Reading Time:

8 minutes
Ostomy Filters

Ostomy Filters

Ostomy filters are useful accessories that help prevent gas odor, a major source of stress for ostomates. These filters contain the inevitable gas accumulation in the pouch. Otherwise, it can distend and cause discharge problems, particularly in colostomy patients

“Colostomies tend to emit more odor than ileostomies because of the bacterial abundance in the colon. When sigmoid and descending colostomies are irrigated, odor is much less evident. Ileostomates experience almost continual peristaltic waves which sweep the ileum and prevent stagnation of the intestinal contents, thereby eliminating much of the bacterial growth that occurs with colostomies. Urine has a characteristic smell, but a foul odor could be a sign of infection. Certain foods will affect the odor of both feces and urine — eggs, onions, spicy foods, cabbage, and fish to name a few — you may want to cut down on your consumption of these if odor is bothering you.”1

Ostomates may have concerns after their surgery, especially about how they will live a normal life. “These fears center around worries that the collection system will leak or that odor will escape and that the system will be noticeable even though their outer clothing. Part of these problems are due to the discharge of flatus into the pouch which can cause an embarrassing distention of the pouch.

In order to overcome the problem of gas build-up within the pouch, it has been suggested that the pouch be provided with a tortuous path vent opening a tortuous path and a deodorizing filter. Other proposals have involved filters which could be attached to the pouch, or filters attached over a vent opening in the pouch wall, It has also been suggested to employ a pouch having a deodorizing vent opening in its upper edge disclose a pouch having a vent opening in the outer pouch wall opposite and above the stomal aperture covered by a deodorizing filter. Multi-layered filters adapted to be sealed over a vent opening in the pouch wall.”2

Foods that Promote and Control Odor and Gas

“Certain foods can make odors worse. If you have an issue with food-related odors, you may want to avoid these foods. You might also choose to eat them at times when you are less concerned about odor.

 Foods that promote odor

  • Fish
  • Eggs
  • Onions
  • Garlic
  • dried peas and beans
  • Asparagus
  • Fried foods
  • Vegetables of the cabbage family: broccoli, brussels sprouts, cabbage, turnip and cauliflower

 Some foods can help you control odor

  • Parsley
  • Yogurt and buttermilk

Excessive gas

If you find that you have too much gas, you can eat fewer gas-forming foods. You can also eat them at times when gas production is not a concern to you.

Foods that may promote gas formation

  • Dried peas and beans
  • Melons
  • Eggs
  • Beer and carbonated beverages (pop)
  • Onions and related vegetables
  • Strong cheeses such as Roquefort
  • Vegetables of the cabbage family: broccoli, brussels sprouts, cabbage, turnip and cauliflower
  • Dairy products (if you are lactose intolerant)

To help decrease gas formation

  • Chew your food well
  • Do not chew gum
  • Do not use drinking straws
  • Try not to talk with food in your mouth. 3

How do these filters work?

Ostomy filters can help solve gas build-up and unwanted odors. The filters are made of activated charcoal which is a type of specially treated charcoal with enhanced absorption properties. According to some, coconut husks activated charcoal is the best. The filter has several useful functions.

  1. Help in offering an escape vent for gas in the pouch. This prevents pouch distension
  2. Eliminates or reduces ostomy discharge related odor.
  3. Patient’s comfort
  4. Reducing embarrassing odor situations
  5. Giving the patient the confidence needed to pursue personal and social interests.

Ostomy filters are used in all types of ostomies. The two main types of ostomy filters are the ones already attached to the pouch and those that are separate from the pouch and have to be fixed by the patient or medical professional.

Multiple brands of ostomy filters are available in the market. Although they are all designed to reduce or eliminate gas and odor problems, they may not work to the same degree of patient’s satisfaction. An ostomate may have to experiment with several types to determine which one works best for them.

“An ostomy pouch having a deodorizing filter element affixed to the outer pouch wall. The filter element consists of a polymeric film cover that is welded or adhesively attached to the outer polymeric pouch wall and an insert of gas deodorizing material located between the polymeric film cover and the polymeric pouch wall. The outer pouch wall and the polymeric film cover are each provided with an aperture. The apertures are not aligned and are covered by opposite ends of the deodorizing material insert. Thus, the build-up of gas pressure within the pouch will cause the gas to travel into the filtering element, through the insert of deodorizing material, and finally be vented to the atmosphere.

A multi-stage filter that resists contact contamination by semi-liquid waste collected in the bag. Gases emitted from the stoma into an ostomy bag and gases that issue from waste material confined in the bag are usually evacuated through a deodorizing filter. A gas outlet is thus provided in the ostomy bag, normally adjacent the deodorizing filter to ensure that the outward flow of gas passes through the filter. Most ostomy bags can generally be worn a few days before the deodorizing capability of the filter begins to lose effectiveness. The exhausted filter can then be replaced if the bag has provision for replaceable filters as in ostomy bags. If there is no provision for filter replacement as in the ostomy bag, the entire bag is disposed of and replaced when the filter is no longer an effective deodorizer. If the deodorizing filter is inadvertently contaminated by contact with waste material that accumulates in the bag, it may be desirable to replace the disposable bag immediately. Waste material contact with a deodorizing filter can occur as a result of physical activity by the wearer that shifts the contents of the bag toward the deodorizing filter, especially if such waste material is of a liquid or semi-liquid consistency. Contact of the deodorizing filter with semi-liquid waste material will often clog the filter, thereby preventing adequate deodorization and evacuation of waste gas. Whenever a filter is contaminated by contact with semi-liquid waste material and such contamination impedes the function of the filter, the filter or bag should be replaced as soon as possible.

Filter contamination from contact with semi-liquid waste also commonly occurs when an individual is asleep or reclining because the ostomy bag is in a relatively horizontal orientation. In such instances, gas pressure may build up in the bag because of the lowered rate of gas evacuation due to filter clog. Pressure release can thus occur through an undesirable break in the bag seal at the stoma. If the leak or seal break is not detected, it can result in the soiling of an individual’s garments. It is thus desirable to provide an ostomy bag with a multi-stage filter system that prevents semi-liquid waste material from contaminating a deodorizing element but does not inhibit evacuation of gaseous waste through the deodorizing element.

The multi-stage filter includes a gas transmissive protection device for a deodorizing element that is impassable to semi-liquid waste material. The gas transmissive protection device precedes the deodorizing element or filter such that gaseous waste must pass through the protection device before it passes through the filter. The ostomy bag is a dual chamber structure with one chamber provided with a waste inlet opening to receive semi-liquid waste and gaseous waste. The other chamber is provided with a gas outlet and a multi-stage filter having a deodorizing element. The chambers are communicable, through a communication port or opening.

When the ostomy bag has a single chamber, the protection filter is a two layer structure with different pore counts that overlap the deodorizing filter.

When the ostomy bag has dual chambers, the protection filter, without overlaying the deodorizing filter, is disposed across the flow path of gaseous waste to the deodorizing filter such that any gaseous waste that reaches the deodorizing filter must flow through the protection filter. Thus, semi-liquid waste material cannot contact the deodorizing filter since it cannot bypass the protection filter to reach the deodorizing filter.4

Other Ways to Prevent Odor

“Clean the tail of your drainable pouch. Emptying regularly is important but just as important to odor control is wiping out the inside of the end of the pouch tail before you replace the clip. Try to keep stool from collecting, or “pancaking” at the top of your pouch, as this can contribute to leaks and wafer undermining. Pancaking is a common annoyance, especially if you are spending a lot of time lying down or sitting. Clothing that restricts the top of the pouch can also cause pancaking. Try putting a tablespoon of mineral oil inside the top of the bag when you change it to help things slide to the bottom. Vegetable sprays work too, as do lubricating products from ostomy manufacturers

No matter what style of pouch you use, you’ll be able to find the same pouch that comes with a filter. Advantage: The filters remove odor from gas. These filters use charcoal to neutralize odor as it is passed from the pouch. One type of filter is within the pouch itself. A second type of filter can be attached to the outside of any pouch.

Some people find that their appliances develop an odour that they dislike despite their best efforts to keep everything clean. Everybody’s body chemistry is different and some folks can wear one brand without annoyance while others think it smells funny. If your appliance is fitting you well, you’re not getting leaks and nobody else can smell anything but you still don’t think it smells right, you might consider trying other brands. Changing the pouch more frequently often helps. You’ll be more self-conscious about scent for a while after you have an ostomy. This sensitivity will diminish over time as you gain in confidence and realize nobody is smelling anything.

Ask your WOC Nurse which type of filter might be better for you.”5

Properties of a Quality Ostomy Filter

  • Ostomy filters allow gas to escape while eliminating foul odors or liquid discharge.
  • The filter should effectively scavenge hydrogen sulfide and methyl mercaptan gases, which constitute the main sources of the foul odor from an ostomy pouch.
  • The ostomy filter should have an outer protective layer that prevents liquids from soaking the activated charcoal inside. This layer allows the patient to engage in swimming and other water activities safely. A filter without this layer forces the patient to use tapes and other protective wear.

To achieve these properties, manufacturers must consider the use of special materials and filter design. Sufficient surface area and a material that allows free airflow in a controlled activated charcoal environment contribute to effective odor prevention. Also, the special material prevents fluids from inside or outside the pouch from entering the ostomy filter thanks to its both hydrophobic (water repelling) and oleophobic (oil repelling) properties.

If ostomy gas and odor are not controlled, these factors can contribute to depression and social withdrawal. Using a good quality ostomy filter, the patient gains more confidence and leads a productive life. Seek help from an ostomy nurse to select a fitting appliance for you.

María Laura Márquez
13 October, 2018

Written by

María Laura Márquez, general doctor graduated from The University of Oriente in 2018, Venezuela. My interests in the world of medicine and science, are focused on surgery and its breakthroughs. Nowadays I practice my profession...read more:

Leave a Reply

If you would also like a response sent to your email please add it in the email box below.