What are the diagnostic criteria and treatment options for Obstructive Sleep Apnea (OSA)?

Diagnosis of Obstructive Sleep Apnea

Polysomnography (PSG) is the gold standard for diagnosing OSA in adults, though home sleep apnea testing (HSAT) is acceptable for uncomplicated patients at high risk for moderate-to-severe disease. 1

Diagnostic Approach

Initial Clinical Evaluation

Diagnostic testing must be performed in conjunction with a comprehensive sleep evaluation that identifies:

• Excessive daytime sleepiness (cardinal symptom) 1, 2
• Habitual loud snoring 1, 2
• Witnessed apneas, gasping, or choking episodes 1, 2
• Morning headaches, nocturia, and unrefreshing sleep 2, 3
• Diagnosed hypertension (important risk factor) 1, 2

Diagnostic Testing Recommendations

Do NOT use questionnaires, clinical tools, or prediction algorithms alone to diagnose OSA - these have low diagnostic accuracy and high risk of misclassification despite being less burdensome. 1, 4

For Uncomplicated Patients at High Risk:

Use either PSG or HSAT when patients have: 1

• Excessive daytime sleepiness PLUS
• At least 2 of the following: habitual loud snoring, witnessed apnea/gasping, or diagnosed hypertension 1, 2

HSAT Technical Requirements: 1, 4

• Minimum sensors: nasal pressure, chest/abdominal respiratory inductance plethysmography, and oximetry (OR peripheral arterial tonometry with oximetry and actigraphy)
• Minimum 4 hours of technically adequate oximetry and flow data
• Must be administered by AASM-accredited sleep center under board-certified sleep medicine physician supervision
• Raw data must be reviewed and interpreted by qualified physician

Mandatory PSG (NOT HSAT) for Complicated Patients:

Use in-laboratory PSG when patients have: 1, 4

• 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
• Concern for other sleep disorders (central hypersomnolence, parasomnias, movement disorders)

When Initial Testing is Inadequate

If HSAT is negative, inconclusive, or technically inadequate, proceed to PSG - this is a strong recommendation to avoid missing the diagnosis. 1, 4

If initial PSG is negative but clinical suspicion remains high, consider repeat PSG due to night-to-night variability in sleep parameters. 1, 4

Split-Night Protocol Option

A split-night protocol (diagnostic study followed by CPAP titration same night) may be used instead of full-night diagnostic PSG when clinically appropriate, though this is a weaker recommendation. 1

Diagnostic Criteria for OSA

OSA is diagnosed when: 5, 3

• AHI ≥5 events/hour WITH associated symptoms (excessive sleepiness, witnessed apneas, etc.), OR
• AHI ≥15 events/hour regardless of symptoms

Severity Classification

Based on Apnea-Hypopnea Index (AHI) or Respiratory Disturbance Index (RDI): 5

• Mild OSA: AHI/RDI ≥5 and <15 events/hour
• Moderate OSA: AHI/RDI ≥15 and ≤30 events/hour
• Severe OSA: AHI/RDI >30 events/hour

The AHI represents the sum of apneas (complete airway obstruction) and hypopneas (partial obstruction with ≥3% oxygen desaturation or arousal) per hour of sleep. 5, 3

Common Pitfalls to Avoid

HSAT underestimates OSA severity by 10-26% compared to PSG due to lack of EEG/EOG/EMG sensors and higher data loss rates (3-18%). 4 This is acceptable for high-risk uncomplicated patients but problematic for those with mild-to-moderate disease or comorbidities.

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. 4

Nocturnal pulse oximetry alone has 85-94% sensitivity for moderate-to-severe OSA but cannot distinguish obstructive from central sleep apnea and should not replace definitive testing. 2