Is the warning and/or alarm signal visual, auditory, or tactile? If audio, how loud is it? Patients may need a pump with vibrating warnings and alarms.
• In case of a major technical problem, is a backup pump provided? What are the procedures to obtain a backup pump if one is not provided at the time of purchase? How quickly does the patient receive the replacement pump?
• What is the repair policy? If the pump is returned for problems, is it repaired and reissued to the patient, or is a new pump provided? Are refurbished pumps redistributed?
Infusion Set and Tubing Options
Infusion sets distributed by the various pump and pump supply manufacturers may be interchangeable to work with several different brands of pumps or they may be proprietary and brand-specific. Some sets may be designed specifically for a particular age group, such as pediatric. It is best to check with each pump company for specific availability and recommendations and make sure your patient explores all the options with the assistance of the pump manufacturer.
An infusion set is inserted subcutaneously and the set “base” is attached to the insertion site with self-adhesive dressing or tape. An infusion set is worn for 1–3 days and then removed and discarded. Infusion sets left in longer can lead to infection and/or scarring, which slows insulin delivery. Although many brands exist, there are basically two types of infusion sets: metal/steel needle cannula and Teflon cannula, and both types are available in various models. Most infusion sets connect to an insulin pump using a Luer-lock connection, and thus are universal and can be used with a variety of pumps. Advise the potential pumper to be aware of pumps that use a proprietary infusion set, as their choice of infusion sets will be limited unless the pump has an adapter that allows it to accept a Luer-lock infusion set (Roche 2012).
A metal/steel needle infusion set is inserted at a 45- to 90°-angle and requires that the needle stay under the skin. The insertion base and tubing are attached to the site with either self-adhesive or separate dressing or tape. A metal/steel needle infusion set can be disconnected from the infusion site (close to the site or several inches from the site), thus providing lifestyle comfort for physical activity, bathing, and sexual activity. A variety of needles are available by type (straight or bent) and length. Children and lean adults may need shorter needles, and active people may need longer needles to guarantee subcutaneous insertion and placement. A metal/steel needle set may be appropriate for patients who have problems with kinking or dislodgment of Teflon cannula sets. A metal/steel needle set is made of surgical stainless steel and can contain up to 12% nickel and may not be appropriate for people who experience an allergic reaction to nickel or stainless steel (Roche 2012). Some people find the metal/steel needle sets to be uncomfortable because the needle may “pinch” or be felt during physical activity or movement. A metal/steel needle set should be changed every 24 to 48 hours (Roche 2012). A major advantage of the metal/steel needle infusion set is the guarantee of insulin delivery, as a metal/steel needle cannot kink below the skin like a Teflon cannula set. Many parents of child pumpers like them because they are easy to teach to the child’s teacher or babysitter in case the child’s usual cannula set becomes dislodged. Metal/steel needle infusion sets are also often recommended during pregnancy because they may be easier than a Teflon cannula to insert in the abdominal area or a “hard to reach” (such as the upper hip/buttocal) area and they guarantee insulin delivery with no risk of a kinked or bent cannula.
The metal/steel needle infusion sets had been in use for several decades when pumps were first introduced. They are generally less costly than the soft Teflon cannula sets but are not as commonly used today. Some people choose to alternate use of both types of sets depending on their activity or exercise.
An allergic reaction to the adhesive in the dressing or the glue used to manufacture the infusion sets can occur; trial and error with different products is recommended to determine individual sensitivity.
Because every person can react differently to infusion set material, suggest your patient try a variety of sets. Pump manufacturers and trainers may be able to provide a sample of a few different sets for the patient to try.
A soft Teflon cannula set uses a stainless steel introducer needle that is threaded into the cannula for a 20- to 90°-angle subcutaneous insertion, depending on the brand and the angle of the needle (angled 30 to 45° versus straight 90°). Teflon cannula sets are latex-free and do not contain PVC (polyvinyl chloride). After insertion the needle is removed (having been under the skin just a few seconds), leaving only the cannula below the skin and the infusion set base at the site. The set base has self-adhesive tape or dressing. With a 30°- to 45°-angled set, there is a clear “window” area in the self-adhesive tape, allowing visibility of the site of the catheter insertion. The clear window allows the user to detect the status of the site, including signs of redness or other problems. A 90°-angle set does not have a viewing window, and the user may not be aware of dislodgment or problems until hyperglycemia occurs. Some people find the length of a cannula infusion set introducer needle intimidating and require reassurance and practice in insertion. Some cannula infusion sets have an insertion device to help with insertion (see below). A cannula set can be more comfortable to wear than a metal/steel needle set because the patient cannot feel the set when bending, twisting, or exercising.
Teflon cannula sets may be straight or angled and come in different lengths ranging from 5.5 to 17 mm. The shorter lengths are typically inserted at a 90° angle, while the longer lengths are inserted at a 20 to 45° angle. A short cannula (5.5 or 6 mm) may have a higher failure rate in non-slender adults and probably should not be used initially except in slender patients. And cannula infusion sets come in a variety of models: some are stationary, while others can rotate or change position depending on how the user prefers the tubing to be directed (right or left side, upward or downward). Additionally, some manufacturers offer infusion sets in a choice of colors other than white/clear. New infusion set models are introduced fairly frequently; be aware of the latest available options.
Depending on the brand, a Teflon cannula set can be inserted manually, or with a built-in injector that is disposed after use, or an optional handheld device to facilitate insertion of the needle. Some people prefer the use of an injector system or device, while others may find the clicking noise bothersome. Over time, most patients develop a preferred angle of manual insertion and placement that cannot be determined with the use of an insertion device. Even if your patient chooses to use an insertion device, recommend the patient also learn manual set insertion in case the inserter device is unavailable or becomes lost or broken. No matter what type of infusion set is used, the set should be inserted in one smooth motion (Roche 2012).
Teflon cannula sets can also disconnect at or close to the site, providing lifestyle comfort and flexibility. The user unclips the tubing from the set base, leaving only the base and subcutaneous cannula in place, while removing the tubing and the pump. Some infusion sets may disconnect a few inches from the set base, leaving a short tubing “tail.” Some disconnect sets are self-sealing at the time of disconnection, whereas others require covers at the site as well as the end of the tubing.
A Teflon cannula set is more commonly used than a metal/steel infusion set. The latter is an option that you may recommend if your patient experiences problems with Teflon infusion set kinks or dislodgment, but this is not as common as it had been in past decades. Teflon cannula sets must be changed every 48 to 72 hours.
Some infusion sets are packaged with or without tubing, and some are packaged with extra “bases,” which allow changing of the metal/steel needle or Teflon cannula every few days, while using the tubing for several days longer, depending on the type of insulin used and other factors (see Sets with tubing). The latter type of packaging may be priced less than standard set base/tubing combination packages. Most infusion set combination packages are packaged 10 sets/box.
Discuss the features and benefits of each type of set—metal/steel and Teflon cannula—with your patient.
