Preterm infants experience a nadir in cerebral oxygenation during sleep three months after hospital discharge

Aim: Preterm infants are at increased risk of Sudden Infant Death Syndrome (SIDS) and frequently experience short central apnoeas which can occur in isolation or a repetitive pattern (periodic breathing). We investigated the relationship between central apnoeas experienced before and over the 6 months after hospital discharge and cerebral oxygenation. Methods: Preterm infants born between 28 and 32 weeks gestational age (GA) were studied during supine daytime sleep at 32–36 weeks post menstrual age (PMA) (n = 40), 36–40 weeks PMA (n = 27), 3-months corrected age (CA) (n = 20) and 6-months CA (n = 26). Cerebral tissue oxygenation (TOI), peripheral oxygenation (SpO₂) and heart rate were recorded continuously. The percentage total sleep time (%TST) spent having central apnoeas at each study and cerebral fractional oxygen extraction (SpO₂-TOI/SpO₂) were calculated. Results: %TST spent with central apnoeas decreased with increasing age in both active sleep (AS) and quiet sleep (QS). TOI tended to be lower and cerebral fractional oxygen extraction higher at 3 months compared to the other studies and this reached statistical significance compared to 32–36 weeks in QS. Conclusion: The nadir in cerebral tissue oxygenation at 3 months of age coincides with the peak risk period for SIDS and this may contribute to increased risk in these infants.