Infusion Set Basics

The article below is written by Joslin Diabetes Center (www.joslin.org), a nonprofit teaching and research affiliate of Harvard Medical School. Joslin does not endorse commercial products or services.

The proper use of infusion sets is essential for successful insulin pump therapy. Selecting the type of infusion set and the tubing length should be matched to your individual needs.

Infusion sets have three parts:

  • Tubing -- The tubing is the part that attaches to the insulin reservoir. One end of the tubing inserts into the pump and the other end is attached to the insertion site.
  • Infusion sets and cannulas --This is the part that attaches to your body with self-adhesive or tape. The cannula, or catheter, is inserted right under your skin so that insulin can be delivered.
  • Detachable part -- There’s a part of the infusion set that is detachable, allowing you to temporarily disconnect your tubing and pump for activities such as bathing, swimming and exercise, for example.

Considerations for Choosing an Infusion Set

Every pump and pump supply manufacturer distributes infusion sets, and many of these infusion sets are interchangeable, meaning that they can work with different brands of pumps. The decision as to which infusion set to choose can be somewhat confusing, as there are a lot to choose from! Here are some pointers to help you narrow your choices. Don’t forget to discuss your choice of infusion set with your diabetes care provider, diabetes educator or pump trainer.

  • Tubing length. Infusion set tubing comes in different lengths, ranging from about 23 inches to 40 inches. Tubing that’s too short can pull at the insertion site, loosening the adhesive and possibly pulling out the infusion set. Tubing that’s too long can get caught on door knobs, backs of chairs and other objects (including people!). In general, longer tubing works well if you put your pump under your pillow or on your bedside table when sleeping; if you attach your pump to your pants; if you’re a woman and you wear your pump on the inside of your thigh. If you’re a woman, shorter tubing is a good choice if you carry your pump in your bra or if you wear your pump on your skirt waistband, for example. You may find that both shorter and longer tubing works well for different situations, so you might want to keep both lengths on hand.
  • Insertion angle. A 90-degree infusion set is inserted straight into the body. If you can pinch up about ¾ of an inch of fat at the insertion site, then you can use a 90-degree set. This angle is good for people who have a bit more “padding” and for people who are a little nervous about inserting a needle underneath the skin. A 30- or 45-degree infusion set is inserted obliquely, meaning, at an angle. These sets work well for leaner people with less body fat. Also, these sets are helpful for people who have issues with sets coming out, because you can see where the catheter is inserted into the skin.
  • Metal vs. Teflon cannula. There are two types of insulin sets: metal and Teflon (plastic). A metal infusion set has a cannula that is metal, and it’s inserted at a 90 degree angle. Metal infusion sets are helpful for people who have problems with kinking or with infusion sets coming out. A Teflon infusion set is more flexible and often, more comfortable than metal sets. However, the downside is that they are more likely to kink, or bend, which means that insulin delivery can be interrupted.

Your diabetes educator or pump trainer will help you decide on the best type of infusion set for you. Once you get ready to go on the pump, you’ll learn more about how to insert and change your infusion sets, as well as how to troubleshoot for any issues such as skin irritation or unexplained hyperglycemia.

As always, be sure to discuss any concerns or questions that you have about infusion sets or pump therapy, in general, with your pump trainer or diabetes educator.