Obstructive Sleep Apnoea
Several sleep-related breathing disorders can interfere with a person's ability to obtain a healthy rest at night. These conditions are fairly common in adults, and somewhat less so in children. One of these disorders is obstructive sleep apnoea, or OSA.
In OSA, the breathing is briefly and repeatedly completely stopped or reduced during one's sleep. The term "apnoea" is used to describe a cessation of breathing that lasts for at least ten seconds during sleep. This type of apnoea occurs when the airway collapses and completely closes off the passageway. When this happens, the tongue falls back into the throat just a little and further blocks the airway.
The different causes of OSA closely resemble those of snoring and can include all types of physical characteristics or conditions that tend to restrict airflow by reducing the size and shape of the airway. Some of these can include large tonsils, tongues and uvulas, as well as stuffy noses.
Narrow airways can also occur because of genetic conditions. Children and adults with Down syndrome have a higher incidence of this condition because of larger tongues, smaller oral cavities and reduced muscle tone.
However, the most common cause for OSA is simply being overweight. Those people who have a Body Mass Index (BMI) over 27 have twice the chance of having OSA or a problem with snoring. Individuals vary as to exactly how much extra weight will cause them to experience snoring and OSA. For some people it could be 10 pounds, while for others it could be 100 pounds. Some people develop OSA even though they are at their ideal weight; however, these people would normally have a worsening of the symptoms of OSA if they gain weight.
What Happens During OSA
During an episode of apnoea, the lung and its related musculature continue to try to breathe and the abdomen and the chest continue to move. Oxygen levels in the bloodstream drop as no new oxygen is entering the lungs. In the meantime, carbon-dioxide levels are rising, as the lungs are unable to expel the old air.
The human body contains a number of receptors that keep track of carbon dioxide levels and and send "distress" signals to the brain. The brain receives this signal and tells the body to respond in order to end the apnoea. The end result is a gasp or snort to clear the airway, which is frequently accompanied by a slight arousal lasting a few seconds or more.
The number of risk factors one has increases the chances they actually have OSA. Thses include snoring, obesity, having a large neck (17 inches or greater in mean, 16 inches or larger in women), being over the age of 40, having high blood pressure, and using cigarettes and alcohol.
The diagnosis of OSA can only be accurately made through an overnight sleep study. These specialists agree that approximately 4 percent of men and about 2 percent of women have OSA. This condition can occur in any adult age group, although it is most common between the ages of 40 and 65. The severity of OSA can worsen over time if left untreated.
Researchers estimate that 2 percent of healthy have OSA, and anywhere from 10 to 20 percent of the children who are habitual snorers have OSA. In some cases, the sleep specialist may also identify other medical conditions which are contributing to the sleep apnoea.
Possible Consequences of OSA
About half of the fatal car crashes which occur are thought to be caused by drivers who are nodding off while driving, and a large percentage of these accidents are believed to be directly related to OSA. Also, the risk of sudden cardiac death is greatly increased in people who have OSA or who are habitual snorers.
Several of the current treatments used for OSA are also utilized for people with snoring problems. These include positional therapy, losing weight, oral appliances and surgery. All of these treatments are more successful in curing OSA if the condition is mild, though all can help to reduce the severity of moderate to severe apnoea.
The most widely-0used and effective treatment for OSA is something called Continuous Positive Airway Pressure, or CPAP. CPAP involves delivering filtered room air into the patient's airway. This occurs through a mask worn over the nose or face. The air is gently blown into the back of the throat, thus preventing the airway from collapsing while the individual is asleep.
Several different mask types are now available, and a person can choose the mask which provides the best comfort and fit for their face. If the person's home tends to be dry or the throat and nasal passages are dry after a CPAP treatment, a small, heated humidifier can be added to the CPAP machine. The CPAP unit is generally small enough to fit on a bedside stand or table and is about the size of a small fan. CPAP units also come with carrying cases so they can be taken along when the individual has to travel away from home.
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