After a sleep apnea diagnosis, the first step in therapy is usually a positive airway pressure device. The type used depends on the kind of apnea: obstructive sleep apnea (OSA), central sleep apnea (CSA), or a combination of both. The severity of the apnea and its result on other health conditions is also considered, as well as individual response to a given treatment.
What is CPAP?
CPAP, or continuous positive airway pressure, is the most commonly used sleep apnea therapy. CPAP uses a motorized device to draw and pressurize air from the room. The air goes through flexible tubing to a mask that prevents the upper airway from collapsing during sleep. People with mild to severe OSA use CPAP, but higher air pressure is used for severe disorders.
What is APAP?
APAP, or automatic positive airway pressure, uses the same techniques as CPAP. Although the machine and gear look the same as CPAP, APAP has different settings. Rather than being limited to a single pressure, it includes a range of pressures. The machine automatically fluctuates, based on built-in algorithms that sense subtle changes in breathing, when delivering air. APAP is used for individuals who sleep on their back, experience apnea during the dream cycle, or have nasal congestion and allergies.
What are bilevel pressure devices?
BPAP, or bilevel positive airway pressure, is also known as BiPAP or bilevel PAP. Although the equipment resembles CPAP, its settings are different from CPAP or APAP. Bilevel machines provide two pressures: one for inhalation (IPAP) and one for exhalation (EPAP). The pressure level is stronger for the inhalation and weaker for the exhalation. Bilevel machines can be adjusted to coordinate with the number of breaths per minute or to detect and compensate for shifts in breathing. BPAP may be used by people who do not respond well to CPAP or by patients who have congestive heart failure or lung disorders. It is also an effective therapy for central sleep apnea.
What is ASV?
ASV, or adaptive servo-ventilation, is the most advanced form of air ventilation therapy. These devices resemble CPAP equipment, but they use specific settings and sophisticated technology that is effective when other forms of therapy have failed. ASV machinery is used for people who were originally diagnosed with CSA but later developed symptoms of CSA not relieved by BPAP. ASV algorithms are designed to maintain healthy levels of oxygen, in addition to a consistent breathing rate. These devices are used to treat mixed sleep apnea and Cheyne Stokes, a breathing disorder. ASV should not be used for some patients with heart failure.