Chapter 41

1. Problem. An infant has just had an apneic episode with bradycardia. Apnea is the absence of breathing for >20 s or a shorter pause (>10 s) associated with oxygen desaturation or bradycardia (<100 beats/min). Central apnea is the complete absence of respiratory effort. Obstructive apnea occurs when an infant breathes but no airflow is present because of an obstruction. Mixed apnea is both central and obstructive apnea. Periodic breathing is three or more respiratory pauses lasting >3 s separated by normal respiratory intervals not longer than 20 s. This is not associated with bradycardia. Apnea of prematurity (AOP) is most prevalent in premature infants <36 weeks' gestation and is most commonly central or mixed apnea. Apnea is very common: >50% of infants <1500 g and 90% of infants <1000 g have it.

2. Immediate questions

1. What is the gestational age of the infant? Apnea and bradycardia are common in premature infants. In term infants, they are uncommon and usually associated with a serious disorder in the infant or a maternal condition such as magnesium treatment or maternal exposure to narcotics. Apnea in a term infant is never physiologic; it requires a full workup to determine the cause.

1. Was significant stimulation needed to return the heart rate to normal? An infant requiring significant stimulation (eg, oxygen by bag-and-mask ventilation) needs immediate evaluation and treatment. An infant who has had one episode of apnea and bradycardia not requiring oxygen supplementation may not need a full evaluation unless the infant is term.

1. If the patient is already receiving medication (eg, methylxanthine) for apnea and bradycardia, is the dosage adequate? Determine the serum drug level.

1. Did the episode occur during or after feeding? It was felt that gastroesophageal reflux (GER) caused apnea and bradycardia because it was observed when regurgitation of formula into the pharynx occurred after feeding. This has been a source of much debate with recent studies showing no temporal relationship. Consider aspiration in an infant who has been doing well and feeding. Insertion of a nasogastric tube may cause a vagal reflex, resulting in apnea and bradycardia.

1. How old is the infant? Apnea and bradycardia in the first 24 h are usually pathologic. The peak incidence of apnea of prematurity occurs between 5 and 7 days postnatal age but can occur earlier.

3. Differential diagnosis. Causes of apnea and bradycardia can be classified according to diseases and disorders of various organ systems, gestational age, or postnatal age.

1. Diseases and disorders of various organ systems

1. Head and central nervous system

1. Perinatal asphyxia.

1. Intraventricular or subarachnoid hemorrhage.

1. Meningitis.

1. Hydrocephalus with increased intracranial pressure.

1. Cerebral infarct with seizures.

1. Seizures.

1. Respiratory system

1. Hypoxia.

1. Airway obstruction.

1. Lung disease.

1. Inadequate ventilation or performing extubation too early.

1. Cardiovascular system

1. Congestive heart failure.

1. Patent ductus arteriosus.

1. Cardiac disorders such as congenital heart block, hypoplastic left heart syndrome, and transposition of the great vessels.

1. Gastrointestinal (GI) tract

1. Necrotizing enterocolitis (NEC). Apnea has been associated with the onset of NEC.

1. Gastroesophageal reflux (GER) is thought by some investigators to be related to AOP; however, to date, no research has shown a relationship between the two. Some studies suggest antireflux surgery can reduce apnea in preterm infants at highest ...

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