Sleep Apnea: Is Your Snoring an Inconvenience or a Serious Life-Threatening Disorder?

Sleep apnea is a far more common -- and far more serious -- disorder than most people realize. Its actual prevalence is not known with any accuracy because it is grossly under diagnosed. Therefore, we can only estimate from samples in the population. The most often given estimate is that approximately 18,000,000 people in the United States are afflicted with sleep apnea. Only about ten percent of this number is known and diagnosed.

So what is this virtually endemic disorder? Literally, apnea means "without breath," and this is exactly what it is describing. In sleep apnea, there are periods during which the afflicted individual stops breathing. Normally, during sleep, breathing is relatively smooth and continuous; there is little pause between the end of one breath and the beginning of the next, perhaps two or three seconds during slow, relaxed respiration, but rarely much more than that. Apnea is defined as a pause of ten seconds or more. A pause of ten seconds between breaths during sleep means that something is wrong.

In general terms, there are two sources of possible problems in breathing. One is when something is blocking the airway; the other is when the brain does not get the signal to breath to the muscles. The first, and more common type is called obstructive apnea; the second is called central apnea. Sometimes, these two combine in the same individual, a condition labeled, "mixed-complex."

Normally, during sleep, the muscles of the tissues that surround the airway relax, lose the tone that they have during wakefulness and the soft tissues surrounding the airway, which include the palate, tongue, epiglottis, tonsils, mucosal lining, and the blood vessels and fat deposits in the neck, can narrow the airway. This phenomenon causes snoring, but when the obstruction becomes complete, or nearly so, it blocks the airway to a degree that interferes with respiration -- obstructive apnea.

In central apnea, there is a neurological impairment from disease, injury, or drugs that interferes with the mechanism that tells the brain that there is not enough oxygen and it needs to send a signal to the respiratory muscles to take a breath. Many common sedatives, including over the counter sleep aids and alcohol, can suppress the respiratory center to cause, or contribute to, apnea. In both etiologies, the apneic events cause hypoxia, or a lack of oxygen, which sets off a series of physiologic changes that result in partial awakening, allowing the individual to take a breath. In other words, instead of deep and restful sleep, the person with sleep apnea actually is awakening periodically for brief periods of time. Almost always, these periods of wakefulness do not reach a sufficient alertness to be remembered. In other words, the sufferer from sleep apnea usually does not know about the interruption in sleep and believes that he or she has slept soundly all night. Instead of experiencing the full cycle of restful sleep, apnea interrupts this process from five to over thirty times an hour. Five to fifteen apneic events is considered mild; fifteen to thirty, is considered moderate, and over thirty is considered severe. Even the so-called mild apnea, though, can have serious consequences.

We all need to breath, and we all need to sleep. If we do not get enough oxygen to maintain normal homeostatic processes, there are many consequences, none of them good. Similarly, a lack of deep, and particularly, rapid eye movement (REM) sleep, also has potentially serious consequences. The body's attempt to breath causes a disruptive activation of the sympathetic (fight or flight) nervous system. This, in turn, causes a series of events that are only partially understood, but the net result is an increase in the likelihood of pulmonary hypertension (not good) and cardiac events, including angina (chest pain -- also not good) and myocardial infarction ("heart attack," really, really not good). The degree to which sleep apnea is a risk factor for these serious consequences is not trivial. Depending on the degree of the illness, the risks of some serious event are increased several fold. And I haven't even mentioned stroke.

OK, those, and more, are possible consequences of the hypoxia (low oxygen) of sleep apnea. The loss of good sleep has its own effects. For one thing, it makes people sleepy. In fact, one of the common ways of measuring the severity of sleep apnea is a scale (Epworth Sleepiness Scale) of how likely the person is to fall asleep during the day while engaged in various activities; as one of these is driving, the seriousness of this problem is apparent. Of course, it is obvious how much chronic fatigue and sleepiness can interfere with everything in life, causing inefficiency, depression, and what looks like attention deficit disorders. Just awakening every morning feeling groggy and tired despite believing that you have had a full night's sleep is annoying, itself, but feeling bad all day is even worse.

Risk Factors

Who is at risk for sleep apnea? The easy answer to this is, "everybody," but some people are more at risk than others. Until recently, sleep apnea was considered to be primarily an adult disorder. However, a recent study (Tarasiuk et al., 2007) studied 156 children between the ages of three to five, who had been diagnosed with obstructive sleep apnea, and found problems of general health that echoed adult problems, including a 40% increase in hospital visits. Therefore, although less frequent in children, it is still serious and demands early treatment. However, as I said, some people are more at risk than others. Who? What is known to correlate with the disorder?

Positive family history of the disorder.

Obesity, especially central obesity.

Particular bone structure that impinges on the airway; simply having a thick neck appears to be related to this.

Being male. Men are at higher risk than females, except menopausal women.

African Americans, Mexicans, and Pacific Islanders are all at increased risk compared to North American Caucasions.

Age: It is more common over forty.

A variety of medical disorders such as diabetes, hypertension, hypothyroidism, and certain vascular diseases.

Smoking

Alcohol and other depressant drug use.

Sleep posture and habits (more about this below).

Note that of these ten risk factors, five of them are at least partly under the control of the individual. Weight, smoking, drugs, and sleep habits are obviously mutable to some extent. Moreover, treatment and control of the medical disorders, such as diabetes and hypertension also affect, materially, the likelihood of being afflicted. Under treatment strategies, these will be discussed somewhat further.

Related to the mechanical causes of airway blockage, sleep apnea sometimes comes during pregnancy, and usually resolves after delivery. However, it is of importance to treat it during the period it appears, perhaps all the more because of the demands of the pregnancy. Among other problems, this could predispose to pre-eclampsia, a potentially very serious condition. Vigilance during pregnancy is of critical importance.

What to Do

First, it is important to recognize the presence of the disorder. There are several ways to do this before the definitive diagnostic procedure that involves a sleep laboratory, which most people do not have in their homes. The most important of these involves simple observation. Snoring is the first cue. Obstructive apnea, the most common type, is virtually always associated with pretty bad snoring. If you do not live alone, you have a potential observer who probably already knows whether or not you snore. However, you must then convince the person to stay awake and watch you while you sleep, not necessarily a popular occupation. If the observer sees even one episode of not breathing for at least ten seconds, it should be explored further. It is a very good idea for the observer to keep a notebook on the number of episodes and when they occur. In addition, noting the position in which the person is sleeping is important to obtain information to present to the sleep specialist, who is the next stop. Sleeping on one's back exacerbates obstructive apnea simply because gravity helps collapse the soft tissue into the airway. Sometimes, just getting used to sleeping on one's side can be enough to prevent apneic episodes. Therefore, the observer should note whether and how much position affects the breathing.

Although it is possible to have sleep apnea without the concomitant snoring (if it is central), an observer can still note the episodes easily, because the hypoxia causes sudden gasping as the individual partially awakens to get a breath. If you have symptoms of sleep apnea, such as the daytime sleepiness, and do not have anyone willing to observe you while you sleep, there are relatively simple devices that you can use to make the preliminary diagnosis. The key problem in sleep apnea, of course, is the hypoxia, the low oxygen levels in the blood. Well, this can be measured by a simple device that clips over the fingertip, called a pulse oxymeter. These measure the percentage of oxygen saturation in the blood. While these are relatively inexpensive and simple to use, they don't do the user any good if he can't read them while sleeping. However, there is an advanced model of this device that will trip an alarm when the oxygen level falls below the level that the user sets (usually about 80%).This, of course, fully awakens the sleeper and that constitutes evidence of one apneic episode. Any such episode is enough to send one for a referral to a sleep specialist, who then, depending on the degree of the problem, will explain the following principles to reduce or eliminate the apnea, or recommend a more drastic treatment. The self help recommendations will be some version of the following advice:

If you are overweight, lose it.

Do not take sedatives or alcohol at night.

Exercise good sleep hygiene; that is go to bed and get up at the same hour every day.

Get eight or more hours of sleep. (Note, most physicians will say at least seven, but the research suggests that more is better.)

Don't smoke

Sleep on your side.

Now, if it were easy to lose weight, stop smoking, stop drinking, and change lifestyles, most mild cases of sleep apnea could be thus controlled. However, most of the time, following all of that advice completely would be about as likely as finding my pet pig flying around the house. So, in the real world, in which this advice rarely works, or cases of more severe apnea, one of two general approaches will be recommended, surgery or CPAP. Although there is a third alternative, involving a dental appliance, it is of limited practical value in part because of the degree of specialized dental expertise, and in part because of limited success. Surgery or CPAP are the most likely recommendations.

Surgery used for sleep apnea is usually aimed at either enlarging the airway, or reducing the excess soft tissue that occludes it during sleep. If the bony architecture is abnormal, this can, sometimes be corrected to improve breathing. There are several different procedures used, depending mostly on the particular individual problem presented. Without going into the details of these procedures, I shall only say that most of them should work well, theoretically. However, in practice, they are only successful some of the time. Defining the "some," of course, depends on the precise case, but few procedures are fool proof, or even close. The less invasive use of a CPAP appliance is usually tried first.

CPAP stands for "continuous positive airway pressure." What this means is that air is forced into a mask that is fitted over the patient's nose so that instead of depending on the negative pressure from the lungs to draw in a breath, the air is pushed through the tissues into the nose and, therefore, the trachea. It simply helps the person breath, compensating for the occluded airway. It works. It works well in most cases. (If there is a severe central apnea from brain injury, ventilators might be required but that is rare.) A soft, flexible mask is either fitted or actually molded to the patient's face, ideally so that there is no leakage of air. Air is streamed through the mask with controlled pressure and valves for exhaling. Usually, as the name implies, the pressure is maintained, but a few people find it much more comfortable if there is a mechanism to relieve the pressure during exhalation. Some devices do this, but it is usually unnecessary. The pressure is adjusted to the minimum amount that prevents any apneic events. The machines are adjustable from a pressure of about three cm. of water up to twenty. Most patients respond to somewhere between six to twelve cm. (water) pressure. Of course the least effective amount is desirable because higher pressures can be uncomfortable and even dangerous.

The most frequent reason for failure of a CPAP is non-compliance. Some people simply do not feel comfortable wearing an appliance every night, but when it is used successfully for a few days, the improvement in every aspect of life can be so dramatic that many patients will never sleep without it. In fact, most companies that sell or rent these appliances maintain a 24 hour, seven day a week emergency service to guarantee uninterrupted service. One common issue that causes discomfort is dry air that is irritating to the mucosa. This can be effectively avoided by a heated water chamber that the air passes over between the fan and the mask. I strongly recommend that anyone who receives a CPAP machine insist on this feature. It is important to keep the water chamber clean, but it is worth the effort in the added comfort.

Conclusion

Snoring is often treated as a joke, or, at most, an annoyance to those who listen to it. However, it can be a sign of a serious and common malady that is anything but funny. Snoring can be a sign of obstructive sleep apnea, a disorder both more common and far more serious than most people realize. Estimates of prevalence run as high as over seven percent of the adult population in the United States, 90% of which are undiagnosed and untreated. Even mild cases of sleep apnea have potentially serious and always uncomfortable consequences. It deprives the body of the benefits of full, restful sleep, and, at the same time causes a lack of adequate oxygen. This not only makes people sleepy during the day, it increases the likelihood of severe disorders ranging from hypertension and heart attacks to strokes. There are, however, effective treatments. Everyone needs to be cognizant of the symptoms of sleep apnea and to take its presence seriously.

Tarasiuk, A, et al. Elevated morbidity and health care use in children with obstructive sleep apnea syndrome. American Journal of Respiratory and Critical Care Medicine. 175(1):55-61, January, 2007.