Decoding EPR and the Flex Technologies on CPAP Machines

March 15, 2019

Decoding EPR and the Flex Technologies on CPAP Machines

If you’re researching or shopping for a new CPAP machine, chances are you are either new to CPAP therapy or you’re replacing one you already have. We’ve said this many times before, CPAP machines these days are packed with incredible technology, but what exactly? CPAP machines have integrated wireless and battery-powered options, bluetooth capabilities, remote monitoring and reports at your fingertips through apps on your phone. Another technology which we will be focusing on is a technology called EPR or FLEX which are both comfort features to increase comfort and compliance for all users. 

What exactly is EPR or FLEX ? Continue reading as we break down some fancy acronyms and abbreviations. Learn what EPR means and the difference between the types of Flex available as we simplify the terms much as we can. Here we go!

CPAP machines have “comfortable” settings that allows the CPAP therapy to mimic your natural breathing pattern as much as possible. Resmed calls this feature EPR while Philips Respironics calls this comfort feature Flex.

Resmed defines their comfort setting as EPR - Expiratory Pressure Relief. In other words, making it easier for you to exhale or providing a deeper exhale with each breath while on CPAP. For example, your CPAP pressure setting is 10cmH20 with function EPR 3 on...you would be inhaling at 10chH20 and exhaling at a dropped pressure of 7cmH20 and will return to 10cmH20 on the inhale.  

There are 4 settings for EPR on a Resmed machine: OFF, Setting 1 = mild comfort (1 cm H20), Setting 2 = medium comfort (2 cm H20), Setting 3 = maximum comfort (3 cm H20).

Philip Respironics calls their comfort setting Flex. Flex comfort feature provides users with pressure relief on various (CPAP, APAP or BiPAP) modes of therapy. There are various types of Flex available. C-Flex, A-Flex, Bi-Flex and C-Flex+.

C-Flex, identical as EPR on Resmed, it lowers pressure during exhalation for users to adjust to therapy and works on a breath-by-breath basis.  Using the same example from earlier, your CPAP pressure setting is 10cmH20 with function EPR 3 on...you would be inhaling at 10cmH20 and exhaling at a dropped pressure of 7cmH20 and will return to 10cmH20 on the inhale. 

C-Flex also has 4 settings for on their machines: OFF, Setting 1 = mild comfort (1 cm H20), Setting 2 = medium comfort (2 cm H20), Setting 3 = maximum comfort (3 cm H20)

Following along so far? Good, let’s keep going.

Bi-Flex works on BiPAP mode and offers pressure relief at both inhalation and exhalation. Bi-Flex setting offers pressure relief at 3 important areas- the transition from exhalation to inhalation, the transition from inhalation to exhalation and during the exhalation.

 A-Flex works within Auto-CPAP mode. Like C-Flex, A-Flex provides pressure relief at the beginning of exhalation and like Bi-Flex softens transition avoiding spike ups from inhalation to exhalation. It's a smoother and more comfortable feeling. A-Flex mimics your natural breath the most.

C-Flex+ (Plus) is a newer setting within the more advanced CPAP machines when in fixed-CPAP mode.  Like C-Flex, C-Flex+ provides pressure relief at the beginning of exhalation. Like A-Flex, C-Flex+ offers a smoother or softer transitioning from inhalation to exhalation providing additional comfort when in fixed-CPAP mode.

If you got a blank stare and feeling a bit confused, we don’t blame you - it can be confusing. The take home message is EPR and Flex are both comfort settings available on Resmed and Respronics machines. They come in different modes to ultimately make your adjustment to therapy more comfortable by mirroring your most natural breathing patterns possible regardless of your CPAP pressure.

What function is best for you? Ultimately, it comes down to personal comfort and preference. You’ll need to give the functions at various settings a test drive. Some people like EPR and Flex, some don’t use them and others even dislike these comfort settings. These settings may bring on other problems - possibly make your apnea better or worse or the pressure changes may increase your chances of experiencing mask leaks.

After all that’s said, many do find the comfort functions helpful. This is the part where we say try it, see what setting works best for you!





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