Sleep Apnea
Introduction
Up to one fifth of accidents on motorways and other monotonous roads may be caused by drivers falling asleep at the wheel. Many accidents
are attributed to "driver inattention" but once vehicle faults, traffic offences, poor road or weather conditions, alcohol and
specific medical causes are excluded, closer inspection suggests driver sleepiness may be the cause. Evidence for this includes the apparent
failure to respond to traffic and road conditions generally and, in particular, the absence of signs of emergency braking.
Driver sleepiness may be caused by modern life styles preventing adequate rest. It may be made worse by shift working combined with the
monotonous nature of certain types of driving. Alertness fluctuates naturally throughout the day. Driving between 2am and 7am increases the
risk of a sleep related accident. Most people also tend to be less alert during the mid-afternoon or after a heavy meal. All drivers
need to address these problems responsibly.
However, some medical conditions may cause excessive sleepiness. These will greatly increase any normal tendency to sleepiness. The most
common medical cause is OBSTRUCTIVE SLEEP APNOEA SYNDROME (OSA). This condition occurs most commonly, but not exclusively, in overweight
individuals, particularly those with a large neck size. Partners often complain about the snoring and notice that sufferers seem to have
irregular breathing during sleep. Sufferers of OSA rarely wake from sleep feeling fully refreshed and tend to fall asleep easily when
relaxing.
OSA is one of the few medical conditions that has been shown to increase significantly the risk of traffic accidents. However, once
diagnosed, there is very effective treatment available, normally through specialist centres. The greatest danger is prior to diagnosis,
when the significance of the symptoms is not appreciated. A road traffic accident may be the first clear indication of the condition. All
drivers, especially professional drivers, and doctors need to be much more aware of the risks of sleepiness from this treatable cause.
- Types of Sleep Apnea
- Causes of Sleep Apnea
- Diagnosing Sleep Apnea
- Treating Sleep Apnea
- Further Reading
Types of Sleep Apnea
Sleep apnea is a common disorder in which you have one or more pauses in breathing or shallow breaths while you sleep. Breathing pauses
usually last for several seconds and often occur 5 to 30 times or more an hour. Typically, normal breathing then starts again,
sometimes with a loud snort or choking sound.
Sleep apnea is usually a chronic (ongoing) condition that disrupts your sleep 3 or more nights each week. You often move out of deep sleep
and into light sleep when your breathing pauses or becomes shallow, which results in poor sleep quality that makes you tired during the day.
Sleep apnea is one of the leading causes of excessive daytime sleepiness. There are two main types of apnea. One type is obstructive. In
this condition, the pipe that carries air into the lungs gets blocked intermittently. The other type is central, which means that the
trigger in the brain that signals breathing intermittently stops working. Obstructive sleep apnea (OSA) is the condition that we are most
concerned with.
Obstructive sleep apnea (OSA)
In OSA, the pharynx (throat) repeatedly collapses during sleep. The person with OSA fights to breathe against a blocked airway, resulting
in decreased oxygen levels in the blood. Eventually, the sense of suffocation wakes the person, the throat muscles contract, the airway
opens, and air rushes in under high pressure. When the airway is opened, the rushing air allows the patient to once again drift back into
sleep, but creates a loud gasping sound. People with OSA are generally not aware that this is happening, although their partners often have
severely disrupted sleep from the snoring and gasping. This cycle repeats itself many times throughout the night, and this constant waking
from deep sleep, as well as the loss of oxygen in the blood, can cause next-day sleepiness, brain fog, poor concentration, and mood
changes. Another side effect of OSA is high blood pressure.
Key Information
There is a lot of controversy about how common OSA is. There is not even an agreement about how to define it. Generally, if the throat closes off for at least ten seconds, with no air flow, it is considered to be an apneic episode. This lack of breathing for ten seconds is enough to cause the oxygen level to drop in the blood and to cause one to go from deep sleep into light sleep. Many sleep specialists define sleep apnea as having five or more episodes of decreased breathing per hour in association with daytime sleepiness. Although some specialists estimate that OSA is present in only 3 percent of the adult population, a recent study of all patients in five general medicine doctors' offices suggested that approximately 17 percent of adults had clinically significant sleep apnea (defined as having at least fifteen episodes an hour of non-breathing during sleep). This study shows that when a doctor looks for it, sleep apnea is very common.
Although sleep apnea is diagnosed by a positive overnight sleep study, fewer than 8 of the 10,000 patients at these practices had been referred for a sleep study in the previous year, though it would be expected that as many as 1,700 of them had sleep apnea. This is because doctors simply have not been trained to look for OSA. In fact, as noted in an editorial in a recent issue of the Annals of Internal Medicine, "The real problem is the lack of education at all levels about all sleep disorders. Physicians have been shown to receive, on average, a total of only 2.1 hours of formal education in sleep medicine during their medical school training. Sleep history is typically skipped in the general history." When physicians did receive training about sleep apnea, the number of patients they sent for sleep apnea testing increased dramatically.
Causes of Sleep Apnea
The main reason for OSA is being overweight. If more fat deposits develop in the rest of your body, they also occur in the tissue
surrounding the throat. When you get into certain positions, the placement of your head can actually cause compression of the pipe that
carries air into the lungs. The primary symptoms associated with sleep apnea are snoring and daytime sleepiness.
Having a neck circumference of seventeen inches or more also predisposes one to OSA. Because we inherit certain physical characteristics of
the throat, there also appears to be a genetic predisposition to sleep apnea.
There are other problems that occur besides the daytime sleepiness in sleep apnea. As noted above, high blood pressure is common. A number of studies have also shown that patients with severe sleep apnea are at a two to seven-fold increased risk of having an automobile accident. There is also a possible risk of heart and lung damage as a result of untreated OSA. Although some doctors do not consider OSA to be significant until there are fifteen or more apneic episodes per hour of sleep, evidence suggests that even five or more episodes per hour are associated with increased risk of auto accidents and high blood pressure.
Diagnosing Sleep Apnea
Symptoms that suggest sleep apnea are snoring, being overweight, hypertension, daytime sleepiness, periods where breathing stops at night,
and frequent auto accidents. If you have several of these symptoms, you should have an overnight sleep study done. During this test,
several aspects of sleep are measured. An electroencephalogram (EEG) measures the brain wave patterns that tell the depth of sleep and
gives a printout of how much time is spent in the various stages of sleep. It can also tell how long it takes to fall asleep, how many
times you wake during the night, and how many actual hours of sleep you get. Respiratory monitors can measure air flow and tell if the
blood oxygen level is dropping, which demonstrates the apnea. The test should also be able to check for leg movements to look for restless
leg syndrome (more about this below) and to monitor for snoring as well.
These tests can be very expensive, costing approximately two thousand dollars. Because of the cost, insurance companies are sometimes
hesitant to pay for it. It is a good idea to have the sleep laboratory get preauthorization from your insurance company before the test is
done. Because of the high cost, it is common to have what is called a split-night study. When this is done, the technician spends the
first half of the night looking for evidence of clinically important sleep apnea. If they find it, they put a mask on you that gently keeps
up the pressure in your throat, which in turn keeps your airway from collapsing. This is like gently blowing into a balloon to keep the
opening open. They will do a continuous positive airway pressure (C-pap) titration to determine the optimum mask pressure needed to
keep your airway open. Because of the study's cost, it is certainly reasonable to do a split-night study all in one night, rather than
coming back for a second night to do the C-pap titration, which would double the cost.
One recommendation however it is to simply videotape yourself sleeping for an hour or two. Set up the camera so it is at your feet looking
towards your head. That way you can look for signs of both restless leg syndrome and sleep apnea. If you do have snoring and periods where
you stop breathing, see if this occurs predominantly when you are laying on your back. If so, simply wearing a tight pyjama top or
T-shirt at night that has a tennis ball sewn into the area by the small of your back may be enough to keep you from laying on your back
while sleeping - which may be enough to eliminate the problem.
Some sleep testing machines can be used at home. These machines are often more effective (even though they monitor fewer variables) because
you are more likely to be able to have a normal night's sleep in the familiarity of your own home.
Treating Sleep Apnea
There are several treatments for sleep apnea and they fall into three main treatment categories: behavioral, pharmacologic, and mechanical.
Behavioral Treatments
As noted above, being overweight is the main cause of OSA. Because of this, weight loss is one of the most effective ways to treat it.
Markedly cutting back on your carbohydrate intake and increasing your protein intake can help as well, as many people with this also have
severe daytime somnolence. Some prescribe medications can help to treat the daytime sleepiness that also assist with weight loss, among
them dextroamphetamine (Adderall, Dexedrine), thyroid hormone, and certain antidepressants.
Avoid sleeping in positions that cause you to snore and have sleep apnea, especially lying on your back. As noted above, Sleep apnea can
often be decreased by taking a tennis ball, putting it into a cloth pocket and then sewing it into the mid-back of your pyjama shirt.
Then, when you lie on your back, the tennis ball makes it uncomfortable, forcing you to roll onto your side or stomach without waking you.
Finally, avoid bedtime alcohol and other substances that can aggravate sleep apnea.
Pharmacologic Treatments
A number of drugs have been used for OSA, but with limited success. A few patients have also been helped by supplemental oxygen. This is especially helpful if you live at high altitude. Drugs that contribute to weight loss (including the ones noted above), as well as antidepressants that help weight loss, such as Prozac, can also be useful. It is important, though, to not take these drugs later in the day if they interrupt sleep.
Mechanical Treatments
There are several mechanical devices that change the shape of the upper airway and help to prevent the throat from collapsing. Orthodontic devices can help to keep the lower jaw and tongue forward. These are most likely to be helpful for mild cases of sleep apnea and for people who who cannot tolerate the C-pap machine. A nasal C-pap is a mask that is kept over your face while you sleep. It keeps constant pressure in your airway and, as noted above, helps to keep the airway inflated and open while sleeping. Unfortunately, to three quarters of people with sleep apnea are not able or willing to continue with the C-pap treatment because of the noise of the machine, the discomfort of wearing the mask, and the cost. Most patients find that if they can tolerate the C-pap for three to six months, the treatment becomes second nature and comfortable.
Another possibility is surgery to reshape the throat so it stays open during sleep. Removing the tonsils, nasal surgery, and surgically trimming back the soft palate and the uvula (the tiny thing that hangs down in the back of your throat) are the most common treatments performed. Although these surgeries can be very helpful for snoring, they are less likely to help the sleep apnea. A new technique, in which stick like implants or high-frequency radio waves are used to scar areas in the soft palate and tongue and thus shrink them, shows promise.
It is controversial whether using more aggressive treatments for sleep apnea are worthwhile for people who have fewer than fifteen episodes of apnea per hour. The more conservative approaches (for example, weight loss and avoiding sleeping on your back) are a more reasonable way for those with mild apnea to begin treatment.
Further Reading
The information laid out above has been reproduced from DVLA and Jacob Teitelbaum M.D. (USA). You can read more on this and other symptons
that cause Sleep Apnea by visiting the links below for further information on this subject.
