WHAT IS SLEEP APNEA?

Sleep apnea is a serious, potentially life-threatening condition that is far more com-mon than generally understood. Firstdescribed in 1965, sleep apnea is a breathingdisorder characterized by brief interruptionsof breathing during sleep. It owes its nameto a Greek word, apnea, meaning want ofbreath. There are two types of sleep apnea:central and obstructive. Central sleepapnea, which is less common, occurs whenthe brain fails to send the appropriate sig-nals to the breathing muscles to initiate res-pirations. Obstructive sleep apnea is farmore common and occurs when air cannotflow into or out of the persons nose ormouth although efforts to breathe continue.

In a given night, the number of involuntarybreathing pauses or apneic events may beas high as 20 to 30 or more per hour. Thesebreathing pauses are almost always accom-panied by snoring between apnea episodes,although not everyone who snores has thiscondition. Sleep apnea can also be charac-terized by choking sensations. The frequentinterruptions of deep, restorative sleep oftenlead to early morning headaches and exces-sive daytime sleepiness.

Early recognition and treatment of sleepapnea is important because it may be associ-ated with irregular heartbeat, high bloodpressure, heart attack, and stroke.

F A C T S A B O U T

N A T I O N A L I N S T I T U T E S O F H E A L T HN A T I O N A L H E A R T , L U N G , A N D B L O O D I N S T I T U T E

Sleep Apnea

WHO GETS SLEEP APNEA?

Sleep apnea occurs in all age groups andboth sexes but is more common in men (itmay be underdiagnosed in women) and pos-sibly young African Americans. It has beenestimated that as many as 18 millionAmericans have sleep apnea. Four percentof middle-aged men and 2 percent of mid-dle-aged women have sleep apnea alongwith excessive daytime sleepiness. Peoplemost likely to have or develop sleep apneainclude those who snore loudly and also areoverweight, or have high blood pressure, orhave some physical abnormality in the nose,throat, or other parts of the upper airway.Sleep apnea seems to run in some families,suggesting a possible genetic basis.

WHAT CAUSES SLEEP APNEA?

Certain mechanical and structural problemsin the airway cause the interruptions inbreathing during sleep. In some people,apnea occurs when the throat muscles andtongue relax during sleep and partially blockthe opening of the airway. When the mus-cles of the soft palate at the base of thetongue and the uvula (the small fleshy tissuehanging from the center of the back of thethroat) relax and sag, the airway becomesblocked, making breathing labored andnoisy and even stopping it altogether. Sleepapnea also can occur in obese people whenan excess amount of tissue in the airway

causes it to be narrowed. With anarrowed airway, the person contin-ues his or her efforts to breathe, butair cannot easily flow into or out ofthe nose or mouth. Unknown to theperson, this results in heavy snoring,periods of no breathing, and frequentarousals (causing abrupt changesfrom deep sleep to light sleep).Ingestion of alcohol and sleepingpills increases the frequency andduration of breathing pauses in peo-ple with sleep apnea.

HOW IS NORMAL BREATHINGRESTORED DURING SLEEP?

During the apneic event, the personis unable to breathe in oxygen and toexhale carbon dioxide, resulting inlow levels of oxygen and increasedlevels of carbon dioxide in the blood.The reduction in oxygen and increasein carbon dioxide alert the brain toresume breathing and cause anarousal. With each arousal, a signalis sent from the brain to the upperairway muscles to open the airway;breathing is resumed, often with aloud snort or gasp. Frequentarousals, although necessary forbreathing to restart, prevent thepatient from getting enough restora-tive, deep sleep.

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WHAT ARE THE EFFECTS OFSLEEP APNEA?

Because of the serious disturbancesin their normal sleep patterns, peo-ple with sleep apnea often feel verysleepy during the day and their con-centration and daytime performancesuffer. The consequences of sleepapnea range from annoying to life-threatening. They include depres-sion, irritability, sexual dysfunction,learning and memory difficulties,and falling asleep while at work, onthe phone, or driving. It has beenestimated that up to 50 percent ofsleep apnea patients have high bloodpressure. Although it is not knownwith certainty if there is a cause andeffect relationship, it appears thatsleep apnea contributes to highblood pressure. Risk for heart attackand stroke may also increase in thosewith sleep apnea. In addition, sleepapnea is sometimes implicated insudden infant death syndrome.

WHEN SHOULD SLEEP APNEABE SUSPECTED?

For many sleep apnea patients, theirspouses are the first ones to suspectthat something is wrong, usuallyfrom their heavy snoring and appar-

ent struggle to breathe. Coworkersor friends of the sleep apnea victimmay notice that the individual fallsasleep during the day at inappropri-ate times (such as while driving a car,working, or talking). The patientoften does not know he or she has aproblem and may not believe it whentold. It is important that the personsee a doctor for evaluation of thesleep problem.

HOW IS SLEEP APNEA DIAGNOSED?

In addition to the primary carephysician, pulmonologists, neurolo-gists, or other physicians with spe-cialty training in sleep disorders maybe involved in making a definitivediagnosis and initiating treatment.Diagnosis of sleep apnea is not sim-ple because there can be many differ-ent reasons for disturbed sleep.Several tests are available for evaluat-ing a person for sleep apnea.

Polysomnography is a test thatrecords a variety of body functionsduring sleep, such as the electricalactivity of the brain, eye movement,muscle activity, heart rate, respira-tory effort, air flow, and blood oxygen levels. These tests are usedboth to diagnose sleep apnea and todetermine its severity.

The Multiple Sleep Latency Test(MSLT) measures the speed of fallingasleep. In this test, patients aregiven several opportunities to fallasleep during the course of a daywhen they would normally be awake.For each opportunity, time to fallasleep is measured. People withoutsleep problems usually take an aver-age of 10 to 20 minutes to fallasleep. Individuals who fall asleep inless than 5 minutes are likely to

O P E N A I R W AY B L O C K E D A I R W AY

3require some treatment for sleep dis-orders. The MSLT may be useful tomeasure the degree of excessive day-time sleepiness and to rule out othertypes of sleep disorders.

Diagnostic tests usually are performedin a sleep center, but new technologymay allow some sleep studies to beconducted in the patients home.

HOW IS SLEEP APNEA TREATED?

The specific therapy for sleep apnea istailored to the individual patientbased on medical history, physicalexamination, and the results ofpolysomnography. Medications aregenerally not effective in the treat-ment of sleep apnea. Oxygen admin-istration may safely benefit certainpatients but does not eliminate sleepapnea or prevent daytime sleepiness.Thus, the role of oxygen in the treat-ment of sleep apnea is controversial,and it is difficult to predict whichpatients will respond well. It is im-portant that the effectiveness of theselected treatment be verified; this isusually accomplished by polysom-nography.

Behavioral Therapy

Behavioral changes are an importantpart of the treatment program, andin mild cases behavioral therapy maybe all that is needed. The individualshould avoid the use of alcohol,tobacco, and sleeping pills, whichmake the airway more likely to col-lapse during sleep and prolong theapneic periods. Overweight personscan benefit from losing weight. Evena 10 percent weight loss can reducethe number of apneic events for mostpatients. In some patients with mildsleep apnea, breathing pauses occuronly when they sleep on their backs.In such cases, using pillows and otherdevices that help them sleep in a sideposition is often helpful.

Physical or MechanicalTherapy

Nasal continuous positive airwaypressure (CPAP) is the most commoneffective treatment for sleep apnea.In this procedure, the patient wears amask over the nose during sleep, andpressure from an air blower forces airthrough the nasal passages. The airpressure is adjusted so that it is just

N A T I O N A L C E N T E R O N

S L E E P D I S O R D E R S

R E S E A R C H ( N C S D R )

The mission of the NCSDR is to support

research, training, and education about

sleep disorders. The center is located

within the National Heart, Lung, and

Blood Institute (NHLBI) of the National

Institutes of Health. The NHLBI sup-

ports a variety of research and training

programs focusing on cardiopulmonary

disorders in sleep, designed to fill criti-

cal gaps in the understanding of the

causes, diagnosis, treatment, and pre-

vention of sleep-disordered breathing.

A P A T I E N T U S I N G C PA P

U.S. DEPARTMENT OF HEALTH

AND HUMAN SERVICES

Public Health Service

National Institutes of Health

National Heart, Lung, and

Blood Institute

NIH Publication No. 95-3798

September 1995

enough to prevent the throat fromcollapsing during sleep. The pres-sure is constant and continuous.Nasal CPAP prevents airway closurewhile in use, but apnea episodesreturn when CPAP is stopped orused improperly.

Variations of the CPAP deviceattempt to minimize side effects thatsometimes occur, such as nasal irrita-tion and drying, facial skin irrita-tion, abdominal bloating, maskleaks, sore eyes, and headaches.Some versions of CPAP vary thepressure to coincide with the per-sons breathing pattern, and othersstart with low pressure, slowlyincreasing it to allow the person tofall asleep before the full prescribedpressure is applied.

Dental appliances that repositionthe lower jaw and the tongue havebeen helpful to some patients withmild sleep apnea or who snore butdo not have apnea. Possible sideeffects include damage to teeth, softtissues, and the jaw joint. A dentistor orthodontist is often the one to fitthe patient with such a device.

Surgery

Some patients with sleep apnea mayneed surgery. Although several sur-gical procedures are used to increasethe size of the airway, none of themis completely successful or withoutrisks. More than one procedure mayneed to be tried before the patientrealizes any benefits.

Some of the more common proce-dures include removal of adenoidsand tonsils (especially in children),nasal polyps or other growths, orother tissue in the airway and cor-rection of structural deformities.Younger patients seem to benefitfrom these surgical procedures morethan older patients.

Uvulopalatopharyngoplasty (UPPP) isa procedure used to remove excess tis-sue at the back of the throat (tonsils,uvula, and part of the soft palate).The success of this technique mayrange from 30 to 50 percent. Thelong-term side effects and benefits arenot known, and it is difficult to predictwhich patients will do well with thisprocedure.

Laser-assisted uvulopalatoplasty(LAUP) is done to eliminate snoringbut has not been shown to be effectivein treating sleep apnea. This proce-dure involves using a laser device toeliminate tissue in the back of thethroat. Like UPPP, LAUP maydecrease or eliminate snoring but notsleep apnea itself. Elimination of snor-ing, the primary symptom of sleepapnea, without influencing the condi-tion may carry the risk of delaying thediagnosis and possible treatment ofsleep apnea in patients who electLAUP. To identify possible underlyingsleep apnea, sleep studies are usuallyrequired before LAUP is performed.

Tracheostomy is used in persons withsevere, life-threatening sleep apnea. Inthis procedure, a small hole is made inthe windpipe and a tube is insertedinto the opening. This tube staysclosed during waking hours, and theperson breathes and speaks normally.It is opened for sleep so that air flowsdirectly into the lungs, bypassing anyupper airway obstruction. Althoughthis procedure is highly effective, it isan extreme measure that is poorly tol-erated by patients and rarely used.

Other procedures. Patients in whomsleep apnea is due to deformities of thelower jaw may benefit from surgicalreconstruction. Finally, surgical proce-dures to treat obesity are sometimesrecommended for sleep apnea patientswho are morbidly obese.

F O R M O R E

I N F O R M A T I O N

Information about sleep

disorders research can be

obtained from the NCSDR.

In addition, the NHLBI

Information Center can

provide you with sleep

education materials as well

as other publications relat-

ing to heart, lung, and

blood diseases.

National Center on Sleep

Disorders Research

Two Rockledge Centre

Suite 7024

6701 Rockledge Drive

MSC 7920

Bethesda, MD 20892-7920

(301) 435-0199

(301) 480-3451 (fax)

NHLBI Information Center

P.O. Box 30105

Bethesda, MD 20824-0105

(301) 251-1222

(301) 251-1223 (fax)

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