G/GJ tubes: Low-profile G tubes (Mic-Key)

​​A low-profile G tube is a type of feeding tube that sits close to the skin and is easy to conceal. If your child has a low-profile G tube, you will need to know:
  • how to take care of it at home
  • how to change it on your own.

There are several different brands of low-profile G tubes. Here are some you might encounter:

  • Mic-Key
  • Nutriport
  • AMT Mini One

At SickKids, you will most often see the Mic-Key, often referred to as the “Mic-Key button.” Therefore, this article will focus on that brand. However, the general guidelines are applicable to all low-profile G tubes (also referred to as “tubes” or “G tubes” in this article).

Taking care of your child’s low-profile G tube

The balloon of a 12 French (FR)–size low-profile G tube can safely hold 3 to 5 mL of sterile or distilled water. The balloon of 14 FR–size (or larger) low-profile G tube can safely hold 5 to 10 mL of sterile or distilled water. Do not fill the balloon with saline, as it evaporates more quickly, or air. Do not feed your child through the balloon port. Filling the balloon with more or less water can affect the position of the tube. Less water makes the tube stick out and more water brings the tube closer to the skin. If the tube is so tight you see an indentation in your child’s skin, you can decrease the amount of water in the balloon. If the tube sticks out too much, you can increase the amount of water in the balloon.

It is important to check the amount of water in the balloon at least once a week. Use a slip-tip syringe to do this.

  1. Insert a 5 mL syringe into the low-profile G tube’s balloon port (marked “BAL” on a Mic-Key).
  2. Remove all the water from the balloon. Throw the old water away. It is normal for the water to become discoloured.
  3. Reinflate the balloon with new sterile or distilled water.

It is normal for less water to be removed from the balloon compared with what you put in. This is because some of the water might have evaporated. There could be a difference of up to 0.5 mL.

  • If there is a difference of more than 0.5 mL of water between what you put in and what you remove from the balloon (because you remove less water than normal), the balloon may be damaged and the tube may need to be replaced with a new tube.
  • If you attempt to remove water and there is nothing there, reinflate the balloon with the amount of water you normally put in. After three to four hours, attempt to withdraw this water. If you get all the water back, the balloon may simply have been empty before. You can then re-inflate the balloon with the amount of water you normally put in and check the balloon volume every two to three days to be sure there are no further problems. If you do not get any water back when you withdraw after three to four hours, the balloon is likely damaged and the tube will need to be replaced.

The G tube’s extension set should be changed every two to three weeks. It is important to clean the extension set between each use and remove it from the G tube when it is not in use.

Continue to flush the tube with at least 5 to 10 mL of water before and after each feed and medication dosing, and every four hours during continuous feeds. This helps prevent the tube from becoming blocked.

Keep the low-profile G tube and stoma as dry and clean as possible. No dressings are needed.

How often should you change the low-profile G tube?

Most G tube manufacturers do not give a set time for how long you can use the tube. They suggest that it can stay in as long as it is functioning without leaks or defects. The tube should be changed at least every six to eight months to prevent leaks, which could cause the tube to accidentally fall out.

When changing the tube, it is important to remember the risks involved.

  • Infection. When you replace the tube, the stoma (the opening in the stomach) and the tract (the passage through the stomach) can become irritated and bacteria can be introduced. This increases the risk of infection. Always wash your hands before handling the tube and continue to clean the site with soap and water. Keep the site open to air.
  • Increased granulation tissue. Removing an old tube and inserting a new one can irritate the skin and cause granulation tissue. This is a common occurrence. Use hypertonic salt water soaks or silver nitrate​ to manage granulation tissue.
  • Perforation. There is a possibility that, when inserting a new tube, it could puncture a new space inside the body. This happens extremely rarely. If your child has instant intolerance (vomiting) or severe pain after their first feeding with a new tube, go to the emergency room for assistance. A G tube check may need to be organized in the radiology department.

How to change your child’s low-profile G tube

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Supplies

  • New low-profile G tube
  • Antibacterial soap
  • Warm water
  • Washcloth
  • Sterile or distilled water
  • Three 5-mL slip-tip syringes (provided with the tube)
  • Water-based lubricant or jelly

Procedure

  1. Wash your hands with soap and water, and prepare your equipment and supplies.
    • Draw 5 mL of water into one syringe (to fill the balloon) and 5 mL of water into another syringe (to flush the tube). Leave the third syringe empty.
    • Prepare your washcloth with soap and water on one part of the cloth and non-soapy water on another part, and keep a third part dry.
  2. Check that the balloon of the new G tube is not broken: Inflate the balloon with 5 mL of water and gently squeeze the balloon to check for leaks caused by defects. Remove all the water from the balloon, drawing what you’ll need to refill the balloon back into the syringe.
  3. Remove the water from the balloon of the old G tube using the empty 5 mL syringe. Throw the water and syringe away.
  4. Remove the old G tube. It is normal for the inner part of the tube to be brown or black. This is caused by acidic stomach contents. Throw away the old tube.
  5. This is a great time to assess the stoma (i.e., the opening in the stomach) for any changes, such as redness, drainage, rash, or granulation tissue. Wash the stoma with soap and water, rinse it with non-soapy water, then let it air dry it or pat it dry with a washcloth.
  6. Lubricate the new low-profile G tube and, at a slight angle, insert it into the stoma, following the existing tract. The tube may be slightly resistant and it is okay to exert light force. Try to time insertion with when your child breaths in, as they are most relaxed at that time.
  7. Once the tube is in place, inflate the balloon with the amount of water you usually put in.
  8. Check that the tube is in the stomach by connecting the extension set to the G tube and leaving it open for stomach contents to flow out. If no stomach contents flow out, have your child sit up and forward, or pull back using a syringe. Once you see stomach contents, flush the tube with at least 5 mL of water.

What happens if the low-profile G tube accidentally falls out?

If the G tube accidentally falls out or gets pulled out​, do the following:

  1. Check if the balloon is broken by filling it with 5 mL of water. If you do not see a leak, remove the water from the balloon, wash the G tube with soap and water and reinsert it into the stoma as described above. Fill the balloon with the amount of water you normally use. Check the balloon every two to three days to be sure there are no further problems.
  2. If the G tube is broken, replace it with a new tube as described above.
  3. If you cannot replace the G tube, call your G tube specialist to book an appointment for a tube change. In the meantime, to make sure the stoma and tract do not close, insert a Foley catheter. Measure the Foley catheter so that it is between 4 and 6 cm in length, lubricate its tip, then insert it into your child’s stoma. Tape the Foley catheter to your child’s tummy. Then close the end of the Foley catheter using a Foley catheter plug or the middle part of a 5 mL syringe until you are ready to feed or give medications to your child. The Foley catheter should be one FR-size smaller than the FR size of your child’s tube. For example, if your child has a 12 FR–size tube, you will insert a 10 FR–size Foley catheter.

You should always carry an emergency kit that includes a back-up G tube or Foley catheter, water-based lubricant or jelly, and tape in case of unexpected tube changes.

Key points

  • A low-profile G tube is a type of feeding tube that sits close to the skin and is easy to conceal.
  • The low-profile G tube should be changed at least every six to eight months to prevent the balloon from leaking and the G tube from accidentally falling out.
  • The G tube extension set should be changed every two to three weeks.
  • When changing the tube, carefully wash the area and monitor the stoma and tract for changes, such as redness, rash, granulation tissue, or drainage.
  • Always carry an emergency kit that includes a back-up low-profile G tube or Foley catheter, water-based lubricant or jelly and tape.
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Holly Norgrove, RN, BScN

9/7/2015
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At SickKids

If you are a SickKids patient, contact the G tube resource nurse at 416-813-7270, extension 4, with any questions or concerns related to your child’s low-profile G tube or stoma.​

Resources

For more information, visit www.mic-key.com.

Notes: