What are the recommended CPAP (Continuous Positive Airway Pressure) settings for an adult patient with a history of Pulmonary Embolism and possible underlying sleep apnea, who is also on anticoagulation therapy with Eliquis (Apixaban)?

CPAP Settings for Adult with Pulmonary Embolism and Possible Sleep Apnea

Start CPAP at 4 cm H₂O and titrate upward in 1 cm H₂O increments every 5 minutes until apneas, hypopneas, RERAs, and snoring are eliminated, with a typical therapeutic range of 8-15 cm H₂O for most adults. 1

Initial CPAP Settings

• Begin at 4 cm H₂O as the standard minimum starting pressure for adult patients 1, 2
• For patients with elevated BMI, consider starting at a higher pressure (6-8 cm H₂O), though this lacks strong evidence 1, 2
• The history of pulmonary embolism and anticoagulation with apixaban does not alter standard CPAP titration protocols, as these conditions are not contraindications to CPAP therapy 1

Titration Protocol

Increase pressure systematically:

• Raise CPAP by 1 cm H₂O increments 1
• Wait at least 5 minutes between adjustments to assess response 1
• Continue titrating until all respiratory events are eliminated: apneas, hypopneas, respiratory effort-related arousals (RERAs), and snoring 1

Target endpoints:

• Achieve at least 30 minutes without breathing events 1
• Include at least 15 minutes of supine REM sleep at the final pressure, as this represents the most vulnerable sleep stage 1

Maximum Pressure Thresholds

• Standard maximum: 15 cm H₂O for most adults with uncomplicated OSA 1, 3
• If obstructive events persist at 15 cm H₂O, consider switching to BiPAP rather than exceeding this threshold 1
• Absolute maximum for CPAP is typically 20 cm H₂O, though this is rarely needed 3

Pressure Exploration

After achieving control of respiratory events, you may "explore" higher pressures to optimize upper airway resistance:

• Increase by 2 cm H₂O but no more than 5 cm H₂O above the control pressure 1
• This addresses residual flow limitation that may cause arousals despite elimination of frank apneas 1
• Monitor for patient tolerance during this exploration phase 1

Patient Tolerance Adjustments

If the patient awakens complaining of excessive pressure:

• Immediately reduce to a lower pressure that the patient reports as comfortable enough to allow return to sleep 1
• Patient comfort supersedes algorithmic targets 4
• Resume gradual titration from this lower baseline 1

Alternative: Auto-Titrating PAP (APAP)

For patients with moderate to severe OSA without significant comorbidities (heart failure, COPD, central sleep apnea), APAP can be used:

• Set minimum pressure at 4 cm H₂O and maximum at 15-20 cm H₂O 2, 5
• The 90th-95th percentile pressure from 30 days of APAP data often provides adequate control and may be lower than manual titration pressures 6
• Manual titrations may overestimate pressure requirements, particularly in patients with higher BMI 6

Clinical Context for This Patient

Key considerations:

• The pulmonary embolism history does not contraindicate CPAP; in fact, treating OSA may reduce cardiovascular risk 1
• Anticoagulation with apixaban does not alter CPAP settings or titration approach 1
• If "possible" sleep apnea has not been confirmed by diagnostic polysomnography, obtain this first before initiating CPAP 1
• Close clinical follow-up is essential to assess treatment effectiveness and adherence 5

Common Pitfalls to Avoid

• Don't start too high: Beginning above 4-5 cm H₂O without justification may reduce tolerance 1, 2
• Don't rush titration: Waiting less than 5 minutes between adjustments doesn't allow adequate assessment 1
• Don't ignore patient complaints: Forcing high pressures when the patient is uncomfortable leads to poor adherence 1, 4
• Don't confuse with acute heart failure management: The settings discussed here are for chronic sleep-disordered breathing, not acute cardiogenic pulmonary edema 3

When to Switch to BiPAP

If continued obstructive events occur at 15 cm H₂O of CPAP, or if the patient is intolerant of high CPAP pressures, switch to BiPAP:

• Start with IPAP 8 cm H₂O and EPAP 4 cm H₂O 1, 4
• Maintain minimum pressure support (IPAP-EPAP differential) of 4 cm H₂O 1, 4
• Maximum IPAP for adults ≥12 years is 30 cm H₂O 4