Obstructive sleep apnea

Last updated: July 28, 2023

Summarytoggle arrow icon

Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is typically associated with obesity. It is characterized by obstruction of the upper airways due to the collapse of the pharyngeal muscles during sleep, which causes multiple episodes of interrupted breathing (apnea and hypopnea events), leading to alveolar hypoventilation. Severe daytime sleepiness due to sleep disruption is a common symptom. Partners of affected individuals commonly describe observing restless sleep and irregular snoring, gasping, or choking episodes. The diagnosis is based on polysomnography or home sleep apnea testing. Many patients develop hypertension secondary to OSA, the cardiovascular consequences of which can reduce life expectancy. First-line treatment consists of nightly continuous positive airway pressure (CPAP); alternatives include oral appliances and surgical interventions. Lifestyle changes such as weight loss, avoidance of precipitating factors (e.g., alcohol), and improvement of sleep hygiene are recommended.

Definitiontoggle arrow icon

  • Obstructive sleep apnea: (OSA): a sleep-related breathing disorder in which airflow significantly decreases or ceases due to upper airway obstruction (typically in the oropharynx) [1][2]
  • Abnormal breathing events
    • Apnea: complete or nearly complete (≥ 90%) cessation of inspiratory airflow for ≥ 10 seconds [1][3]
    • Hypopnea: airflow reduction by ≥ 30% of the pre-event baseline for ≥ 10 seconds in combination with either desaturation by ≥ 3% or arousal from sleep [3][4][5]
    • Respiratory effort-related arousal (RERA): arousal from sleep due to increased respiratory effort or reduced airflow for ≥ 10 seconds without significant hypopnea or apnea [3]

Epidemiologytoggle arrow icon


Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

An increased neck circumference (> 40 cm) is the most important risk factor for OSA.

Pathophysiologytoggle arrow icon

Clinical featurestoggle arrow icon

  • Typical symptoms [5]
    • Restless sleep with waking, gasping, or choking
    • Loud, irregular snoring with apneic episodes (third-party reports)
    • Excessive daytime sleepiness (e.g., patient falls asleep, microsleep while seated)
    • Morning headaches
  • Signs of complications, including:
    • Impaired cognitive function (e.g., impaired concentration, memory loss) [4]
    • Depression [10]
    • Decreased libido [11]
    • Hypertension with increased pulse pressure [12]

Obstructive sleep apnea is one of the most common causes of secondary hypertension. [13]

Diagnosticstoggle arrow icon

General principles [4][5]

  • A detailed evaluation should include:
  • Screening for OSA
    • Standardized screening questionnaires may be used to assess risk for OSA in certain clinical settings (e.g., STOP-BANG questionnaire for preoperative evaluation).
    • Screening asymptomatic patients is not routinely recommended. [14]
  • Sleep studies are required to confirm the diagnosis and determine the severity of OSA (e.g., using the apnea-hypopnea index).

The diagnosis of obstructive sleep apnea requires sleep studies and should not be made based on clinical tools or questionnaires alone. [4]

STOP-BANG questionnaire: S – Snoring loudly, T – feeling Tired or fatigued, OObserved apneas during sleep, P – high blood Pressure, BBMI > 35, AAge > 50 years, NNeck circumference > 40 cm, G – male Gender. [15]

Laboratory tests

Laboratory tests are not usually considered useful in the diagnosis of OSA but can help identify physiological consequences of OSA and detect associated conditions.

Sleep studies [4][5]

In-laboratory polysomnography (PSG)

  • Description: Physiologic variables are recorded during sleep to diagnose sleep-related disorders.
  • Indications
    • Patients with significant cardiovascular or respiratory disease
    • Suspicion of other types of sleep-related disorders
    • Circumstances precluding a home assessment [4]
    • Home sleep apnea testing is inconclusive or negative.
  • Findings
    • Apnea and hypopnea events
    • Oxygen desaturation
    • Respiratory effort-related arousal events, possibly causing sleep fragmentation
    • In some cases, signs of associated comorbidities (e.g., hypertension, cardiac arrhythmias) [5][18]
  • Important considerations
    • Consider repeated testing if the initial test is negative and clinical suspicion remains (first night effect). [4][5]
    • Consider split-night testing. [4]

In-laboratory polysomnography is the gold standard for the diagnosis of sleep-related breathing disorders and can also help identify other sleep-related conditions (e.g., seizures).

Home sleep apnea testing (HSAT)

  • Description: an ambulatory screening method for sleep-related breathing disorders that assesses ventilation and oxygenation parameters but not sleep stages or arousal events
  • Indications
    • Patients with a high pretest probability for OSA and no significant comorbidities
    • In-laboratory testing is not feasible.
  • Findings: cardiorespiratory findings similar to those in PSG

Due to its lower sensitivity, HSAT cannot be used to rule out the diagnosis of OSA. [4]

Interpretation of sleep study findings [1][4]


Scores are calculated based on sleep study findings and are then used to diagnose OSA and determine its severity.

  • Apnea-hypopnea index (AHI): number of apneas plus hypopneas per hour of sleep
  • Respiratory disturbance index (RDI): number of apneas plus hypopneas plus RERAs per hour of sleep [19]
  • Respiratory event index (REI): number of apneas plus hypopneas with desaturation of ≥ 4% per hour of recorded time

Diagnostic criteria for OSA [4][20]

Depending on the type of sleep study used, different scores can be calculated. Any of them can be used to diagnose OSA.

  • AHI/RDI/REI ≥ 5 in patients with symptoms of OSA and/or associated comorbidities
  • OR AHI/RDI/REI ≥ 15 in patients without symptoms

Classification of OSA by severity [21]

Severity is graded by the number of sleep-related obstructive breathing events, most commonly using the AHI.

  • AHI 5–15: mild OSA
  • AHI 16–30: moderate OSA
  • AHI > 30: severe OSA

Differential diagnosestoggle arrow icon

Central sleep apnea (CSA) syndromes [22][23]

Types of CSA [22][23]
Nonhypercapnic CSA Hypercapnic CSA
  • Reduced central ventilatory drive or reduced ventilation due to underlying disease → ↑ hypoventilation during sleep due to loss of wakeful breathing drive apnea → ↑ PaCO2 → arousal and increased ventilation → ↓ PaCO2 hypoventilation → cycle repeats [24]

The 3 C’s of Central sleep apnea are Congestive heart failure, CNS trauma or toxicity, and Cheyne-Stokes breathing.

Hypoventilation disorders

Alveolar hypoventilation is defined as an elevation of PaCO2 > 45 mmHg.

Obesity hypoventilation syndrome (Pickwickian syndrome) [27][28]

Patients presenting with respiratory failure due to OHS are frequently misdiagnosed with COPD. [28]

Other sleep-related hypoventilation disorders

Sleep-related hypoventilation disorders are defined as sustained desaturation (SpO2 ≤ 88% for > 5 minutes) with a rise in pCO2 during sleep. [20]

The differential diagnoses listed here are not exhaustive.

Treatmenttoggle arrow icon

Approach [21][33][34]

  • Treat all patients with diagnosed OSA.
  • First-line treatment: positive airway pressure (PAP)
  • Consider alternative treatment in patients who are unable to tolerate or decline PAP: [1][35][36]
    • Oral appliances
    • Upper airway modifications
    • Positional therapy
  • Supportive care should include management of risk factors, e.g., weight loss and sleep hygiene.

Nocturnal positive pressure therapy is the therapy of choice in OSA. The success of therapy is highly dependent on patient adherence.

Positive airway pressure (PAP)

  • Description: Pressure is used to pneumatically splint collapsible airways open to reduce the frequency of respiratory events. [18]
  • Types
  • Procedure
    • Should be used over the entire sleep period [33]
    • Initial titration can be done using in-laboratory or APAP devices. [33]
    • Minimum starting pressures

Encourage inpatients to continue using PAP during their admission, if possible, as sudden discontinuation is associated with recurrence of OSA symptoms. [37][38]

Alternative treatment options [1][21]

Conservative treatment

Conservative treatment options are usually only appropriate for mild to moderate disease.

  • Oral appliances [35][39]
    • Devices are worn during sleep to maintain mandibular advancement and prevent airway collapse.
    • Custom-fitted titratable devices are preferred.
  • Positional therapy: : devices to keep patients in a lateral as opposed to supine sleeping position [40]

Upper airway modification [36]

Supportive treatment [1]

Complicationstoggle arrow icon


We list the most important complications. The selection is not exhaustive.

Prognosistoggle arrow icon

  • The mortality rate is higher in patients with severe OSA who do not receive adequate treatment.
  • CPAP ventilation can significantly lower the risk of mortality in OSA.

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Referencestoggle arrow icon

  1. Walker HK, Hall WD, Hurst WJ, Silverman ME, Morrison G. Clinical Methods: The History, Physical, and Laboratory Examinations. Butterworths ; 1990
  2. Levitzky MG. Using the pathophysiology of obstructive sleep apnea to teach cardiopulmonary integration. Adv Physiol Educ. 2008; 32 (3): p.196-202.doi: 10.1152/advan.90137.2008 . | Open in Read by QxMD
  3. Eckert DJ, Jordan AS, Merchia P, Malhotra A. Central Sleep Apnea. Chest. 2007; 131 (2): p.595-607.doi: 10.1378/chest.06.2287 . | Open in Read by QxMD
  4. Aurora RN, Chowdhuri S, Ramar K, et al. The Treatment of Central Sleep Apnea Syndromes in Adults: Practice Parameters with an Evidence-Based Literature Review and Meta-Analyses. Sleep. 2012; 35 (1): p.17-40.doi: 10.5665/sleep.1580 . | Open in Read by QxMD
  5. Baillieul S, Revol B, Jullian-Desayes I, Joyeux-Faure M, Tamisier R, Pépin J-L. Diagnosis and management of central sleep apnea syndrome. Expert Rev Respir Med. 2019; 13 (6): p.545-557.doi: 10.1080/17476348.2019.1604226 . | Open in Read by QxMD
  6. Randerath W, Verbraecken J, Andreas S, et al. Definition, discrimination, diagnosis and treatment of central breathing disturbances during sleep. Eur Respir J. 2016; 49 (1): p.1600959.doi: 10.1183/13993003.00959-2016 . | Open in Read by QxMD
  7. Yancy CW, Jessup M, Bozkurt B, et al. 2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Failure Society of America. Circulation. 2017; 136 (6).doi: 10.1161/cir.0000000000000509 . | Open in Read by QxMD
  8. Mokhlesi B, Masa JF, Brozek JL, et al. Evaluation and Management of Obesity Hypoventilation Syndrome. An Official American Thoracic Society Clinical Practice Guideline. Am J Respir Crit Care Med. 2019; 200 (3): p.e6-e24.doi: 10.1164/rccm.201905-1071st . | Open in Read by QxMD
  9. Masa JF, Pepin J-L, Borel J-C, Mokhlesi B, Murphy PB, Sanchez-Quiroga MA. Obesity hypoventilation syndrome. Eur Respir Rev. 2019; 28 (151): p.180097.doi: 10.1183/16000617.0097-2018 . | Open in Read by QxMD
  10. Sateia MJ. International Classification of Sleep Disorders-Third Edition. Chest. 2014; 146 (5): p.1387-1394.doi: 10.1378/chest.14-0970 . | Open in Read by QxMD
  11. Wright SM, Aronne LJ. Causes of obesity. Abdom Imaging. 2012; 37 (5): p.730-732.doi: 10.1007/s00261-012-9862-x . | Open in Read by QxMD
  12. Boeing S, Randerath WJ. Chronic hypoventilation syndromes and sleep-related hypoventilation. J Thorac Dis. 2015; 7 (8): p.1273-85.doi: 10.3978/j.issn.2072-1439.2015.06.10 . | Open in Read by QxMD
  13. Thorpy MJ. Classification of Sleep Disorders. Neurotherapeutics. 2012; 9 (4): p.687-701.doi: 10.1007/s13311-012-0145-6 . | Open in Read by QxMD
  14. Katz ES, McGrath S, Marcus CL. Late-onset central hypoventilation with hypothalamic dysfunction: A distinct clinical syndrome. Pediatr Pulmonol. 2000; 29 (1): p.62-68.doi: 10.1002/(sici)1099-0496(200001)29:1<62::aid-ppul10>;2-m . | Open in Read by QxMD
  15. Veasey SC, Rosen IM. Obstructive Sleep Apnea in Adults. N Engl J Med. 2019; 380 (15): p.1442-1449.doi: 10.1056/nejmcp1816152 . | Open in Read by QxMD
  16. Mohammadieh A, Sutherland K, Cistulli PA. Sleep disordered breathing: management update. Intern Med J. 2017; 47 (11): p.1241-1247.doi: 10.1111/imj.13606 . | Open in Read by QxMD
  17. Berry RB, Budhiraja R, Gottlieb DJ, et al. Rules for Scoring Respiratory Events in Sleep: Update of the 2007 AASM Manual for the Scoring of Sleep and Associated Events. J Clin Sleep Med. 2012; 08 (05): p.597-619.doi: 10.5664/jcsm.2172 . | Open in Read by QxMD
  18. Kapur VK, Auckley DH, Chowdhuri S, et al. Clinical Practice Guideline for Diagnostic Testing for Adult Obstructive Sleep Apnea: An American Academy of Sleep Medicine Clinical Practice Guideline. J Clin Sleep Med. 2017; 13 (03): p.479-504.doi: 10.5664/jcsm.6506 . | Open in Read by QxMD
  19. Corral-Penafiel J, Pepin J-L, Barbe F. Ambulatory monitoring in the diagnosis and management of obstructive sleep apnoea syndrome. Eur Respir Rev. 2013; 22 (129): p.312-324.doi: 10.1183/09059180.00004213 . | Open in Read by QxMD
  20. Rising prevalence of sleep apnea in U.S. threatens public health. Updated: September 29, 2014. Accessed: February 27, 2017.
  21. Punjabi NM. The epidemiology of adult obstructive sleep apnea. Proc Am Thorac Soc. 2008; 5 (2): p.136-143.doi: 10.1513/pats.200709-155MG . | Open in Read by QxMD
  22. Chen YH, Keller JK, Kang JH, Hsieh HJ, Lin HC. Obstructive Sleep Apnea and the Subsequent Risk of Depressive Disorder: A Population-Based Follow-up Study. J Clin Sleep Med. 2013; 09 (05): p.417-423.doi: 10.5664/jcsm.2652 . | Open in Read by QxMD
  23. Liu L, Kang R, Zhao S, et al. Sexual Dysfunction in Patients with Obstructive Sleep Apnea: A Systematic Review and Meta-Analysis. J Sex Med. 2015; 12 (10): p.1992-2003.doi: 10.1111/jsm.12983 . | Open in Read by QxMD
  24. Phillips C, O’Driscoll D. Hypertension and obstructive sleep apnea. Nature and Science of Sleep. 2013: p.43.doi: 10.2147/nss.s34841 . | Open in Read by QxMD
  25. Rimoldi SF, Scherrer U, Messerli FH. Secondary arterial hypertension: when, who, and how to screen?. Eur Heart J. 2013; 35 (19): p.1245-1254.doi: 10.1093/eurheartj/eht534 . | Open in Read by QxMD
  26. Mangione CM, Barry MJ, et al. Screening for Obstructive Sleep Apnea in Adults. JAMA. 2022; 328 (19): p.1945.doi: 10.1001/jama.2022.20304 . | Open in Read by QxMD
  27. Shahid A, Wilkinson K, Marcu S, Shapiro CM. STOP-Bang Questionnaire. Springer New York ; 2011: p. 371-383
  28. Gangaraju R, Sundar KM, Song J, Prchal JT. Polycythemia Is Rarely Caused By Obstructive Sleep Apnea. Blood. 2016; 128 (22): p.2444-2444.doi: 10.1182/blood.v128.22.2444.2444 . | Open in Read by QxMD
  29. Chung F, Chau E, Yang Y, Liao P, Hall R, Mokhlesi B. Serum Bicarbonate Level Improves Specificity of STOP-Bang Screening for Obstructive Sleep Apnea. Chest. 2013; 143 (5): p.1284-1293.doi: 10.1378/chest.12-1132 . | Open in Read by QxMD
  30. Kushida CA, Chediak A,et al. Clinical Guidelines for the Manual Titration of Positive Airway Pressure in Patients with Obstructive Sleep Apnea. J Clin Sleep Med. 2008; 04 (02): p.157-171.doi: 10.5664/jcsm.27133 . | Open in Read by QxMD
  31. Gottlieb DJ, Whitney CW, Bonekat WH, et al. Relation of Sleepiness to Respiratory Disturbance Index. Am J Respir Crit Care Med. 1999; 159 (2): p.502-507.doi: 10.1164/ajrccm.159.2.9804051 . | Open in Read by QxMD
  32. Qaseem A. Management of Obstructive Sleep Apnea in Adults: A Clinical Practice Guideline From the American College of Physicians. Annals of Internal Medicine. 2013.doi: 10.7326/0003-4819-159-7-201310010-00704 . | Open in Read by QxMD
  33. Patil SP, Ayappa IA, Caples SM, Kimoff RJ, Patel SR, Harrod CG. Treatment of Adult Obstructive Sleep Apnea With Positive Airway Pressure: An American Academy of Sleep Medicine Systematic Review, Meta-Analysis, and GRADE Assessment. J Clin Sleep Med. 2019; 15 (02): p.301-334.doi: 10.5664/jcsm.7638 . | Open in Read by QxMD
  34. Patil SP, Ayappa IA, Caples SM, Kimoff RJ, Patel SR, Harrod CG. Treatment of Adult Obstructive Sleep Apnea with Positive Airway Pressure: An American Academy of Sleep Medicine Clinical Practice Guideline. J Clin Sleep Med. 2019; 15 (02): p.335-343.doi: 10.5664/jcsm.7640 . | Open in Read by QxMD
  35. Ramar K, Dort LC, Katz SG, et al. Clinical Practice Guideline for the Treatment of Obstructive Sleep Apnea and Snoring with Oral Appliance Therapy: An Update for 2015. J Clin Sleep Med. 2015; 11 (07): p.773-827.doi: 10.5664/jcsm.4858 . | Open in Read by QxMD
  36. Aurora RN, Casey KR, Kristo D, et al. Practice parameters for the surgical modifications of the upper airway for obstructive sleep apnea in adults.. Sleep. 2010; 33 (10): p.1408-13.doi: 10.1093/sleep/33.10.1408 . | Open in Read by QxMD
  37. Kohler M, Stoewhas A-C, Ayers L, et al. Effects of Continuous Positive Airway Pressure Therapy Withdrawal in Patients with Obstructive Sleep Apnea. Am J Respir Crit Care Med. 2011; 184 (10): p.1192-1199.doi: 10.1164/rccm.201106-0964oc . | Open in Read by QxMD
  38. Tran K, Cimon K, Severn M, Pessoa-Silva CL, Conly J. Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: a systematic review.. PLoS ONE. 2012; 7 (4): p.e35797.doi: 10.1371/journal.pone.0035797 . | Open in Read by QxMD
  39. Basyuni S, Barabas M, Quinnell T. An update on mandibular advancement devices for the treatment of obstructive sleep apnoea hypopnoea syndrome. J Thorac Dis. 2018; 10 (S1): p.S48-S56.doi: 10.21037/jtd.2017.12.18 . | Open in Read by QxMD
  40. Srijithesh PR, Aghoram R, Goel A, Dhanya J. Positional therapy for obstructive sleep apnoea. Cochrane Database Syst Rev. 2019.doi: 10.1002/14651858.cd010990.pub2 . | Open in Read by QxMD
  41. Eastwood PR, Barnes M, MacKay SG, et al. Bilateral hypoglossal nerve stimulation for treatment of adult obstructive sleep apnoea. Eur Respir J. 2019; 55 (1): p.1901320.doi: 10.1183/13993003.01320-2019 . | Open in Read by QxMD
  42. Baptista PM, Costantino A, Moffa A, Rinaldi V, Casale M. Hypoglossal Nerve Stimulation in the Treatment of Obstructive Sleep Apnea: Patient Selection and New Perspectives. Nat Sci Sleep. 2020; Volume 12: p.151-159.doi: 10.2147/nss.s221542 . | Open in Read by QxMD
  43. Lee SA, Paek JH, Han SH. Sleep hygiene and its association with daytime sleepiness, depressive symptoms, and quality of life in patients with mild obstructive sleep apnea. J Neurol Sci. 2015; 359 (1-2): p.445-449.doi: 10.1016/j.jns.2015.10.017 . | Open in Read by QxMD
  44. Lam B, Sam K, Mok WY, et al. Randomised study of three non-surgical treatments in mild to moderate obstructive sleep apnoea. Thorax. 2006; 62 (4): p.354-359.doi: 10.1136/thx.2006.063644 . | Open in Read by QxMD
  45. Müller M, Jürgens J, Redaèlli M, Klingberg K, Hautz WE, Stock S. Impact of the communication and patient hand-off tool SBAR on patient safety: a systematic review. BMJ Open. 2018; 8 (8): p.e022202.doi: 10.1136/bmjopen-2018-022202 . | Open in Read by QxMD
  46. Dorasamy P. Obstructive sleep apnea and cardiovascular risk. Ther Clin Risk Manag. 2007; 3 (6): p.1105-1111.
  47. Sleep Apnea linked to Heart Disease . Updated: February 27, 2017. Accessed: February 27, 2017.
  48. Gaultier C. Sleep-related breathing disorders 6: Obstructive sleep apnoea syndrome in infants and children: established facts and unsettled issues. Thorax. 1995; 50 (11): p.1204-1210.
  49. Katz ES, Mitchell RB, D'ambrosio CM. Obstructive sleep apnea in infants. Am J Respir Crit Care Med. 2012; 185 (8): p.805-816.doi: 10.1164/rccm.201108-1455CI . | Open in Read by QxMD
  50. Risk of motor vehicle accidents is higher in people with sleep apnea. Updated: March 10, 2015. Accessed: February 27, 2017.

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