Fixed Pressure Machines

A fixed pressure CPAP machine is a type of CPAP device that delivers one consistent level of air pressure throughout the entire night. Unlike an Automatic (APAP) machine, that adjusts its pressure in real time, a fixed pressure CPAP provides a steady, pre-set pressure that has been prescribed by your doctor determined from sleep study and/or assessments made by your doctor during consultations.

This consistent pressure acts as a gentle, continuous splint to keep your airway open and prevent apnoea events from occurring. Because the machine does not fluctuate its pressure, many users find fixed pressure therapy simple, predictable, and easy to adapt to, especially once the optimal pressure has been established.

Fixed pressure CPAP machines are a reliable choice for people with stable, well-defined pressure requirements. They work particularly well for those whose breathing patterns do not vary significantly throughout the night or across different sleep stages and sleeping positions. With fewer pressure changes, the therapy experience can feel smoother and more uniform, making fixed pressure CPAP a trusted option for long-term CPAP users.

The key difference between a fixed pressure CPAP and an Automatic (Auto) CPAP machine lies in how each device delivers air pressure throughout the night. A fixed pressure CPAP is set to one prescribed pressure, most often determined during an overnight sleep study and/or clinical assessment by your doctor or sleep and respiratory physician. The fixed pressure CPAP machine delivers that exact pressure consistently from the moment you fall asleep until morning. This steady, unchanging pressure acts as a reliable cushion to keep your airway open and prevent apnoea events.

Because a fixed pressure CPAP does not adjust automatically, it does not respond to natural fluctuations in your breathing or airway stability. For example, changes such as rolling onto your back, moving into deeper stages of sleep, experiencing nasal congestion, or consuming alcohol can all influence your pressure needs. During these times, the pre-set pressure may feel stronger than necessary during one part of the night and just right or even slightly insufficient during another. Despite this, fixed pressure therapy remains highly effective for people whose pressure requirements stay stable and predictable.

In contrast, an Auto CPAP constantly analyses your breathing and adjusts pressure within a set range. When early signs of airway collapse appear, it increases pressure and when your breathing stabilises, it reduces it again. This dynamic behaviour is why Auto CPAP is considered more adaptive and often more comfortable for users who experience variable pressure needs.

Comfort is another important distinction. Because a fixed CPAP always delivers the prescribed pressure, some users particularly those sensitive to higher settings may feel the airflow is a little strong when lying down or during light sleep. This sensation can take time to get used to, especially for new CPAP users. Auto CPAP machines, by comparison, tend to feel gentler because they operate at lower pressures when your airway is relaxed and stable, increasing only when necessary.

That said, many long-term CPAP users prefer the consistency and simplicity of fixed pressure therapy. Once they are accustomed to the prescribed pressure, the predictable airflow can feel steady, reliable, and free of the subtle fluctuations that occur with Auto CPAP. Combined with features like ramp settings and exhalation relief, fixed pressure therapy can still offer a comfortable and effective experience for the appropriate users.

Choosing a fixed pressure CPAP offers several important benefits that make it a reliable, effective, and often more streamlined option for managing obstructive sleep apnoea. Unlike an Automatic (APAP) machine which continuously adapts its pressure, a fixed pressure CPAP delivers one consistent, prescribed level of pressure throughout the night. For many users, this simplicity translates into stable therapy, predictable performance, and a smoother long-term experience.

One of the strongest advantages of fixed pressure therapy is its predictability. Because the machine delivers the same pressure all night, users do not feel the subtle increases and decreases that occur with Auto CPAP. This consistency can make therapy feel steadier, less distracting, and easier to get accustomed to especially for those who are sensitive to airflow changes or who prefer a “set and forget” approach. Many long-term CPAP users find that once they’re comfortable with their prescribed pressure, a fixed setting feels more natural than a constantly adjusting one.

Fixed pressure CPAP is also highly effective for people whose airway obstruction responds well to a single therapeutic pressure. If a sleep study or CPAP titration has identified that one pressure reliably treats apnoea events across all sleep stages and positions, there is often no need for the machine to make further adjustments. In these cases, fixed pressure CPAP provides table, dependable therapy without unnecessary complexity.

Because the pressure does not fluctuate, some users find that mask fit, leakage, and comfort are easier to manage. A steady pressure means fewer sudden bursts of airflow that can disturb sleep, irritate the nose, or increase the likelihood of leaks. With the help of settings like ramp and expiratory relief, fixed CPAP machines can still provide a gentle start to the night and support easier breathing during exhalation.

Fixed pressure CPAP is also commonly recommended for people with certain complex or atypical breathing patterns. While Auto CPAP algorithms are designed for uncomplicated obstructive sleep apnoea, they may not be appropriate for individuals with central sleep apnoea, Cheyne–Stokes respiration, hypoventilation, neuromuscular disorders, or treatment-emergent central apnoea. In these cases, physicians often prefer fixed pressure CPAP or more advanced devices like BiPAP or ASV because tight control over pressure delivery is medically necessary. A stable, non-adaptive pressure ensures the therapy remains safe and predictable.

Another benefit of fixed pressure CPAP is its role in clinical assessment and fine-tuning. Because the pressure remains constant, clinicians can more easily evaluate therapy performance, detect issues such as residual snoring or mask leaks, and determine whether adjustments are needed. For some treatment plans, clinicians may intentionally prescribe fixed pressure CPAP to confirm that a specific pressure is effective before transitioning a user to APAP or another mode.

For people who have already undergone an in-lab titration or who have long-standing, consistent pressure requirements, fixed CPAP can be an efficient long-term solution. Lifestyle changes like weight gain, congestion, or illness may require periodic pressure reassessment, but for stable users, a fixed setting avoids the need for continually adapting algorithms or wide pressure ranges.

Fixed pressure CPAP machines also appeal to users who value simplicity and reliability. These machines typically have fewer adjustable settings, straightforward menus, and a more predictable feel, all of which reduce therapy complexity. For some, especially older users or those who prefer minimal technology, the simplicity of a fixed machine increases confidence and long-term adherence.

In summary, a fixed pressure CPAP is an excellent choice when your therapeutic pressure is well established, when you prefer a consistent and predictable airflow, or when your medical condition requires tightly controlled pressure delivery. Its steadiness, simplicity, and proven effectiveness make fixed pressure CPAP a trusted long-term therapy option for many people with obstructive sleep apnoea. As always, your sleep physician or CPAP consultant can help determine whether a fixed pressure machine is the best fit for your specific needs, comfort preferences, and health goals.

While Auto CPAP (APAP) machines offer adaptability and often feel more comfortable because they adjust pressure throughout the night, there are many situations where a fixed-pressure CPAP is still the more appropriate or clinically recommended option. Understanding these scenarios can help clarify why your sleep physician may choose a fixed setting even though APAP sounds more flexible or technologically advanced.

1. When your pressure needs are stable, predictable, and well established

Fixed pressure CPAP therapy is particularly effective when a sleep study or CPAP titration has shown that one specific pressure reliably controls your obstructive sleep apnoea. In these cases, your airway responds consistently to a single setting, meaning variable pressure isn’t necessary.

Many people appreciate the predictability of fixed CPAP. There are no fluctuations in pressure, no shifts in sensation, and no adjustments for the brain to acclimate to during sleep. For users who prefer simplicity or who have already adapted well to their prescribed setting, fixed CPAP can feel more comfortable and less distracting than the continuously changing pressures of an Auto CPAP.

2. For certain complex or atypical breathing disorders

While APAP machines are highly effective for most people with standard obstructive sleep apnoea, they are not suitable for every sleep-related breathing condition. Some patients—particularly those with more complex or unstable breathing patterns—may require more controlled pressure delivery than an APAP algorithm can provide. In these cases, fixed-pressure CPAP may be used, but many patients are more appropriately managed with bilevel (BiPAP) therapy instead.

Conditions where APAP is often not recommended include:

• Central sleep apnoea
• Cheyne–Stokes respiration
• Treatment-emergent central apnoea
• Certain neuromuscular disorders
• Hypoventilation syndromes

In these situations, the primary issue isn’t airway collapse but disrupted respiratory signalling or impaired ventilatory drive. Because APAP continually adjusts pressure, it may unintentionally destabilise breathing. More specialised devices—often bilevel systems—provide the stable, precise, and supportive ventilation needed for safer and more effective therapy.

3. When clinicians need consistent pressure for assessment or troubleshooting

Fixed pressure CPAP is sometimes used as a diagnostic or evaluation tool within a treatment plan. Because the pressure remains constant, clinicians can more accurately observe how your body responds without the added variable of automatic adjustments.

Situations where this is beneficial include:

• Confirming the effectiveness of a specific therapeutic pressure
• Assessing long-term stability of respiratory events
• Troubleshooting issues such as residual snoring, leaks, or pressure intolerance
• Monitoring therapy outcomes in a controlled, unchanging environment

By holding the pressure steady, clinicians can pinpoint the cause of certain symptoms more easily and make targeted adjustments or decide whether transitioning to APAP is appropriate later.

4. When patients prefer the simplicity and feel of a steady pressure

Comfort and confidence play a major role in CPAP success. Some users find the fluctuating sensation of APAP pressure changes distracting or unsettling, especially if they are light sleepers or sensitive to airflow variations. For these individuals, the smooth, consistent flow of a fixed-pressure device can feel more natural and easier to sleep with.

Fixed CPAP machines also tend to have simpler menus and fewer adjustable settings, which can be appealing for users who prefer a “set-and-forget” approach with minimal complexity. For long-term CPAP users accustomed to a fixed pressure, staying on a steady setting can be both comfortable and reassuring.

Auto CPAP machines offer versatility and dynamic pressure support across a wide range of situations, but fixed pressure CPAP still has a vital role in sleep therapy. It may be preferred when your pressure needs are stable and clearly defined, when specific medical conditions require consistent pressure, or when clinicians need a controlled pressure setting for evaluation. Personal comfort and preferences also play a key role. Many users simply sleep better with the reliability and simplicity of fixed-pressure therapy.

If you’re uncertain which mode is best for you, discuss your sleep study results and symptoms with one of our Sleep and Respiratory Physicians or Sove CPAP Consultants. We can help you choose the option that best aligns with your breathing patterns, comfort preferences, and long-term treatment goals.

Yes, your sleeping position can influence how effectively a fixed pressure CPAP controls your airway. But unlike an Auto CPAP machine, a fixed pressure machine cannot adjust to those changes in real time. This means the relationship between sleep position and therapy effectiveness is important to understand, especially for people who shift positions frequently overnight.

When you sleep on your back, gravity tends to pull the tongue and soft tissues backwards into the throat. This narrows the upper airway, making it more prone to obstruction. As a result, many people naturally require a higher pressure when sleeping supine to prevent apnoea, snoring, and airflow limitation. If your prescribed fixed pressure was determined based on a sleep study conducted while you slept partly or mostly on your back, then it should already account for this need.

However, if your pressure was titrated while you were sleeping in a different position, most commonly on your side, it may not fully compensate for the increased airway collapse that can occur when you roll onto your back at home. Side sleeping generally requires less pressure because the airway remains more open due to the reduced gravitational pull on the soft tissues. People who sleep mostly on their side often experience excellent results with fixed pressure because their airway demand stays relatively stable.

The challenge comes from night-to-night variability. If you switch between side sleeping and back sleeping, or if your pressure needs change due to REM sleep, weight fluctuations, alcohol intake, nasal congestion, or muscle relaxation, a fixed pressure may not always match your highest pressure requirement. In these cases, you might notice residual snoring, feeling less rested, or waking with symptoms like dry mouth or early-morning fatigue.

Despite these limitations, many people do exceptionally well on fixed pressure CPAP, especially those whose airway behaviour is consistent across different positions. Strategies such as positional therapy, using supportive pillows, or adjusting sleep posture can further improve results.

If you’re unsure whether your sleeping position is affecting your therapy, your CPAP data, symptoms, and feedback from your provider can help determine whether your pressure remains appropriate or whether a pressure adjustment or transition to an Auto CPAP might offer more tailored support.

A correct fixed pressure setting should keep your airway open throughout the night, allowing you to sleep comfortably and wake feeling refreshed. While only your sleep clinician can formally confirm the ideal pressure, there are several signs you can look for at home to understand whether your current setting is working effectively.

Signs your pressure is likely correct:

• You wake feeling more rested and alert.
• Your bed partner notices less snoring or no snoring at all.
• You’re not experiencing choking, gasping, or frequent awakenings.
• You can breathe comfortably against the pressure without feeling air-starved.
• Your CPAP data (if available on your machine or app) shows low residual events such as apnoeas, hypopnoeas, and leak issues.
• Morning symptoms such as headaches, dry mouth, or fogginess are improving.

Signs your pressure may be too low:

• You still snore while using the CPAP.
• You wake up during the night feeling like your airway is collapsing.
• You feel tired, unrefreshed, or foggy despite regular use.
• Your machine reports high residual AHI (Apnoea–Hypopnoea Index).
• You experience morning headaches or daytime sleepiness.

A pressure that’s too low often means the airflow isn’t strong enough to keep your airway consistently open.

Signs your pressure may be too high:

• You feel uncomfortable breathing out against the pressure.
• You experience excessive dryness, burping, bloating, or air swallowing (aerophagia).
• You wake feeling “puffed up” or gassy.
• You notice new mask leaks caused by high airflow.
• Your sleep feels fragmented even though the machine is running.
• A pressure that’s too high can cause discomfort and reduce sleep quality, even if it controls apnoeas.

What to do if you’re unsure

If you’re having ongoing symptoms, noticing discomfort, or seeing unusual data trends, it’s important to speak with one of our Sleep and Respiratory Physicians or our CPAP Consultants. We can review your sleep study results, check your data, and determine whether your pressure needs adjustment. It is advised to never change clinical settings yourself without discussion with a clinician.

Many people do extremely well with fixed pressure CPAP, but your needs can change over time due to factors such as weight changes, ageing, sleep position, and general health. Checking in periodically helps ensure your therapy stays effective and comfortable.

Yes, fixed pressure CPAP machines can be highly effective for people with mild or moderate obstructive sleep apnoea (OSA), provided the pressure has been properly titrated by a sleep specialist.

Mild or moderate OSA typically responds well to a consistent stable airway pressure because the degree of obstruction is often predictable and does not fluctuate as widely as in more complex cases.

During a sleep study, doctors determine the exact amount of pressure needed to prevent apnoea, snoring, and airway collapse. A Fixed Pressure CPAP simply delivers that prescribed level every night, offering reliable and consistent therapy. Many people in the mild-to-moderate range experience excellent results, including reduced snoring, better sleep quality, improved daytime alertness, and overall better wellbeing.

Fixed Pressure CPAPs can also be a good choice for individuals who sleep mostly in one position, have stable weight, and don’t experience large nightly changes in breathing patterns. They are also often recommended for users who prefer a simpler, predictable therapy experience without automatic adjustments.

Ultimately, both fixed and auto-adjusting devices can treat mild or moderate OSA effectively. Your sleep physician or CPAP consultant can help determine which option best suits your sleep patterns, lifestyle, and comfort needs.

A Fixed Pressure CPAP is not necessarily harder to get used to, but the adaptation experience can be different compared to an Auto CPAP (APAP).

With a fixed-pressure device, you receive one consistent pressure level throughout the entire night. This works extremely well for many people, especially once the correct pressure has been identified through a sleep study or titration. However, because the pressure does not drop during lighter sleep or periods of stable breathing, some users may initially feel that the airflow is stronger than expected.

Auto CPAP machines, by contrast, can start at a lower pressure and increase only when needed, which some users find easier in the early stages of therapy. That said, many people adapt quickly to fixed pressure, particularly when features like ramp, expiratory relief (EPR), or humidification are used to improve comfort.

For users who prefer predictability, a Fixed Pressure CPAP can actually feel more stable and less distracting. It also eliminates the sensation of pressure changes throughout the night, which some people find disruptive on an Auto CPAP.

With proper mask fitting, comfort settings, and support, most users whether on fixed or auto therapy adapt within a few weeks.

In most cases, you should not change your Fixed Pressure CPAP setting on your own.

The pressure level is a prescribed medical setting determined by a sleep physician or specialist based on your sleep study results. That pressure is carefully chosen to prevent airway collapse, reduce snoring, and treat apnoea events consistently throughout the night. Adjusting it without clinical guidance can lead to under-treatment or over-treatment, both of which can create new problems.

If the pressure is too low, the airway may continue to collapse, causing ongoing apnoea, poor sleep quality, morning headaches, and daytime fatigue. If the pressure is too high, you may experience discomfort, mask leaks, excessive dryness, difficulty exhaling, or aerophagia (air swallowing).

If you feel your pressure is uncomfortable or not working well for you, it’s important to speak with your doctor or one of Sove’s CPAP Consultants. They can review your therapy data to determine whether an adjustment is needed. In some cases, they may recommend a new titration study or a brief trial using an Auto CPAP to reassess your pressure needs.

Our CPAP consultants at Sove can safely make any necessary changes while ensuring your therapy remains both effective and comfortable.

Yes, most modern Fixed Pressure CPAP machines include a full range of comfort features such as ramp, EPR (Expiratory Pressure Relief), humidification, and auto-climate control. Even though the therapy pressure is fixed, manufacturers design these devices to be as comfortable and user-friendly as possible.

The ramp feature allows the machine to start at a lower, more comfortable pressure and gradually increase to your prescribed setting over a set period. This can make it easier to fall asleep, particularly if your fixed pressure is on the higher side.

EPR works by slightly reducing the pressure each time you exhale, making breathing feel more natural and less forceful. This is especially helpful for new users adjusting to therapy or those who find it difficult to breathe out against continuous pressure.

Most fixed devices also include heated humidifiers and heated tubing, which help prevent dryness, congestion, and irritation. Some models also offer climate control that automatically adjusts humidity and temperature to maintain consistent comfort.

Overall, even though the treatment pressure remains constant, fixed pressure CPAP machines are equipped with a suite of comfort features designed to support smooth, easy, and restful therapy.

Yes, Fixed Pressure CPAP can significantly reduce or even eliminate snoring, even in individuals who do not have diagnosed obstructive sleep apnoea. Snoring happens when the airway partially narrows and the soft tissues vibrate during breathing. CPAP works by delivering a steady flow of air pressure that keeps the airway open, preventing the tissue vibration that causes snoring.

However, using a Fixed Pressure CPAP solely for snoring should always be discussed with a healthcare professional first. Snoring can sometimes be a sign of underlying sleep-disordered breathing or mild OSA, even if you haven’t been formally diagnosed. A sleep assessment can determine whether CPAP is the most appropriate treatment or whether alternative solutions such as positional therapy, weight management, oral appliances, or lifestyle modifications would be more suitable.

When CPAP is recommended for snoring, a fixed pressure setting may be used to stabilise the airway consistently throughout the night. This can be particularly helpful if your snoring is constant, predictable, and not heavily influenced by sleep position or other variables.

In many cases, fixed pressure CPAP provides a simple, reliable, and highly effective solution for disruptive snoring that affects relationships, sleep quality, and wellbeing.

Yes, fixed pressure CPAP machines are generally compatible with all major mask types, including nasal masks, nasal pillow masks, and full-face masks. Because the machine delivers a single, continuous pressure, it does not require a specific mask style to function correctly. This gives you the flexibility to choose a mask based on comfort, facial structure, sleep habits, and breathing preferences.

Nasal masks and nasal pillows work well for users who breathe primarily through their nose and prefer a lightweight, minimal design. They tend to feel less bulky and are often more comfortable at lower fixed pressures.

Full-face masks are ideal for those who breathe through their mouth, experience nasal congestion, or require higher therapy pressures. They provide a secure seal even when mouth breathing occurs.

Yes, Fixed Pressure CPAP machines can absolutely be used while travelling or camping, although a few considerations will help ensure a smooth experience. Many fixed devices are reasonably portable and can be carried in their travel cases for flights, road trips, or hotel stays. They are approved for airline use, and most can run on international voltages with the appropriate plug adapter.

For camping or off-grid travel, you can use a CPAP battery pack that’s compatible with your machine. Some batteries are designed specifically for CPAP devices and can provide one or more nights of power depending on your pressure setting, plus whether you use humidification. Turning off the heated humidifier and heated tube can greatly extend battery life.

If you frequently travel, you might consider adding a travel CPAP machine, although your primary fixed device will still work perfectly well in most environments.

Ensure you check airline policies before flying, pack your equipment in carry-on luggage, and keep your prescription or machine documentation handy.

Overall, with the right accessories and a bit of preparation, a fixed pressure CPAP can be used anywhere whether it is at home, in a hotel, on a plane, and even in the great outdoors.

Yes, most modern fixed pressure CPAP machines include built-in data recording features that track your nightly therapy and overall progress. Even though the pressure remains constant, these devices still monitor key indicators such as usage hours, mask leaks, snoring, and an estimated Apnoea–Hypopnoea Index (AHI). This information helps you and your clinician understand how effective your treatment is and whether any adjustments may be required over time.

Many devices also connect to smartphone apps, cloud platforms, or clinician dashboards via Bluetooth or Wi-Fi. These apps provide user-friendly reports that show sleep trends, therapy scores, and tips for improving comfort. Being able to view your data empowers you to take an active role in your treatment and stay consistent with therapy.

Clinicians rely on this data during follow-up reviews to identify issues such as persistent snoring, mask leak patterns, or pressure intolerance. Even though fixed devices deliver just one pressure, the data allows a healthcare provider to determine whether the current setting is appropriate or if a reassessment is needed.

In short, fixed pressure CPAP machines offer the same modern monitoring features found in Auto CPAP machines, ensuring you receive dependable, trackable, and well-supported therapy.

Yes, people can begin treatment with a fixed pressure CPAP and later transition to an Auto CPAP (APAP) machine if their needs change or if their clinician recommends a more adaptive mode of therapy. Switching is straightforward, but it should always be guided by a sleep physician or CPAP consultant to ensure the new device is set up correctly.

A transition may be considered if:

• Your pressure needs become more variable due to weight changes, new medications, alcohol use, or lifestyle factors
• You begin experiencing congestion, positional apnoea, or inconsistent sleep patterns
• Your fixed pressure no longer fully controls your symptoms
• You’re seeking more comfort or flexibility in your therapy
• Your clinician wants access to additional auto-adjusting diagnostic insights

Auto CPAP machines can adapt to nightly fluctuations in breathing and can help identify optimal pressure ranges for long-term treatment. Some patients even start on fixed therapy and later switch to APAP for travel, comfort, or diagnostic clarity.

It’s also worth noting that many APAP machines can switch into fixed-pressure mode if needed, offering both options in one device.

Overall, transitioning from fixed to auto CPAP is common, safe, and often beneficial when done under proper clinical supervision.