What is Sleep Apnea

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. The standard definition of any apneic event includes a minimum 10 second interval between breaths, with either a neurological arousal, a blood oxygen desaturation of 3-4% or greater, or both arousal and desaturation. 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 (i.e., a combination of central and obstructive) constituting 0.4%, 84% and 15% of cases respectively. Breathing is interrupted by the lack of respiratory effort in central sleep apnea; in obstructive sleep apnea, breathing is interrupted by a physical block to airflow despite respiratory effort. In complex (or "mixed") sleep apnea, there is a transition from central to obstructive features during the events themselves.

Regardless of type, the individual with sleep apnea is rarely aware of having difficulty breathing, even upon awakening. Sleep apnea is recognized as a problem by others witnessing the individual during episodes or is suspected because of its effects on the body. 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.

Common Sleep Apnea Definitions

What are Portable Oxygen Concentrators

A number of manufacturers have introduced portable oxygen concentrators. Typically, these use some version of pulse flow or demand flow to deliver oxygen only when the patient is inhaling. However, there are portable oxygen concentrators with up to 3 LPM of continuous-flow oxygen. This device also has pulse flow available to either provide higher flows or reduce power consumption. These portable concentrators typically plug into a wall outlet like the larger, heavier stationary concentrators.

Portable oxygen concentrators usually can also be plugged into a vehicle DC adapter, and most have the ability to run from battery power as well, either for ambulatory use or for use away from power or for airplane travel. The FAA has approved portable oxygen concentrators for use on commercial airlines.

Historically, demand or pulse flow concentrators have not been used for nocturnal use—sleeping. If the nasal cannula moves such that the concentrator is not able to detect when the patient is inhaling, it is unable to deliver the pulse while the patient is inhaling.

The primary pulse dose systems on the market today are the Invacare XPO2, and Inogen One.  As for portable oxygen concentrators capable of delivering continuous flow as well as pulse dose there are the SeQual Eclipse 3 , Invacare Solo 2 and DeVilbiss iGo.

Common Oxygen Therapy Definitions