Exhalation Pressure Relief Defined
By Andrew Senske, President CPAP-Supply.com
Last Updated 12/7/2006 5:02:00 PM



There are a few new buzz words in the CPAP lexicon these days, chief among them the terms C-Flex, EPR, and SoftX. In this article I'll explain what these technologies are all about and how they can help patients using CPAP therapy.

To the uninitiated the thought of wearing a CPAP mask every night is not a pleasant one. This is understandable - in fact, it's how I feel - considering what happens when the mask is placed on your face and the CPAP machine is turned on. The air starts blowing, and it's going to blow for 8 hours or so. Even while you're trying to exhale, the machine will keep blowing... and blowing... and blowing.

First time users may get the sense that they're not going to be able to overcome the pressure of the CPAP machine and that there's no way they'll be able to tolerate even just a few minutes - let alone a full night - of CPAP therapy. CPAP therapy does, indeed, take some getting used to, and modern CPAP equipment is making this lifestyle adjustment easier by offering technology to assist in providing relief during exhalation.

Exhalation pressure relief isn't new technology. Bilevel CPAP machines, which have been around for quite a while, provide a high inhalation pressure and a low exhalation pressure. However, the pressure differential in bilevel CPAP machines is more precise than that of a regular CPAP machine using a newer pressure relief technology. Bilevel CPAP machines have historically been used by people with more serious breathing conditions such as one might have with chronic lung disease. More recently CPAP users have started to opt for bilevel CPAP machines due to the "softening" of the airflow during exhalation, and the more natural feeling provided by the pressure differential.

Today there are a wide range of technologies available in "regular" CPAP machines - and also improved technologies in bilevel CPAP machines - which allow for relief during exhalation and higher levels of patient comfort.

The most widely known pressure relief technology is called C-Flex. Developed by Respironics C-Flex is a technology found on the REMstar line of CPAP machines. As a patient begins exhalation the delivered pressure is reduced. Upon inhalation the delivered pressure immediately returns to the prescribed pressure setting. The result is effective and comfortable CPAP therapy. C-Flex is not the same as a bilevel CPAP machine. On a bilevel CPAP machine two different pressure settings are programmed into the machine - an exhalation pressure and an inhalation pressure. At each breath the bilevel CPAP machine adjusts to the precise pressure setting that has been programmed. A machine with C-Flex is similar with the primary difference being that the exhalation pressure isn't necessarily exactly the same for each breath.

Some ResMed S8 CPAP machines feature ResMed's EPR technology. Of course, EPR is an acronym for Expiratory Pressure Relief, which is very similar to C-Flex and provides a very similar end result for the patient.

The Invacare Polaris EX offers patients SoftX technology. SoftX provides exhalation relief, but the technology is different than that found in the Respironics and ResMed machines. Rather than changing motor speed - as happens with C-Flex and EPR - the SoftX technology uses an active, variable resistance valve and a constant speed motor to ensure quick and natural pressure changes. With SoftX the exhalation pressure isn't reduced. Rather, a change in the valve position diverts air away from the patient during exhalation. As with C-Flex and EPR the end result is increased patient comfort.

All three of these technologies - C-Flex, EPR, and SoftX - have three comfort levels which determine the degree of the pressure drop from inhalation to exhalation. The maximum pressure drop is approximately 3 cm H2O. This is a limitation that you would not have if you were you to choose a bilevel CPAP machine.

The question of which technology is better is difficult to answer. Perhaps the motors on the Polaris EX CPAP machines will last longer since they're constant speed. Maybe the variable resistance valve on the Polaris EX will fail sooner than a motor on a REMstar or S8 CPAP machine. It could be that all three technologies offer the exact same user experience.

So now you might be wondering if there are any drawbacks to pressure relief technology. The only complaint I've heard from customers regarding exhalation pressure relief is the sound it makes. The difference in motor speed in the REMstar and S8 machines is audible and can be distracting to the sensitive ear, especially if you're not expecting it. The overwhelming response among CPAP users is that pressure relief technology is a welcome addition to the newer models of CPAP machines. The nice thing about pressure relief, though, is that it can be turned off. If you don't like it for whatever reason, you don't have to use it.

Andrew Senske
President
www.cpap-supply.com

CPAP-Supply.com is a leading online retailer of CPAP equipment. Located in Spokane, WA CPAP-Supply.com has been serving thousands of customers around the world since 2001. Founded on a belief that patients are their own best primary care providers, CPAP-Supply.com understands the importance of educating patients and customers on both the effects of and treatment for obstructive sleep apnea. For more information visit CPAP-Supply.com or call toll free 1-888-955-2727.

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REMstar Auto CPAP Machine with Exhalation Pressure Relief

REMstar Auto CPAP Machine with Exhalation Pressure Relief