CPAP vs APAP: What's the Difference?
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If you've been researching sleep apnea treatment options, you've probably encountered both CPAP and APAP machines. While these devices share the same goal of helping keep your airway open during sleep, they deliver therapy differently.
Understanding the differences between CPAP and APAP therapy can help you have a more informed discussion with your healthcare provider and better understand your treatment options.
Quick Overview
Both CPAP and APAP machines are designed to treat obstructive sleep apnea by delivering pressurized air through a mask while you sleep.
The primary difference is how therapy pressure is delivered.
CPAP
CPAP stands for Continuous Positive Airway Pressure.
A CPAP machine delivers one prescribed pressure setting throughout the night.
APAP
APAP stands for Automatic Positive Airway Pressure.
An APAP machine automatically adjusts pressure within a prescribed range based on your breathing patterns and therapy needs.
How CPAP Therapy Works
A CPAP machine delivers a constant pressure level throughout therapy.
For example, if your prescribed pressure is 10 cmH₂O, the machine will continue delivering that pressure while you sleep unless adjusted by your healthcare provider.
CPAP therapy has been used successfully for many years and remains one of the most common treatments for obstructive sleep apnea.
Advantages of CPAP
- Consistent therapy pressure
- Simple operation
- Proven treatment option for obstructive sleep apnea
- Often effective for patients with stable pressure requirements
Considerations
Because the pressure remains constant, some users may feel they are receiving more pressure than needed during certain portions of the night.
Comfort preferences vary from person to person.
How APAP Therapy Works
An APAP machine continuously monitors breathing patterns and automatically adjusts pressure throughout the night.
Rather than operating at one fixed pressure setting, APAP machines work within a prescribed pressure range.
When additional pressure is needed, the machine increases pressure. When less pressure is needed, the machine reduces pressure accordingly.
Advantages of APAP
- Automatically adjusts to changing therapy needs
- May provide lower pressures when higher pressures are unnecessary
- Can adapt to changes in sleep position
- Can respond to variations in breathing patterns throughout the night
Considerations
Some users prefer the predictability of a fixed-pressure CPAP machine. The best option depends on individual therapy requirements and personal comfort preferences.
CPAP vs APAP Comparison
| Feature | CPAP | APAP |
|---|---|---|
| Pressure Delivery | Fixed pressure | Automatic pressure adjustments |
| Pressure Setting | Single prescribed setting | Prescribed pressure range |
| Therapy Adaptation | Constant throughout the night | Adjusts based on breathing needs |
| Treatment Goal | Maintain an open airway | Maintain an open airway |
| Prescription Required | Yes (U.S.) | Yes (U.S.) |
Which Machine Is Better?
One of the most common questions patients ask is whether APAP is better than CPAP.
The answer is that neither machine is universally better.
Both therapies can be highly effective when prescribed appropriately.
The best option depends on factors such as:
- Sleep study results
- Severity of obstructive sleep apnea
- Prescribed pressure requirements
- Therapy comfort
- Healthcare provider recommendations
Many patients achieve successful treatment with either CPAP or APAP therapy.
Why Would Someone Choose a CPAP?
A healthcare provider may recommend CPAP therapy when a consistent pressure setting is appropriate for the patient's treatment needs.
Some users also appreciate the simplicity of fixed-pressure therapy and prefer knowing exactly what pressure will be delivered throughout the night.
Why Would Someone Choose an APAP?
APAP therapy may be recommended for patients whose pressure needs vary throughout the night.
Because APAP machines automatically adjust pressure, some users find them more comfortable than fixed-pressure therapy.
However, the appropriate therapy choice should always be determined by a healthcare provider.
Similarities Between CPAP and APAP
Although much attention is given to their differences, CPAP and APAP machines share many similarities.
Both:
- Treat obstructive sleep apnea
- Use a mask, hose, and therapy machine
- Deliver pressurized airflow
- Require a prescription in the United States
- May include heated humidification
- Can help improve sleep quality when used consistently
Do CPAP and APAP Machines Require a Prescription?
Yes.
In the United States, both CPAP and APAP machines are regulated medical devices and require a valid prescription.
Customers outside the United States should verify local requirements before purchasing a machine, as regulations vary by country.
For additional information, read our guide: Do You Need a Prescription for a CPAP Machine?
Related Resources
To learn more about sleep therapy devices, see:
Final Thoughts
CPAP and APAP machines are both effective treatments for obstructive sleep apnea, but they approach therapy differently. CPAP machines deliver one continuous pressure setting, while APAP machines automatically adjust pressure within a prescribed range throughout the night.
Neither therapy is inherently better than the other. The best choice depends on your diagnosis, prescription, therapy needs, and healthcare provider's recommendations.
If you're considering sleep apnea treatment, consult with your healthcare provider to determine which therapy option is most appropriate for your situation.