Mechanisms and management of central sleep apnea.

Central sleep apnea is not a single disease but represents the final pathway in a large group of heterogeneous disorders. Control of normal breathing during sleep relies upon finely coordinated anatomical and physiological mechanisms and their destabilization leads to central apnea. The causes of central sleep apnea can be classified into 4 groups: neurologic disorders, periodic breathing, upper airway abnormalities, and idiopathic syndromes. Clinical features result from the interaction between the underlying disorder and control of respiration. Two different prototypes emerge: patients who are hypercapnic (central hypoventilation and/or impaired respiratory mechanics) and those who are eucapnic or hypocapnic (periodic breathing and idiopathic hyperventilation). The causes and severity of apnea can be determined by clinical assessment, pulmonary function testing, and overnight polysomnography. Further management involves specific treatment of the underlying condition and reducing the sequelae of recurrent apneas during sleep, namely cardiorespiratory dysfunction and sleep disruption. This review outlines an approach to the management of central sleep apnea based upon an understanding of its pathophysiology.