Obstructive Sleep Apnea

See Also

Definitions

Obstructive Sleep Apnea
1. Cessation of air flow DESPITE respiratory effort
  1. Contrast with Central Sleep Apnea which is a cessation of respiratory effort
2. Obstruction in low pharynx (between base of Tongue and Larynx)
3. Airway obstruction at night results in apnea, hypopnea and snoring
4. Associated wih Daytime Somnolence and morning Headaches
Central Sleep Apnea
1. Cessation of air flow and respiratory effort for at least 10 seconds
2. Effects diaphragmatic or intercostal effort
Hypopnea
1. Slow or shallow breathing
Apnea
1. Paused breathing

Epidemiology

More common in men (by 3 fold)
1. However women are likely underdiagnosed (esp. postmenopausal, not on HRT)
Prevalence increases with age (esp. over age 60 years old) and Obesity
1. Prevalence based on Apneas and Hypopneas (AHI) >5/hour in ages 30 to 60 years of age
2. Worldwide global Prevalence of OSA is approaching 1 billion (50% are moderate to severe)
3. Prevalence has been gradually growing in the U.S.
  1. As of 2019, Obstructive Sleep Apnea affects 17% of women and 34% of men in the U.S.
  2. Daytime Somnolence is present in ~25% of those with diagnosis
References
1. Benjafield (2019) Lancet Respir Med 7(8):687-98 +PMID: 31300334 [PubMed]

Pathophysiology

Breathing stops (apnea) or is decreased (hypopnea) during sleep
1. Results from upper airway obstruction despite persistent respiratory effort
2. Contrast with Central Sleep Apnea, in which respiratory effort is interrupted
Obstruction in low pharynx (between base of Tongue and Larynx)
1. Airway obstruction at night results in apnea, hypopnea and snoring
2. Leads to intermittent Hypoxia, autonomic fluctuation and fragmented sleep
3. Associated wih Daytime Somnolence and morning Headaches

Causes

Adults
1. Narrow airway (key factor)
  1. Narrows most in the hypopharynx (below Tongue)
  2. Can narrow to pencil diameter in some patients
2. Obesity and short neck
3. Hypognathia
4. Jaw deformities
5. Large Tongue and uvula
6. Neurologic deficits (central or peripheral)
Children (occurs in 1-3% of children)
1. See Obstructive Sleep Apnea in Children

Risk Factors

Sleep deprivation or excessive Daytime Sleepiness
CNS Depressant medications
Chronic nasal congestion
Obesity (especially morbid Obesity qualifying for Bariatric Surgery, BMI >35 kg/m2, OR >4)
Middle age or older (ages 40-70 years old)
Male gender (OR 1.7 to 3.0)
Post-menopausal women not on HRT (OR 2.8 to 4.0)
Alcohol Abuse
Tobacco Abuse
Family History of Obstructive Sleep Apnea
Underdiagnosed Populations
1. Black patients
  1. Severe Obstructive Sleep Apnea is twice as likely as in white patients
  2. Kaufmann (2023) Ann Am Thorac Soc 20(6): 921-6 +PMID: 36867521 [PubMed]
2. Pregnancy (with Obesity)
  1. OSA in pregnancy is associated with Preeclampsia, Cardiomyopathy and higher mortality
  2. (2021) Obstet Gynecol 137(6):e128-44 +PMID: 34011890 [PubMed]

Associated Conditions

Obesity-Hypoventilation Syndrome (Pickwickian syndrome)
1. Associated with a higher risk of Heart Failure, Pulmonary Hypertension and death
2. Obstructive Sleep Apnea (OSA) is comorbid in 90% of Obesity-Hypoventilation Syndrome patients (severe in 70%)
3. However, only 10 to 20% of patients with OSA have Obesity-Hypoventilation Syndrome
Atrial Fibrillation (OR 4.0)
Major Depression (OR 2.6)
Congestive Heart Failure (OR 2.4)
Cerebrovascular Accident (OR 1.6 to 4.3)
Hypertension, especially Refractory Hypertension (OR 1.4 to 2.9)
Coronary Artery Disease (OR 1.3)
Type 2 Diabetes Mellitus (OR 1.2 to 2.6)
Nocturnal Cardiac Arrhythmia
Pulmonary Hypertension

Symptoms
Adults

Excessive Daytime Sleepiness or Somnolence (73 to 90% of patients)
1. Falling asleep at wheel or in conversation
2. May also present with alternative terminology
  1. Fatigue
  2. Tiredness
  3. Lack of energy
Nocturnal Gastroesophageal Reflux (50 to 75% of patients)
Loud snoring (50 to 60% of patients)
Morning Headache on awakening (12 to 18% of patients experience on 50% of mornings)
Gasping or Choking during sleep (10 to 15% of patients)
Witnessed apnea (10 to 15% of patients)
Nocturnal Hypertension and Arrhythmias
Nocturia (30% of patients awaken to urinate at least twice per night)
Nocturnal confusion
Intellectual deterioration or Cognitive Impairment (26% of patients)
Mood changes (20 to 40% of patients)

Symptoms
Children

See Obstructive Sleep Apnea in Children
Minimal Hypersomnolence if any
Nocturnal Enuresis
Excessing nighttime sweating
Developmental Delay
Learning difficulties (e.g. ADHD)

Signs

General appearance
1. Short neck
2. Overweight (Obesity in 70% of cases)
Nasopharynx
1. Nasal Polyps
2. Severe septal deviation
3. Large residual adenoid tissue
Oropharynx
1. Macroglossia
2. Large Tonsils
3. High arched Palate and narrow oropharyngeal opening
4. Micrognathia (small jaw) and Retrognathia (posterior chin position)
5. Mallampati Score 3 or 4
  1. Disproven: Does not predict Obstructive Sleep Apnea risk
Larynx and trachea
1. Large obstructive lesions
Neck circumference (best predictor of Sleep Apnea)
1. Men: >17 inch (42.5 cm) neck circumference
2. Women: >16 inch (40.6 cm) neck circumference

Differential Diagnosis

See Sleepiness
Central Sleep Apnea

Complications

See Sleep Apnea
Increased mortality, cardiovascular event and stroke risk (2-3 fold increased risk)
1. Yaggi (2005) N Engl J Med [PubMed]
2. Heilbrunn (2021) BMJ Open Respiratory Research 8:e000656 [PubMed]
Cardiovascular Disease
1. Arial fibrillation
2. Congestive Heart Failure
3. Cerebrovascular Accident
4. Hypertension is closely associated with Sleep Apnea
  1. Risk of developing Hypertension with mild to moderate OSA: Odds Ratio 2-3
  2. Peppard (2000) N Engl J Med [PubMed]
Public health concern
1. Higher health care utilization (more frequent hospitalizations, for longer durations, and higher costs)
2. Associated with more MVAs and workplace injuries

Diagnostics

Indications for Obstructive Sleep Apnea (OSA) Screening
1. Symptoms suggestive of OSA (e.g. snoring, witnessed apnea, Daytime Somnolence, or gasping while asleep)
2. Poorly controlled Hypertension
3. Heart Failure
4. Pulmonary Hypertension
5. Nocturnal Angina
6. Recurrent Atrial Fibrillation
7. Pregnant women (with BMI >30 kg/m2, Hypertension or diabetes)
Screening Tools for Symptomatic Patients (USPTF does not recommend general screening)
1. STOP-Bang Questionnaire
  1. Consider as part of preoperative assessment
2. Elbow Signs
  1. Of those with Sleep Apnea, 97% report being elbowed by their bed partner due to apnea or snoring
  2. Fenton (2014) Chest 145(3): 518-24 [PubMed]
See Polysomnogram (Sleep Study)
1. See Sleep Study for diagnostic criteria
Portable home monitoring devices (overnight oximetry)
1. Test Sensitivity 80%
2. Avoid in known cardiovascular disease (Sleep Study is preferred in these patients)
3. Cost is approximately 20% of a Sleep Study
4. Less specific than Polysomnogram
  1. Unable to distinguish CHF, COPD or Parasomnias from Sleep Apnea

Diagnosis
Based on AASM ICSD3 Criteria

Criteria A (at least one of the following)
1. Awakens short of breath, gasping or Choking
2. Impaired sleep-related quality of life (e.g. Sleepiness, Fatigue, Insomnia)
3. Witnessed (e.g. sleep partner) habitual snoring or breathing interruptions (apneas) during sleep
Criteria B
1. Polysomnogram (Sleep Study) or home Sleep Apnea test with >=5 apnea/hypopnea events/hour
Criteria C
1. Polysomnogram (Sleep Study) or home Sleep Apnea test with >=15 apnea/hypopnea events/hour
Interpretation: Obstructive Sleep Apnea diagnosis
1. Criteria A and B are both present OR
2. Criteria C is present (with or without other supporting features or criteria)
References
1. (2023) International Classification of Sleep Disorders, 3rd Edition, AASM

Grading
Severity

See Sleep Study
Respiratory Disturbance Index (RDI) <5 apnea/hypopnea events/hour
1. No Obstructive Sleep Apnea
2. No treatment necessary except:
  1. Disruptive snoring
  2. Serious comorbidity (e.g. CHF)
  3. Upper Airway Resistance Syndrome
    1. Consider if significant Sleepiness and Fatigue
Respiratory Disturbance Index (RDI) 5 to 14 apnea/hypopnea events/hour
1. Mild Obstructive Sleep Apnea
2. Diagnostic if symptoms or cardiovascular comorbidities
3. Consider Upper Airway Resistance Syndrome
Respiratory Disturbance Index (RDI) 15 to 29 apnea/hypopnea events/hour
1. Moderate Obstructive Sleep Apnea
2. Diagnostic for all patients regardless of symptoms or comorbidities
Respiratory Disturbance Index (RDI) >=30 apnea/hypopnea events/hour
1. Severe Obstructive Sleep Apnea

Management
Non-surgical

See Sleep Hygiene
Airway Management Measures
1. Offer Positive Airway Pressure to all patients meeting AASM ICSD3 Diagnostic Criteria (see above)
2. Continuous Positive Airway Pressure (CPAP)
  1. See CPAP for Obstructive Sleep Apnea
  2. Do not use without Sleep Study
    1. CPAP will worsen Central Sleep Apnea (use BiPAP instead)
  3. Available with auto-titrating positive airway pressure (machine adjusted)
    1. Auto-titrating machines are contraindicated in patients with significant comorbidity
  4. Encourage at least 4 hours per night usage (50% discontinuation rate at 1 year)
    1. See CPAP for improving compliance
    2. Nasal masks and humidified air improves compliance
  5. Available as nasal pillows (preferred by patients) or full Face Mask
  6. Improves sleep, decreases snoring, less Daytime Somnolence, better quality of life
  7. Decreases systolic Blood Pressure, LVEF, Insulin Resistance and Serum Triglycerides
3. Bilevel Pap (BIPAP) Indications
  1. Hypoventilation during sleep (e.g. Obesity-Hypoventilation Syndrome)
  2. High airway pressures required
  3. Difficulty exhaling against fixed pressure
Weight loss
1. Obesity is present in 70% of patients with Obstructive Sleep Apnea
2. Sleep Apnea significantly improved with 9-14 kg loss
3. Snoring in 19 asymptomatic obese male snorers
  1. Only mild decrease with interventions
    1. Oxymetazoline Nasal Decongestant
    2. Foam wedge support to sleep on side
  2. Marked decrease with weight loss
    1. Three kilogram weight loss
      1. Snores cut in half (176/hour)
    2. Six kilogram weight loss
      1. Snoring nearly eliminated
4. Reference
  1. Braver (1995) Chest 107:1283-8 [PubMed]
Avoid supine body position during sleep
1. Sew a tennis ball in the back of a night shirt (or vests with posterior bumpers)
  1. Makes sleeping on back too uncomfortable
2. Propping pillows
3. Position alarms
Oral appliance (less effective alternatives to CPAP)
1. Indicated in patients intolerant of CPAP, to move jaw forward or fix Tongue in position during sleep
  1. Less effective than positive airway pressure (but better tolerated)
2. Require frequent replacement (typically fitted by dentist)
3. Device types
  1. Mandibular Advancement Device (preferred)
  2. Tongue retaining device (insufficient evidence)
4. References
  1. Ramar (2015) J Clin Sleep Med 11(7):773-27 +PMID: 26094920 [PubMed]
Potentially helpful Medications
1. Intranasal Corticosteroids
  1. Chronic Rhinitis
  2. Nasal Polyps
  3. Septal deviation
2. Tricyclic Antidepressants
3. Wakefulness Promoters (in conjunction with PAP for refractory Daytime Somnolence)
  1. Solriamfetol (Sunosi)
  2. Modafinil
Avoid harmful medications
1. Avoid CNS Depressant or Sedative medications (e.g. Benzodiazepines, Benzodiazepine Receptor Agonists)
2. Sedatives may worsen Sleep Apnea
Hospitalized patients with undiagnosed OSA
1. Elevate head of bed
2. Provide Supplemental Oxygen while sleeping
3. Schedule outpatient Sleep Study
4. Do not use empiric CPAP (worsens central apnea)
  1. BIPAP is safer if empiric treatment is used
Other experimental measures that may be helpful
1. Neurostimulators to Hypoglossal Nerve (increases tone of upper airway Muscles)

Management
Surgery

Precautions
1. Bariatric Surgery is effective in improving Sleep Apnea in 75% of obese patients
  1. Refer to Bariatric Surgery for BMI >35 kg/m2, unable to use PAP, and failing conventional weight loss strategy
  2. However, OSA typically persists despite Bariatric Surgery, and should be considered an OSA treatment adjunct
2. No other surgical intervention (e.g. UPPP or mandibular advancement) has shown significant or consistent benefit
  1. However, consider in BMI <40 kg/m2 and unable to use PAP
  2. May reduce Sleepiness, snoring, Blood Pressure and quality of life
3. Longterm adverse effects are associated with airway procedures, but are uncommon
  1. Dysphagia
  2. Dysgeusia
  3. Mandibular Paresthesia
  4. Aspiration Pneumonia
  5. Globus Pharyngeus
  6. Poor cosmetic result
4. References
  1. Kent (2021) J Clin Sleep Med 17(12):2499-505 +PMID: 34351848 [PubMed]
Procedures
1. Uvulopalatopharyngoplasty (UPPP)
  1. No longer recommended due to low efficacy
  2. Laser or excision of redundant posterior pharynx
  3. Only effective in 30-50% of patients
    1. Airway narrows below level where surgery occurs
    2. May consider in intolerance to PAP due to pressure-related adverse effects
  4. Modified procedures
    1. Laser-assisted uvulopalatoplasty
    2. Radiofrequency ablation
2. Hypoglossal Nerve Stimulator
  1. May be most effective of the surgical interventions
  2. Consider in moderate to severe OSA, intolerant to PAP, and BMI <32 kg/m2
  3. Ratneswaran (2021) Sleep Breath 25(1):207-18 +PMID: 32388780 [PubMed]
3. Maxillomandibular advancement
  1. Indicated for receding chin and jaw
  2. More effective than UPPP
4. Tracheotomy
  1. Measure of last resort only

References