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Obstructive sleep apnea - Introduction

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of obstructive sleep apnea.

Introduction:

Obstructive sleep apnea (OSA) is a disorder in which a person stops breathing during the night, perhaps hundreds of times. These gaps in breathing are called apneas. The word apnea means absence of breath. An obstructive apnea episode is defined as the absence of airflow for at least 10 seconds.

Sleep apnea is usually accompanied by snoring, disturbed sleep, and daytime sleepiness. People might not even know they have the condition.

Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) occurs when tissues in the upper throat collapse at different times during sleep, thereby blocking the passage of air. In general, OSA occurs as follows:

On its way to the lungs, air passes through the nose, mouth, and throat (the upper airway).
Under normal conditions, the back of the throat is soft and tends to collapse inward as a person breathes.
Dilator (widening) muscles work against this collapse to keep the airway open. Interference or abnormalities in this process cause air turbulence.
If the tissues at the back of the throat collapse and become momentarily blocked, apnea occurs. Breath is temporarily stopped. In most cases the person is unaware of it, although sometimes they awaken and gasp for breath.
In some cases, the interference is incomplete (called obstructive hypopnea) and causes continuous but slow and shallow breathing. In response, the throat vibrates and makes the sound of snoring. Snoring can occur whether a person breathes through the mouth or the nose. (Snoring often occurs without sleep apnea.)
Apnea decreases the amount of oxygen in the blood, and eventually this lack of oxygen triggers the lungs to suck in air.
At this point, the patient may make a gasping or snorting sound but does not usually fully wake up.

Obstructive sleep apnea is defined as five or more episodes of apnea or hypopnea per hour of sleep (called apnea-hypopnea index or AHI) in individuals who have excessive daytime sleepiness. Patients with 15 or more episodes of apnea or hypopnea per hour of sleep are considered to have moderate- sleep apnea.

Other Causes of Apnea

Central sleep apnea is much less common. It is caused by some problem in the central nervous system, most likely a failure of the brain to signal the airway muscles to breathe. In such cases, oxygen levels drop abruptly and usually the sleeper wakes with a start. Often people with central sleep apnea recall waking up. They generally experience less sleepiness during the day than people with obstructive sleep apnea. Heart disease, and in particular heart failure, is the most common cause of central sleep apnea.
Mixed apnea is the term used when central and obstructive sleep apneas occur together.
Upper airway resistance syndrome (UARS) is a condition in which patients snore, wake frequently during the night, and have excessive daytime sleepiness. However, UARS patients do not have the breathing abnormalities that characterize sleep apnea and they do not show a reduction in blood oxygen levels. Unlike apnea, UARS is more likely to occur in women than in men. Treatments are similar to those of sleep apnea. It is not known if UARS has any serious health complications.

Resources

www.sleepapnea.org -- American Sleep Apnea Association
www.aasmnet.org -- American Academy of Sleep Medicine
www.sleepfoundation.org -- National Sleep Foundation
www.nhlbi.nih.gov/sleep -- National Center on Sleep Disorders Research
www.sleepeducation.com -- Sleep Education from the American Academy of Sleep Medicine

References

Ahmed M, Patel NP, Rosen I. Portable monitors in the diagnosis of obstructive sleep apnea. Chest. 2007 Nov;132(5):1672-7.

Ballard RD. Management of patients with obstructive sleep apnea. J Fam Pract. 2008 Aug;57(8 Suppl):S24-30.

Basner RC. Continuous positive airway pressure for obstructive sleep apnea. N Engl J Med. 2007 Apr 26;356(17):1751-8.

Berry RB, Hill G, Thompson L, McLaurin V. Portable monitoring and autotitration versus polysomnography for the diagnosis and treatment of sleep apena. Sleep. 2008 Oct 1;31(10):1423-31.

Bradley TD, Floras JS. Obstructive sleep apnoea and its cardiovascular consequences. Lancet. 2009 Jan 3;373(9657):82-93. Epub 2008 Dec 26.

Chan AS, Lee RW, Cistulli PA. Dental appliance treatment for obstructive sleep apnea. Chest. 2007 Aug;132(2):693-9.

Collop NA, Anderson WM, Boehlecke B, Claman D, Goldberg R, Gottlieb DJ, et al. Clinical guidelines for the use of unattended portable monitors in the diagnosis of obstructive sleep apnea in adult patients. Portable Monitoring Task Force of the American Academy of Sleep Medicine. J Clin Sleep Med. 2007 Dec 15;3(7):737-47.

Darrow DH. Surgery for pediatric sleep apnea. Otolaryngol Clin North Am. 2007 Aug;40(4):855-75.

Franklin, KA, Anttila H, Axelsson S, Gislason T, Maasilta P, Myhre K I, et al. Effects and side-effects of surgery for snoring and obstructive sleep apnea--a systematic review. Sleep. 2009 Jan 1; 32(1): 27-36.

Friedman M, Schalch P. Surgery of the palate and oropharynx. Otolaryngol Clin North Am. 2007 Aug;40(4):829-43.

Gami AS, Somers VK. Sleep apnea and cardiovascular disease. Libby P, Bonow RO, Mann DL, Zipes DP, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. St. Louis, Mo: WB Saunders; 2007:chap 74.

Hirshkowitz M. The clinical consequences of obstructive sleep apnea and associated excessive sleepiness. J Fam Pract. 2008 Aug;57(8 Suppl):S9-16.

Institute for Clinical Systems Improvement (ICSI). Diagnosis and treatment of obstructive sleep apnea in adults. Bloomington (MN): Institute for Clinical Systems Improvement (ICSI); 2007 Mar.

Kezirian EJ, Weaver EM, Yueh B, Khuri SF, Daley J, Henderson WG. Risk factors for serious complication after uvulopalatopharyngoplasty. Arch Otolaryngol Head Neck Surg. 2006 Oct;132(10):1091-8.

Li KK. Hypopharyngeal airway surgery. Otolaryngol Clin North Am. 2007 Aug;40(4):845-53.

Marshall NS, Wong KK, Liu PY, Cullen SR, Knuiman MW, Grunstein RR. Sleep apnea as an independent risk factor for all-cause mortality: the Busselton Health Study. Sleep. 2008 Aug 1;31(8):1079-85.

Morgenthaler T, Alessi C, Friedman L, Owens J, Kapur V, Boehlecke B, et al. Practice parameters for the use of actigraphy in the assessment of sleep and sleep disorders: an update for 2007. Sleep. 2007 Apr 1;30(4):519-29.

Morgenthaler TI, Aurora RN, Brown T, Zak R, Alessi C, Boehlecke B, et al. Practice parameters for the use of autotitrating continuous positive airway pressure devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome: an update for 2007. An American Academy of Sleep Medicine report. Sleep. 2008 Jan 1;31(1):141-7.

Morgenthaler TI, Kapen S, Lee-Chiong T, Alessi C, Boehlecke B, Brown T, Coleman J, et al. Practice parameters for the medical therapy of obstructive sleep apnea. Sleep. 2006 Aug 1;29(8):1031-5.

Mulgrew AT, Fox N, Ayas NT, Ryan CF. Diagnosis and initial management of obstructive sleep apnea without polysomnography: a randomized validation study. Ann Intern Med. 2007 Feb 6;146(3):157-66.

Owens JA. Sleep medicine. Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. St. Louis, MO: WB Saunders; 2007:chap 18.

Patel NP, Ahmed M, Rosen I. Split-night polysomnography. Chest. 2007 Nov;132(5):1664-71.

Patil SP, Schneider H, Schwartz AR, Smith PL. Adult obstructive sleep apnea: pathophysiology and diagnosis. Chest. 2007 Jul;132(1):325-37.

Somers VK, White DP, Amin R, Abraham WT, Costa F, Culebras A, et al. Sleep apnea and cardiovascular disease: an American Heart Association/American College of Cardiology Foundation Scientific Statement from the American Heart Association Council for High Blood Pressure Research Professional Education Committee, Council on Clinical Cardiology, Stroke Council, and Council on Cardiovascular Nursing. J Am Coll Cardiol. 2008 Aug 19;52(8):686-717

Sundaram S, Bridgman SA, Lim J, Lasserson TJ. Surgery for obstructive sleep apnoea. Cochrane Database Syst Rev. 2005 Oct 19;(4):CD001004.

Waller EA, Bendel RE, Kaplan J. Sleep disorders and the eye. Mayo Clin Proc. 2008 Nov;83(11):1251-61.

Young T, Finn L, Peppard PE, Szklo-Coxe M, Austin D, Nieto FJ, et al. Sleep disordered breathing and mortality: eighteen-year follow-up of the Wisconsin sleep cohort. Sleep. 2008 Aug 1;31(8):1071-8.

Reviewed last on: 6/23/2009
Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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