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Nixon G.M.,Melbourne Childrens Sleep Center | Nixon G.M.,Monash Institute of Medical Research | Nixon G.M.,Monash University | Mihai R.,Melbourne Childrens Sleep Center | And 2 more authors.
Journal of Pediatrics | Year: 2011

Objective: To determine predictors of continuous airway pressure (CPAP) adherence in children. Study design: Analysis of CPAP usage data for children between 2004 and 2008. Results: During the study period, 32 children were prescribed CPAP; 2 failed to accept the mask, and 30 (mean ± SD age 9.1 ± 5.3 years) were included in further analysis. In the first 2 to 3 months of treatment, average (± SD) CPAP use was 4.7 ± 2.7 hours/night. Hours of use were not affected by age, sex, baseline obstructive apnea-hypopnea index, intellectual disability, or socioeconomic status (P >.05). Of the children, 10 (33%) used CPAP for one hour or more on more than 6 nights per week and were defined as consistent users. Consistent users treated with CPAP for significantly longer on nights of use than intermittent users (7.2 ± 2.0 hours vs 4.7 ± 2.4 hours, P =.008). The hours of use differed between the two groups after the second night of treatment (P <.05), and this difference persisted for the first 3 months of therapy. Conclusions: Children who attempted to use CPAP at least 6 nights a week were treated with CPAP for a longer time on the nights of use. Usage in the first week of treatment predicted longer term use over 2 to 3 months. Monitoring adherence in the first week of treatment and intervening in cases of low adherence may improve long-term CPAP use. Copyright © 2011 Mosby Inc. All rights reserved.

Biggs S.N.,Monash Institute of Medical Research | Biggs S.N.,Monash University | Nixon G.M.,Monash Institute of Medical Research | Nixon G.M.,Monash University | And 3 more authors.
Sleep Medicine Reviews | Year: 2014

Sleep disordered breathing (SDB) is common in children and describes a continuum of nocturnal respiratory disturbance from primary snoring (PS) to obstructive sleep apnoea (OSA). Historically, PS has been considered benign, however there is growing evidence that children with PS exhibit cognitive and behavioural deficits equivalent to children with OSA. There are two popular mechanistic theories linking SDB with daytime morbidity: hypoxic insult to the developing brain; and sleep disruption due to repeated arousals. These theories apply well to OSA, but children with PS experience neither hypoxia nor increased arousals when compared to non snoring controls. So what are we missing? This review summarises the literature examining daytime morbidity in children with PS and discusses the current debates surrounding this relationship. Specifically, questions exist as to the sensitivity of our standard assessment techniques to measure subtle hypoxia and arousal. There is also a suggestion that the association between PS and daytime morbidity may not be mediated by nocturnal respiratory disturbance at all, but by a number of other comorbid, but perhaps unrelated factors. As approximately 70% of children with SDB are diagnosed with PS, but are rarely treated, a paradigm shift in the investigation of PS may be required. © 2014 Elsevier Ltd.

Vandeleur M.,Melbourne Childrens Sleep Center | Davey M.J.,Melbourne Childrens Sleep Center | Nixon G.M.,Melbourne Childrens Sleep Center | Nixon G.M.,Monash Institute of Medical Research
Journal of Paediatrics and Child Health | Year: 2013

Aims To examine sleep study findings in children with Prader-Willi syndrome (PWS) referred for polysomnography (PSG) before commencement of growth hormone (GH) and to evaluate the impact of sleep testing on treatment decisions. Methods The sleep unit database was used to identify all cases over an 8-year period (2003-2011). Standard overnight PSG was performed in the sleep laboratory. Obstructive sleep apnoea (OSA) was defined by an obstructive apnoea-hypopnoea index >1/h. Age, symptoms of OSA, tonsillar size and body mass index (BMI) Z-score were obtained through chart review. Results OSA was diagnosed in 15 of 34 (44%) cases identified. Those with OSA were significantly older (P = 0.009) and more likely to have enlarged tonsils (P = 0.05) than those without OSA. There was no difference in BMI Z-score or the presence of symptoms of OSA. GH was deferred in 13 (38%) pending treatment for OSA. Conclusions OSA was frequently present in children with PWS referred simply to meet the requirement for PSG before starting GH. OSA was more likely in older children and those with enlarged tonsils. GH treatment was deferred in 38% of cases. This study supports routine performance of PSG prior to GH, regardless of clinical history. © 2013 The Authors. Journal of Paediatrics and Child Health © 2013 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Walter L.M.,Monash Institute of Medical Research | Nixon G.M.,Monash Institute of Medical Research | Nixon G.M.,Melbourne Childrens Sleep Center | Davey M.J.,Melbourne Childrens Sleep Center | And 3 more authors.
Sleep Medicine | Year: 2011

Study objectives: Sleep-disordered breathing in children is most prevalent in the pre-school years and has been associated with sleep fragmentation and hypoxia. We aimed to compare the sleep and spontaneous arousal characteristics of 3-5-year-old children with obstructive sleep apnoea (OSA) with that of non-snoring control children, and to further characterise the arousal responses to obstructive respiratory events. Methods: A total of 73 children (48 male) underwent overnight polysomnography: 51 for assessment of snoring who were subsequently diagnosed with OSA (obstructive apnoea hypopnoea index (OAHI) > 1 event per h) and 22 control children recruited from the community (OAHI ≤ 1 and no history of snoring). Results: The OSA group had poorer sleep efficiency (p<. 0.05), spent a smaller proportion of their sleep period time in rapid eye movement (REM) (p<. 0.05), and had significantly fewer spontaneous arousals (p<. 0.001) compared with controls. One-quarter of the children with OSA had a sleep pressure score above the cut-off point for increased sleep pressure. In children with OSA, 62% of obstructive respiratory events terminated in a cortical arousal and 21% in a sub-cortical arousal. A significantly higher proportion of obstructive respiratory events terminated in a cortical arousal during non-REM (NREM) compared with REM (p<. 0.001). Conclusions: These findings suggest that in pre-school children OSA has a profound effect on sleep and arousal patterns. Given that these children are at a critical period for brain development, the impact of OSA may have more severe consequences than in older children. © 2011 Elsevier B.V.

Nisbet L.C.,Monash Institute of Medical Research | Yiallourou S.R.,Monash Institute of Medical Research | Biggs S.N.,Monash Institute of Medical Research | Nixon G.M.,Monash Institute of Medical Research | And 6 more authors.
Sleep | Year: 2013

Study Objectives: In adults and older children, snoring and obstructive sleep apnea (OSA) are associated with elevated blood pressure (BP). However, BP has not been assessed in preschool children, the age of highest OSA prevalence. We aimed to assess overnight BP in preschool children with snoring and OSA using pulse transit time (PTT), an inverse continuous indicator of BP changes. Design: Overnight polysomnography including PTT. Children were grouped according to their obstructive apnea-hypopnea index (OAHI); control (no snoring, with OAHI of one event or less per hour), primary snoring (OAHI one event or less per hour), mild OSA (OAHI greater than one event to five events per hour) and moderate-severe OSA (OAHI more than five events per hour). Setting: Pediatric sleep laboratory. Patients: There were 128 clinically referred children (aged 3-5 years) and 35 nonsnoring community control children. Measurement and Results: PTT was averaged for each 30-sec epoch of rapid eye movement (REM) or nonrapid eye movement (NREM) sleep and normalized to each child's mean wake PTT. PTT during NREM was significantly higher than during REM sleep in all groups (P < 0.001 for all). During REM sleep, the moderate-severe OSA group had significantly lower PTT than the mild and primary snoring groups (P < 0.05 for both). This difference persisted after removal of event-related PTT changes. Conclusions: Moderate-severe OSA in preschool children has a significant effect on pulse transit time during REM sleep, indicating that these young children have a higher baseline BP during this state. We propose that the REM-related elevation in BP may be the first step toward development of daytime BP abnormalities. Given that increased BP during childhood predicts hypertension in adulthood, longitudinal studies are needed to determine the effect of resolution of snoring and/or OSA at this age.

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