C-Flex/EPR: What is the Purpose?


Becoming acclimated to your new CPAP machine may prove to be difficult at first. You are wearing the mask before bed, during nap times, and whenever you find time to sit down and relax. Even with doing everything your technician has recommended, you are still having trouble when it comes to using the machine.

It is not so much that you cannot use the machine. That part is easy enough – on and off, and adjust the mask so that it is comfortable and has little to no leaks. It seems like you are following directions to the ‘T,’ and yet you are still having trouble getting a good night’s rest and feel uncomfortable while using the CPAP machine due to the pressure from the air. This is known as pressure intolerance.

With technology coming into play, it seems that there is a solution for every problem. A few years back, C-Flex and EPR were introduced to the CPAP world. Philips Respironics uses C-Flex technology, while ResMed used EPR (Expiratory Pressure Relief). They both do the same thing for patients using CPAP machines, but are address differently by the manufactures.

Now, remember complaining about the pressure that your machine is blowing? The force is too much, too overwhelming, and it is too much work to try and breathe through that amount of force. This is where C-Flex/EPR comes in. The pressure on your machine is set at specific number that number remains the same as your inhale. As you exhale, the force behind that pressure lessens thanks to the C-Flex/ EPR setting.



The setting ranges from 1- 3, one being the least amount of resistance and three being the most. When you are just starting out, you are more than likely going to start of at a setting of three as that will allow you to exhale with little to no problems. As you continue to use your machine night after night and become use to constant flow of air, you can change the C-Flex/EPR settings as needed. Of course, this all depends on you, the patient. If you feel that it is easier to tolerate the machine, and by extension the therapy, with the C-Flex/EPR setting, than lets not worry about fixing something that ain’t broke.

A study funded by the National Institutes of Health (NIH) conducted in the early 2000’s by researchers at Rhode Island Hospital, Brown Medical School, Brigham Women’s Hospital, and Harvard Medical School compared the benefits of using the C-Flex/EPR feature on a CPAP machine to not using it. The study was done over a time period of three months; there were a total of 89 participants who ranged from ages 25 – 80, and were either male or female. All participants used the same machine – a Philips Respironics REMstar Pro machine (C-Flex technology was used in this scenario).

The participants were split into two groups, and data was collected at week 1, week 2-4, week 6-8, and week 9-12. The data that was collected was measure through SmartCard technology (SIM card), Functional Outcomes of Sleep Questionnaire (FOSQ), and through the Self-Efficacy Scale (measures patient’s confidence in their ability to work their machine).

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Per the results of the study, C-Flex technology “may improve adherence over three months compared to [a] standard CPAP.” Researchers also noted that, “clinical outcomes do not improve consistently, but C-Flex users may be more confident in their ability to adhere to treatment.” They were sure to reiterate that because this was the first study conducted on this subject, other clinical trial should be done to further confirm these results. A statement made by a representative from Philips Respironics, the manufacturer of the REMstar Pro made a statement referencing the study, “[it[ shows patients on C-Flex average one hour and forty – two minuets more sleep per night than patients on CPAP after three months of use.”

Do you use the C-Flex/EPR setting on your machine? Have you tried using the machine as it without the setting to see and feel the difference? What are you thoughts on the settings? Let me know!

For more information on the study that was done, please visit the following links:

For information on how to change your C-Flex/ERP settings, on your machine, or to order new supplies, please visit out website: www.cpapoffice.com


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