CPAP vs BiPAP vs APAP: Every Type of PAP Therapy Device Explained by a Licensed RRT

CPAP vs BiPAP vs APAP: Every Type of PAP Therapy Device Explained by a Licensed RRT

Your sleep study came back positive for obstructive sleep apnea — and now your doctor says you need a PAP machine. But "PAP" isn't a single device. It's an entire category of treatment technology, and choosing the right type makes a significant difference in how comfortable, effective, and sustainable your therapy will be.

As a licensed Registered Respiratory Therapist (RRT), I've set up thousands of patients on PAP devices. Here is a clear, clinical breakdown of every major PAP device type — what it does, who it's best for, and what to consider before buying.

CPAP: Continuous Positive Airway Pressure

How It Works

CPAP is the most commonly prescribed device for obstructive sleep apnea. It delivers a single, fixed pressure throughout the entire night, measured in centimeters of water pressure (cmH₂O). This constant pressurized airflow acts as a pneumatic splint, keeping the upper airway from collapsing during sleep.

Prescribed Pressure Range

Most patients are prescribed between 4–20 cmH₂O. Your specific setting is determined by your sleep study — either from a full titration night in a lab or, increasingly, from an at-home titration using an APAP device.

Who It's Best For

  • Patients with moderate to severe OSA who have been lab-titrated to a known optimal fixed pressure
  • Patients who tolerate fixed pressure well during adjustment
  • Patients seeking the widest insurance coverage and simplest device

Best CPAP Options at MyRespCo

If you want the simplest, most proven fixed-CPAP experience, the RRT-Certified Refurbished ResMed AirSense 10 AutoSet ($379.99) can be locked to a fixed pressure setting or run in full APAP mode — giving you maximum flexibility. Alternatively, the New ResMed AirSense 11 AutoSet ($749) is the most advanced CPAP platform on the market today.

APAP: Auto-Adjusting Positive Airway Pressure

How It Works

APAP — also called Auto-CPAP or AutoPAP — uses onboard algorithms to continuously monitor your breathing and adjust pressure in real time within a prescribed range. When your airway needs more support (REM sleep, sleeping on your back), pressure rises. When you're breathing easily, it backs off. This delivers the minimum effective pressure at every moment throughout the night.

Who It's Best For

  • Patients who haven't had a formal lab titration but have a documented OSA diagnosis
  • Patients whose pressure needs vary due to sleep position, weight fluctuations, alcohol, or seasonal allergies
  • New CPAP users who want the machine to "find" their optimal pressure during the adjustment period
  • Most straightforward OSA cases — APAP is now the preferred starting point for many sleep medicine physicians

Best APAP Options at MyRespCo

BiPAP: Bilevel Positive Airway Pressure

How It Works

BiPAP delivers two distinct pressure levels: a higher pressure during inhalation (IPAP) and a lower pressure during exhalation (EPAP). This bilevel design makes breathing against pressure significantly easier, particularly for patients who struggle to exhale at higher CPAP pressures.

Who It's Best For

  • Patients requiring high pressures (typically above 15 cmH₂O) who find exhalation uncomfortable on CPAP
  • Patients with central sleep apnea, where the brain fails to send proper breathing signals
  • Patients with COPD, hypoventilation syndromes, or neuromuscular diseases affecting breathing
  • Patients who have tried and failed CPAP therapy due to exhalation discomfort

BiPAP Options at MyRespCo

ASV: Adaptive Servo-Ventilation

How It Works

ASV is a highly sophisticated device designed for complex or treatment-emergent central sleep apnea. It continuously analyzes your breathing pattern and delivers targeted pressure support to stabilize ventilation, preventing both apneas and hypopneas. It essentially "learns" your normal breathing rhythm and compensates for deviations.

Who It's Best For

  • Patients with Cheyne-Stokes respiration
  • Patients who develop central apneas after starting CPAP therapy (treatment-emergent central sleep apnea)
  • Complex sleep-disordered breathing that doesn't respond to standard PAP

Critical Warning: ASV is contraindicated in patients with symptomatic heart failure with reduced ejection fraction (HFrEF). This device requires explicit prescription and close clinical monitoring. Do not choose it without direct specialist guidance.

AVAPS: Average Volume-Assured Pressure Support

How It Works

AVAPS targets a specific tidal volume — the amount of air moved per breath — and automatically adjusts pressure support to ensure adequate ventilation even when breathing effort changes. This is a highly specialized device typically managed in coordination with a pulmonologist or sleep medicine physician.

Who It's Best For

  • Patients with obesity hypoventilation syndrome (OHS)
  • Patients with neuromuscular diseases like ALS or muscular dystrophy
  • Patients with COPD and elevated CO₂ (hypercapnia)

Key Features to Evaluate on Any PAP Device

Integrated Humidification

Dry pressurized air causes nasal and throat irritation — one of the top reasons patients abandon therapy. All modern PAP devices include a heated humidifier. For maximum comfort, look for machines with heated tubing ($49.99 for ResMed AirSense 10) to prevent rainout and maintain ideal moisture levels through the night.

Data Connectivity

The best machines transmit nightly therapy data via cellular or Wi-Fi to cloud platforms like myAir (ResMed) or DreamMapper. This lets your respiratory therapist remotely monitor your AHI, leak rates, and usage hours without in-office visits. Our CPAP Compliance Review & Data Report ($50) service lets a licensed RRT analyze your data and deliver actionable recommendations.

Mask Compatibility

Your PAP machine is only as effective as your mask interface. We carry three mask styles to fit every sleeper:

Which PAP Device Is Right for You?

For most new patients with straightforward obstructive sleep apnea, APAP is the best starting point. It's the most flexible, self-adjusting, and forgiving option. If you've struggled with exhalation or your physician has specified bilevel support, BiPAP is the right move. If you need help interpreting your sleep study and making the right device choice, don't guess — get clinical guidance.

Our $49.99 RT Consultation with a Licensed Respiratory Therapist covers your sleep study data, therapy history, and gives you a clear recommendation based on clinical evidence — not commission. We also offer a CPAP Setup & Education Session ($75) once your machine arrives to make sure everything is configured correctly from day one.

Frequently Asked Questions

What is the difference between CPAP and APAP?

CPAP delivers a single fixed pressure all night. APAP automatically adjusts pressure breath-by-breath within a set range. For most patients, APAP is more comfortable because it only delivers the pressure you actually need at any given moment.

Do I need a prescription for a CPAP machine?

Yes, CPAP machines require a prescription in the United States. Our RT Consultation ($49.99) includes a clinical evaluation that can facilitate your prescription.

Is a BiPAP better than a CPAP?

"Better" depends on your diagnosis. BiPAP is not superior to CPAP for standard OSA — it's a different tool for different clinical indications. Most OSA patients do perfectly well on CPAP or APAP at a much lower cost.

Related Guides