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When do you need BiPAP rather than CPAP? Understand when bilevel therapy is recommended, who needs a BiPAP machine and how your diagnosis guides the decision.
What Is CPAP?
CPAP stands for Continuous Positive Airway Pressure. A CPAP machine delivers a continuous level of positive airway pressure through a mask while you sleep. The pressure helps keep the upper airway open and is commonly used to treat obstructive sleep apnoea (OSA). CPAP can be delivered at a fixed pressure or, with an auto-adjusting CPAP or APAP machine, adjusted within a prescribed pressure range according to breathing patterns detected by the device. For many people with OSA, CPAP or APAP can provide effective treatment when the prescribed pressure, mask and equipment are suitable.
What Is BiPAP?
BiPAP is commonly used to describe bilevel positive airway pressure therapy. You may also see the terms BPAP or BiLevel. Unlike standard CPAP, which provides one continuous pressure, bilevel therapy provides two pressure levels:
The higher pressure used when breathing in. Provides the pressure support needed to keep the airway open during inhalation. Set higher than the EPAP by the prescribing clinician.
The lower pressure used when breathing out. The difference between IPAP and EPAP can make breathing feel more natural for some people and provides pressure support when it is clinically appropriate.
The ResMed AirCurve 11 VAuto, for example, is an auto-adjusting bilevel PAP device that provides separate IPAP and EPAP levels.
What’s the Difference Between CPAP and BiPAP?
The simplest way to understand the difference is to look at how pressure is delivered.
| Feature | CPAP | BiPAP |
|---|---|---|
| Pressure levels | One continuous pressure | Two pressure levels |
| Breathing in | Same prescribed pressure | Higher IPAP |
| Breathing out | Same prescribed pressure | Lower EPAP |
| Main purpose | Helps keep the airway open | Provides separate inspiratory and expiratory pressure |
| Typical use | Common treatment for OSA | Used when bilevel therapy is clinically appropriate |
| Prescription | Based on individual treatment needs | Requires appropriate clinical assessment and prescribed settings |
When Is BiPAP Recommended?
There is no single pressure number or test that automatically means someone needs BiPAP. When is BiPAP recommended? It depends on the person’s diagnosis and why separate inspiratory and expiratory pressures may be beneficial.
A clinician may consider bilevel therapy when:
- A person requires separate IPAP and EPAP pressures
- Continuous pressure is difficult to tolerate despite appropriate troubleshooting
- Additional pressure support is clinically required
- A person’s particular respiratory or sleep-related breathing condition is better suited to bilevel therapy
- A person has been assessed and prescribed bilevel treatment following their clinical evaluation
Mask leaks, poor mask fit, dryness, pressure intolerance and other equipment issues may sometimes be addressed without changing the type of PAP therapy. NICE guidance, for example, recommends considering auto-CPAP in some people who need high pressure only at certain times or who have difficulty tolerating fixed-level CPAP.
Can High CPAP Pressure Mean You Need BiPAP?
Not necessarily. This is one of the most common questions about BiPAP. Some CPAP and APAP machines can provide relatively high pressures, so a high prescribed CPAP pressure on its own does not mean that bilevel therapy is required. However, if the prescribed pressure is difficult to tolerate, or if your clinician believes that separate inspiratory and expiratory pressures would be more appropriate, they may consider bilevel therapy. So BiPAP for high pressure is not simply a matter of reaching a particular pressure number. The decision should be based on your overall treatment needs rather than pressure alone.
What If You Cannot Tolerate CPAP?
If CPAP is difficult to tolerate, the first step is usually to identify what is causing the problem.
A poorly fitting mask can cause leaks, pressure marks or general discomfort. A different mask size or style may improve comfort without requiring a different type of machine.
Leaks can be caused by mask positioning, movement during sleep, an unsuitable size or worn components. Before assuming you need BiPAP for CPAP intolerance, check the mask fit and follow the manufacturer’s fitting instructions.
Some people find breathing out against continuous positive pressure uncomfortable. If this continues despite appropriate mask fitting and troubleshooting, speak to your healthcare professional. They can determine whether another PAP mode may be appropriate.
Nasal or mouth dryness can make PAP therapy more difficult to tolerate. Humidification may help some people, depending on their equipment and individual circumstances. If dryness or other nasal symptoms continue, speak to your healthcare professional.
Does CPAP Intolerance Mean You Need BiPAP?
Not always. BiPAP for CPAP intolerance may be considered in some circumstances, but CPAP intolerance can have many different causes. For example, someone may struggle because of an uncomfortable mask, mask leaks, dryness, nasal congestion, difficulty breathing against continuous pressure, claustrophobia or discomfort, problems with equipment setup, or pressure settings that need clinical review. Some of these problems may be addressed without changing from CPAP to BiPAP. If you continue to struggle with CPAP despite addressing these issues, speak to your healthcare professional about your options.
Can You Change From CPAP to BiPAP?
A person using CPAP may be assessed for bilevel therapy if their healthcare professional believes it is appropriate. For example, someone prescribed CPAP for OSA may be reviewed if they continue to have problems tolerating or responding to their treatment. The decision may take into account factors such as:
- Your diagnosis
- Sleep study results
- Therapy data
- Current pressure settings
- Symptoms
- Mask fit and comfort
- Other health conditions
- How well you are able to use your current therapy
Changing from CPAP to BiPAP should not be treated as simply changing to a different machine. The appropriate therapy mode and settings need to be determined as part of your clinical care.
ResMed AirCurve 11 VAuto
CPAP or BiPAP: Which One Do You Need?
So, do I need CPAP or BiPAP? The answer depends on your diagnosis and prescribed treatment rather than which machine appears more advanced.
- You have been prescribed standard CPAP therapy
- You have obstructive sleep apnoea
- Your prescribed pressure is effectively treating your breathing events
- You are able to use your current therapy comfortably
- You do not require separate inspiratory and expiratory pressure levels
- A healthcare professional has prescribed bilevel therapy
- You require separate IPAP and EPAP pressure levels
- Continuous pressure is difficult to tolerate despite troubleshooting
- Additional pressure support is clinically required
- Your respiratory condition is more suited to bilevel therapy
What About the Mask?
The machine is only one part of your PAP setup. Your mask also needs to provide a comfortable and reliable seal. This is important with any PAP therapy because leaks can affect comfort and treatment. Depending on your prescribed therapy and personal needs, you may use nasal pillows, nasal masks or full-face masks. The most suitable mask can depend on your breathing pattern, facial structure, sleep position and comfort. If you are already using a mask successfully with your current machine, check compatibility before changing equipment.
