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 car, working, or talking).
The patient often does not know he or she has a
problem and may not believe it when told. It is
important that the person see a doctor for evaluation
of the sleep problem.
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 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.
