Introduction
Down syndrome (DS) is one of the most common birth defects in the United
States with approximately 6000 births annually, resulting in an
estimated birth prevalence of 14 per 10,000 live births.(Parker et al.
2010) Infant with DS (I-DS) are at a high risk of congenital morbidity
including congenital heart disease, gastrointestinal disorders, and
metabolic abnormalities(Benhaourech et al. 2016; Miller and Cosgriff
1983; Stoll et al. 2015) frequently requiring intensive care unit
admission.(Martin et al. 2018; Seither et al. 2021; So et al. 2007)
Sleep disordered breathing (SDB) is a common comorbidity imposing
additional burden on I-DS.(Lee et al. 2018) Unique craniofacial features
of DS, macroglossia, and shortened palate and midface hypoplasia along
with generalized hypotonia make I-DS highly susceptible to OSA.(Maris et
al. 2014) Additionally, these patients are at risk for hypoxemia and
hypoventilation due to coexisting conditions such as congenital heart
disease, smaller lung volumes and hypotonia.(Fan et al. 2017; Wong and
Rosen 2017) Cardiovascular and neurocognitive consequence of
longstanding and untreated childhood SDB(Capdevila et al. 2008; Greene
and Carroll 1997) can be even more detrimental in children with DS. In
particular, the risk of pulmonary hypertension and cor-pulmonale in
children with DS(Breslin et al. 2014) can be markedly increased in the
presence of SDB. Moreover, impaired sleep quality affects daytime
function, behavior and quality of life.(Bassell et al. 2015) Therefore,
screening for SDB in its entirety (i.e., beyond OSA) is important in
early childhood. The American Academy of Pediatrics (AAP)’s published
anticipatory guidelines for children with DS recommends that a
discussion be held with the parents at least once during the first 6
months of life to screen for symptoms suggestive of OSA; snoring,
witnessing breathing pauses, heavy breathing, uncommon sleep positions,
frequent nocturnal awakening, daytime symptoms and/or behavioral
concerns that could be associated with poor sleep.(Bull 2011) The AAP
also recommends referral to a sleep physician for further examination
and evaluation of a possible OSA if any of the symptoms occur. Despite
these recommendations, I-DS are not commonly referred for SDB
evaluation. The AAP recommends assessing for symptoms of OSA, and
recommends referral to a pediatric sleep laboratory for polysomnography
(PSG) by 4 years of age for all children with DS due to poor correlation
between parent report and PSG results but suggests it to be performed
after the first year of life,.(Bull 2011) By age 4
years old a child with OSA may already have negative outcomes or
comorbidities associated with untreated hypoxemia or hypoventilation.
Despite the clinical implication of SDB in early age, studies
exclusively examining infants with DS are rare. In this study we aimed
to assess the prevalence of OSA, central sleep apnea (CSA), sleep
hypoxemia and sleep hypoventilation, and the impact of
adenotonsillectomy (AT) on SDB in I-DS.