Apnea is a common problem in preterm infants that may be due to prematurity or an associated illness. In term infants, apnea is always worrisome and demands immediate diagnostic evaluation. Periodic breathing must be distinguished from prolonged apneic pauses because the latter may be associated with serious illnesses.
Apnea is a feature of many primary diseases that affect neonates . These disorders produce apnea by direct depression of the central nervous system’s control of respiration (hypoglycemia, meningitis, drugs, hemorrhage, seizures), disturbances in oxygen delivery (shock, sepsis, anemia), or ventilation defects (pneumonia, RDS, persistent pulmonary hypertension of the newborn [PPHN], muscle weakness).
Idiopathic apnea of prematurity occurs in the absence of identifiable predisposing diseases. Apnea is a disorder of respiratory control and may be obstructive, central, or mixed.
Obstructive apnea (pharyngeal instability, neck flexion, nasal occlusion) is characterized by absent airflow but persistent chest wall motion. Pharyngeal collapse may follow the negative airway pressures generated during inspiration, or it may result from incoordination of the tongue and other upper airway muscles involved in maintaining airway patency.
In central apnea, which is caused by decreased central nervous system (CNS) stimuli to respiratory muscles, airflow and chest wall motion are absent. Gestational age is the most important determinant of respiratory control, with the frequency of apnea being inversely related to gestational age. The immaturity of the brainstem respiratory centers is manifested by an