Central Sleep Apnea, Hypoventilation Syndrome, and Sleep in High Altitude

Abstract

Central sleep apnea (CSA) syndromes (CSAS) and sleep-related hypoventilation disorders encompass a group of sleep-related breathing disorders with diverse pathophysiology, ranging from instability of the respiratory metabolic control system to impaired lung function or chest wall mechanics. Based upon their effect on arterial CO2 concentration, these diseases can be divided into two groups: those with “hypocapnic–eucapnic CSA” and those with “hypercapnic CSA.” Even though the clinical presentation and sleep-related complaints may overlap, characteristic patterns in the polysomnographic airflow, overnight oximetry trace, and pulmonary function test can differentiate them further. The current evidence supports the treatment of CSA with modified methods of delivering positive airway pressure. Otherwise, limited evidence is available to support pharmacological intervention. Practical application of gas therapy is limited to nocturnal oxygen supplementation for the treatment of CSAS related to congestive heart failure (CHF). Further research is needed to expand our knowledge of CSAS pathophysiology and to develop novel therapeutic strategies.