Paediatrics - Sleep and Respiratory

An infant undergoes dramatic developmental changes in heart and blood pressure control systems during its first six months of life. This development affects the ability to compensate for a drop in blood pressure (hypotension) or reduced blood oxygen levels (hypoxaemia).

Premature infants are at an increased risk of hypoxaemia, which can lead to death. This risk is significantly greater during sleep than during wakefulness. The reason for this is still unknown, but scientists in The Ritchie Centre are examining the ability of infants to respond to stress during sleep in a bid to understand how and why these dangerous conditions occur, and if these conditions leave any long-lasting effects on premature infants.

Currently we are examining how immature control of breathing which manifests as frequent pauses in breathing or apnoeas can affect developmental outcomes. We have shown in preterm infants who had been discharged home that apnoeas continue to occur and these are associated with falls in brain oxygen levels. In our current studies we are following preterm infants from the neonatal unit to 6 months after term corrected age to identify if pauses in breathing during sleep are related to poor developmental outcomes at 6 months and 2 years of age.

It is believed failure to arouse from sleep is one of the mechanisms involved in Sudden Infant Death Syndrome or SIDS, but why this affects some infants and not others is still unknown. Our studies have been investigating infant sleep and control of arousal responses to understand how major SIDS risk factors alter these pathways. We have developed novel techniques to measure blood pressure and brain oxygen levels non-invasively during sleep and have demonstrated that blood pressure control and brain oxygen levels are reduced when healthy low risk infants are slept prone (on their tummies) the major risk factor for SIDS. n studies funded by the National Health and Medical Research Council of Australia, the team is studying infants born preterm to investigate why these infants are at much greater risk for SIDS than those born at term. We have been examining the effects of sleeping position on blood pressure and brain oxygen levels in preterm infants who are routinely slept prone, to improve respiration, in the neonatal intensive care unit.