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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.
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 performance suffer. 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 patient does 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.
Dr. Ahmed BaHammam
Director Sleep Disorders Center
King Khalid University Hospital
Associate Professor, College of Medicine, King Saud University
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