Introduction

History and definition

Obstructive sleep apnoea syndrome (OSAS) in children was first reported almost 40 years ago (Guilleminault et al., 1976) as a rare condition, and this first research focused mainly on the syndrome's severe form and its comorbidities, e.g. cor pulmonale. In 2002 the American Academy of Pediatrics (AAP) published a technical report on the diagnosis and management of childhood OSAS using the following definition of the syndrome:

This definition is still considered valid today. According to the American Academy of Sleep Medicine Manual (AASM, 2012), when assessing sleep and associated events an obstructive apnoea in children is scored when there is an absence (or >90% reduction) of airflow that lasts for two or more missed breaths and is associated with maintained inspiratory effort. An obstructive hypopnoea is described as having a >30% reduction in airflow associated with a ≥4% decrease in oxygen desaturation and/or arousal and also lasts for two or more missed breaths with preservation of respiratory effort. OSAS is considered the most important manifestation of the spectrum of sleep-disordered breathing (SDB), which includes several disorders such as primary snoring and upper airway resistance syndrome, among others (Nespoli et al., 2013). The syndrome's prevalence during childhood varies in different epidemiological studies between 1% and 6% and it peaks between two and eight years of age (Balbani et al., 2005; Lumeng & Chervin, 2008; Marcus et al., 2012).