The term ‘sleep disordered breathing’ encompasses a range of conditions characterised by abnormal breathing during sleep; in many cases this is associated with narrowing or obstruction of the upper airway (pharynx). The disordered breathing ranges from intermittent, partial obstruction of the airway without sleep disturbance (snoring) to, at the other end of the spectrum, frequent apnoeas associated with repetitive hypoxaemia and arousals leading to sleep disruption and daytime sleepiness. The term ‘obstructive sleep apnoea’ (OSA) refers to intermittent obstruction of the airway, irrespective of the presence of daytime symptoms. If symptoms result, the condition is called obstructive sleep apnoea syndrome (OSAS), also known as obstructive sleep apnoea/hypopnoea syndrome (OSAHS).
Sleep disordered breathing also includes: 1) central sleep apnoea (CSA), in which periodic cessation of breathing occurs without obstruction of the airway and which, in adults, is seen mainly in heart failure; and 2) obesity hypoventilation syndrome (OHS) in which breathing is reduced throughout sleep, with or without accompanying narrowing or obstruction of the upper airway.
Sleep disordered breathing is very common in Europe but no statistics are collected routinely on the associated morbidity or mortality.
This chapter will focus primarily on OSAS, which is a major public health problem in most developed countries.