The benefits of continuous positive airway pressure machines (CPAP) for patients with obstructive sleep apnea (OSA) are quickly reversed when the therapy is withdrawn, according to a new Swiss study. The findings appear in the American Journal of Respiratory Care and Critical Care Medicine.
For the study, researchers recruited patients who had been previously diagnosed with OSA and treated with CPAP. Patients were randomized to either continue CPAP therapy or to withdraw CPAP (maintaining a subtherapeutic level) for 2 weeks. After baseline polysomnography, patients underwent nightly at-home assessment of respiration and oxygen saturation each day of the study period. Patients were also assessed for subjective and objective sleepiness, psychomotor performance, blood pressure and heart rate, endothelial function, systemic inflammation, insulin resistance, and urinary catecholamines. The polysomnography was repeated at the end of the two-week period.
At the end of the study, the researchers found a significant increase in apneic events, oxygen desaturations, and the number of arousals during sleep. As a consequence of the recurrence of sleep-disordered breathing, subjective sleepiness increased in the CPAP withdrawal group.
The researchers also noted that endothelial function deteriorated considerably in the CPAP withdrawal group, and there was a marked increase in blood pressure and heart rate after 14 days. Additionally, the researchers found a significant increase in urinary catecholamines, hormones consistent with sympathetic nervous system activation.
These findings imply that withdrawal of CPAP therapy for even a short time has a measurable negative effect on the cardiovascular system.
Source: American Thoracic Society