What
is Sleep Apnea?
Who Gets Sleep Apnea?
What Causes Sleep Apnea?
How is Normal Breathing
Restored During Sleep?
What are the Effects of Sleep
Apnea?
When Should Sleep Apnea be
Suspected?
How is Sleep Apnea Diagnosed?
How is Sleep Apnea Treated?
For More Information
WHAT IS
SLEEP APNEA?
Sleep apnea is a serious, potentially lifethreatening
condition that is far more common than generally
understood. First described in 1965, sleep apnea
is a breathing disorder characterized by brief interruptions
of breathing during sleep. It owes its name to a
Greek word, apnea, meaning “want of breath.” There
are two types of sleep apnea: central and obstructive.
Central sleep apnea, which is less common, occurs
when the brain fails to send the appropriate signals
to the breathing muscles to initiate respirations.
Obstructive sleep apnea is far more common and occurs
when air cannot flow into or out of the person’s
nose or mouth although efforts to breathe continue.
In a given night, the number of involuntary breathing
pauses or “apneic events” may be as high as 20 to
30 or more per hour. These breathing pauses are
almost always accompanied by snoring between apnea
episodes, although not everyone who snores has this
condition. Sleep apnea can also be characterized
by choking sensations. The frequent interruptions
of deep, restorative sleep often lead to early morning
headaches and excessive daytime sleepiness. Early
recognition and treatment of sleep apnea is important
because it may be associated with irregular heartbeat,
high blood pressure, heart attack, and stroke.
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WHO GETS SLEEP APNEA?
Sleep apnea occurs in all age groups and both sexes
but is more common in men (it may be underdiagnosed
in women) and possibly young African Americans.
It has been estimated that as many as 18 million
Americans have sleep apnea. Four percent of middle-aged
men and 2 percent of middle- aged women have sleep
apnea along with excessive daytime sleepiness. People
most likely to have or develop sleep apnea include
those who snore loudly and also are overweight,
or have high blood pressure, or have some physical
abnormality in the nose, throat, or other parts
of the upper airway. Sleep apnea seems to run in
some families, suggesting a possible genetic basis.
WHAT CAUSES SLEEP APNEA?
Certain mechanical and structural problems in the
airway cause the interruptions in breathing during
sleep. In some people, apnea occurs when the throat
muscles and tongue relax during sleep and partially
block the opening  of
the airway. When the muscles of the soft palate
at the base of the tongue and the uvula (the small
fleshy tissue hanging from the center of the back
of the throat) relax and sag, the airway becomes
blocked, making breathing labored and noisy and
even stopping it altogether. Sleep apnea also can
occur in obese people when an excess amount of tissue
in the airway causes it to be narrowed. With a narrowed
airway, the person continues his or her efforts
to breathe, but air cannot easily flow into or out
of the nose or mouth. Unknown to the person, this
results in heavy snoring, periods of no breathing,
and frequent arousals (causing abrupt changes from
deep sleep to light sleep). Ingestion of alcohol
and sleeping pills increases the frequency and duration
of breathing pauses in people with sleep apnea.
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HOW IS NORMAL BREATHING RESTORED
DURING SLEEP?
During the apneic event, the person 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 an 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 a loud snort or
gasp. Frequent arousals, although necessary for
breathing to restart, prevent the patient from getting
enough restorative, deep sleep.
WHAT ARE THE EFFECTS OF SLEEP
APNEA?
Because of the serious disturbances in their normal
sleep patterns, people with sleep apnea often feel
very sleepy during the day and their concentration
and daytime performance suffer. The consequences
of sleep apnea range from annoying to life threatening.
They include depression, irritability, sexual dysfunction,
learning and memory difficulties, and falling asleep
while at work, on the phone, or driving. It has
been estimated that up to 50 percent of sleep apnea
patients have high blood pressure. Although it is
not known with certainty if there is a cause and
effect relationship, it appears that sleep apnea
contributes to high blood pressure. Risk for heart
attack and stroke may also increase in those with
sleep apnea. In addition, sleep apnea is sometimes
implicated in sudden infant death syndrome.
WHEN SHOULD SLEEP APNEA BE
SUSPECTED?
For many sleep apnea patients, their spouses are
the first ones to suspect that something is wrong,
usually from their heavy snoring and apparent struggle
to breathe. Coworkers or friends of the sleep apnea
victim may notice that the individual falls asleep
during the day at inappropriate times (such as while
driving a working, or talking). The patient often
does not know he or she has problem and may not
believe it when told. It is important that the person
see a doctor for evaluation of the sleep problem.
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HOW IS SLEEP APNEA DIAGNOSED?
In addition to the primary care physician, pulmonologists,
neurologists, or other physicians with specialty
training in sleep disorders may be involved in making
a definitive diagnosis and initiating treatment.
Diagnosis of sleep apnea is not simple because there
can be many different reasons for disturbed sleep.
Several tests are available for evaluating a person
for sleep apnea. Polysomnography is a test that
records a variety of body functions during sleep,
such as the electrical activity of the brain, eye
movement, muscle activity, heart rate, respiratory
effort, air flow, and blood oxygen levels. These
tests are used both to diagnose sleep apnea and
to determine its severity. The Multiple Sleep Latency
Test (MSLT) measures the speed of falling asleep.
In this test, patients are given several opportunities
to fall asleep during the course of a day when they
would normally be awake. For each opportunity, time
to fall asleep is measured. People without sleep
problems usually take an average of 10 to 20 minutes
to fall asleep. Individuals who fall asleep in less
than 5 minutes are likely to require some treatment
for sleep disorders. The MSLT may be useful to measure
the degree of excessive daytime sleepiness and to
rule out other types of sleep disorders. Diagnostic
tests usually are performed in a sleep center, but
new technology may allow some sleep studies to be
conducted in the patient’s home.
HOW IS SLEEP APNEA TREATED?
The specific therapy for sleep apnea is tailored
to the individual patient based on medical history,
physical examination, and the results of polysomnography.
Medications are generally not effective in the treatment
of sleep apnea. Oxygen administration may safely
benefit certain patients but does not eliminate
sleep apnea or prevent daytime sleepiness. Thus,
the role of oxygen in the treatment of sleep apnea
is controversial, and it is difficult to predict
which patients will respond well. It is important
that the effectiveness of the selected treatment
be verified; this is usually accomplished by polysomnography.
Behavioral Therapy
Behavioral changes are an important part of the
treatment program, and in mild cases behavioral
therapy may be all that is needed. The individual
should avoid the use of alcohol, tobacco, and sleeping
pills, which make the airway more likely to collapse
during sleep and prolong the apneic periods. Overweight
persons can benefit from losing weight. Even a 10
percent weight loss can reduce the number of apneic
events for most patients. In some patients with
mild sleep apnea, breathing pauses occur only when
they sleep on their backs. In such cases, using
pillows and other devices that help them sleep in
a side position is often helpful.
Physical or Mechanical Therapy
Nasal continuous positive airway pressure (CPAP)
is the most common effective treatment for sleep
apnea. In this procedure, the patient wears a mask
over the nose during sleep, and pressure from an
 air
blower forces air through the nasal passages. The
air pressure is adjusted so that it is just enough
to prevent the throat from collapsing during sleep.
The pressure is constant and continuous. Nasal CPAP
prevents airway closure while in use, but apnea
episodes return when CPAP is stopped or used improperly.
Variations of the CPAP device attempt to minimize
side effects that sometimes occur, such as nasal
irritation and drying, facial skin irritation, abdominal
bloating, mask leaks, sore eyes, and headaches.
Some versions of CPAP vary the pressure to coincide
with the person’s breathing pattern, and others
start with low pressure, slowly increasing it to
allow the person to fall asleep before the full
prescribed pressure is applied. Dental appliances
that reposition the lower jaw and the tongue have
been helpful to some patients with mild sleep apnea
or who snore but do not have apnea. Possible side
effects include damage to teeth, soft tissues, and
the jaw joint. A dentist or orthodontist is often
the one to fit the patient with such a device.
Surgery
Some patients with sleep apnea may need surgery.
Although several surgical procedures are used to
increase the size of the airway, none of them is
completely successful or without risks. More than
one procedure may need to be tried before the patient
realizes any benefits. Some of the more common procedures
include removal of adenoids and tonsils (especially
in children), nasal polyps or other growths, or
other tissue in the airway and correction of structural
deformities. Younger patients seem to benefit from
these surgical procedures more than older patients.
Uvulopalatopharyngoplasty (UPPP) is a procedure
used to remove excess tissue at the back of the
throat (tonsils, uvula, and part of the soft palate).
The success of this technique may range from 30
to 50 percent. The long-term side effects and benefits
are not known, and it is difficult to predict which
patients will do well with this procedure. Laser-assisted
uvulopalatoplasty (LAUP) is done to eliminate snoring
but has not been shown to be effective in treating
sleep apnea.
This procedure involves
using a laser device to eliminate tissue in the
back of the throat. Like UPPP, LAUP may decrease
or eliminate snoring but not sleep apnea itself.
Elimination of snoring, the primary symptom of sleep
apnea, without influencing the condition may carry
the risk of delaying the diagnosis and possible
treatment of sleep apnea in patients who elect LAUP.
To identify possible underlying sleep apnea, sleep
studies are usually required before LAUP is performed.
Tracheostomy is used in persons with severe, life-threatening
sleep apnea. In this procedure, a small hole is
made in the windpipe and a tube is inserted into
the opening. This tube stays closed during waking
hours, and the person breathes and speaks normally.
It is opened for sleep so that air flows directly
into the lungs, bypassing any upper airway obstruction.
Although this procedure is highly effective, it
is an extreme measure that is poorly tolerated by
patients and rarely used. Other procedures. Patients
in whom sleep apnea is due to deformities of the
lower jaw may benefit from surgical reconstruction.
Finally, surgical procedures to treat obesity are
sometimes recommended for sleep apnea patients who
are morbidly obese.
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U.S. DEPARTMENT OF HEALTH AND HUMAN
SERVICES
Public Health Service - National Institutes of Health
National Heart, Lung, and Blood Institute
NIH Publication No. 95-3798, September 1995
FOR MORE INFORMATION
Information about sleep disorders research can be
obtained from the NCSDR. In addition, the NHLBI
Information Center can provide you with sleep education
materials as well as other publications relating
to heart, lung, and blood diseases.
National Center on Sleep - Disorders
Research
Two Rockledge Centre, Suite 7024
6701 Rockledge Drive
MSC 7920
Bethesda, MD 20892-7920
(301) 435-0199
FAX: (301) 480-3451
NHLBI Information Center
P.O. Box 30105
Bethesda, MD 20824-0105
(301) 251-1222
FAX: (301) 251-1223
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