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. Some patients use both types of sets and alternate depending on their activity.
Infusion set tubing comes in lengths ranging from 18 to 43 inches, depending on the manufacturer and the set. Manufacturers usually offer two or three tubing length options. Some manufacturers offer both clear and colored tubing. The colored tubing may help make it easier for the patient to view the insulin flow and detect air bubbles, which, if large (extending several inches), can account for non-delivery of insulin resulting in unexpected hyperglycemia.
Patients choose tubing length depending on their physical activity, sleeping habits, and clothing. For example, restless sleepers and people who wear their pump in their sock need longer tubing; those who wear the pump at their waist may prefer shorter tubing. Longer tubing may prevent dislodgment of the infusion set when using the bathroom (toilet) while the pump is attached to or in the pockets of pants that have been lowered to the floor. Any excess tubing can be easily tucked into the patient’s clothing and kept out of sight and there are companies that make devices that roll up tubing.
Additionally, some infusion sets allow tubing to be “directed,” i.e., the tubing position on the base can be changed, depending on the direction preferred by the user (right, left, upward, downward). Tying the tubing in knots does not impede the delivery of insulin, as the tubing is co-extruded (i.e., it has an inner small-diameter tube inside an outer tube). Advise the patient that if s/he would like to try different infusion sets or tubing lengths, their next order can include other available options offered by their pump manufacturer. The same is true for infusion set dressings, as some patients may experience an allergic skin reaction to the self-adhesive tape and may need to try another brand.
Customer Service and Other Practical Considerations
The pump manufacturer sales personnel should explain the start-to-finish process to both the potential pump user and to his or her healthcare professional or team. The pump patient must be confident that technical support and assistance are available 24 hours a day, 7 days a week. All pumps should have the company’s toll-free customer service number displayed on the back of the pump and/or remote device and corresponding communication devices (BG meter, CGM device).
Another consideration is the procedure for ordering supplies. The pump wearer should know what types of infusion sets, accessories, batteries, and specific pump items, such as cartridges/syringes, are needed. Most likely, replacement supplies are obtained by mail order from the pump manufacturer or pump supplier as contracted by the patient’s insurance company. Rarely are pump supplies available through a local pharmacy. Some manufacturers or supply companies offer to send the patient supplies routinely and automatically. What role does the manufacturer play in verifying insurance coverage for supplies?
On average, the price of an insulin pump ranges between $6,000 and $8,000, and most come with a 4-year warranty. Some pumps may cost less, as they may have disposable components, thus, less costly “hardware.” Medicare currently allows a pump to be replaced every 5 years (DHHS 2013). Supplies, including batteries, pump cartridges/syringes, infusion sets, skin prep items (and other items such as tape/dressing) can cost in excess of $1,500 each year. Help the patient understand the price of both the pump and supplies. Insurance coverage ranges from 50 to 100%, with most averaging about 80% coverage. Some insurance companies may provide coverage for the pump but not the supplies, or vice versa. Some patients have insurance policies with a high deductible or a low cap, such as $500/year, for durable medical equipment or medical supplies, which may be unfeasible for some patients.
The pump manufacturer should give a detailed cost estimate in writing to the patient and keep in touch with the patient throughout the insurance verification and pump and pump supplies ordering process. Usually, a pump manufacturer insurance specialist handles this process. The patient is required to sign an assignment of benefits document, allowing the pump manufacturer to determine the type and amount of insurance coverage provided. This can take one day to several weeks to process. An insulin pump is a prescription item, and the prescribing physician must provide the prescription and/or an order for an insulin pump and corresponding pump supplies to the patient and/or insurance company. Some insurance companies require a letter of medical necessity from the prescribing physician with additional documentation, which may include:
• Several weeks or months of SMBG records
• Recent A1C levels
• Reasons why an insulin pump may be necessary, e.g., erratic glucose pattern correction, preconception, pregnancy, diabetes complications requiring improvement in control, or lifestyle change
Almost every pump manufacturer has a standard “letter of medical necessity” checklist form. An individualized letter from the healthcare professional is rarely required except in the case of an appeal following a pump coverage rejection.
Some insurance providers may allow only certain contracted brands of insulin pumps. The patient should check with their insurance provider to confirm whether or not this is the case before selecting and ordering a pump. Patients who decide