Central sleep apnoea—a clinical review

Central sleep apnoea (CSA) is characterised by recurrent apnoeic episodes with no associated respiratory effort. Compared to obstructive sleep apnoea (OSA) it is not as commonly seen in sleep centres accounting for about 5-10% of clinic patients. It is, however, quite common in patients with heart failure, in patients with some neurological disorders and in those on high dose opiates. Complex CSA is now well recognised in continuous positive airway pressure (CPAP) treated OSA. Symptoms of CSA include sleep fragmentation, insomnia and daytime hypersomnolence, which is usually not as severe as in OSA. Despite a lot of research into CSA in the past two decades the condition is still poorly understood and treatment is still suboptimal perhaps owing to its aetiological and pathophysiological diversity and heterogeneity