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How does a feeding tube work?

For people with certain medical conditions who are unable to eat by mouth, feeding tubes can provide the nutrients they need to survive while continuing to use and preserve the functionality of the GI (gastrointestinal) tract. This type of enteral (using the GI tract) nutrition is often achieved via ETF (enteral tube feeding). ETF usually consists of a small, thin tube that is inserted either through the mouth or nose, or directly into the stomach or intestine. This tube brings nutrients via a specialized liquid formula that includes protein, carbohydrates and fats along with vitamins and minerals for complete nutrition.

There are several different methods to move the liquid nutrients through the tube during feeding. The most common feeding techniques include the following:


Feeding methods


With gravity feeding, a bag of formula is on a pole higher than the individual. The formula is then poured via tubing connected to the feeding tube. The tube from the bag connects to the clamped feeding tube. Once the clamp is opened, gravity pushes the formula into the feeding tube; the flow can be adjusted using a regulator clamp.



An enteral pump provides a controlled delivery of liquid nutrition into the stomach or small intestine. This method can be used for continuous or bolus (set amount delivered at once) feedings.



Formula is poured into a syringe that is inserted into the clamped feeding tube. Once the clamp is opened, gravity pushes the formula into the feeding tube. With the syringe method, you will need to have several feedings during the day.

Along with the feeding method, your doctor or other health care provider will determine the rate at which the liquid nutrition will be administered to best meet your needs. Predetermined volumes of feedings that are given at different times during the day are called boluses. These are administered at a faster rate than feedings that are intermittent. Another option is continuous or cyclic feedings when the nutrition is fed into the tube throughout a longer period of time, anywhere from 8 – 12 hours (cyclic) or 8 – 24 hours (continuous).


Related articles:
What is enteral nutrition?
What types of feeding tubes are available?
Commonly asked questions about enteral tube feeding