What are the indications for Continuous Positive Airway Pressure (CPAP) therapy?

Indications for Continuous Positive Airway Pressure (CPAP) Therapy

CPAP is strongly recommended as the initial therapy for patients diagnosed with obstructive sleep apnea (OSA), particularly those with moderate to severe OSA (AHI ≥15 events/hour) or those with excessive daytime sleepiness. 1

Primary Indications for CPAP Therapy

Obstructive Sleep Apnea (OSA)

• Moderate to severe OSA: AHI ≥15 events/hour 1
• Mild OSA (AHI 5-14 events/hour) with any of the following:
  • Excessive daytime sleepiness
  • Impaired quality of life related to sleep
  • Comorbid hypertension
  • Cardiovascular disease
  • Stroke history or risk factors 1

Severity-Based Recommendations

• Severe OSA (AHI ≥30 events/hour): Strongest indication for CPAP therapy due to increased cardiovascular morbidity and mortality risk 1
• Moderate OSA (AHI 15-29 events/hour): Strong indication for CPAP, especially with symptoms or comorbidities
• Mild OSA (AHI 5-14 events/hour): Consider CPAP if symptomatic or with cardiovascular comorbidities 1

Symptom-Based Indications

• Excessive daytime sleepiness
• Sleep fragmentation
• Impaired cognition
• Mood disorders associated with OSA
• Morning headaches
• Nocturia
• Witnessed apneas during sleep 1, 2

Special Clinical Scenarios

Cardiovascular Conditions

• Hypertension: CPAP indicated for OSA patients with hypertension, particularly treatment-resistant hypertension 1
• Stroke prevention: CPAP recommended for OSA patients with stroke risk factors 1
• Heart failure: CPAP indicated for OSA (but caution with central sleep apnea/Hunter-Cheyne-Stokes breathing) 1

Central Sleep Apnea

• CPAP may be indicated in some forms of central sleep apnea, particularly when there is a component of upper airway obstruction 1
• Caution: For patients with heart failure and predominant central sleep apnea/Hunter-Cheyne-Stokes breathing, adaptive servo-ventilation rather than CPAP may be considered, though this remains controversial 1

Monitoring and Adherence Considerations

Adherence Criteria

• Optimal adherence defined as CPAP use for >4 hours per night for >70% of nights 1
• Medicare/insurance criteria: Usage for ≥4 hours per night for ≥70% of nights during a consecutive 30-day period within the first 90 days of therapy 1

Predictors of Better CPAP Adherence

• Higher AHI and ESS (Epworth Sleepiness Scale) scores 1, 3
• Younger age
• Greater BMI
• Higher oxygen desaturation index 3
• Presence of witnessed snoring 1

Therapeutic Effectiveness Assessment

Primary Outcomes to Monitor

• Resolution of daytime sleepiness
• Improvement in quality of life
• Reduction in AHI to <5 events/hour
• Normalization of oxygen saturation
• Improvement in sleep quality 1, 2

Secondary Outcomes

• Blood pressure control
• Reduction in cardiovascular risk
• Improvement in cognitive function
• Reduction in motor vehicle accident risk 1, 4

Common Pitfalls and Caveats

Adherence Challenges

• Approximately 30-50% of patients prescribed CPAP therapy are non-adherent 5
• Patients with mild-moderate OSA (AHI around 30) often show poor compliance compared to those with very severe OSA 3

Important Considerations

• CPAP effectiveness depends on proper mask fit and pressure settings
• Regular follow-up is essential to address side effects and adherence issues
• CPAP tracking systems provide valuable data on usage, mask leak, and residual AHI 1
• Alternative therapies (mandibular advancement devices, positional therapy, etc.) should be considered for patients who cannot tolerate CPAP 1

Contraindications

• Recent facial or skull base surgery
• Pneumothorax
• Severe bullous lung disease
• Recurrent sinus or ear infections (relative contraindication)

CPAP remains the gold standard treatment for OSA due to its high efficacy in reducing symptoms and potentially improving cardiovascular outcomes 4, 6. Early intervention to address adherence issues is critical for long-term treatment success 1.