pediatrics
Apnea of Prematurity
Pathophysiology of Apnea of Prematurity
Apnea of prematurity is a developmental disorder caused by immaturity of neurologic and/or mechanical function of the respiratory system. Apnea may be characterized as Central (most common) Obstructive A mixed pattern Central apneais caused by immature medullary respiratory control centers. The specific pathophysiology is not understood completely but appears to involve a number of factors, including abnormal responses to hypoxia and hypercapnia. This is the most common type of apnea of prematurity. Obstructive apneais caused by obstructed airflow, neck flexion causing opposition of hypopharyngeal soft tissues, nasal occlusion, or reflex laryngospasm. Mixed apneais a combination of central and obstructive apnea. All types of apnea can cause hypoxemia, cyanosis, and bradycardia if the apnea is prolonged. Because bradycardia can also occur simultaneously with apnea, a central mechanism may be responsible for both. About 18% of infants who have died of sudden infant death syndrome ( Sudden Unexpected Infant Death (SUID) and Sudden Infant Death Syndrome (SIDS) ) had a history of Periodic breathingis repeated cycles of 5 to 20 seconds of normal breathing alternating with brief (< 20 seconds) periods of apnea. This phenomenon is common among preterm infants and is not considered apnea of prematurity and has little or no clinical significance. Apneic episodes in preterm infants should not be attributed to prematurity until serious causes (eg, infectious, cardiac, metabolic, respiratory, central nervous system, thermoregulatory) have been ruled out. 