High-Yield Back Matter

PAP Mode Comparison Guide

CPAP

Primary purpose: Airway splinting

Pressure type: One fixed

Backup rate: None

Treats obstruction: Yes

Treats central events: No

Ventilatory support: No

APAP

Primary purpose: Auto-adjusting splinting

Pressure type: Auto-range

Backup rate: None

Treats obstruction: Yes

Treats central events: No

Ventilatory support: No

Bilevel PAP

Primary purpose: Splinting + ventilatory support

Pressure type: IPAP + EPAP (fixed PS)

Backup rate: None

Treats obstruction: Yes (via EPAP)

Treats central events: No

Ventilatory support: Yes (via PS)

BPAP-ST

Primary purpose: Splinting + support + backup

Pressure type: IPAP + EPAP (fixed PS)

Backup rate: Yes (timed)

Treats obstruction: Yes (via EPAP)

Treats central events: Yes (timed breaths)

Ventilatory support: Yes (via PS + backup)

ASV

Primary purpose: Splinting + adaptive stabilization

Pressure type: EPAP + variable PS

Backup rate: Adaptive (variable)

Treats obstruction: Yes (via EPAP)

Treats central events: Yes (adaptive PS)

Ventilatory support: Yes (variable PS)

EPAP, IPAP, and Pressure Support Quick Reference

• EPAP (Expiratory Positive Airway Pressure): The lower pressure during exhalation. Functions like CPAP — maintains airway patency and prevents obstructive events. Adjust EPAP for persistent obstruction.

• IPAP (Inspiratory Positive Airway Pressure): The higher pressure during inspiration. Provides additional support during inhalation.

• Pressure Support (PS): IPAP minus EPAP. The mechanical assistance provided during inspiration. Increase PS to augment ventilation and tidal volume.

• Formula: PS = IPAP − EPAP

Mask and Interface Selection Guide

Leak Troubleshooting Guide

1. Check mask cushion seating on the face — reposition

2. Verify correct mask size (too large or too small both leak)

3. Adjust strap tension (snug, not overtightened)

4. Assess for mouth leak with nasal interface — add chin strap or switch to oronasal

5. Check tubing connections and circuit integrity

6. Verify exhalation ports are clear

7. Reassess at each pressure change — higher pressure can disrupt a previously good seal

Event-to-Action Reasoning Framework

High-Yield PAP Exam Traps

1. Increasing CPAP for central apnea — central events need mode change, not more pressure

2. Treating leak with pressure instead of fixing the mask

3. Confusing IPAP with pressure support — PS = IPAP minus EPAP

4. Assuming spontaneous bilevel has backup breaths — it does not

5. Using ASV in HFrEF (LVEF ≤ 45%) — contraindicated per SERVE-HF

6. Applying adult rules to pediatric patients — lower pressures, smaller masks

7. Making pressure decisions from wake breathing — wait for sleep

8. Ending titration without REM/supine confirmation — highest pressure need

9. Using APAP for central sleep apnea — algorithm may worsen centrals

10. Confusing BPAP-ST with ASV — different mechanisms for central events

Key PAP Titration Terms

• AHI: Apnea-Hypopnea Index — respiratory events per hour of sleep

• ASV: Adaptive servo-ventilation — breath-by-breath adaptive pressure support

• Backup rate: Minimum breaths per minute delivered when spontaneous effort is absent (BPAP-ST)

• BPAP-ST: Bilevel positive airway pressure, spontaneous/timed mode

• CPAP: Continuous positive airway pressure — one fixed pressure throughout the respiratory cycle

• EPAP: Expiratory positive airway pressure — the anti-obstruction pressure in bilevel modes

• IPAP: Inspiratory positive airway pressure — the inspiratory pressure in bilevel modes

• Pressure support: IPAP minus EPAP — the ventilatory assistance provided during inspiration

• Rise time: Speed at which IPAP pressure is reached — affects comfort

• TECSA: Treatment-emergent central sleep apnea — centrals appearing after PAP controls obstruction

• Ti: Inspiratory time — duration of machine-delivered (timed) breaths

• Titration: Process of determining the therapeutic pressure for PAP therapy

Adult Versus Pediatric Quick Reference

Final RPSGT PAP Checklist

Before the examination, confirm you can:

• Calculate pressure support (IPAP − EPAP)

• Identify when to increase vs. decrease pressure

• Distinguish obstructive from central events and respond correctly

• Select the appropriate mask for a given patient scenario

• Recognize and manage leak (intentional vs. unintentional)

• Know when to escalate to the supervising clinician

• Understand CPAP, APAP, bilevel PAP, BPAP-ST, and ASV indications

• Identify ASV contraindications (HFrEF, LVEF ≤ 45%)

• Recognize TECSA and appropriate management

• Apply pediatric-specific titration considerations

• Use the Event-Signal-Leak-Response-Safety framework

Suggested Educational References

• BRPT RPSGT Examination Blueprint (current version)

• BRPT RPSGT Candidate Handbook

• AASM Manual for the Scoring of Sleep and Associated Events

• AASM Clinical Practice Guidelines for PAP Titration

• AASM Clinical Guideline for Central Sleep Apnea

• AAST Technical Guidelines for PAP Titration

About the Author

Vansh Tiwari has a multidisciplinary background spanning cybersecurity and healthcare. His work and study in cybersecurity include offensive-security assessment, red-team methodology, vulnerability analysis, and malware analysis, with an emphasis on identifying weaknesses responsibly and strengthening defensive understanding. His healthcare background supports his interest in clinical education, technical accuracy, and making complex professional subjects easier to understand.

That combination shapes how the ELI Explains series is written: every topic is broken down the way a careful analyst approaches an unfamiliar system — what does it do, why does it behave this way, and where does it fail — and then rebuilt in plain language that respects both the science and the reader.

Through the ELI Explains series, he develops structured learning resources designed to make challenging technical and healthcare concepts more accessible, practical, and memorable for students, professionals, and curious readers alike.

End of ELI Explains PAP Titration: The 100-Question RPSGT Review