Guidelines for Obstructive Sleep Apnea
Polysomnography (PSG) in an accredited sleep laboratory under supervision of a board-certified sleep physician is the gold standard for diagnosing OSA in adults, and should be performed in conjunction with a comprehensive sleep evaluation. 1
Diagnostic Testing Approach
Initial Clinical Evaluation Requirements
Before any diagnostic testing, conduct a comprehensive sleep evaluation that specifically assesses: 1, 2
- Excessive daytime sleepiness (cardinal symptom)
- Habitual loud snoring
- Witnessed apneas, gasping, or choking episodes
- Diagnosed hypertension
- Comorbidities including obesity, cardiovascular disease, stroke, and congestive heart failure 2, 3
Clinical tools, questionnaires, and prediction algorithms (including STOP-BANG) must NOT be used to diagnose OSA in the absence of PSG or home sleep apnea testing (HSAT), as they have low diagnostic accuracy and high risk of misclassification. 1, 2
When to Use PSG vs. HSAT
Use PSG (Mandatory - STRONG Recommendation):
PSG is required for patients with: 1, 2
- Significant cardiorespiratory disease
- Potential respiratory muscle weakness from neuromuscular conditions
- Awake hypoventilation or suspected sleep-related hypoventilation
- Chronic opioid medication use
- History of stroke
- Severe insomnia
- Symptoms suggesting other sleep disorders
HSAT May Be Used (STRONG Recommendation):
HSAT with a technically adequate device can be used for uncomplicated adult patients with signs and symptoms indicating increased risk of moderate to severe OSA. 1 This includes patients with excessive daytime sleepiness PLUS at least two of: 1, 2
- Habitual loud snoring
- Witnessed apnea/gasping/choking
- Diagnosed hypertension
Technical requirements for HSAT: 4, 2
- Must include minimum sensors: nasal pressure, chest and abdominal respiratory inductance plethysmography (RIP), and oximetry
- Alternative: peripheral arterial tonometry (PAT) with oximetry and actigraphy
- Must be administered by AASM-accredited sleep center under board-certified sleep medicine physician supervision
- Requires minimum 4 hours of technically adequate oximetry and flow data during habitual sleep period
Critical Algorithm for Negative or Inadequate Results
If a single HSAT is negative, inconclusive, or technically inadequate, PSG MUST be performed. 1, 4 This is a STRONG recommendation because HSAT cannot detect arousal-based respiratory events (respiratory effort-related arousals) and has high false-negative rates. 4
If initial PSG is negative but clinical suspicion remains high, consider a second PSG. 1 This is a WEAK recommendation due to night-to-night variability in OSA severity.
Split-Night Protocol
A split-night diagnostic protocol may be used instead of full-night diagnostic PSG if clinically appropriate. 1 This is a WEAK recommendation.
Criteria for split-night protocol: 1
- Moderate to severe OSA observed during minimum 2 hours of recording time on diagnostic portion
- At least 3 hours available to complete CPAP titration
- Absence of conditions likely to interfere with successful diagnosis and treatment
Diagnostic Criteria for OSA
OSA is diagnosed when: 2
- AHI ≥5 events/hour WITH associated symptoms (excessive sleepiness, unrefreshing sleep, fatigue, insomnia, snoring, witnessed apneas), OR
- AHI ≥15 events/hour regardless of symptoms
Severity classification based on AHI: 2
- Mild: AHI ≥5 and <15 events/hour
- Moderate: AHI ≥15 and ≤30 events/hour
- Severe: AHI >30 events/hour
Critical Pitfalls to Avoid
HSAT systematically underestimates OSA severity by 10-26% compared to PSG because it calculates events per hour of recording time rather than actual sleep time. 2 This can lead to underdiagnosis and undertreatment.
Nocturnal pulse oximetry alone has 85-94% sensitivity for moderate-to-severe OSA but cannot distinguish obstructive from central sleep apnea and should never replace definitive testing. 2
Do not use HSAT for general screening without knowledge of sleep-related history and complaints, or in patients with comorbid conditions where evidence is insufficient. 2
Obesity is strongly associated with OSA (up to 75% of OSA patients are obese), and weight loss significantly improves AHI values. 5 Consider this when interpreting results and planning treatment.
Follow-Up Testing Indications
Follow-up PSG or HSAT is NOT recommended for routine reassessment of asymptomatic patients on PAP therapy. 6
Follow-up PSG or HSAT IS recommended for: 6
- Recurrent or persistent symptoms despite good PAP adherence
- Assessment of response to non-PAP interventions (mandibular advancement devices, surgery, positional therapy)
- Clinically significant weight gain or loss since diagnosis
- Development or change in cardiovascular disease
- Unexplained PAP device-generated data
Follow-up PSG (not HSAT) may be used for reassessment of sleep-related hypoxemia and/or hypoventilation following treatment initiation. 6