Does snoring despite using Continuous Positive Airway Pressure (CPAP) therapy indicate that the treatment is not working for a patient with sleep apnea?

Snoring Despite CPAP Use

Snoring while on CPAP does not necessarily mean the therapy is failing, but it indicates the need to evaluate CPAP settings, mask fit, and adherence to determine if pressure adjustments are required. 1

Understanding Snoring on CPAP

Snoring during CPAP therapy can occur for several distinct reasons, and each requires a different approach:

Primary Causes to Investigate

Inadequate CPAP pressure is the most common reason for persistent snoring, as the current pressure may be insufficient to maintain upper airway patency throughout all sleep stages and body positions. 1 CPAP should be increased by at least 1 cm H₂O with intervals no shorter than 5 minutes when snoring persists, specifically when at least 3 minutes of loud or unambiguous snoring are observed in patients ≥12 years. 1

Mask leak represents another critical factor, as air escaping around the mask interface reduces the effective pressure delivered to the airway, allowing the upper airway to collapse and produce snoring. 1

Poor adherence patterns may mean the patient is not using CPAP during the times when snoring occurs, or is removing it during the night. 2 CPAP must be used for the entirety of sleep periods to be effective. 2

CPAP Efficacy vs. Snoring Elimination

CPAP remains highly effective even when some residual snoring persists, as the primary therapeutic goal is eliminating apneas, hypopneas, and oxygen desaturations—not necessarily all snoring. 1, 3 The severity of sleep apnea is measured by the apnea-hypopnea index (AHI), and CPAP is considered effective when it reduces the AHI to acceptable levels (<5 events/hour ideally), improves oxygen saturation, and eliminates daytime symptoms. 3, 4

Snoring without associated apneas or hypopneas may represent upper airway resistance syndrome (UARS), where increased respiratory effort causes arousals but not frank apneas. 5 In these cases, CPAP pressure exploration above the pressure that eliminates apneas may be warranted, but should not exceed 5 cm H₂O above the control pressure. 1

Clinical Algorithm for Persistent Snoring on CPAP

Step 1: Verify CPAP Adherence and Usage

• Confirm the patient uses CPAP for ≥4 hours/night for >70% of nights, as this threshold is associated with clinical benefit. 3
• Review device data to identify if snoring occurs during CPAP use or when the device is off. 2

Step 2: Assess Mask Fit and Leak

• Examine for excessive leak (>24 L/min typically indicates significant leak). 1
• Ensure proper mask fitting and consider alternative mask interfaces if leak persists. 1

Step 3: Evaluate Pressure Adequacy

• Review if current pressure eliminates apneas and hypopneas but allows persistent snoring. 1
• Consider pressure titration study if snoring is associated with daytime sleepiness, frequent arousals, or other symptoms despite apparent AHI control. 1, 5

Step 4: Consider Pressure Adjustment

• Increase CPAP by 1-2 cm H₂O increments if loud snoring persists for ≥3 minutes. 1
• Maximum recommended CPAP is 20 cm H₂O for patients ≥12 years. 1
• If patient complains pressure is too high, restart at a lower comfortable pressure. 1

Step 5: Rule Out Alternative Causes

• Assess for nasal obstruction, which may require intranasal corticosteroids or nasal surgery as concomitant therapy. 1
• Evaluate medications that may worsen OSA, including sedatives, opioids, and agents causing weight gain. 1
• Consider positional dependency if snoring occurs only in supine position. 1

Important Caveats

Weight gain can increase CPAP pressure requirements, as body mass index correlates with required CPAP levels. 1 Patients who gain weight after initial titration may need pressure re-evaluation. 6

Alcohol and sedatives worsen upper airway collapsibility and should be avoided, as they can cause snoring even with adequate CPAP pressure. 1

Mouth breathing can cause snoring despite adequate nasal CPAP pressure, and may require a full-face mask or chin strap. 1

Treatment-emergent central apneas (complex sleep apnea) may develop on CPAP and require bilevel PAP with backup rate rather than simple pressure increases. 1

When CPAP May Not Be Working

CPAP is considered inadequate when:

• AHI remains elevated (>5-10 events/hour) despite therapy. 3
• Oxygen desaturations persist during sleep. 3
• Daytime sleepiness and other OSA symptoms continue unabated. 3, 4
• Cardiovascular complications (resistant hypertension, arrhythmias) remain uncontrolled. 3

In these scenarios, attended polysomnography with CPAP titration is warranted to optimize settings. 1