Continuous Positive Airway Pressure

Abstract

Abstract Continuous positive airway pressure (CPAP) therapy remains the mainstay of treatment for obstructive sleep apnea (OSA). CPAP devices have seen a rapid evolution from the technological standpoint. The device components continue to become better to allow patient acceptance, comfort, and adherence. Expiratory pressure relief, heated humidification, and data management have been introduced in an attempt to improve adherence. Despite significant advances in the design and function of CPAP devices, the adherence to therapy remains a significant challenge. A dose–response relation to therapy and outcomes has been recently demonstrated. Newer tools to measure outcomes of treatment with CPAP therapy for OSA have been developed and have shown promise. The study of factors affecting adherence have demonstrated the important role of the nasal cross-sectional area in adherence to therapy. Many other factors affecting adherence have been studied separately. There is a greater need to study these factors as a bundle. The effect of provider training, head end elevation, and treatment of concomitant sleep disorders needs greater emphasis in future studies. The changing landscape of reimbursement is likely to impact CPAP therapy and delivery of services significantly. CPAP is a method of treating certain sleep-related breathing disorders (SRBD) such as OSA, central sleep apnea (CSA), and upper airway resistance syndrome (UARS). CPAP devices, also sometimes termed flow generators or blowers, create a continuous flow of air to achieve a target pressure. CPAP therapy primarily works by providing a pneumatic splint to the collapsible muscular structure of upper airway in the treatment of SRBD. Another mechanism of the action for CPAP is thought to be increased functional residual capacity (FRC) of lungs. An increased lung volume is thought to provide traction to the trachea and pharynx and thus indirectly increase the diameter of the pharyngeal airway. Increased FRC and decreased work of breathing are important when treating hypoxemic respiratory failure with CPAP; however, experiments conducted by Abbey et al. did not support the notion of increased FRC as a factor in overcoming OSA. In the treatment of CSA, CPAP is thought to reverse the activation of upper airway receptors, which cause reflex central apnea when the airway collapses, particularly in the supine position.