monitor that sounds an alarm if the newborn stops breathing for a prolonged time or if the heart rate slows. Depending on the length of the episodes, stoppage of breathing may decrease the oxygen levels in the blood, which results in a bluish discoloration of the skin (cyanosis). Low levels of oxygen in the blood may slow the heart rate (bradycardia).
Apnea can sometimes be a sign of a disorder, such as infection of the blood (sepsis), low blood sugar (hypoglycemia), or a low body temperature (hypothermia). Therefore, the doctor evaluates the newborn to rule out these disorders when there is a sudden or unexpected increase in frequency of episodes.
Treatment
Treatment of apnea depends on the cause. Apnea caused by obstruction of the pharynx may be decreased by keeping the newborn lying on his back or side with his head in the midline position. If episodes of apnea become frequent, and especially if the newborn has cyanosis, the newborn may be treated with a drug that stimulates the respiratory center, such as caffeine or aminophylline. If these treatments fail to prevent frequent and severe episodes of apnea, the premature newborn may need treatment with continuous positive airway pressure (CPAP) or a ventilator.
Virtually all premature newborns stop having episodes of apnea several weeks before they reach term. Although a few infants are discharged from the hospital and placed on home monitors before they have completely outgrown their episodes of apnea, this practice is not standard or generally accepted. An association between apnea in the premature newborn and the risk for sudden infant death syndrome (SIDS (see Section 23, Chapter 267)), which usually occurs months after birth, has not been proven. Likewise, there is no proof that discharging an infant home on an apnea monitor decreases the risk of SIDS.
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