Abstract
Sleep related breathing disorders (SRBD) have historically been under-recognised and under-treated. Obstructive sleep apnoea(OSA) affects approximately 3% of children. In line with the increased recognition of SRBD there has been an increase in demand for diagnostic services. We determined the awareness of SRBD amongst Irish paediatricians, examined the provision of sleep services to children throughout the country between 2007 and 2011 and audited diagnostic sleep services in a tertiary centre in 2011. Amongst respondents there was an awareness of SRBD but a poor understanding of diagnostic evaluation with 31/46 (67) referring to inappropriate services. There has been a sharp increase in both diagnostic sleep tests (433-1793 [414]) and in the use of non-invasive ventilation (NIV) (31-186 [627]) for treatment of SRBD between 2007 and 2011. Paediatric sleep services are organized in an ad-hoc manner nationally with significant service variation. The use of domiciliary overnight oximetry reduced the requirement for more formal polysomnography by 70%.
Introduction
Sleep related breathing disorders (SRBD) have a high prevalence in the paediatric population, and as awareness of SRBD has increased, demand has increased on existing sleep services1. The commonest type of SRBD in children is obstructive sleep apnoea (OSA) which has a prevalence of approximately 3%2 and is more common in certain high risk groups such as those with trisomy 21 (50-70%)3, craniofacial disorders4, sickle cell anaemia5, mucopolysaccharidoses6, and neuromuscular disorders7. OSA in children is associated with impaired neurobehavioural functioning, long term cardiac morbidity, impaired academic performance and increased health care utilisation, all of which improve with treatment8. The investigation and management of OSA can be very resource intensive and expensive9. Nocturnal polysomnography (PSG) in a sleep laboratory represents the gold standard for the diagnosis of OSA but is costly and time-consuming10,11. Pulse oximetry is an increasingly used abbreviated testing modality for the evaluation of children with suspected OSA12-14. Overnight oximetry is cheap, easily performed at home and is a useful diagnostic test for OSA in some circumstances9. A subset of children diagnosed with OSA will go on to require treatment with non-invasive ventilation (NIV), usually over the long term2. The need for NIV is more commonly seen in children with pre-existing medical conditions15. With increasing awareness of the high prevalence of SRBD and increasing demand for diagnostic testing, more children will be diagnosed with OSA and will require treatment. This will impact on paediatric ENT services and also lead to an increase in the number of children requiring ongoing NIV. In young children, treatment with NIV involves intensive follow up and support. In light of the increased demand on paediatric sleep services and variations in the approach to SRBD across the country, we sought to assess the awareness of the investigation and management of SRBD in children among paediatricians, and determine the level of service provision in the area over the last number of years. We further sought to examine in detail the provision of diagnostic sleep services in a single tertiary centre and formally assess the utility of domiciliary overnight oximetry to obviate more formal testing in our patient population.
Methods
A survey on awareness of SRBD in children and the referral pathways used was designed and emailed to consultant paediatricians registered with the Royal College of Physicians in Ireland. Data on the provision of paediatric sleep services between 2007 and 2011was gathered directly from respiratory physicians in all centres that provide services. An audit of diagnostic sleep services at Our Lady’s Children’s Hospital Crumlin (OLCHC) during 2011 was performed with particular emphasis on the effectiveness of screening oximetry. Information was gathered from patients’ medical notes, sleep files and hospital databases. First line diagnostic tests were included in the audit providing full clinical information was available. Studies with incomplete datasets, follow up studies, NIV titration studies and monitoring studies were excluded. The data were analysed using Microsoft Excel.
Results
Awareness of SRBD and sleep services among paediatricians
The response rate to the survey was 20% (46/230). The majority (36/46[78%]) had no training in SRBD. The majority (28/46 [61%]) correctly identified the prevalence of OSA in children, with 35/46 (76%) knowing the prevalence of OSA in children with trisomy 21. The majority (31/46[67%]) said that they ‘always’ or ‘often’ ask about sleep as part of systems review. A third of respondents (15/46 [33%]) were working in hospitals where downloadable oximetry was available. Most respondents (31/46[67%]) referred to ENT when a child presented with a history suggestive of OSA.
National Services
As of 2011 six centres in Ireland (OLCHC, Children’s University Hospital, Temple Street [TSH], National Children’s Hospital, Tallaght [NCH], Cork University Hospital [CUH], University Hospital Galway [UHG], University Hospital Limerick [UHL]) were providing some level of structured paediatric sleep service. All centres could provide overnight oximetry and/or oximetry/capnography combined (TCO2). Three of these centres also perform abbreviated polysomnography, two of which have the ability to perform full polysomnography. None of the centres provided multiple sleep latency testing (MSLT). The number of studies performed nationally has increased significantly in recent years; from 433 diagnostic sleep tests in 2007 to 1793 studies in 2011 (414% increase). There was also a 627% increase in the number of children on NIV nationally from 31 in 2007 to 185 in 2011 (Table 1). There were no funded posts in any of the centres for the delivery of paediatric sleep services. Clinicians in all centres reported a progressive increase in the proportion of their practice dedicated to paediatric sleep problems over the course of the four years. Marked differences in approach to diagnostic testing and service provision were seen across the country.
Diagnostic sleep service in OLCHC
We looked in detail at the provision of diagnostic sleep services in OLCHC, which carried out 1001 of the 1793 studies (56%) that were performed nationally in 2011. In OLCHC there was a 380% increase in the number of tests performed from 208 in 2007 to 1001 in 2011. Two hundred and forty five charts were reviewed. Two hundred and thirty four first line diagnostic studies had full clinical information available and were suitable for inclusion in the audit (127 oximetry, 53 TCO2 and 54 abbreviated polysomnography). The median wait time for an outpatient test was four months (range one day–sixteen months). The service was accessed by all subspecialty groups (Figure 1). The indication for the majority of the studies (206/234 [88%]) was to assess for OSA. Other indications included assessment of hypoventilation (19/234 [8%]), central apnoeas (4/234 [2%]), hypoxia (1/234 [0.4%]) and a combination of these (4/234 [2%]). Of the total number of studies 123/234 (53%) were performed in the child’s home. Most oximetries (111/127 [87%]) were performed at home, with most abbreviated polysomnographies (42/54 [78%]) and all TCO2s (53/53 [100%]) being performed in hospital.
Most children (154/234 [66%]) had an underlying medical condition (Table 2). Of children without an underlying diagnosis 45/80 (56%) had OSA, and in children with an underlying medical condition 71/154 (46%) had OSA. Figure 2 details the clinical pathway of the 127 children who had oximetry performed. Most children (71/127 [56%]) were diagnosed with OSA following a first oximetry and required no further testing. Overall 80 of 127 children (63%) were diagnosed with OSA following testing with oximetry and this figure rose to 85/127 (67%) following a combination of oximetry and abbreviated polysomnography (Figure 2). By utilising overnight oximetry as a screening tool for OSA the number of polysomnography studies required was reduced by 70%. In parallel to increased diagnostic testing we saw a striking increase over the study period in the number of children on NIV at OLCHC from 9 in 2007 to 86 in 2011. Of the cohort of children who had a first line diagnostic test in 2011, the majority of children diagnosed with OSA were referred to ENT (74/85 [87%]), and of these 9 (12%) required treatment with NIV. Three children (4%) were treated with NIV without being referred to ENT.
Discussion
We describe the provision of paediatric diagnostic sleep services in Ireland. We have no local prevalence data for OSA and are using international data which quotes a prevalence of 1-5%2. This suggests that there are approximately 10-50,000 children in Ireland with OSA16. The proportion of children that are being referred for investigation and treatment is very low. The increasing awareness and recognition of SRBD in Ireland has resulted in an increased demand on services which mirrors the increased awareness and demand that is being seen internationally1. As recognition of SRBD further increases it is likely that this will result in further increases in referrals to paediatric respiratory and ENT services. The survey response rate was poor, likely reflecting some degree of discomfort with the subject matter. Among respondents there was a good awareness of SRBD, again this is likely to be biased, however understanding of diagnostic evaluation and of available sleep services was poor with many referring to inappropriate services or locations. There was a significant increase in all types of diagnostic tests over the period of the study. This was most marked with TCO2, likely partly related to its increasing availability over the duration of the study. The lowest increase in numbers was seen with polysomnography. This likely reflects both the resource intensive nature of the test, thus the limited scope to increase numbers and the increasing use of screening tests with their relative ease of use and lower cost. In OLCHC there was a wide spectrum of disorders among the group of children with pre-existing medical conditions, underlining the need for awareness of, and concentrated expertise in, paediatric sleep medicine in tertiary centres looking after children with complex medical conditions.
The Royal College of Paediatrics and Child Health (RCPCH) published evidence-based recommendations for the diagnosis and management of disorders of sleep physiology and respiratory control in children, and the organisation of such services nationally in the UK in 20098. No similar recommendations exist in Ireland at present. Currently there is a good national network providing testing for SRBD in Ireland and this network has the potential to expand and consolidate. The majority (1469/1793 [82%]) of studies in Ireland in 2011 were carried out in Dublin. This distribution of caseload is incongruous with a situation where the disorder has a very high prevalence, with the large majority of children likely to have no underlying medical condition. For paediatric OSA, a more efficient system would ensure high volume, low complexity work is carried out locally with more low volume high complexity work directed to tertiary services. The use of oximetry as a screening tool for OSA has been increasing worldwide. Oximetry has been shown to have a high positive predictive value for OSA12 and shorten the diagnostic and treatment process for those with severe OSA17. Our audit in OLCHC shows that oximetry was heavily used as a screening tool for OSA in all children, leading to a marked reduction in the need for formal inpatient sleep studies and saving considerable resources. Further studies are needed comparing oximetry with polysomnography as a screening tool for OSA as our audit was not designed to assess this. Our audit was carried out in a tertiary centre with a high proportion of children with an underlying medical condition (66%) which may not reflect the national situation accurately. One would expect the test to perform as well or better within a cohort of otherwise healthy children. We have also seen an increase in the use of NIV in line with the increased testing. In our study, 14% of children diagnosed with OSA went on to need NIV. There are no co-ordinated services in place to look after the current number, or the expected increase in future numbers of children on NIV.
In conclusion, we report for the first time on the provision of diagnostic sleep services to children in Ireland. Ireland has a good network of centres capable of providing this service but the provision of services is currently disorganised and variable across the country. The use of oximetry screening has the potential to reduce the demand for polysomnography and provide an effective and affordable service to a greater number of children closer to their homes.
Correspondence: A Walsh
Department of Neonatology, The Coombe Women and Infants University Hospital, Cork St, Dublin 8
Email: [email protected]
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