Research outline - SIDS and Sleep Apnea Research

Within: Bosch Institute, Kids Research Institute

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Research program

Our research at the University of Sydney is laboratory-based and has two main themes.

The first is to examine the consequences of exposure to intermittent hypoxia during early development; to do this we study piglets because they are a good model for brain and physiological development during early life. Intermittent hypoxia and nicotine exposure are the two risk factors for SIDS that we study. Infants who sleep prone may experience intermittent hypoxia and cigarette smoke exposure is now the most common, modifiable risk factor for infant death from SIDS. Intermittent hypoxia is also a consequence of obstructive sleep apnoea, which is a common condition we see in the sleep laboratory.

The second main theme of our laboratory work is the study of brain abnormalities in piglets and in infants who died from SIDS. We utilise traditional methods of immunohistochemistry to examine the brain tissue of the piglets after they experience intermittent hypoxia or nicotine. We collaborate with the Forensic Insititue to examine small amounts of brain tissue from infants who died from SIDS and study whether the abnormalities could arise from prone sleeping or cigarette smoke exposure.

Our PhD student, Samantha Tang has helped develop new methods (particularly proteomics and MALDI-TOF) to study this tissue, and Dr. Machaalani (along with Dr. Anne-Maree Hennessy) is starting to study how preeclampsia or prematurity can affect the development of the brain. Dr Waters and Dr. Machaalani worked with research groups in Kentucky (USA) and Grenoble (France) to establish these new research techniques, along with other researchers at the University of Sydney.

At the Children's Hospital, our PhD students are responsible for new and exciting research developments.

Dr. Joanna MacLean has provided much-needed information about how the presence of a cleft lip and/or cleft palate increases the risk for sleep-disordered breathing in infants, how this affects the development of their ventilatory control and with Ms Courtney Smith, will be examining how this impacts on their neurocognitive development.

The standard recommendation to treat obstructive sleep anoea (OSA) is adenotonsillectomy. However, our ENT surgeons also frequently undertake adenoidectomy to treat mild OSA. Surprisingly, there is very little formal evidence about the effectiveness of this treatment. For her MPhil, Ms Rebecca Hensley is studying the impact of adenoidectomy on OSA. Initially, by questionnaire, but then with sleep studies and she will also assess neurocognitive outcomes.

Chenda Castro is coordinating a randomised study of the effectiveness of adenoidectomy compared to other treatments for mild OSA.

Where adenotonsillectomy is not adequate to treat OSA, we use nasal mask CPAP to treat OSA in children. During her PhD Ms Carla Evans, who has extensive experience with the use of nasal CPAP, is studying how the presence of obstructive sleep apnoea interacts with obesity to influence cardiovascular function in children.

Alan Cheng is an ENT surgeon who is co-supervising these clinical studies and using sleep studies to provide improved evaluation of the treatment outcomes for children with difficult airway disorders.

With the support of the Australasian Sleep Trials Network, we have developed a multicentre Paediatric Sleep Centre collaboration across Australia. We have established the protocol to undertake a definitive study of whether adenotonsillectomy improves the IQ in children with OSA. This study needs funding to be propertly run; the application has been submitted to a number of grant agencies and we will continue to seek funding for this important project.

Research support (2008/09)

Establishment of a multicenter Randomised Trial to evaluate whether Adenotonsillectomy improves IQ in pre-school children
Australasian Sleep Trials Network ($15,000)

Ventilatory Responses in children with obstructive sleep apnoea
A/Prof Karen Waters - The Financial Markets Foundation for Children ($66,250)

Carla Evans is funded by an NHMRC Biomedical scholarship
($28,000 per year for 3 years)

Joanna MacLean is supported by a University of Sydney International Student Scholarship