Apnoea of prematurity and arousal from sleep

The incidence of sudden infant death syndrome (SIDS) has been found to be c onsistently higher in preterm and low birth weight infants than in infants, born at term and this increase is inversely related to gestational age. Th e incidence and severity of apnoea of prematurity, are also inversely relat ed to gestational age. The aim of this study was to investigate whether a n eonatal history of apnoea/bradycardia affected the maturation of arousal re sponses. Twenty-five premature infants were studied. A perinatal risk score was determined for each infant and infants were divided into those with a neonatal history of apnoea/bradycardia (n = 16) and those without (n = 9). All infants were studied using daytime polysomnography on three occasions: (a) a preterm study around 36 weeks gestation. (b) within 3 weeks of term, and (c) 2-3 months: post-term. Multiple measurements of arousal threshold ( cmH(2)O) in response to air-jet stimulation applied alternately to the nare s: were made in both active sleep (AS) and quiet sleep (QS). Arousal thresh olds were elevated in apnoeic infants compared to control infants in both A S (P < 0.05) and QS (P < 0.001) at the term study and in QS at 2-3 months p ost-term (P < 0.01). In addition. arousal thresholds were positively correl ated with perinatal risk score in both sleep states, in all studies, with t he exception of AS at 2-3 months when all infants were readily arouseable. We conclude that a history of prematurity with neonatal apnoea has a persis ting effect on decreasing arousabilty from sleep and these infants may be a t (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.