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FAQ9:   What about Foam Stoma Covers and Heat/Moisture-Exchangers (HME's)?

(Courtesy of David Blevins, IAL News Editor)

There will be major coverage on HMEs in the January issue of the "IAL News." A shorter version will appear either in a future issue of the WWJ, or something more in the Hints Section.

The wearing of the best stoma covers actually gives laryngectomees a health advantage over non-laryngectomees since many agents of infection such as bacteria and at least some viruses would be deposited on the OUTside of a stoma cover rather than on the inside of our noses. The better stoma covers actually have the effect of walking around with benefits a non-lary could only obtain by wearing a surgical mask, or other breathing protection gear.

Foam patches are low tech - HMEs are high tech; and with all the advantages AND disadvantages those terms suggest.

A foam patch is cheaper than HMEs and is simply a square of foam typically applied via a peel off glued edge which is attached above the stoma. Most are open on the other three sides. The top glued side acts like a hinge so you flip it up to manually occlude your stoma, or put your handkerchief to catch a cough. The primary purpose is to filter incoming air, but it can also be dampened to increase the humidity of inhaled air, and they will retain a little moisture from exhaled breath. You can see examples of foam patches (and read about alternative stoma covers including HMEs) in this issue of the WWJ:


I find it really helps to look at a picture of these various things to better understand them. "A picture. . . (is really) . . . worth (at least). . . a thousand words." It helps to look at catalogs or look at the items on the websites of suppliers such as ATOS, Inhealth, Kapitex, Bivona, etc.

HME stands for Heat/Moisture Exchange. HMEs are also filters made of foam, but are thicker little foam disks inside of plastic housings. They are attached in one of two ways. One is via a glued on-housing. The housing goes completely around the stoma, and the HME snaps into the hole in the center of it.

A second way to use the HME filter is to put it into a lary tube (vent, button). The tube extends down into the stoma, and the HME snaps into the top. Those who have problems with stenosis (microstoma, or shrinking of the stoma) have probably used one in the past or continue to use one. Here is an article which shows a photo of the glued on housing ready to have an HME inserted, and also the lary tubes into which an HME can be fitted:


The article above also shows an HME filter. HMEs filters can stand alone, or be combined with a hands-free valve such as the one pictured in the article which permits TEP users to speak without occluding their stomas with thumb or finger. Some vendors such as Inhealth sell both an HME by itself, and also the HME combined with a hands-free valve for TEP speakers. People who use an AL or esophageal speech can use the HME filter by itself.

There are several manufacturers of HMEs, and their properties differ. Several impregnate their foam disks with salt and an antibiotic. The salt helps to store water vapor exhaled from the breath into the foam so it can be picked up and returned to the lungs when you inhale. So it is doing what the mucus lining of your nose and throat used to do. The antibiotic helps neutralize bacteria on the inside of the stoma, and from air coming in.

The HME is superior in its ability to filter air. Just the fact that it is attached on all four sides would produce improved filtration over the patch even without a tighter "weave" (smaller holes) in most HME filters compared to patches.

Are all foam patches the same? No. Some have smaller holes than others. Many of us who have tried a number of foam patches prefer the one from Kapitex, although it is a more expensive than most others. It has smaller holes and appears to hold more moisture when dampened than most others. But you should experiment with them and make up your own mind.

HMEs also are better at retaining heat than foam filters. Before we had the laryngectomy the temperature of the air reaching our lungs was close to body temperature - 98.6 degrees. After laryngectomy, the air reaching our tracheas and lungs is almost always cooler, and this, along with being drier, causes us to product more mucus as a defense mechanism.

The wearing of an HME will eventually reduce coughing and excessive mucus production, although seeing a major difference will typically take a week or more. The HMEs will retain more heat than foam patches since, again, they are sealed on all sides. And they are also thicker and concentrate moving the air through a smaller area than the patch.

One unique feature of the HMEs over the patch is that they restore some resistance to incoming and outgoing air. According to research, this resistance improves oxygen saturation of the blood. It improves gas exchange, and causes the lungs to more fully inflate and deflate. However, some of those with pulmonary disease would not want this feature since it can make their breathing even more difficult. It is a matter of trading off benefits versus disadvantages.

Brands of HMEs differ in their ability to provide resistance. The brand of HME which gives the greatest emphasis to providing variable resistance is the Kapitex system. They have three different filters which provide differing amounts of resistance (and filtration) such as when exercising (least resistance), versus sleeping (most resistance). At present, they just have the HME and not the hands-free valve combination, although they might be working on a combination. ATOS is probably next with an emphasis in their HME on resistance along with filtration, warming and retaining moisture. They are also coming out with a very different high tech design for a combination HME and hands-free value. The valve works on a very different principle than the Inhealth or Bivona types. Both of these use a flap valve, while the ATOS Provox uses what amounts to a ball bearing as their valve. However, it remains to be seen if the new HME/hands-free will stand up to the more simple flap design and be cost competitive.

Drawbacks to HMEs: There are several. One is hassle. Many people experience problems in keeping a seal, although keeping the seal in an HME filter alone is easier than a HME/hands-free valve combination since you create pressure inside your stoma to shut the hands-free valve, and this speeds blowing the seal along with the ability of mucus to erode the seal.

With the housing you also apply glue, and this also adds time to preparing to go out and face the world as you carefully clean the skin around the stoma, let it dry, apply glue and wait for it to dry (or use a self-gluing housing, but which is more expensive). Another problem is that if you are wearing an HME and you cannot pull it out to avoid a cough, you can coat the inside of the filter with mucus and must change it even if you just installed it since it is not recommended to wash the HME filters even it that would remove the mucus since you would also be washing out the antibiotic and salt.

A major drawback to using an HME and/or hands-free valve is cost. But this has changed for many since Medicare now covers filters and HMEs. But it is important to remember that Medicare alone does not cover 100% of the cost, so you need to look into that issue since most will require co-payments from you unless you have supplemental insurance.

Foam patches and HMEs should be changed daily, so there is that cost. And the HME filters are more expensive than most foam squares. They range from $1- $3 or more, and because of accidents, you may have to use more than one in a 24 hour period. The throw away housings are another expense, and even the "permanent" housings much eventually be thrown out and replaced when they become stiff. Those who use an HME filter or HME/hands-free valve have fewer hassles using the lary tube approach, but probably most hands-free valve users will not be able to keep a seal without also using it in combination with a housing because of the amount of pressure needed to close the valve.

In conclusion, if someone were to tell me that they were about to conduct exhaustive scientific research on the overall effectiveness of different kinds of stoma filters and invited me to predict how the research would come out, here is how I would guess the research would rank the most common kinds of stoma covers from most effective to least effective overall:

HME FILTERS (best filtration and heat and moisture retention; unique ability to provide resistance) Disadvantages: hassle and cost.

MOST FOAM PATCHES (better filtration than cloth covers. Ability to retain some moisture and heat). Disadvantages: daily expense, less effective at heat/moisture retention. No significant ability to provide resistance.

LINED CLOTH COVERS (provides greater filtration than unlined, and a lint free lining so cloth fibers are kept out of stoma). Disadvantages: less effective at filtration than patches. Most types of cloth shed fibers, and some will get into stoma. Less effective for moisture, heat retention and no ability to provide resistance.

UNLINED CLOTH COVERS (better filtration than open knit or crocheted covers) Disadvantages: less filtration than lined ones and more potential for cloth fibers to enter stoma than lined ones. Less effective heat and moisture retention. No ability to provide resistance.

LOOSE KNIT COVERS such as crocheted or knitted (provides some filtration and potential for moisture augmentation through dampening) Disadvantages: less effective in filtering or retaining heat or moisture. No ability to provide resistance.

NO COVER (only advantage is zero resistance for those with significant pulmonary disease). Disadvantage: no filtration, humidity or heat retention, resistance. Increased exposure to infection.

Do I list them this way because I use the HME? Nope. I actually use mostly lined cloth covers, occasionally unlined ones, and foam squares. And I have used HMEs alone or with hands-free valves only on a couple of occasions. My reasons are as stated: hassle and cost. But I may eventually change my mind about this, particularly when I become Medicare-eligible. Right now my private insurance carrier seems to cover zero lary supplies, including those prescribed by my doctor other than Nystatin. But insurance policies vary.

If you would like to experiment with HMEs several of the vendors are offering free sample kits for you to try them out. I know ATOS and Inhealth do. I believe Kapitex does as well, and you can check with Bivona. Call their toll-free numbers listed on our suppliers pages and find out. I will be trying each of them I can get my hands on whether I end up routinely using
one or not.

Regards, David Blevins (David6511@aol.com)


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