What is a HME (Heat Moisture Exchanger)

  • By Clay Rollyson
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What is a HME?

A HME or Heat Moisture Exchanger is a device that you use in-line with a breathing tube to keep moisture in your airway. In a natural breathing process your upper airway will add moisture to the air that you are breathing. This ensures that your lungs operate correctly and that you remain comfortable. For people that use CPAP or people that have a tracheostomy you will probably have to add more moisture to the air to make sure that you are comfortable and that your lungs function correctly. A HME does this for people in those scenarios that can not use a humidifier system. We see that need for a HME on Travel CPAPs or CPAP Machines that do not have integrated heated humidifiers.

How does a HME Work?

A HME captures moisture from your exhaled breath so that as you inhale that moisture can be reused. It is usually is a foam-like or corrugated paper material encased in plastic. It is designed to connect to the breathing tube near the point of exhalation. Some of them are treated with a solution that helps them retain moisture as the moisture passes by in your exhalation. When you inhale that moisture is picked up in the air and transferred by to you.

How do you install a HME?

A HME connects in your breathing tube close to the point of exhalation. On a CPAP Machine this is usually at the connection between the CPAP Mask and the CPAP Tubing. This allows it to collect the maximum amount of moisture as you exhale. There are a few Universal HMEs that are designed to fit moist CPAP machines. These are usually connections of 22mm. However, there are a few of them that are designed to fit specific CPAP Machines. An example of this would be the Humidix made by ResMed. It is built to fit only the AirMini Travel CPAP. The Humidx integrates directly into either the CPAP Mask or the CPAP Mask junction.

Can I use a HME on my CPAP?

Yes, using a HME on CPAP is a very common thing to do. It is mainly done when you are using your CPAP without a heated humidifier. For instance, most Travel CPAPs do not have heated humidifiers. In this case using one is a great option to keep you from drying out while traveling with your CPAP. Some CPAP users have the ability to separate their humidifier from the CPAP. This allows them to travel without the complication and extra clutter of the humidifier. In this case using one would work great as well.  

How long does a HME last?

A HME is a disposable product and is not designed for long term use. Not only will the performance of it fall over time, but the cleanliness is something to consider as well. If you are exhaling into something night after night, eventually things start to grow. Things like Mold, Mildew and Bacteria. Most HMEs are designed to work for between 1 week and 4 weeks. The Humidix by ResMed that we discussed above is good for 30 days. Our generic Universal HME is good for about 7 days. So it is important to change them frequently and to have extras.