Apnea of prematurity
| Apnea of prematurity | |
|---|---|
| Specialty | Pediatrics |
| Symptoms | Apnea, bradycardia, intermittent hypoxemia |
| Usual onset | Prematurity, particularly before 34 weeks' gestation |
| Types | Central apnea, obstructive apnea, mixed apnea |
| Causes | Developmental immaturity of respiratory control and upper airway regulation |
| Prognosis | Resolves with increasing age |
| Frequency | Nearly all infants born at or before 28 weeks' gestation; about 20% at 34 weeks |
Apnea of prematurity (AOP) is a disorder in infants who are preterm that is defined as cessation of breathing (apnea) that lasts for more than 20 seconds or is accompanied by hypoxia or bradycardia. Apnea of prematurity is often linked to earlier prematurity (younger gestational age).
Apnea is traditionally classified as either obstructive, central, or mixed:
- Obstructive apnea may occur when the infant's neck is hyperflexed or conversely, hyperextended. It may also occur due to low pharyngeal muscle tone or to inflammation of the soft tissues, which can block the flow of air though the pharynx and vocal cords.
- Central apnea occurs when there is a lack of respiratory effort. This may result from central nervous system immaturity, or from the effects of medications or illness.
- Mixed apnea involves elements of both obstructive and central apnea. Many episodes of apnea of prematurity may start as either obstructive or central, but then involve elements of both, becoming mixed in nature.
Over 50% of infants who are born preterm are estimated to be affected by apnea of prematurity. Infants who are born weighing less than 1000 g have close to a 100% risk of being affected by apnea of prematurity. Most premature infants are affected by 'central' apnea due to the developmental stage of their respiratory tract.
Apnea of prematurity can increase the risk of chronic health conditions including retinopathy and increases the risk of problems with the infant's neurological development. Apnea lasting more than 60 seconds may result in death or disability.
The main treatment for apnea of prematurity has been pharmaceutical treatment with methylxanthines that have a mechanism of action of bronchodilation and a stimulant of the respiratory system to promote spontaneous breathing. Caffeine and theophylline are the common medications used.