[Apnea during sleep and wakefulness in term newborns]

Abstract

Apneas in the different sleep states are commonly observed in the full-term healthy newborn infant. Central and short apneas prevail whilst apneas greater than 15 sec. are rare; a marked incidence of short apneas (less than 10 sec.) was observed in active sleep, even though apneas are not exclusive of active sleep. There is a strong inter-individual variability of apnea incidence. Apnea incidence in a state is not positively correlated to apnea incidence in different behavioural states: on the contrary there seems to be an opposite correlation between incidence in AS and QS. Apnea occurrence is positively correlated, in individuals, to the periodic breathing percentage. Apneas number and their duration is markedly lowered already in the second month of life. Periodic breathing must be considered a feature of immaturity. Obstructive apneas are less frequent than central apneas: their survey requires sophisticated technics with the aid of simultaneous recording of several breathing parameters. Relationship between central apneas/ obstructive apneas and mixed apneas is not known. Certainly obstructive and mixed apneas occurrence has been underestimated because of technical difficulties deriving from their survey. The meaning of an incidence of short apneas markedly higher than normal in full-term newborn infants is controversial and not clear, individuals with long apneas and subjects with short apneas in excess have been considered infants at SIDS risk. It is not clear whether periodic breathing and apneas depend on a common pathogenesis; the correlation between high incidence of periodic breathing in postnatal period and SIDS risk is still controversial. Few Authors suggest to treat newborn infants with extended apneas in sleep and considerable percentage of periodic breathing with aminophylline. The relation between gastro-oesophageal reflux and apnea has been recently evidenced. Central apneas and obstructive apneas during breast and bottle feeding have also been documented. Differently from pre-term infant apneas, bradycardia, although not exceptional, is not frequent during apneas in full-term newborn infants.