Insulin Pump Infusion SetsWhat You Need to Know to Make the Right Choice.
Insulin pumps and how they work.
Before we get into the ins and outs of infusion sets, let’s take a close look at insulin pumps. Insulin Pumps are a delivery system that make it easier for many people living with diabetes to ensure more accurate insulin treatments, which, in turn, makes it easier to maintain targeted blood sugar levels.
Essentially, insulin pumps are small, computerized devices that mimic the way the human pancreas works by delivering minimal doses of short-acting insulin at a prescribed rate as determined by a diabetes physician and care team. Insulin Pumps can also be programmed to deliver calculated amounts of additional insulin at mealtimes, based on glucose levels and carbohydrate intake.
Most insulin pumps are able to integrate wirelessly with glucose meters, and many will work seamlessly with continuous glucose monitoring systems for additional ease. Recent advancements in insulin pump technology also include new “patch pumps”, such as the OmniPod Dash System, capable of delivering insulin through a “pod” that does not require the exterior tubing necessary with traditional pumps (more on this to come).
What is an Infusion Set
An infusion set is the delivery system that transmits the insulin from a traditional insulin pump into the body. Since, most people still rely on traditional insulin pumps, this post focuses on the importance of choosing the right infusion set. These delicate systems come in a variety of models and configurations, and choosing the right one is critical to the comfort and ease with which you will receive your insulin.
Infusion Set Components
There are four primary components of an infusion set and understanding them is key to making the right choice. They are:
Cannula – a minute plastic or metal tube that slips beneath the skin to infuse insulin into the fatty tissue just below the skin’s surface. Cannulas are usually implanted around the stomach area; however, they can also be placed on the thigh, upper arm, hips or buttocks. Which site works best really depends on your infusion set, body type, lifestyle, and personal preferences.
Hub – a plastic unit with adhesive dressing that holds the cannula firmly in place to prevent slipping or disconnection.
Tubing – a flexible tube available in varying lengths that carries the insulin from the pump to the infusion site.
Connector – this is how the tubing connects to the actual pump and insulin reservoir or cartridge.
All traditional infusion sets use these components. But there are some pretty dramatic variances. As we dig deeper into some of these insulin set components, you’ll quickly learn why understanding your options is vital to meeting your insulin needs, while staying as comfortable and carefree as possible.
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Cannula - Fixed or Flexible?
Infusion set cannulas come in two primary forms. A fixed cannula is made of metal. A flexible cannula is made of Teflon. As you can imagine, the fixed variety has little, if any, play in it, while a flexible cannula provides some freedom of motion.
At first blush, you might be wondering why anyone would choose a fixed cannula? There are actually some very good reasons.
- Children - Kids tend to bump and bang around a lot during those active times, and a fixed cannula, while somewhat less comfortable, is also almost impossible to bend. In other words, you can be far more certain that your child’s insulin delivery will not be impeded due to a kinked or bent cannula. This is important because for children even a slight interruption in insulin can have dramatic impacts.
- Allergies - Flexible cannulas are made of materials like Teflon that some people are sensitive to, which is obviously a great reason to go with a metal cannula.
Still, the majority of diabetics who use insulin pumps choose a flexible cannula. They are certainly more comfortable. In fact, once in place, most people hardly notice they are there. The added flexibility makes these cannulas a great choice for active adults who don’t want to feel the uncomfortable tugging that can occur with fixed cannulas.
Angle of Insertion
Infusion sets come in two varieties in terms of the angle in which the cannula is inserted into the skin. Some models feature cannulas that enter straight in at a 90° angle, while others slip in at an angle somewhere between 20° and 45°.
So, what is the difference?
For starters, a 90° cannula means you will need less length to penetrate the subcutaneous tissue. For those with needle phobia, this can be a big advantage. Going straight in also means you use up less surface area when inserting, which means there’s less tissue to heal upon removal. That’s also a nice plus.
So why consider an angled insertion? Because going straight in at 90° also means you’re going in at a specified depth. This can present a problem for people with diabetes who are leaner and have less fatty tissue. Effective insulin delivery is done by infusing just below the skin and before penetrating the muscle tissue beneath it. An angled approach provides far greater wiggle room to find that sweet spot, particularly in athletes and others who have minimal fatty tissue.
Yes, cannulas come in various lengths ranging from 6mm on the short end to 13mm on the longer end. Being that the goal is to infuse just below the skin, choosing the ideal length depends on the angle of insertion and how much subcutaneous fatty tissue an individual has before meeting the muscle layer.
As a general rule, for most adults and kids the shorter lengths are perfectly effective and will provide a more comfortable experience. However, for those who have higher a Body Mass Index (BMI), it may be necessary to go with a longer cannula.
Much of the decision also hinges on personal preference and comfort level, as well as the recommendations of doctors and care teams.
Some infusion sets using spring-loaded, one-touch insertion devices, while others require you to manually insert the cannula. Once again, what works best is really a matter personal preference.
A younger person who wants control over the speed and force of insertion might prefer the manual method. Additionally, this method results in less “garbage”, so those who are interested in reducing their environmental footprint might also prefer putting things in their own hands.
Individuals who have lost some dexterity, as well as those suffering from arthritis or other conditions impacting motor control, will likely prefer the worry-free ease of using an insertion device. Of course, this also holds true for anyone with needle phobia. If the thought of giving yourself a shot gets you a little queasy - go with automatic insertion. You won’t be alone. Most people lean this way these days, if nothing else, for the ease and convenience.
The good news here is that most infusion set manufacturers offer a variety of tubing lengths with their infusion sets. What is the proper length for you? That’s something you’ll have to determine for yourself. Some factors that will likely help you decide include:
- Insertion site - stomach, arm, thigh, buttock
- Bathroom routine (long enough to be comfortable, not so long as to be inhibiting)
- Snags – you don’t want to get snagged on doorknobs, etc.
- Daily routine - do you sit at a desk all day or does your job require a lot of movement?
You just might have to experiment with a few lengths before you get it right. But that’s okay, this is an easy adjustment.
The most comfortable area to insert an infusion set tends to be the abdomen, which coincidentally also has a very consistent insulin absorption rate. For these reasons, the stomach is where most people place their cannulas.
However, as pointed out earlier, the thighs, arms and buttocks can also be used, though, the arms usually have a much slower insulin absorption rate, and this is an important fact to consider before choosing it as an insertion site.
A few other general considerations include:
– Avoid areas that have scar tissue
– Avoid areas that might be covered with tight clothing
– Avoid areas with tattoos or body piercings
– Stay at least two inches away from the naval
– Keep all insertion equipment stored in manufacturer’s packing until use
– Clean insertion sites with soap and water to prevent infection
Many insulin pumps feature a universal connector called a Luer-lock, which is compatible with any infusion set that uses the same mechanism.
Some top insulin pump manufacturers, however, such as Medtronic, have chosen to develop propriety infusion set connectors designed to exclusively optimize their own insulin pumps. It’s important to note that if you go with one of these companies, you’ll need to use one of the insulin sets carefully designed and calibrated for their pumps. However, this shouldn’t pose a problem as Medtronic and other manufacturers offer a wide range of infusion set choices based on cannula type and length, insertion method, tubing length, etc. If the pump works for you, rest assured, you’ll be able to find the right infusion set to go with it.
Hopefully, you now know a little more about infusion sets and the different factors to consider when deciding on the one that’s right for you. However, we’d be remiss if we didn’t say that there’s a lot more to learn than you’ll find in this or any other blog. As always, your diabetes physician and care team are the foremost sources for information and insight into what your individual diabetes care plan should include and what it should not. Always consult with your doctor before making any decisions regarding your diabetes treatment regimen.
For a great selection of diabetes care and treatment products, we invite you to shop at diabeticwarehouse.org.
Diabetic Warehouse is a trusted supplier of diabetes care products and accessories. For more information and to explore a complete range of products, including test strips, syringes and needles, glucose monitoring systems, and more, visit www.diabeticwarehouse.org.