Feeding and Venting Part II- Venting while Tube Feeding

In this video we'll walk through all things related to venting children with a feeding tube (or g tube), including basic steps, troubleshooting, positioning and more.

This series is going to cover the how-to and some top tips for gravity feeding, syringe feeding and venting for children with feeding tubes.  We are not specifically covering feeding for infants less than a year old or children who use feeding pumps, but venting applies to any child with a feeding tube, regardless of how the feedings are administered.
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In the first video we talked about comfort and making sure the tube feeding is going well and developing a Plan B when the feeding isn’t going well. And now we’ll get started on the second topic in this series, which is venting.  Venting is one of those topics that I think is very underrated in terms of its usefulness.

Venting can be an incredible tool, not only to keep your child comfortable during a feeding but also to understand how your child is processing food and whether the food needs are changing.
 
What is venting?
Venting is a quick procedure where excess air (and even food) is allowed to flow out of the stomach by using a syringe. Venting is so important to tube feeding because not only does it release excess air in the digestive track that can be problematic BUT IT ALSO gives you a lot of information about how the feeding is going and even more generally, about what your child’s feeding needs may be as they change over time.

So first, how does air get in the stomach?

There are multiple ways:

1. Some air is a natural consequence of tube feeding
2. Some children swallow air
3. Some children can generate air from the breakdown of a particular food
4. Some children can have a bacterial overgrowth that causes air buildup
5. Some children have other structural or motility issues which can cause excess air buildup
6. If a child has a nissen fundoplication (or nissen) air buildup is more common because excess air can’t be expressed through burping.

In our first clip we go over the basics of how to vent.

You can see that here we’re following the basic steps:

1. Insert feeding extension
2. Flush the feeding extension with a few mL’s of water
3. Remove the plunger from the syringe (we prefer using 35 mL syringes for this purpose)
4. Allow air and food to pass into the syringe
5. You may want to gently press on the stomach
6. You may want to turn the child from side to side to see if any air comes out
7. You may find that at certain times you get more air by placing the syringe low to the side of the child and other times you may get more air by placing the syringe higher above the stomach
8. You may want to keep a cloth and/or a 32 oz graduate nearby

 
How often do you vent? 

For our child, we typically vent prior to a feeding, about every 20%-25% or so throughout the feeding and then we vent about 10 minutes after the feeding.  We also vent periodically between meals or as free water is given. Venting takes about 30-60 seconds. Our son has both a feeding tube and a nissen, which can trap air more frequently in the stomach, so that is something we take into consideration. Once you experiment with venting and, as we’ll talk about later, once you make sure that your child is actually in the right position to vent effectively, you can figure out your own venting protocol.  Whatever you decide, make sure that is communicated to everyone who is feeding your child to make sure that your child is consistently comfortable during feedings.

So once you vent, a couple of things to keep in mind:

Are you getting a LOT of excess air? If so, you may want to examine what the child ate to see if there could be a food intolerance, particularly if you are introducing new foods (like a blenderized diet).   If this is a new issue and food is not the culprit, you may want to consult your GI to see if there could be another issue going on like bacterial overgrowth.   If your child is constantly building up excess air (like from swallowing air for example) you may want to talk to your doctor about using a Farrell bag which funnels air out of the stomach continuously.
Here are a few additional clips of venting, what it looks and sounds like.

Here’s one other concept for venting that I think is very, very important and may be overlooked.  I am going to demonstrate on a bottle in the video.  Pretend the bottle is a stomach, and the feeding tube is the black dot on the bottle.  When the bottle is upright, its like a child sitting in an upright position.  Where is the air?  Its at the top?  Where is the feeding tube?  It’s in the middle.  Is the air near the feeding tube?  No?  If you vent this child, will you really be getting the excess air out of the stomach?  Only maybe. If I turn the bottle, this is similar to a child laying flatter.  Is the air near the feeding tube?  Yes. My point is this: you may be going through the motions of venting and you may be getting some air and some stomach contents, but I think it is VITAL that you experiment with different positions to vent and you may find you are much more successful in a more reclined position, simply because of the physics of air in the stomach relative to the feeding tube placement, even if your child tolerates eating while sitting upright.

Now what else does venting tell us?  Venting can show us how much food is coming back out into the syringe.  If you’re in the beginning of the meal, and stomach motility is optimal, you likely won’t see a whole lot of food coming back out.  If you’re closer to the end of the meal, it would be more expected to see more food coming out into the syringe, but a LOT of excess food (like more than ~1 oz or 35 mL) may indicate a few things:

1. The feeding is going too fast
2. The feeding volume may be too much or the amount of calories may be too much
3. If eating a blended diet, one of the foods in the feeding may not be tolerated well OR there could be more fat or fiber in the meal than the child can tolerate.

 
I’ll give you two specific examples:
We find with our son that sometimes we need to increase his calories if he’s going through a growth spurt.  Once he is done with that spurt, sometimes we find he becomes overly full and isn’t accepting the same volume and calories as before- when he starts consistently backing up food into the syringe for several meals in a row when we vent him during feedings, we know that we need to pull down the calories and volume somewhat. 

Another example is that when we were first experimenting with foods for a blenderized diet, we tried avocado.  When we fed him the blend with avocado, he would back up a lot of food in the syringe during venting.  We learned that the combination of fat and fiber in this particular food was not a good fit and slowed down the rate at which his stomach processed food.

On the other hand, if you’re bolus feeding (i.e., not using a feeding pump and/or doing continuous feeds) and getting minimal stomach contents toward the middle or end of a feed (or nothing) two things could be going on:

1) you may want to look into whether your child is getting enough food at a given feed and/or enough hydration. OR
2)  and this is critical, when you vent toward the mid or endpoint of the feeding, and you do not get much of any stomach contents, this can also indicate that something is blocking the feeding tube and preventing air and food from passing.  By the end of the feeding, there should be some nice flow of stomach contents coming out into the syringe.  If there’s nothing, you should be a suspicious.

This gets to our number one troubleshooting technique for venting.  Actually, you can use this trick for venting or feeding.  We call it the “reverse vent” because instead of removing the plunger and allowing the stomach contents or air to naturally flow into the syringe, you are going to leave the syringe plunger in the syringe and actively pull out some of the stomach contents.  Sometimes you will find that fiber from the food or even mucus in the stomach can be blocking the flow of air or stomach contents from coming out of the feeding tube.  If you are going through the motions of venting but nothing is coming out, the child can actually be building excess air or be getting overly full, uncomfortable and even nauseated, and you might not know it because the flow of stomach contents out of the tube is blocked.

If you reverse vent and you pull back “gunk” into the syringe (a few mL’s) we discard that and then try flushing and venting again to make sure we’re getting air and food back into the syringe. We include a clip of what this looks like.
 
So those are the basics on venting. As you can see, venting can be an incredible tool, not only to keep your child comfortable during a feeding but also to understand how your child is processing food and whether the food needs are changing.
 
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Thanks everyone!

Additional links: More on stomach air and venting:
https://www.feedingtubeawareness.org/gas-bloat/