Sleep Apnea Information
Sleep apnea is a sleep disorder characterized by pauses in breathing during sleep. Each episode, called an apnea lasts long enough so that one or more breaths are missed, and such episodes occur repeatedly throughout sleep.
Sleep apnea symptoms may be present for years (or even decades) without identification, during which time the sufferer may become conditioned to the daytime sleepiness and fatigue associated with significant levels of sleep disturbance.
Sleep apnea is diagnosed with an overnight sleep test called a polysomnogram, or a "Sleep Study".
Clinically significant levels of sleep apnea are defined as five or more episodes per hour of any type of apnea (from the polysomnogram).
There are three distinct forms of sleep apnea: central, obstructive, and complex.
Central Sleep Apnea
In central sleep apnea, the basic neurological controls for breathing rate malfunctions and fails to give the signal to inhale, causing the individual to miss one or more cycles of breathing. If the pause in breathing is long enough, the percentage of oxygen in the circulation will drop to a lower than normal level (hypoxia) and the concentration of carbon dioxide will build to a higher than normal level (hypercapnia). In turn, these conditions of hypoxia and hypercapnia will trigger additional effects on the body.
Obstructive Sleep Apnea
The early reports of obstructive sleep apnea in the medical literature described individuals who were very severely affected, often presenting with severe hypoxemia, hypercapnia and congestive heart failure. Tracheostomy was the recommended treatment and, though it could be life-saving, post-operative complications in the stoma were frequent.
Complex Sleep Apnea
Complex sleep apnea has recently been described by researchers as a novel presentation of sleep apnea. Patients with complex sleep apnea exhibit OSA, but upon application of positive airway pressure, the patient exhibits persistent central sleep apnea. This central apnea is most commonly noted while on CPAP therapy, after the obstructive component has been eliminated. This has long been seen in sleep laboratories, and has historically been managed either by CPAP or BiLevel therapy. Adaptive servo-ventilation modes of therapy have been introduced to attempt to manage this complex sleep apnea. Studies have demonstrated marginally superior performance of the adaptive servo ventilators in treating Cheyne-Stokes breathing, however, no longitudinal studies have yet been published, nor have any results been generated which suggest any differential outcomes versus standard CPAP therapy.
Treatment of Sleep Apnea
The most common treatment and arguably the most consistently effective treatment for sleep apnea is the use of a continuous positive airway pressure (CPAP) device , which splints the patient's airway open during sleep by means of a flow of pressurized air into the throat. However the CPAP machine only assists inhaling whereas a BiPAP machine assists with both inhaling and exhaling, and is used in more severe cases.
Articles
