Auto Adjusting CPAP Machines or APAPs adjust to your ideal pressure on a breath by breath basis. They can accommodate pressure changes from weight gain or loss, alcohol before bed and changing sleeping positions during sleep. They are very popular among savvy online shoppers for their advanced air flow settings and their support of therapy tracking software, off grid power options and heated humidification.
An APAP (Automatic Positive Airway Pressure) machine automatically adjusts on a breath by breath basis to blow the minimum pressure needed to keep your airway open during sleep. This allows your machine to provide you with your ideal pressure nightly.
APAPs tend to be more advanced than CPAPs in that they normally offer more therapy tracking information and more comfort features. You can learn more about therapy tracking information in our Software section of the Learning Center.
Every APAP machine can be placed in a CPAP mode to blow one straight pressure like a CPAP. However, no CPAP can automatically adjust pressure like an APAP. An example of an APAP machine is the DeVilbiss IntelliPAP AutoAdjust that comes with built in Smart Code therapy tracking software.
Some CPAP users find it more pleasant to breathe with an APAP than with CPAP. The pressure delivered by an APAP machine automatically changes as needed to deliver the minimal pressure required to maintain the airway. The pressure delivered by a CPAP machine is set to a single pressure, the highest necessary to keep the airway open as determined during the sleep study. This is the case even when the higher pressure is needed only a fraction of the time.
Data capable machines track your therapy progress and performance over time. Therapy data can be used to spot issues and used to see how changes to your CPAP setup effects your overall treatment. You and your doctor can use the therapy information to make changes in your setup. Some changes might be altering the mask or fit or increasing or decreasing your pressure to see if your therapy performance improves to ensure you are getting effective treatment.
The data capable machines not only let you know how many hours the machine was used, like pure compliance tracking machines, but also tracks advanced information such as AHI, Leak Rate, and Average Pressure (if using an APAP).
Depending on the machine, the information can be reviewed or accessed
Compliance tracking machines only track the numbers of hours the machine is used. These machines do not track any advanced information such as AHI or leak rate.
Compliance machines are basic machines which the manufacturers made to be able to track usage hours. Compliance tracking machines are a manufacturer response to Medicare requirements that mandate DME (Durable Medical Equipment) providers show the Medicare patient used the equipment for the required minimum number of hours set by Medicare. DME providers cannot continue to be paid by Medicare without this information.
There is one billing code for all CPAP and APAP machines. Therefore a DME will be paid the same from Medicare or insurance whether they provide a patient with a more expensive machine that is data capable with more comfort features or a basic compliance tracking machine. Therefore, compliance tracking machines are the most common type of machine that is provided to patients through local DMEs.
There is software created to show the compliance information from the machine, however CPAP.com does not recommend purchasing this software. This data will only tell you how many hours you actually used the machine. It will not tell you how effective your therapy is.
CPAP machines which record full data (such as AHI and leak info):
We provide our customers with many tools to make informed decisions about their machine purchases. Options include:
We work very hard to provide many different ways for our customers to compare products. Here are the machine product guides we have created and maintain:
Machines come with a six foot hose, power cord, at least one filter, and manuals. Most manufacturers include a carrying case which is designed specifically for their equipment. CPAP / BiPAP / APAP machines do not come with a delivery system or mask. CPAP Masks must be purchased separately.
To see the list of what specifically comes with each machine, you can browse for a machine. Then on the product page, click the "Specs" tab to see a full list of what comes with the machine.
The ramp button on a machine is a feature that allows for a gradual pressure build-up to your prescribed pressure. The feature is enjoyed by those with high pressures because they ease up to their pressure.
Exhalation relief is a comfort feature offered by two manufactures which reduces the air flow at the time of exhalation making the breathing process more natural.
A-Flex is a form of exhalation relief which helps the air pressure from an APAP machine mirror a person's breathing. Like C-Flex, A-Flex provides flow-based pressure relief at the beginning of exhalation. Like Bi-Flex, A-Flex softens the pressure transition from inhalation to exhalation to provide additional comfort in an auto-CPAP mode.
A-Flex Easy Breathing Technology Visual Graph
Bi-Flex is a feature that makes breathing back against CPAP pressure easier to do. Bi-Flex pressure relief technology offers pressure relief at the transition from exhalation to inhalation, at the transition from inhalation to exhalation, and during exhalation to make BiPAP therapy more like natural breathing.
Bi-Flex Easy Breathing Technology Visual Graph
C-Flex is a pressure relief feature that makes breathing back against CPAP pressure easier to do by reducing the pressure at the beginning of exhalation and returning to therapeutic pressure just before inhalation. Independent studies conducted by leading universities indicate that patient comfort, and therefore, patient CPAP compliance, is higher with machines that use C-Flex. C-Flex is a technology invented by Respironics, is proprietary, and is not available on other brands of CPAP Machines.
C-Flex Easy Breathing Technology Visual Graph
C-Flex vs. Traditional CPAP: Brown University Study
cpaptalk.com Interview, C-Flex in the Remstar Pro and Remstar Auto
C-Flex+ is an improved pressure relief technology over the previous C-Flex technology. Like C-Flex, C-Flex+ reduces the pressure at the beginning of exhalation. Like A-Flex, C-Flex+ softens the pressure transition from inhalation to exhalation to provide additional comfort in fixed-CPAP mode.
C-Flex+ Easy Breathing Technology Visual Graph
C-Flex only works at the start of an exhale. Bi-Flex works during the transition from exhalation to inhalation, the transition from inhalation to exhalation and during exhalation.
EPR (Expiratory Pressure Relief) is a pressure relief feature developed by ResMed. EPR reduces pressure during exhalation in order to make breathing more comfortable. Easy-Breathe technology applies a smooth waveform that helps make breathing feel more natural.
EPR with Easy Breath Manufacturer Fact Sheet
Yes. Federal law requires we have a valid prescription on file before we ship your mask, machine and/or humidifier.
We provide many easy ways to get your prescription:
An APAP prescription must contain all of the following information:
All CPAP masks work with all machines.
Yes, all CPAPs use at least one filter that is usually a type of foam material and washable. Some CPAPs offer finer filtration with the addition of a disposable paper filter.
Cleaning and changing filters is the only maintenance required for a CPAP machine.
The filters are located at the back of the machine at the air intake. The image below shows the black foam filter at the back of the Everest 3 CPAP Machine.
Washable foam filters should be cleaned as soon as they become discolored. Manufacturers recommend foam filters be rinsed weekly under clear running water and allowed to air dry before being reinstalled in the machine. If the machine is used in a very dusty environment, the foam filter may require more frequent cleaning.
Disposable filters are not intended to be cleaned but rather changed out, disposing of the used filter. Manufacturers recommend changing the disposable filter once a month, more frequently if used in a very dusty environment.
Yes. CPAP therapy should be used every night. In the USA, your CPAP machine and mask are not counted as a carry on item for air travel. Some locations in Asia and Europe may count it as a carry on, but all will allow it. Check with the carrier you are using for travel.
Air Travel: Call your airline. Each airline has a different policy on whether or not you can use your CPAP while in flight, and if they have a power source available.
CPAP therapy should be used every night. Your CPAP or BiPAP machine and equipment should go with you on trips. There are some tips to help with your travel:
The only care a CPAP or BiPAP machine requires is to clean or change the filters at the air intake. This keeps the internal parts from accumulating dust. Fine paper filters should be changed out every 30 days, or when they appear soiled. Foam washable filters should be rinsed with clear running water once a week, allowed to air dry, and reinserted.
There are some other suggested actions to care for your machine:
Wondering which filters work for your machine? Or trying to find the right replacement power cord? To find what parts are compatible with your machine or to find what parts of your machine are replaceable you can:
When a physician orders a pressure change, or a patient moves to an area with a very different altitude and does not have an altitude compensating machine, there are a number of ways to ensure you are receiving CPAP therapy at the correct pressure.
Sleep laboratories and sleep disorder centers may be willing to make this pressure change. Just call a big local hospital or ask you physician for sleep lab phone numbers. Be sure to take your prescription.
A second way is to do it yourself. We sell manometers that are very portable, accurate, and simple to use. All the machines we sell come with instructions on how to set pressure to physician orders. Most patients have little trouble doing this themselves. If you need help we can talk you through the procedure.
Gauge Manometer (for pressure measurements)
Fisher and Paykel Water Column CPAP Manometer with HC325 Chamber
A third option is to ship the machine to us with the new prescription. We will set it and ship it back.
It is the law and good common sense to run all sleep disorder devices at the prescribed pressure. If you think your prescribed pressure is wrong, talk to your physician.
Most CPAP and BiLevel machines today are designed to operate on both AC and DC battery currents. In the United States, the AC current from a wall outlet is 110 volts. Overseas, the AC current is usually 220 or 240 volt. Most batteries produce 12 volt DC current.
We include information about the power needs and capacities on the CPAP.com pages our products. Please see the "Power" tab on any machine product page for this information. You can also see a summary of the voltage range and whether it is DC capable on our Compare Charts.
Here is a video explaining differences in power cords and power supplies of various CPAP machines:
All CPAPs will operate on DC power with the use of an inverter to change the current from DC to AC before it reaches the machine. However, many will operate on DC power without the need for an inverter, just a power cord that plugs into the CPAP and ends in a cigarette lighter plug.
Inverters do require a lot of power. If you need to use an inverter to run your machine on battery power, the inverter will probably take about half the life off the battery.
To determine if your CPAP will operate without an inverter, look for a DC outlet on the machine, either at the back or on the side, with a single opening directly in the center. It should be labeled "DC Power" or similar term. You can also review our Compare Charts to see if your machine has a optional DC cable option.
Here is a video describing different DC cable and battery options for various machines:
There are a lot of back up battery choices out there that can give you peace of mind in case of a power outage. The Transcend Travel CPAP Machine has Battery Options available for that can set up as a fail-over, back up battery. Review the "Power" Tab on the machine page.
CPAP.com sells battery packs to accompany your machine if an integrated battery is not available. Visit CPAPtalk for more advice specific to your needs, or view this past thread on the topic here.
Using a heated humidifier on a 12volt battery power source will significantly reduce the amount of power provided. In most cases, usage is reduced to less than half the estimated operational time. CPAPs or BiPAPs requiring inverters reduce the power time even more.
Please note that some heated humidifiers are not capable of being operated on 12volt battery power sources. The later M Series heated humidifiers with the 6'' 'pigtail' connectors are capable of running on 12volt DC power sources. Earlier model M Series heated humidifiers without the pigtail are not 12Volt capable, nor are the Legacy model REMstar and stand-alone H2 humidifiers.
For optimum performance of your battery, plan to use your CPAP without the heated humidifier. You may also have the humidifier connected and filled with water, but without the power turned on. This changes a typical heated humidifier into a passive humidifier.
We suggest testing the battery setup you are planning to use with your machine in advance. To determine the actual amount of power time you will receive and whether or not heated humidification is required for your comfort, test the battery at home before traveling.
An adapter may be required to plug a US power cord into a wall outlet in a foreign country. CPAP.com sells an assortment pack of World Traveler Power Adapter Plugs, which allow CPAP machines to plug into different types of wall sockets found in different countries.
All the models CPAP.com sell contain power converters that enable the machine to operate on any AC current from 100 to 240 volts without any adjustment.
For longer battery use, we suggest a deep-cycle marine battery. A CPAP set at 10cm will usually run for about three nights before having to recharge a deep cycle marine battery. A car battery will usually run a machine for 8 hours and still start the car.
There are small, portable battery packs that will operate a CPAP set at 10cm for at least one night, or about eight hours. CPAP.com sells full battery kits that come with everything needed to run your machine off battery power including the right cables needed for your machine and a battery. You can find the battery kit for your machine here. On each battery kit page, you can input your machine and pressure setting to see an estimate battery life for your machine.
First you need to determine if your machine is configured to operate on DC power and has a DC power outlet. If your machine does have a DC power outlet and you want to run your marine battery, then you will need the correct DC cable for your machine and an adapter cable that fits over the cigarette lighter plug and ends in alligator clips.
CPAP.com sells complete battery kits with everything you need for your machine including the right cables for your machine and the battery. You can find the right battery kit for your machine here.
If your machine does not have a DC power outlet, then you will also need an inverter to be able to run your machine on battery power.
If you have questions about the specific power needs of your machine, review the "Power" tab on your machine's product page, or give us a call at 1-800-356-5221.
Bloating is a sign that you are swallowing the CPAP air. There is no real medical solution, but we have found that sleeping position may be a factor. Try sleeping as flat as possible first, even without a pillow. If that position doesn't help, try sleeping on your side or elevated, whichever one you don't sleep in now.
If changing your position doesn't resolve the problem, talk to your doctor about the possibility of lowering your pressure a bit. It may let a few apneas through, but the trade-off might be worth it.
C-flex drops the pressure on exhale only. A-flex drops the pressure on the exhale but also helps with the transition from inhale to exhale.