Sleep Apnea
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During sleep, all body functions slow down and body muscles relax. This relaxation involves the muscles of the upper airway which help in keeping our airway patent and hence facilitates movement of air from and to the lungs. This relaxation in the muscles of the upper airway does not affect the patency of the upper airway in most people. However, certain people are prone to obstruct their upper airway during sleep either partially or completely. In that group of people, the upper airway repeatedly collapses, causing cessation of breathing or inadequate breathing which result in sleep fragmentation. Sleep fragmentation in turn, results in chronic excessive daytime sleepiness. Complete airway obstruction during sleep is known as Obstructive Sleep Apnea (OSA) and its milder form is known as the Upper Airway Resistance Syndrome.

OSA is a known medical problem that requires medical attention. If left untreated it results in a number of medical complications some of them are potentially life threatening. It affects 2-4% of middle age people. It has been estimated that 18 million Americans have sleep apnea.

Identification:

The key features that indicate a high probability of OSA are; excessive daytime sleepiness, snoring, pauses in breathing during sleep and gasping or choking during sleep. Patients with OSA are usually middle-aged males who are overweight. However, this disorder occurs in all age groups and both sexes and can affect thin people. Some patients may have physical abnormality in the nose, throat, or other parts of the upper airway. Ingestion of alcohol and sleeping pills increases the frequency and duration of breathing pauses in people with sleep apnea.

Sleep Apnea

How Does Airway Obstruction Affect Sleep?

During airway obstruction, the patient is unable to breathe in oxygen and to exhale carbon dioxide, resulting in low levels of oxygen and increased levels of carbon dioxide in the blood. The reduction in oxygen and increase in carbon dioxide alert the brain to resume breathing and cause arousal. With each arousal a signal is sent from the brain to the upper airway muscles to open the airway; breathing is resumed, often with loud snort or gasp. Frequent arousals, although necessary for breathing to restart, prevent the patient from getting enough restorative deep sleep. The arousals are very short and most patients do not recall them.

What Are The Consequences Of Airway Obstruction During Sleep?

Due to the serious disturbances in their normal sleep patterns, people with airway obstruction during sleep often feel very sleepy during the day and their concentration and daytime performanceApneasuffer. The consequences of this sleep disorder range from annoying to life threatening. They include symptoms suggesting depression, irritability, sexual dysfunction, learning and memory difficulties, and falling asleep when the patientdoes not want to. It has been estimated that up to 50% of patient with obstructive sleep apnea have high blood pressure. Fifty to sixty percent of patients with impaired heart function suffer from sleep related breathing disorders. If left untreated, obstructive sleep apnea can cause hypertension, irregular heart beat, heart attack, stroke, motor vehicle and work related accidents due to sleepiness (the risk of motor vehicle accident is three times higher in patients with sleep apnea compared to normal), and poor quality of life.

How Is Airway Obstruction During Sleep Diagnosed?

Diagnosis of sleep apnea is not simple because there can be many different reasons for disturbed sleep. Overnight sleep study (polysomnography) is the test used to both diagnose the disorder and determine its severity.

How Is Airway Obstruction During Sleep Treated?

Treatment is tailored to each individual patient based on medical history, physical examination and the results of the sleep study.

The basic problem in patients with these disorders is airway obstruction, which prevents air from moving in to the lungs. Therefore, oxygen usually does not help in these patients as it does not overcome the mechanical obstruction. Medications are generally not effective in obstructive sleep apnea patients.

The approach to the management of airway obstruction has two components; general measures and specific measures.

General Measures: there are few things that are known to enhance the chance of airway obstruction during sleep like; sleeping pills, alcohol and smoking. Therefore, they should be avoided. In some patients with mild forms of airway obstruction, snoring and airway obstruction happens when they sleep on their back. In those patients sleeping on the side may help eliminating the problem. Such task can be achieved by using some techniques like sewing a pocket in the back of the pijama and putting a tennis ball in it. That will make it uncomfortable to sleep on the back and will gradually train the patient to adopt sleeping on the side. Overweight people are at an increased risk of airway obstruction during sleep. Therefore, losing weight may help. Losing 10% of body weight may result in significant reduction in the obstructing events.

In most cases, general measures do not result in complete cure and need to be supplemented with specific measures.

Specific Measures:

Positive airway pressure (CPAP): this is the gold standard treatment for patients with airway obstruction during sleep. Basically, the patient wears a nasal mask that is connected to a machine that pushes air under positive pressure. This positive pressure air acts as a splint to prevent airway collapse. The machine pressure is adjusted during the overnight sleep study and the minimal pressure required to eliminate airway collapse is used. The patient has to wear it each time he/she goes to sleep. The machine is small and light (≈1.5 kg). It is not noisy and most patients get used to it after some time.

Dental Appliances:

Plastic devices that is designed by the dentist and put inside the mouth during sleep to reposition the lower jaw in order to increase the airway size. They have been shown to be helpful in some patients with mild airway obstruction and those who snore but do not have airway obstruction. It may cause soreness of the jaw in some patients.
Surgery: Several surgical techniques have been developed to increase the size of the airway and hence treat airway obstruction. In children with airway obstruction, surgery is generally the treatment of choice in most of them. However, in adults, the success rate is variable and depends on the experience of the medical center and the surgeon. The long-term side effects and benefits of most surgical procedures are not known yet and it is difficult to predict which patients will do well. It is important for patients to realize that surgery may eliminate snoring but not necessarily airway obstruction. Therefore, all patients should have a follow up overnight sleep study after surgery.

 

Ahmed BaHammam, FACP, FCCP
Professor of Medicine
Director, University Sleep Disorders Center
College of Medicine, King Saud University

Apnea
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