Central sleep apnea reversed by continuous positive airway pressure

Continuous positive airway pressure (CPAP) is an accepted and highly effective method used in the treatment of obstructive sleep apnea (OSA). We have explored the potential utility of CPAP in a patient with sleep apnea without a major contribution of airway obstruction as measured by the usual criteria. The patient showed dramatic clinical and laboratory improvement in central apnea when treated with CPAP. A low level of CPAP (7.5 cm H2O) resulted in the reduction of central apneas from 281 to 32 per night with no significant change in obstructive apneas, which increased from 43 to 59 per night. On a separate night, a higher level of CPAP (12.5 cm H2O) resulted in virtually complete removal of all apneas. Measurement of pharyngeal properties revealed pharyngeal cross-sectional area in the low normal range, but increased pharyngeal compliance. This case illustrates that pharyngeal abnormalities may be present in patients with central sleep apnea, and CPAP may be beneficial in the treatment of this disorder. Although the exact mechanism of action of CPAP in this disorder is unclear, we propose several possibilities that may account for the beneficial effect of CPAP in this patient.