Comparison of the longitudinal effects of persistent periodic breathing and apnoea on cerebral oxygenation in term- and preterm-born infants

Periodic breathing and short apnoeas are common in infants, particularly those born preterm, but are thought to be benign. The aim of our study was to assess the incidence and impact of periodic breathing and apnoea on heart rate, oxygen saturation and brain tissue oxygenation index (TOI) in infants born at term and preterm over the first 6 months after term equivalent age. Nineteen term-born infants (38-42 weeks gestational age) and 24 preterm infants (born at 27-36 weeks gestational age) were studied at 2-4 weeks, 2-3 months and 5-6 months post-term-corrected age during sleep. Periodic breathing episodes were defined as three or more sequential apnoeas each lasting >= 3 s and apnoeas as >= 3 s in duration. The mean duration of periodic breathing episodes was longer in term infants than in preterm infants at 2-4 weeks (P < 0.05) and at 5-6 months (P < 0.05); however, the nadir in TOI was significantly less in the term infants at 2-3 months (P < 0.001). Apnoea duration was not different between groups; however, the decline in apnoea index with postnatal age observed in the term infants was not seen in the preterm infants. Falls in TOI associated with apnoeas were greater in the preterm infants at all three ages studied. In conclusion, periodic breathing and short apnoeas were more common in infants born preterm and falls in cerebral oxygenation were greater than in the term group. The clinical significance of this on neurodevelopmental outcome is unknown and warrants further investigations.