PT - JOURNAL ARTICLE AU - Johan Verbraecken TI - Complex sleep apnoea syndrome AID - 10.1183/20734735.042412 DP - 2013 Sep 01 TA - Breathe PG - 372--380 VI - 9 IP - 5 4099 - http://breathe.ersjournals.com/content/9/5/372.short 4100 - http://breathe.ersjournals.com/content/9/5/372.full SO - breathe2013 Sep 01; 9 AB - Summary Complex sleep apnoea syndrome (CompSAS) is a type of central apnoea characterised by the development or persistence of central apnoeas or hypopnoeas during application of continuous positive airway pressure (CPAP; central apnoea index ≥5 events·h−1). These patients present with predominantly obstructive apnoeas during diagnostic sleep studies. No clinical characteristics have been identified which can distinguish them from patients with a normal response during CPAP titration. Probably, this pattern is provoked by the application of high CPAP pressures in obstructive sleep apnoea syndrome patients with enhanced chemoreceptor sensitivity, or in patients with pronounced sleep fragmentation. Negative feedback is sent to the respiratory centre, via the Hering-Breuer reflex, which can lead to central apnoea. However, these explanations remain hypothetical at present. In a broader perspective, any occurrence of significant central apnoea activity during attempts to restore airway patency could be classified as CompSAS. Treatment modalities consist of prevention on the one hand (avoidance of high pressures and permissive flow limitation), and advanced ventilation techniques (adaptive servo ventilation) on the other hand.