A MIC-KEY feeding tube is a low-profile “button” that sits nearly flush with the skin, held in place by a small water-filled balloon inside the stomach and a flat disc on the outside. Unlike longer gastrostomy tubes, it doesn’t have a permanently attached external tube. Instead, you connect a separate extension set each time you need to feed, give medication, or vent the stomach, then disconnect it when you’re done. Learning the basics of connecting, feeding, cleaning, and maintaining the device takes a little practice, but the process becomes routine quickly.
Understanding the Parts
The MIC-KEY button has three key features you’ll interact with daily. The feeding port is in the center of the button, protected by a one-way valve that prevents stomach contents from leaking out when nothing is connected. The balloon port is a smaller side port where you attach a syringe to add or remove water from the internal balloon. And the external disc is the flat base that rests against the skin.
You’ll also use extension sets, which are the short tubes that snap into the feeding port whenever you need access. Bolus extension sets are used for syringe feedings, while longer extension sets connect to a feeding pump for continuous or slower feeds. These extension sets are separate supplies you’ll need to keep on hand.
Connecting the Extension Set
Every feeding or medication dose starts with attaching an extension set to the button. Line up the black orientation line on the extension set connector with the matching black line on the MIC-KEY port. Push the connector down firmly, then turn it clockwise about three-quarters of a turn until you feel slight resistance. Stop there. Forcing it past that stop point can damage the connector or the valve inside the button.
When you’re finished, reverse the process: turn the connector counterclockwise and pull it straight out. Don’t leave the extension set connected longer than necessary. Prolonged attachment can wear out the one-way valve, which leads to leaking from the center of the button.
Giving a Bolus Feed by Syringe
Bolus feeding means delivering a set volume of formula over a short period, usually by gravity through a syringe. Before you start, wash your hands and make sure the formula is at room temperature. You can test it by placing a few drops on the inside of your wrist, the same way you’d check a baby bottle.
Connect the bolus extension set to the button. Attach a large open-ended syringe (with the plunger removed) to the open end of the extension set, and clamp the extension tubing. Pour formula into the syringe until it’s about half full. Unclamp the tubing briefly so the formula fills the extension set, then clamp it again. Continue filling the syringe and unclamping in this way until the full volume has been delivered. Raising or lowering the syringe controls the flow speed: higher is faster, lower is slower.
Once all the formula has drained through, flush the extension set with water using the same syringe. This clears leftover formula from the tubing and the button, reducing the chance of a clog. Disconnect the extension set when you’re done.
Using a Feeding Pump
For continuous or slower feeds, you’ll connect a pump extension set instead of a bolus set. The locking mechanism is identical: align the black lines, push down, and turn clockwise. The pump controls the rate, so you simply set the volume and speed as directed by your care team, prime the tubing to remove air, connect it to the button, and let the pump run. Flush the tube with water when the feed is complete before disconnecting.
Giving Medications
Liquid medications work best through a MIC-KEY tube. If a medication only comes in pill form, crush it into a fine powder and mix it with a small amount of warm water until it dissolves as fully as possible.
Flush the tube with water before giving the first medication. Then draw up or pour the medication and deliver it through the extension set. If you’re giving more than one medication, give each one separately and flush with water between doses. Mixing different medications together can cause them to clump or interact in ways that clog the tube or reduce their effectiveness. After the last medication, flush with water again. A typical flush volume is about 60 mL, though your care team may recommend a different amount for smaller patients.
Daily Stoma Care
The skin around the stoma (the opening where the tube sits) needs simple daily cleaning to stay healthy. Wash the area gently with warm water and mild soap during baths, cleaning around and underneath the external disc. Pat the skin completely dry afterward. Moisture trapped under the disc is one of the main causes of skin irritation and a condition called granulation tissue.
Granulation tissue is extra skin that can form around the stoma. It looks red and moist, similar to the tissue inside your mouth. It’s common and not dangerous, but it can bleed easily and produce discharge. Keeping the site dry, making sure the tube fits snugly without being too tight, and limiting side-to-side movement of the button all help prevent it. If granulation tissue does develop, a clinician can treat it with silver nitrate, a topical chemical that shrinks the extra tissue.
You should also gently rotate the button a quarter turn during cleaning to prevent the skin from adhering to the disc. If the skin looks red, raw, or has an unusual smell or colored discharge, that’s worth bringing up with your care team.
Checking the Balloon
The balloon inside the stomach slowly loses water over time, which can cause the tube to loosen, leak, or even fall out. Check the balloon volume regularly by attaching a small slip-tip syringe (5 or 10 mL) to the balloon port and withdrawing all the water. Compare what you pull back to the volume printed on your specific tube. If it’s low, refill the balloon with the correct amount of water through the same port. Always use distilled or sterile water for the balloon, as tap water can leave mineral deposits that make the balloon harder to deflate later.
Clearing a Clog
MIC-KEY buttons clog less often than longer feeding tubes because they’re so short, but it does happen. Start by checking the extension set first. Flush it with 5 to 10 mL of warm water. If water flows freely through the extension set on its own (disconnected from the button), the clog is in the button itself. Try a new extension set before assuming the button is blocked.
If the button is clogged, use a slip-tip syringe with warm water and a push-and-pull pulsating motion. Push water in, pull back, push again. This back-and-forth pressure helps break up dried formula or medication stuck inside the valve. If that doesn’t work, you can deflate the balloon, remove the button, and squeeze the tube at the site of the blockage with your fingers, then flush it with at least 5 mL of water before reinserting. Never use sharp objects like wires or toothpicks to clear a clog, as they can puncture the tube or damage the valve.
When to Replace the Tube
MIC-KEY buttons typically need to be replaced about every three months. Over time, the balloon weakens, the valve wears out, and the tube material degrades from constant exposure to stomach acid. Signs that replacement is overdue include persistent leaking from the center of the button (a failing valve), a balloon that won’t hold water, or visible cracking or discoloration of the tube.
Many families learn to do the replacement at home. The process involves deflating the balloon, gently sliding the old button out, and inserting the new one into the same stoma. Your care team can walk you through this the first time and let you know whether home replacement is appropriate for your situation. Always keep a spare button on hand in the correct size so you’re prepared if the tube falls out or fails unexpectedly. A stoma can begin to narrow within hours if left open, so having a backup ready matters.