Breathless No More
Defeating Adult Sleep Apnea
by Ricki Lewis, Ph.D.

Imagine ceasing to breathe for 10 to 20 seconds, then strenuously gasping in  
air, then stopping again--hundreds of times during what is supposed to be     
eight hours of restful slumber. For the sleep apnea sufferer, this happens    
every night.

Fortunately, the relentless lapses in breathing are not remembered, even      
though up to three-quarters of total sleep time may be spent not breathing!

Apnea is Greek for "want of breath," and the condition causes problems in     
both infants (see "Infant Apnea Monitors Help Parents Breathe Easy" in the    
June 1991 FDA Consumer) and adults.

For adults, sleep apnea may actually be more disturbing for the bed-mate      
than for the affected individual, for the frequent fits and starts of         
breathing are often accompanied by snoring reminiscent of a jackhammer.

Fortunately, a variety of highly effective treatments for sleep apnea are     
available. They range from simple solutions, such as taking a decongestant    
or avoiding sleeping on one's back, to surgery. Many sleep apnea sufferers    
find relief with a mask-like device, cleared for marketing by the Food and    
Drug Administration, that painlessly forces air into respiratory passages     
that become blocked during sleep.

Untreated, apnea can greatly affect daytime functioning. Rarely, the only     
daytime hint of the nocturnal turmoil may be a sense of having slept poorly.  
But far more often, the person is aware in many ways that all is not right.   
Awakening is often accompanied by a fierce headache, which lessens in an      
hour or two. But the person may remain irritable and forgetful, often         
finding it difficult to concentrate for the rest of the day. Interest in sex  
may wane, and the person may become depressed.

Annoying as these symptoms are, they aren't the most dangerous. Of far        
greater concern is the tendency of sleep apnea sufferers to fall asleep,      
suddenly, during the day. Dozing can prove embarrassing in business meetings  
or classes, but in some situations, it can be deadly.

Martin Scharf, Ph.D., director of the Center for Research in Sleep Disorders  
in Cincinnati, says, "There are 200,000 auto accidents a year where people    
fall asleep at the wheel. I see people every day who say they fall asleep     
whenever they are at a stop sign."

It's not surprising that people with sleep apnea face a two- to fivefold      
greater risk of being in an auto accident compared with people who do not     
have sleep apnea. The American Sleep Disorders Association calls the          
condition "a potentially life-threatening disorder."

Portrait of a Sleep Apnea Sufferer

Snoring is not always a sign of sleep apnea. One in 10 adults snores, but     
only 1 in 10 snorers has sleep apnea. This accounts for some 6 million        
people, with men outnumbering women 8 to 1. Researchers are not certain why   
the typical sleep apnea patient is a middle-aged overweight man, but they     
think it may have something to do with hormones and neck size.

Scharf explains the neck connection. "In young men, the neck is more          
muscular. When they get older, out of shape, the muscle shrinks and fatty     
deposits come in. Muscle is heavy. When it loses its tone, the airway         
collapses." Neck size is largely inherited--and a hefty neck isn't seen only  
in overweight people.

In one study, researchers at the Osler Chest Unit of Churchill Hospital in    
Oxford, England, queried 900 male patients between the ages of 35 and 65.     
Did they smoke? Drink alcohol? Take drugs? Have a stuffy nose? Measurements   
taken included weight, height, neck circumference, and resting arterial       
oxygen saturation, a measure of how much oxygen is getting into the           
bloodstream. The only two factors that correlated with apnea were alcohol     
intake (which greatly worsens symptoms) and neck size! Weight was implicated  
in a study of more than 1,000 sleep apnea patients at the Stanford Sleep      
Disorder Clinic. Two-thirds of the patients were obese--defined as being 20   
percent or more above ideal body weight.

Premenopausal women are more protected than older women. With menopause, the  
prevalence of sleep apnea among women becomes closer to that for males. But   
which hormone, and how it affects breathing, isn't known, says John Shepard,  
M.D., director of the Sleep Disorders Clinic of the Mayo Clinic in            
Rochester, Minn.

Role in Other Disorders

Experts believe that sleep apnea probably has several causes. Some cases are  
part of an underlying hormonal disorder, such as hypothyroidism (an           
underactive thyroid gland) or acromegaly (excess bone growth due to           
oversecretion of growth hormone). Sleep apnea also occurs in some patients    
with Marfan syndrome, an inherited disorder in which anatomical structures    
built of connective tissue are very weak. A Marfan patient's weakened airway  
may collapse easily, impeding airflow.

The repeated stop-and-go oxygen delivery in apnea stresses the heart and      
blood vessels. Sufferers are "two to three times as likely to have            
hypertension, and have triple the risk of having a stroke, due to oxygen      
levels dropping," says Scharf. The older and more overweight the patient,     
the greater the risk of a cardiovascular complication. Hypertension that      
arises during the night may persist during the day, even though breathing     
while awake is normal.

Richard Millman, M.D., and co-workers at Rhode Island Hospital in Providence  
compared prevalence of hypertension among 152 men with sleep apnea and 904    
men of similar ethnic background and geographic location who did not have     
sleep apnea. When the researchers looked at age and weight, they found that   
the prevalence of hypertension differed in the two groups only among obese    
men aged 25 to 44. Hypertension, they conclude, may develop only in this      
subset of apnea sufferers. Women were not evaluated in the study.

Treatment--Lots of Options

A physician can diagnose sleep apnea and suggest treatment based on the       
patient's complaints of daytime sleepiness, insomnia, awareness of            
obstructed breathing during sleep, snoring, and headache or dry mouth on      
waking. The physician examines the bones of the face and jaw and throat       
structures such as the palates, uvula and tonsils while the patient is in     
various positions, to see the sizes of spaces through which inhaled air can   
pass. X-rays may help envision how these structures lie.

Definitive diagnosis of sleep apnea depends upon the results of a battery of  
tests, called polysomnography, run in a sleep lab (see "Sleep Lab--First      
Step to Treatment"). A diagnosis of sleep apnea is made when polysomnography  
indicates more than five apneic episodes, of 10 seconds or longer duration    
per hour of sleep, plus an irregular heartbeat, frequent arousal during       
sleep, or dips in arterial oxygen saturation.

For mild obstructive sleep apnea, treatment often consists of avoiding        
sleeping on one's back, says Shepard. "Other people have a significant        
problem when the nose is congested, so decongestant therapy may be helpful    
for them. A more drastic treatment, if the patient is very overweight, is     
weight reduction. Also, avoid central nervous system depressants, such as     
alcoholic beverages or hypnotic or sedative drugs," he adds.

Most serious sleep apnea cases can be relieved by a treatment called nasal    
continuous positive airway pressure, or CPAP. CPAP uses a small mask held     
onto the nose by straps, and has pouches that insert into the nostrils. The   
mask is connected to a motor that regulates the amount and pressure of air    
sent into the nose, exerting pressure to keep the nasal passages open. The    
pressure is determined by polysomnography. CPAP works by holding open the     
nose and the back of the throat--Shepard compares it to inflating a bicycle   
tube.

CPAP usually brings immediate relief. Snoring stops. A smooth breathing       
pattern is restored. Blood oxygen levels stabilize. During the first week of  
CPAP therapy, the sleep pattern may still be grossly abnormal, but with       
peaceful stretches of sleep gradually growing, as if the body is trying to    
catch up. Sleep eventually settles down to a more normal pattern, often for   
the first time in years.

Unfortunately, many CPAP users never continue therapy beyond the first        
night, let alone the first week, because they find sleeping with a mask on    
the face uncomfortable. Colin Sullivan, M.D., the University of Sydney        
researcher who invented CPAP in 1981, admits that "sleeping with a nose mask  
and feeling the pressure sensation of CPAP, while not uncomfortable, are      
certainly novel experiences." Shepard points out, however, that the spouses   
of successful CPAP users are most grateful for the newfound silence!

Several CPAP devices have been cleared for marketing by FDA. "The typical     
approval process for any medical device involves the manufacturer submitting  
an application describing a product, and how it is similar to or different    
from devices that are already on the market. We determine if the new device   
is as safe and effective as the previous product," explains Arthur            
Ciarkowski, of FDA's Center for Devices and Radiological Health. Newer CPAP   
devices cleared for marketing by FDA attempt to make the experience more      
pleasant by building air pressure slowly, moisturizing the air to stem the    
common complaint of dry throat, and filtering out dust and pollen.

Before CPAP was invented, severe sleep apnea was treated by tracheostomy--a   
hole made surgically in the throat and a tube inserted to ease breathing.     
Choosing to live with a hole in the throat is a drastic measure, but several  
studies found that tracheostomy patients felt it was worth it to get          
complete relief from their apnea symptoms. Today, this procedure is used      
only in the most extreme cases, such as a person who cannot tolerate CPAP     
and who has severe hypertension with a high risk of heart failure due to      
apnea.

Other forms of surgery might provide relief for the 10 percent of patients    
with serious sleep apnea for whom CPAP does not work. In the nearly           
unpronounceable but helpful uvulopalatopharyngoplasty (UPPP), the back part   
of the soft palate and tissue at the back of the throat are removed, opening  
up more airspace. "It's like a big tonsil- adenoidectomy," says Shepard.

UPPP improves apnea in only about half the cases in which it's used, and the  
ways to predict who will benefit from the procedure are still controversial.  
"We do a skull cephalometric x-ray, which is a lateral skull film. This       
gives us an idea [whether] the patient has a chance of success with           
surgery," says Scharf. In another surgical procedure, called maxillary or     
mandibular advancement, the jaw is fractured and moved forward, creating      
more airspace.

For people with mild sleep apnea for whom first-line measures are             
ineffective and who dislike CPAP, another alternative is a dental device      
that brings the jaw forward, holds back the tongue, or raises the soft        
palate, or some combination of these. Dental devices, too, must be cleared    
for marketing by FDA. In one study of 68 patients using a dental device,      
researchers at the University of New Mexico in Albuquerque found 75 percent   
compliance after seven months, and decreased snoring and daytime sleepiness,  
plus a decrease in the average number of apnea events per hour from 47 to     
20. Dental devices are not as consistently effective as is CPAP, according    
to the American Sleep Disorders Association.

Whatever treatment is prescribed, a follow-up evaluation in a sleep lab       
should take place within three to six months of the start of therapy. And,    
happily, in most cases, the person who once spent most of each night not      
breathing can now enjoy a blissfully restful night--and those close by can    
too!

Ricki Lewis, a writer in Scotia, N.Y., teaches biology at the State           
University of New York at Albany.
Types of Adult Sleep Apnea

In all cases of sleep apnea some part of the respiratory system narrows,      
impairing oxygen intake. Lowered blood oxygen levels then trigger the brain   
to prompt the intake of breath. The sleeper gasps, jump-starting the          
breathing process--until the next halt. But doctors distinguish three         
variations on this theme:

Obstructive Sleep Apnea: The typical person suffering from this most common   
and severe form of apnea is an overweight male between 35 and 50 who usually  
has a small jaw, a small opening to the airway at the back of the throat,     
and a large tongue or tonsils. During sleep, the muscles of the soft palate   
and at the base of the tongue and the uvula (the "punching bag" structure     
hanging in the throat) relax and sag, blocking the airway, which collapses.   
As breathing stops, the diaphragm and chest muscles strain until the block    
is literally uncorked, and a noisy gasp--the snore--is taken. When breathing  
stops, blood oxygen levels fall, forcing the heart to work harder. As a       
result, blood pressure rises, and the heartbeat may even become irregular.    
Obstructive sleep apnea is made worse by drinking alcohol or taking           
tranquilizers, antihistamines, or sleeping pills.

Central Sleep Apnea: In this rarer form of the disorder, the airway remains   
open, but the diaphragm and chest muscles temporarily fail. The dropping      
blood oxygen levels signal the brain, which prompts the person to awaken and  
gasp in a breath. Because the airway is typically open, this apnea sufferer   
does not snore loudly but does have daytime sleepiness. Central sleep apnea   
is more common among people over 60, and is often seen in nursing homes and   
among the ill.

Mixed Apnea: Some people experience long periods of obstructive sleep apnea   
interspersed with brief periods of central sleep apnea.

--R.L.
Sleep Lab--First Step to Treatment

Sleep apnea is often treatable. Many sufferers don't know this, however,      
because only 10 to 25 percent of cases are ever diagnosed. This is either     
because the person is unaware of the snoring or does not know that loud       
snoring is a symptom of apnea.

Can sleep apnea really be dangerous, if you can have it and not even know it?

"I believe to some extent we have oversold [sleep apnea's] life-threatening   
nature. I see people in here who have had sleep apnea for 20 years. Are they  
dying? Only indirectly, because sleep apnea contributes to hypertension,      
accidents, sleepiness, and psychological problems," says John Shepard, M.D.,  
director of the Sleep Disorders Clinic of the Mayo Clinic in Rochester, Minn.

A definitive diagnosis of sleep apnea requires a visit to one of the          
country's 142 sleep laboratories. Here, a variety of tests are conducted      
while the patient sleeps, and physiological measurements are correlated to    
body movements. The entire procedure is called polysomnography.

The patient arrives at the sleep lab about an hour before bedtime. If he or   
she normally drinks alcoholic beverages, the usual amount is consumed at the  
usual time, so that observations match the patient's customary experience. A  
technician then places dime-sized sensors on different parts of the person's  
body. These measure heart rate, brain wave patterns, muscle activity, leg     
and arm movements, and eye movements, which indicate the stage of sleep.

An elastic band holding gauges is strapped around the chest and abdomen to    
track movements of the muscles involved in breathing. A light mask covering   
the mouth and nose measures the respiratory rate, which monitors the          
frequency of apneic episodes. Finally, a test called oximetry measures dips   
in arterial oxygen saturation, the hallmark of sleep apnea.

"In oximetry, a probe is clipped onto the finger or the ear. There is a       
light source. The light goes through the lobe or finger, and the refraction   
of the light is proportional to the [amount of] oxygen in the arterioles of   
the blood," says Martin Scharf, Ph.D., director of the Center for Research    
in Sleep Disorders in Cincinnati.

The automated scanners of the sleep lab produce a readout of each             
measurement, and these can be displayed next to one another so that one       
symptom or sign is easily correlated with another. For example, cessation of  
breathing usually coincides with a dip in oxygen saturation, and both tend    
to occur when the patient is sleeping on his or her back.

A night in a sleep lab is often followed by a daytime multiple sleep latency  
test, which monitors a series of two-hour naps. This test distinguishes       
between sleep apnea and narcolepsy, in which a person falls asleep very       
suddenly during the day. Scharf uses the nap test to quantify a patient's     
report of sleepiness, and to back up polysomnography. "I see people who       
drive a lot, and have a history of falling asleep, like truck drivers. I      
won't say 'you're cured' until I repeat the multiple sleep latency test and   
show they're not sleepy," he says.

Some sleep labs also study the architecture of the nose and throat, using     
x-rays and fiber-optic endoscopes (lights on flexible wires snaked into       
narrow body cavities) to picture upper airway structures.

Video cameras are beginning to be used to do the work of technicians,         
allowing polysomnography to move from a specialized lab setting to a typical  
hospital ward and even to a physician's office. Physiological data are        
superimposed on the video of the sleeping patient.

--R.L.