What are the initial settings for a Continuous Positive Airway Pressure (CPAP) machine?

Initial CPAP Settings for Obstructive Sleep Apnea

Start CPAP at 4 cm H₂O for both pediatric and adult patients, with a maximum of 15 cm H₂O for children under 12 years and 20 cm H₂O for adults. 1

Starting Pressure

• Begin at 4 cm H₂O regardless of patient age, as this is the consensus-based minimum starting pressure supported by multiple levels of evidence 1
• For patients with elevated BMI or those undergoing retitration, consider starting at a higher pressure, though specific predictive formulas lack sufficient evidence 1
• The 4 cm H₂O starting point applies to both full-night and split-night titration studies 1

Pressure Titration Algorithm

Increase CPAP by at least 1 cm H₂O increments, waiting a minimum of 5 minutes between adjustments, with the goal of eliminating all obstructive respiratory events 1

Indications to Increase Pressure:

• For adults (≥12 years): Increase after observing 2 or more obstructive apneas 1
• For children (<12 years): Increase after observing 1 obstructive apnea 1
• For hypopneas: Increase after observing 3 or more hypopneas 1
• For snoring: May increase after 3 minutes of loud/unambiguous snoring in adults or 1 minute in children 1

Titration Increments:

• Standard increments are 1-2.5 cm H₂O, though insufficient data exists to recommend increases larger than 2.5 cm H₂O 1
• For split-night studies, larger increments (2-2.5 cm H₂O) may be prudent given the shorter titration duration 1

Maximum Pressure Limits

• Adults (≥12 years): Maximum 20 cm H₂O 1
• Children (<12 years): Maximum 15 cm H₂O 1
• If obstructive events persist at 15 cm H₂O, consider switching to BiPAP 1

Pressure Exploration

Once respiratory events are controlled, pressure may be increased by an additional 2-5 cm H₂O to optimize upper airway resistance, as residual high resistance can persist despite elimination of apneas and hypopneas 1

• This "exploration" should not exceed 5 cm H₂O above the control pressure 1
• The goal is to normalize esophageal pressure swings or inspiratory flow limitation patterns 1

Patient Tolerance Adjustments

If the patient awakens complaining of excessive pressure, reduce to a lower pressure that allows comfortable return to sleep, then resume gradual titration 1

Common Pitfalls to Avoid

• Starting too high: The 4 cm H₂O starting pressure is evidence-based and should not be arbitrarily increased without specific indications 1
• Increasing too quickly: Wait at least 5 minutes between pressure adjustments to allow adequate assessment 1
• Stopping at event elimination: Consider pressure exploration to address residual upper airway resistance that may cause arousals 1
• Ignoring patient comfort: Pressure intolerance is a major adherence barrier and should prompt immediate adjustment 1

Transition to BiPAP

Switch to BiPAP if:

• Patient is uncomfortable or intolerant of high CPAP pressures 1
• Obstructive events continue at 15 cm H₂O of CPAP 1

When transitioning, start BiPAP at IPAP 8 cm H₂O and EPAP 4 cm H₂O 1