Insulin Pumps

What is an insulin pump?

An insulin pump is a wearable medical device that supplies a continuous flow of rapid-acting insulin underneath your skin. Most pumps are small, computerized devices that are roughly the size of a juice box or a deck of cards.

Insulin pumps are an alternative to multiple daily injection (MDI) insulin therapy (syringe or pen injections) for people with diabetes who require insulin to manage the condition.

The technology for insulin pumps is rapidly evolving. All pumps available in the United States today integrate with CGM (continuous glucose monitoring) technology and offer the ability to automatically adjust your insulin needs based on your current glucose levels.

How does an insulin pump work?

An insulin pump mimics how your pancreas would naturally release insulin. It delivers insulin in one of two ways:

• Small and continuous insulin doses: This is called basal insulin. You’ll likely have multiple basal rates in certain hour increments throughout the day. This is because your body requires different amounts of background insulin throughout a 24-hour period. For example, most people tend to require more background insulin in the morning hours than the evening hours due to natural morning surges in cortisol, which raises your blood sugar. You’ll need to change these basal rates over time as your body and routines change. You’ll work with your healthcare provider to adjust them as needed. All pumps have the ability to automatically adjust basal doses based on your glucose levels from a connected CGM. Most pumps also have a manual setting that allows the pump to deliver basal rates programmed by the user and their healthcare provider.
• Manual surges of insulin when eating and to correct high blood sugar: This is called a bolus. The pump uses the information you enter about your carbohydrate intake and blood sugar level to calculate how much bolus insulin you need. Most pumps recommend a dose to you, which you then confirm or adjust before they deliver the insulin.

Each type and brand of pump has various settings and technology. Examples include:

• Integration with CGM technology to automatically increase, decrease or stop insulin release based on your glucose level.
• Options to manually increase or decrease your basal rate for a certain amount of time.
• Alarms to alert you of a low battery or low reservoir, for example.
• Alarms to alert you if your glucose level is out of range if your CGM communicates with your pump.
• Connectivity to phone apps and other smart devices.

Types of insulin pumps

There are two main types of insulin pumps: those with tubing and those without tubing.

Tubed insulin pumps

As its name suggests, a tubed (tethered) insulin pump has a long, thin tube that connects the pump itself to a cannula under your skin to deliver insulin. Parts of a tubed insulin pump include:

• The pump machine and technology: The pump is made of durable plastic and metal. It has a screen for viewing and selecting different settings and data. Along with the pump technology, it contains a cartridge (reservoir) of insulin. It may have a replaceable or rechargeable battery depending on the brand. The maximum amount of insulin a reservoir can hold varies based on the pump type. But you fill it up based on how much insulin you typically need over two to three days. You can keep the pump in a pocket or clip it to your pants or other clothing items.
• The tubing and infusion set: The tubing (which is several inches long) connects the reservoir of insulin in the pump to an infusion set on your skin. The infusion set sticks to your skin with adhesive and has a smaller, flexible plastic tube (cannula) that goes underneath your skin. The cannula is a few millimeters long. You insert the infusion site manually or with an injecting device. The set has a needle that runs through the cannula so it can pierce your skin during insertion. You then remove the needle so only the cannula remains. You can insert the infusion set on your upper arm, belly, hip, buttock or thigh.

You should change most reservoirs and infusion sets every two to three days. You must change your reservoir if it runs out of insulin. You use new infusion sets, reservoirs and tubing every time. But the pump itself typically lasts for multiple years.

While some tubed insulin pumps are waterproof, people typically disconnect them from the infusion site when they take a shower, bathe or swim. You can then reconnect the pump and tubing to the infusion site afterward. Some tubed pumps are just water resistant, not waterproof.

Tubeless insulin pump

Tubeless insulin pumps (patch pumps) also use a flexible plastic tube (cannula) under your skin. But the insulin reservoir and the cannula are part of one “pod” that sits on your skin with an adhesive patch. There’s no external tubing. You then operate the pump wirelessly with a handheld controller.

You use each pump — or pod — one time. Like a tubed pump, you change it every two to three days and must change it if the reservoir runs out of insulin.

Before attaching the pod, you fill the reservoir with insulin and attach the adhesive to your skin. You then push a button that releases a needle that’s threaded through the cannula in the pod. The needle retracts back into the pod, and the cannula remains under your skin. You can wear the pump on your upper arm, belly, hip, buttock or thigh.

Tubeless insulin pumps are waterproof, so you can bathe and swim with them on.

Brands of insulin pumps

Brands of insulin pumps currently on the market in the United States include:

• iLet® Bionic Pancreas System (tubed pump).
• Medtronic MiniMed™ (multiple tubed pumps).
• Omnipod® (multiple tubeless pumps).
• Tandem® t:slim (multiple tubed pumps).

Another tubeless pump, the Accu-Chek® Solo Micropump System, is only available in the United Kingdom but is awaiting U.S. FDA approval.

Who uses insulin pumps?

Anybody with diabetes who requires synthetic insulin may use an insulin pump. This includes people with Type 1 diabetes — both children and adults — and some people with Type 2 diabetes. People with Type 3c diabetes or monogenic diabetes may use a pump, as well.

Each insulin pump has different Food and Drug Administration (FDA) approvals regarding how old you can be to use it. Some insulin pumps have approval for children as young as 2. Most other pumps have approval for people 7 years and older.

Insulin pumps are one insulin therapy option for diabetes management — they’re a personal choice. You may want to use an insulin pump if you (or your child):

• Find it challenging to reach your target blood sugar range with multiple daily injections (MDI).
• Want more flexibility and precision in dosing insulin.
• Have unpredictable schedules and/or eating habits.
• Require small doses of insulin. This typically applies to toddlers and children with diabetes.
• Have gastroparesis (experience delays in food absorption).
• Experience dawn phenomenon.
• Are preparing for pregnancy.

Who shouldn’t use an insulin pump?

Insulin pumps aren’t the best option for everyone — for a variety of reasons. Some things that may not make you or your child an ideal candidate for an insulin pump include:

• Issues with manual dexterity: You’ll need to use your hands and fingers to load or fill an insulin reservoir and press buttons on the pump. If you have poor dexterity, like from hand arthritis or neuropathy, it may be challenging to use a pump.
• Blindness and low vision: If you have blindness or low vision, you may have limited options with pump technology. You’ll need to consider the available pump features, like screen size, screen contrast, letter and number size and backlighting.
• Issues keeping the pump attached: If you or your child has sensory challenges, for example, or severe skin allergies, a pump may not be best since it must be attached to you at almost all times.

What are the benefits of insulin pumps?

Compared to multiple daily injections, the benefits of an insulin pump include:

• Adjustable insulin delivery (in some pumps) with a variety of settings for different meal types and exercise. This allows more fine-tuning with insulin dosing.
• The ability to merge insulin delivery with CGM technology.
• Access to downloadable data, which can help you and your endocrinologist adjust your management strategy.
• Improved blood sugar levels. Studies of adults and children show that those who use long-term pump therapy maintain significantly better blood sugar management than MDI users.
• Many people who switch from MDI to an insulin pump note an improvement in their quality of life.
• Fewer insulin injections.

Most endocrinologists and diabetes specialists encourage the use of insulin pumps due to their evidence-based benefits.

What are the disadvantages of insulin pumps?

A significant disadvantage of insulin pumps — compared to multiple daily injections — is insulin delivery issues. These can happen for a variety of reasons, including:

• Bent or kinked cannulas: Body tissue under your skin, force or pressure can bend or kink a cannula. This can block the flow of insulin into your body.
• Insulin crystallization: After two to three days, insulin can crystallize — or form fibrils — in the cannula or tubing, which can prevent you from getting the full amount of insulin. This is why it’s important to change most infusion sets or tubeless pumps every two to three days.
• The infusion set becomes disconnected from the tubing: If you have a tubed pump, the tubing can become disconnected from the infusion site without you knowing. The insulin leaks out of the tubing instead of going into your body.
• Inflammation or blood pooling (hematoma) at infusion site: A lot of inflammation or a pool of blood near your cannula can prevent insulin from getting where it needs to go in your body.
• Torn or kinked tubing: Pump tubing can become kinked (like from knots) or torn (for example, your pet might chew through the tubing). This prevents insulin from getting to your body.
• Adhesive issues: Infusion sites and tubeless pumps stick to your skin with adhesives, which makes it possible for them to rip or peel off accidentally or prematurely. You can apply additional adhesives to help prevent this from happening.
• Pump failure: Although it’s rare, your insulin pump can break or malfunction. It could also run out of battery charge.

In some cases, your insulin pump will recognize that there’s a blockage (occlusion) and will alert you to change the pump or infusion set. In other cases, like if your set becomes disconnected from the tubing, the pump can’t recognize the issue. If you use a CGM, you may notice an insulin delivery issue if your glucose level rises for an unexpected reason.

If you go without insulin for a certain amount of time — typically hours — it increases your risk of severe high blood sugar (hyperglycemia) and diabetes-related ketoacidosis (DKA), which is life-threatening.

Because of insulin delivery issues, it’s important to always have a backup plan if you use a pump and act fast. This may look like:

• Carrying insulin and extra pump supplies with you when you’re away from your house.
• Having injectable insulin and syringes or an insulin pen handy.
• Having your pump manufacturer’s customer service number handy so you can get help fast if you have technological issues.

To try to prevent these issues or catch them early, get in the habit of checking your pump and/or infusion set at least once a day. It’s also important to monitor your blood sugar levels regularly.

Other disadvantages

Other factors that you might see as disadvantages of insulin pumps include:

• Cost: Insulin pumps and the supplies they require can be expensive compared to MDI insulin therapy. Cost varies based on your healthcare insurance plan.
• It’s always attached to your body: All pumps are an extra piece of hardware attached to your body. There are many clever and discreet ways to wear pumps, but it can take time to get used to.
• The amount of supplies: Compared to MDI, insulin pumps require more supplies — more “stuff.” This can take up storage space in your living space and require you to pack extra bags for trips, especially long ones.
• Issues with adhesives: Some people experience allergic reactions to skin adhesives that insulin pumps and infusion sets use.

What should I consider when choosing an insulin pump?

There are countless factors to consider when choosing an insulin pump. And it’s a big decision. The good news is that pump manufacturers have lots of information on their pumps as well as trainers that can answer your questions. Your diabetes healthcare provider can also be a great resource.

Some things to consider and ask when choosing a pump include:

• Do you want a tubed or tubeless pump? What are the pros and cons of each?
• What’s the weight, size and look of the pump?
• Which pumps — and pump supplies — does your healthcare insurance cover? What will the estimated yearly cost be?
• What type of customer service does the pump manufacturer offer?
• What will the training be like?
• What compatibilities does the pump have with CGM technology?
• How frequently can you upgrade to a newer pump?
• Is it waterproof or watertight?
• What type of insulin delivery settings and programs does it have?
• What types of alarms and alerts does it have? Does it make sounds and/or vibrate?
• Are you able to read the pump screens?
• What smart devices can it connect to?
• How easy (intuitive) is it to use?
• What kind of software programs does it have for downloadable data you can share with your provider?