Managing Diabetes with Insulin Pumps

Managing Diabetes with Insulin Pumps

Editor’s Note: Laurie Elmes Jenkins, PharmD, CDE, BC-ADM is a clinical pharmacist at Dell Seton Medical Center at the University of Texas. She has specialized in diabetes education and management for more than 25 years in both inpatient and outpatient settings. Her passion is patient education and insulin pump training/management.

So how lucky are we that she’s willing to share her insulin brain with us?! She’s previously written this gem of a post on U-500 insulin, and now she’s back to teach us about insulin pumps. (No lie, I can honestly say I’ve learned about insulin pumps while editing this post than from any prior experiences.)

Be forewarned - it’s a pretty comprehensive post. So grab a coffee and get cozy or bookmark this page and come back to it if need be.

Also, we made a diabetes cheat sheet that will make you a rockstar on the NAPLEX or on your upcoming APPE rotation, so don’t forget to check that out.


Time to (insulin) pump up the knowledge!

 Pumping up insulin pump knowledge…get it?  (Image)

Pumping up insulin pump knowledge…get it? (Image)

Diabetes is a chronic illness requiring a lot of daily management: 

  • Blood glucose (BG) checks

  • Counting carbohydrates

  • Preparing for hypoglycemia

  • Taking medication

  • Checking feet

  • Exercising regularly

It can be overwhelming! Not to mention taking insulin adds yet another layer of complexity to the daily regimen.  Luckily, diabetes tools, devices, phone and tablet apps, and the continuing growth of new insulin formulations can make managing diabetes a bit easier. 

Many people using insulin will take multiple daily injections (MDI) of insulin to maintain tight BG control.  MDI involves using a long acting insulin (aka a basal insulin) once or twice a day plus a rapid acting insulin with meals. 

Yes, you did the math right.

If a patient eats 3 meals a day, MDI means a minimum of 4 subcutaneous injections every day. At a minimum. This can be very time intensive (and uncomfortable) for even the most organized person! 

A popular tool for managing insulin without having to use the MDI strategy is an insulin pump. These are also referred to as Continuous Subcutaneous Insulin Infusions, or CSII. 

Chances are you heard about insulin pumps briefly in pharmacy school, or you may even have a friend or relative using an insulin pump to manage their diabetes. In 2015, the American Diabetes Association estimated that roughly 1 million people worldwide were using an insulin pump to manage diabetes.

To meet this demand in the US, there are currently 4 insulin pump companies and 8 insulin pump models on the market. I’ve listed them here below:

 1. Insulet Corp:  Omnipod   (Image)

1. Insulet Corp: Omnipod (Image)

 2. Medtronic Diabetes:  MiniMed 530G system, MiniMed 630G system, MiniMed 670G system, and MiniMed Paradigm Revel.  This is the MiniMed 670G.  (Image)

2. Medtronic Diabetes: MiniMed 530G system, MiniMed 630G system, MiniMed 670G system, and MiniMed Paradigm Revel. This is the MiniMed 670G. (Image)

 3. Tandem Diabetes Care:  T:flex pump  and  T:slim X2 pump.  This is the T:slim X2.  (Image)

3. Tandem Diabetes Care: T:flex pump and T:slim X2 pump. This is the T:slim X2. (Image)

 4. Sooil Development:  Dana Diabecare IIS.  This is the Dana Diabecare IIS.  (Image)

4. Sooil Development: Dana Diabecare IIS. This is the Dana Diabecare IIS. (Image)

The goal of this post is to provide some basic information so you can interact with your insulin pump patients in a knowledgeable way.

For the record, you probably won’t quite be ready to help a patient transition to a pump after reading this article. That’s a rabbit hole we just don’t have time to get into today.

That being said, you will at least be able to have an intelligent conversation with a pump wearer at your pharmacy. So #win!

For on-going support and help with complex scenarios like this, it’s a good idea to find out who your local Certified Diabetes Educators (CDEs) are and how to refer your patients to them. Some of the insulin pump companies will even partner with CDEs to become pump/product trainers. 

So now that you've gotten your toes wet, let’s start by dispelling some myths and provide some truths about CSII. 

Myth or Truth #1: An insulin pump is surgically implanted.

MYTH!

Insulin pumps are worn externally and most are smaller than a smartphone. Just a bit thicker.

Insulin is loaded into a special syringe called a reservoir and then placed inside the pump. The insulin in the reservoir maintains potency for up to 72 hours. 

“Wait!” you exclaim. “I thought insulin was good for 28 days out of the fridge?!?”

Consider the insulin pump’s neighborhood. It’s like living next to Mordor. The body’s constant 98.6 degrees takes its toll on insulin’s potency much more so than if the insulin lived next to the Shire. Or Rivendell.

But I digress.

 Examples of infusion sets  (Image)

Examples of infusion sets (Image)

Ok. So the pump’s filled reservoir is then connected to an infusion set using a luer lock attachment. This infusion set includes tubing of various lengths and a subcutaneous insertion site with a (usually plastic) cannula.

It’s important to note that there are several different infusion sets on the market and not all are compatible with every pump. 

The cannula is a thin flexible tube ranging from 6-9 mm long that gets the insulin from the reservoir into the patient. Think of it like a flexible needle. This cannula is available in a 90 degree insertion angle or a 20-45 degree insertion angle, but the most commonly used cannula is the 90 degree angle. 

Most infusion sets also have a special insertion device to assist with placement and minimize insertion discomfort.  Some actually have a built-in insertion device. 

Now that we have all the components attached… The tubing has to be primed with insulin, meaning insulin is advanced from the reservoir through the tubing to remove any air bubbles. The cannula is then inserted into the skin, and insulin is further advanced to fill the cannula (aka priming the cannula).

The pump is now ready to go!

To recap: insulin in reservoir —> reservoir in pump —> pump connected to infusion set —> tubing of infusion set primed —> cannula inserted under skin —> cannula filled —> voila! insulin flow can begin!

 It’s the ciiiiircle of (insulin pump) life! Sing with me!! Or don't, that’s cool. I guess.  (Image)

It’s the ciiiiircle of (insulin pump) life! Sing with me!! Or don't, that’s cool. I guess. (Image)

Anyways, every time a new infusion set and cannula are placed, they must be primed and filled, respectively. Infusion sets and cannula sites are exchanged and rotated a minimum of every 72 hours to prevent infection, irritation, and scarring.

There’s also the possibility that the cannula can malfunction. Since the cannula is thin and flexible, it can easily crimp if inserted incorrectly or inserted too close to muscle.  If the cannula becomes crimped, insulin flow may slow or even stop!

This can lead to hyperglycemia pretty quickly and the potential for diabetes ketoacidosis (DKA), especially in type 1 diabetes patients who have very little or no insulin production. 

  • Quick Review: DKA is a serious condition that can lead to coma or even death if left untreated.  It’s most common in people with type 1 diabetes but can also develop in people with type 2 diabetes. DKA occurs when the body’s cells cannot get the glucose they need for energy, and the body burns muscle and fat instead for energy. There may be plenty of glucose in the bloodstream…but not enough insulin to convert the glucose for use in the cells. When the body burns these alternative energy sources, ketones are produced. Ketones are acids that can build up in the blood and poison the body, leading to metabolic acidosis.  

To help prevent this serious complication, an alternative to the plastic cannula is an infusion set with a stainless steel needle. A very thin person or child may prefer this more durable steel needle to help it stay inserted correctly. It’s all about comfort and functionality. But the infusion set with a stainless steel needle would need to be inserted manually rather than with the aid of the aforementioned insertion devices.  

 Red infusion sites are preferred. Teal sites are alternatives.  (Image)

Red infusion sites are preferred. Teal sites are alternatives. (Image)

Patients can wear infusion sets on any subcutaneous site on the body, but the abdomen is preferred for best absorption. The outer thighs, upper arms, hips, and buttocks are alternate locations. 

Pump accessories, carrying cases, and clips are available for the waist, leg, and bra. Ladies can be especially creative in hiding the pump in order to wear that little black dress! But tubing can still get in the way of fashion, everyday activities, and sports.  This is where the ‘tubeless’ pump has the advantage.

The ‘tubeless’ insulin management system (e.g., Omnipod) means that there is no tubing going from the pump to the patient. It is a disposable plastic pod-type device that is filled with insulin prior to use and held to the skin with an adhesive backing. 

 Left: classic insulin pump with infusion set and tubing; Right: tubeless insulin pump.  (Image)

Left: classic insulin pump with infusion set and tubing; Right: tubeless insulin pump. (Image)

The Omnipod contains its own insertion needle that retracts into the pod after the plastic cannula is placed under the skin. It also comes with a handheld Personal Diabetes Manager that communicates wirelessly with the pod.

This type of insulin pump provides freedom from tubing and is popular with kids and athletes. Mom or Dad can adjust the basal rate or bolus from afar without interrupting snack time and without giving an injection by syringe. Then, when the pod is empty, patients can remove and toss it.

This tubeless system seems like the perfect answer, right?

Unfortunately for some, the thickness of the pod is undesirable. Also, patients or caregivers must always have the Personal Diabetes Manager on hand to make changes in the insulin delivery.

How many times have you panicked because you couldn’t find your cell phone?! Let alone your Personal Diabetes Manager…

Myth or Truth #2: An insulin pump is only for people with type 1 diabetes.

MYTH!

An insulin pump is a specialized delivery method for insulin. So technically it can be used by people with either type 1 or type 2 diabetes as long as they require insulin. It’s most appropriate for those using MDI.

That being said, the majority of people using an insulin pump do have type 1 diabetes.

Successful use of an insulin pump depends on whether the patient is a good candidate for a pump and whether insurance will cover the pump and supplies.

So what makes someone a good pump candidate?

There are guidelines that help physicians, CDEs, pump trainers, and patients determine if an insulin pump is the right tool for managing a particular person’s diabetes. Determining this up front is critical for patient safety and success. Pump patients should be…

  • Self-monitoring BG at least 4 times a day

  • Motivated and knowledgeable in diabetes self-care

  • Realistic about what the pump will do for them—and understand it’s not a way to cure diabetes or forget about self-care

  • Able to learn and practice carbohydrate counting, insulin adjustment, and button pushing

  • Connected with a good support team including physician, diabetes educator, and pump trainer

  • (For kids) have a parent or guardian who is willing to assist with pump management

  • Financially able to maintain insulin pump therapy. Initial costs vary from $5000-$8000 to purchase just the pump alone. Then there’s the monthly cost of supplies (~$160) and insulin to be used with the pump.

Whew! So who on earth can afford insulin pumps?!

 Kevin can’t believe the price of insulin pumps either.  (Image)

Kevin can’t believe the price of insulin pumps either. (Image)

As of this post, Medicare is covering insulin pumps for people with type 1 and type 2 diabetes who qualify based on specific lab parameters (low C-peptide, fasting blood glucose, and positive beta-cell antibody test).

Interestingly, if a pump is covered by Medicare, the insulin will be covered as part of the ‘supplies’ for the pump, meaning it will be processed through part B rather than part D. 

But that’s a whole lot of stuff we don’t need to get into right now. If you want to read more on Medicare coverage for insulin pumps, check this out.


Myth or Truth #3: Any type of insulin can be used in an insulin pump.

MYTH!

Back in the day when insulin pumps first became available to the general public, the insulin of choice was Humulin R U-100. Simply because that was the only short acting insulin available.

When insulin analogs became available, they proved to be better options for pumps. Currently, insulin lispro (Humalog U-100), insulin aspart (Novolog U-100), and insulin glulisine (Apidra U-100) are approved for use in insulin pumps.  

  • Note: U-100 means the concentration of insulin is 100 units/ml.  Some people with insulin resistance who take doses exceeding 200 units/day may use Humulin R U-500 (concentration = 500 units/ml) in the pump. BUT U-500 is NOT FDA approved for use in pumps. All insulin pumps are currently manufactured and programmed to use U-100 insulin.

Myth or Truth #4: Using an insulin pump means that your diabetes is really bad.

MYTH!

Any chronic disease that is not managed well can produce outcomes that are ‘really bad’. Some folks with diabetes respond well to oral diabetes meds, non-insulin injectable diabetes meds, or combo therapy.

Others need insulin to maintain BG control and health. The delivery device (i.e., the insulin pump) is just a tool that can be used by some folks to make managing diabetes a bit easier.

Editor’s Note: All of this insulin talk making your head spin in circles? We made a handy diabetes cheat sheet that gives you the breakdown of all insulins (and oral drugs) used in diabetes treatment. Check it out here:

Myth or Truth #5: Once the settings are programmed in the pump, there is no further need to push buttons.

MYTH!

Insulin pumps are like small computers. They deliver insulin doses in 2 ways.

  • The first way is via basal insulin (also called ‘background’ insulin). This insulin is delivered continuously until the pump is paused or the dosage is changed. Some pumps can deliver as little as 0.025 units/hr, and some can go up to a max of 35 units/hr!

    The basal dose is individualized based on what the patient required before the pump modality was initiated, or it can be based on weight. Most pumps allow for programming of up to 48 different basal rates! (Talk about customizing your insulin plan and keeping track of dose changes!)

    Of course, 48 different basal rates may be a wee bit overkill, but it’s good to have options. In reality, even though pumps can essentially adjust to a different rate every 30 minutes, most pump trainers and physicians will start a patient out with 1-2 basal rates per day and adjust as needed. 

    Here’s an example of how a basal rate would be calculated when converting from insulin injections to the pump:

    Let’s say a patient takes a combined total daily dose (TDD) of 80 units of insulin a day (i.e., Lantus 50 units + Humalog 30 units). Before going any further, this TDD is typically reduced by 20 to 25% to account for better medication absorption with the pump compared to MDI.

    So to find the new TDD, 80% or 0.8 of 80 units = 64 units. Therefore, the new working TDD is 64 units.

    Then this new TDD is halved. One half will constitute the basal rate, which will be administered over 24 hours.

    So 50% or 0.5 of 64 units = 32 units. This 24 hour basal dose is then divided by 24, which yields a basal rate of 1.3 units/hr.

    Hold on for a few minutes to learn about the other 50% of the TDD (ooo…bolus doses!).

    • Temp basal insulin: Most pumps have a function that allows patients to put in a temporary basal rate. This is a basal rate that supercedes the programmed rate(s) for a chosen period of time. This temporary rate can run for a maximum of 24 hours before the pump reverts to the original programming. It can be entered as a flat number of units/hr, or it can be set as a percentage of the normal setting.

This temp basal allows patients to make temporary adjustments for things like exercise or illness without changing their regular settings.

So when might this temp basal setting be useful?

Let’s say a patient is running a 5K today. Being a knowledgeable diabetic patient, he knows that his usual basal insulin rates will likely be a little too high because running lowers his blood glucose. That is, he will need less insulin during activity. So he decides to set a temp basal rate to run for 5 hours instead of his normal settings. He determines he will only need ½ of his regular basal during this time, so his temp basal insulin is set at 50%. Once the preset 5 hour time period is up, the pump will revert to his regular basal rate settings.

  • Suspend function: Suspending the pump stops all insulin delivery. This function is useful when disconnecting for showers, water activities, or intimacy. It is also used when changing out infusion sets. When in the suspend mode, the pump periodically alarms to remind patients there is no insulin delivery.

 Good luck measuring 0.025 units on this baby.  (Image)

Good luck measuring 0.025 units on this baby. (Image)

  • The second way an insulin pump can deliver insulin is through a bolus dose. Patients use insulin bolus doses when they eat (mealtime bolus) and/or when their blood glucose is above the target range (correction bolus). The program range for a bolus is 0.025 to 60 units. Bolus doses are just like taking injections of rapid acting insulin except they are administered via the pump.

    And really, could YOU measure 0.025 units accurately on a syringe?!

    So let’s look at these bolus doses in a little more detail…

    • A mealtime bolus is just what it sounds like—it’s the amount of insulin that matches the carbohydrates that a patient plans to eat for that meal. Insulin pump patients learn how to count carbohydrates, and the trainer or physician calculates a carb-to-insulin ratio (CIR) to figure out how to bolus for food.

      For example, a patient’s CIR is 15. That means 1 unit of insulin covers 15 grams of carbohydrates. She plans to have a lunch consisting of 60 grams of carbohydrates. Therefore, she would require 4 units of insulin to ‘match’ the carbohydrates in the meal and keep her glucose in target range.

      Most pumps allow for setting several CIRs throughout the day. A patient may find that they need less insulin for breakfast than for supper, which means that the CIR for breakfast will be higher than the CIR for supper.

      Of note, bolus doses via the pump are not automatically infused like the basal rate(s). The total bolus dose is delivered immediately after a patient presses the ‘activate’ button.

    • Another type of bolus is called a correction bolus. This is administered when the blood glucose is above the target range and no meal is planned. The correction bolus dose is determined by a patient’s sensitivity to insulin. The insulin sensitivity factor (ISF) describes the decrease in blood glucose achieved by 1 unit of insulin.

      The ISF is initially calculated using 1700-1800 divided by TDD.

      For example, for our patient with the TDD of 64 units, 1800 divided by 64 = 28.1. This means that 1 unit of insulin will lower his blood glucose approximately 28 mg/dl. In this example, if his blood glucose between lunch and supper is 224 mg/dl and his goal is 140 mg/dl, he would need to take 3 units to lower his glucose by 84 mg/dl. (That is, 224-140 = 84; 84/28 = 3 units).

      Of course, it never works out this cleanly! So that’s why the pump is very helpful and can deliver doses to hundredths of a unit if needed.

      Two factors that also play into the correction bolus calculation are the blood glucose target (individualized) and active insulin. Hold that thought on active insulin for a moment…

  • Pumps also offer 2 advanced special types of bolus features that can be very helpful. Let’s stress advanced because a new insulin pump patient would not start with these options. The 2 special types of boluses are as follows:

    • A square wave bolus delivers a calculated bolus over a certain period of time (rather than being all at once like a regular bolus).

    • The dual-wave bolus delivers a portion of the bolus immediately and the remainder of the bolus over a specified period of time.

    • These specialized bolus doses come in handy particularly for foods like pizza and Chinese food. Foods high in fat like these take longer to digest. If a patient does a regular immediate mealtime bolus, the food may still be digesting and raising BG long after the insulin has already been metabolized. This can lead to hypoglycemia on the front end of the meal and hyperglycemia on the tail end of the meal.

      • For example, a patient has a CIR of 5 (remember: that’s 5 grams of carbohydrates to 1 unit of insulin). He determines that his pizza meal will be about 75 grams of carbs, so he needs a bolus of 15 units to cover it. But since it’s a high fat meal, he decides to administer those 15 units using a square wave bolus over 2 hours.

      • Let’s take that same example and now make it a dual-wave bolus. Let’s say that same patient would like to administer 25% of his pizza meal bolus immediately and then the remaining 75% over 2 hours. He programs the pump to deliver 3.75 units (25% of 15 units) now and the remainder of the bolus (11.25 units) over 2 hours.

  • Patients with gastroparesis may also use these specialized bolus doses if they have delayed gastric emptying.

Myth or Truth #6:  There is a higher risk of hypoglycemia with insulin pump therapy.  

Possibly…

Insulin pumps allow patients and providers to ‘fine tune’ insulin therapy - all the way down to hundredths of a unit!  However, fine tuning insulin can also lead to hypoglycemia until doses are adjusted properly.

Hypoglycemia happens when BG falls below 70 mg/dl.  Some of the warning signs include shaking, sweating, and fast heart beat.

If BG falls below 50 mg/dl, confusion and abnormal behavior can kick in. 

If not treated at all and BG continues to decrease, it can lead to seizures, coma, and even death.  

Scary! So how is hypoglycemia treated so that it does not become so severe?

Treating hypoglycemia requires a minimum of 15 grams of fast-acting carbohydrates. It’s important to note that not all carbs are created equally, and what is used to treat can make a difference. 

 Hypoglycemia Rule of 15.  (Image)

Hypoglycemia Rule of 15. (Image)

Start with 15 grams of carbohydrates in the form of glucose gel or glucose tablets. Most tubes of glucose gel are 15 grams per tube so patients should swallow the contents of 1 tube for a dose.  The glucose tablets are 4-5 grams of carbohydrate each, so it takes 3-4 tablets per treatment to constitute a dose. 

The glucose tabs aren’t small, but they dissolve very quickly and come in a variety of yummy fruit flavors. Glucose tabs are also very convenient to have available at all times.

Since these glucose products contain a measured amount of glucose per dosage form, their use helps to prevent over-treatment of hypoglycemia. On the other hand, using a piece of hard candy does not provide enough carbohydrate and also takes too long to get into the bloodstream. 

Some patients stash a Snickers bar in their supply cases for emergency treatment of hypoglycemia.  Unfortunately, as yummy as they are, candy that contains fat (i.e., chocolate) takes much too long to digest and is not a safe or quick way to treat hypoglycemia. 

After taking a first dose of glucose, the next step is to recheck the BG in 15 minutes. This guides further treatment. If BG is still <70 mg/dl, treatment is repeated as above with another 15 grams of carbs. Some people need to eat a larger snack or meal after the 2nd treatment dose to ensure that their glucose levels don’t continue to fall.  

Once the patient’s BG returns to a safe zone, it is essential to identify why the hypoglycemia occurred in order to prevent future episodes.

Hypoglycemia can be caused by… 

  • Too much insulin

    • Basal rates too high, too many bolus doses too close together (and not using the $7000 calculator to account for active insulin - see below), wrong programming, manual overrides (not trusting the $7000 calculator)

  • Not enough food

    • Counting carbs incorrectly, not including carbohydrate in the meal but still using insulin

  • Physical activity

So what is this ‘active insulin’ we’ve been name dropping, and why is it a big deal?

All pumps now have a calculation built into the programming called ‘active insulin’, ‘insulin on board’, or something similar. This is a calculation that prevents stacking of insulin doses. Stacking of insulin doses means taking doses too close together, potentially causing hypoglycemia. Active insulin tells patients how much of the last bolus dose is still active in the body and still lowering BG. 

Let’s look at an example of how ‘active insulin’ would affect the insulin dose.

A patient eats lunch consisting of 50 grams of carbs and takes the calculated insulin bolus to cover the 50 grams.  Two hours later when he checks his glucose, it’s 260 mg/dl. His 2 hour post prandial BG goal is <140 mg/dl. He decides to take a correction dose of insulin to get back into range.

The pump calculates what his correction bolus should be based on his ISF.  However, since there is still some active insulin in his system, it deducts a percentage of that calculated correction bolus, giving him a smaller dose. If the patient calculated this correction dose without the aid of the pump, he most likely would not factor in the ‘active insulin’, which could result in stacking doses and hypoglycemia.

Pumps are just tools, but when set up correctly, they can improve A1c and make life with diabetes more manageable.  The key is to trust the pump. 

 A  real  reason to have trust issues. Not against the insulin pump.  (Image)

A real reason to have trust issues. Not against the insulin pump. (Image)

One of my very favorite patients was a gentleman in his 70s who was on a pump for 10 years.  He came to the clinic for help with fine tuning his pump settings.  His A1c fluctuated from 7 to 9 during the time we worked together. He experienced multiple episodes of hypoglycemia and had developed hypoglycemia unawareness  (aka he didn’t have any symptoms or warning signs that he was getting low!).  

When it came down to it, the main issue he had was that he never quite trusted his pump to calculate the right dose.  He was constantly adjusting his pump settings. When I say constantly, I mean he adjusted them several times a week!  In addition to multiple setting changes, he manually did the math for his correction dose to ‘double check’ his pump. If he got a different number than the pump, he would override his pump! 

Long story short… Once the pump is set up with the individualized formulas, the person has to trust it. No math is required, but it’s a good idea to understand how the pump is coming up with the doses patients take. When setting changes are made, there’s a specific way to check these changes by testing BG at certain times. Ideally, there should be about 3 days of solid data before making further setting changes.

It’s a lot of detailed work and can be time consuming initially. But once the settings are fine tuned, the BG will come into target range.  This is where having a good pump expert on your team can be beneficial. 

A knowledgeable physician, endocrinologist, CDE, or pump trainer can download the pump data periodically and analyze it with the patient to determine any patterns that need adjustment.  Adjustments are critical to ensuring that patients maximize the pump and stay safe with it. 

Myth or Truth #7: The pump can hold about a week’s worth of insulin.   

MYTH!

A pump’s reservoir capacity varies by manufacturer. The Omnipod Pod holds 200 units, whereas Tandem’s T:flex pump has a 480 unit reservoir. All other pumps have a 300 unit reservoir capacity. 

Patients who are insulin-resistant require larger doses, so it is beneficial to consider Tandem’s product. Kids usually need much less insulin, so the Omnipod or Medtronic products may work best. 

No matter the size of the reservoir, insulin in a pump starts to lose potency after 3 days. The patient fills the reservoir with an estimated 3 day supply plus an extra 20 units to cover priming the tubing. This is calculated by adding up the basal rates and estimating meal insulin plus correction doses. Fortunately, there is a feature on the pump that totals how much insulin was used in the past 24 hours to aid with this calculation. 

Remember that the infusion set also needs to be changed out every 3 days. Keeping the subcutaneous site inserted longer than 3 days can lead to thickening of the skin and reduced insulin absorption. To prevent this from happening prematurely, the number of times patients have to change the reservoir and infusion set should be minimized, which means having a reservoir that holds enough insulin for the maximum 3 days.

Now, having said all that…  Some patients will try to extend beyond the 3 days in order to conserve supplies.  Some patients also keep the same subcutaneous site in place and just change the tubing.  Neither of these is a good idea - for many reasons - including infection risk, loss of insulin potency, thickening/scarring of the infusion site. 

Myth or Truth #8: Your dreams of being an Olympic swimmer or professional athlete will go unrealized when you go on an insulin pump.

Well — guess that depends on your athletic ability!

One of my favorite inspirational stories is about Gary Hall. He was a 3 time Olympic swimmer…and an insulin pump patient.  After winning 2 gold medals at the 1996 Olympic Games in Atlanta, he was diagnosed with type 1 diabetes. It’s been reported that not one but two separate doctors told Gary that his diagnosis would mean the end of his career. And yet, he went on to break the world record in the men’s 50 meter freestyle race in the 2000 Olympics!

 Gary Hall: Type 1 diabetic and swimming BEAST.  (Image)

Gary Hall: Type 1 diabetic and swimming BEAST. (Image)

It was not an easy journey. It involved a lot of trial and error, many, many blood glucose tests, and fine tuning insulin.  He switched between an insulin pump and multiple daily injections depending on his training regimen. Talk about keeping up with details! Now, this Olympic Hall of Fame athlete is quite an advocate for people with diabetes (and he is still on a pump). 

Let’s look at how water activities would play into using an insulin pump…

The pumps with tubing vary from being water tight to water proof at certain depths.  If a patient falls into the pool, he won’t immediately damage that expensive little computer. But he wouldn’t necessarily go scuba diving with it on if it’s only water tight.

That doesn’t mean patients have to give up water activities. Infusion sets are designed with a quick release mechanism that makes it easy to take the pump off for a short period of time. Just remember that the longer patients are disconnected from the pump, the higher the risk of hyperglycemia.

Of note, the Omnipod system is water proof.  Since there is no tubing, it’s an ideal option for active kids and adults who do water activities.

Hot tubs, steam rooms, and saunas are different stories. Patients definitely don’t want to take pumps into these places! The temps are way too high and can not only damage insulin but can cause pumps to malfunction. Instead, patients can disconnect from their pumps and leave them at room temperature while they enjoy the heat.

Wait a minute…patients can be disconnected from their insulin!?!

Most people can be disconnected from the pump for up to 1 hour to allow for water activities, showers, and intimacy. But again, the longer they are disconnected, the more at risk they are for hyperglycemia.

A little side note - here are some other well-known celebs who use insulin pumps:

  1. Jay Cutler - Chicago Bears quarterback

  2. Bret Michaels - lead singer for Poison

  3. Nick Jonas - lead singer for The Jonas Brothers

  4. Mary Tyler Moore - actress

  5. Nicole Johnson - Miss America 1999

Myth or Truth #8:  Insulin pumps have to be replaced every 1-2 years.

MYTH!

Insulin pumps with tubing are considered durable medical equipment (DME).  Most companies warranty their pumps for 4 years.  That means that unless there is a malfunction or recall, the patient can’t upgrade or switch companies for 4 years without paying out-of-pocket (depending on deductibles).  

Speaking of malfunctioning…. While the pump is still in warranty, most pump companies will ship out a replacement pump within 24 hours if a malfunction occurs.  Some companies even have programs that allow you to ‘rent’ an extra pump for extended out-of-country vacations.  Having a back-up pump when you are on safari in Tanzania would be very comforting!

When patients are considering transitioning to insulin pump therapy, it’s best to meet with a CDE and/or insulin pump trainer who can show them several different pump options.  There are pros and cons to each brand, and the decision should be based on the needs and preferences of the patient—not the CDE, pump trainer, or MD.

Myth or Truth #9: Using an insulin pump during periods of illness requires pre-planning.

TRUTH!

Planning ahead for sick days is a critical part of safe insulin pump management.  A few safety tips include the following:

  1. Change the battery on schedule. Don’t wait for it to alarm with low battery. The Tandem products are charged like a phone, so consider keeping a battery back-up on hand for power outages.

  2. Change the infusion set and reservoir every 72 hours, and keep enough supplies for 2-3 weeks. Deliveries may be delayed.

  3. Have pump settings written down and kept handy (e.g., a wallet card) in case of malfunction or unexpected hospital admission.

  4. Have a back-up plan for using MDI in case of a pump malfunction. Also, keep syringes, insulin vials or pens, and pen needles on hand, and check insulin expiration dates periodically. Unopened insulin vials and pens can be kept refrigerated and used until the manufacturer’s expiration date on the box.

  5. Keep medical emergency contact numbers accessible for family.

  6. Always be prepared for hypoglycemia.

  7. Discuss sick day management with the care team ahead of time, and have a written plan to share with family members.

  8. Check insertion site regularly for irritation, bleeding, or leakage.

  9. If BG is abnormally high, take a correction dose of insulin with the pump, and test again in one to two hours. If it remains elevated, take an injection by syringe to correct the high blood glucose, and change out the tubing, reservoir, and site. Keep a close watch to see if this works for future doses.

  10. Keep ketone testing monitor or urine ketone strips on hand for elevated BG (and make sure they are not expired!).

A note about hospital admissions and insulin pumps…

Most hospitals have a policy in place about patients using insulin pumps during a hospital stay. In all honesty, a majority of hospital physicians and nurses are unfamiliar with the intricacies of insulin pump therapy and are of little assistance to the patient. 

As such, hospital policies may state that the patient is allowed to continue to use a home insulin pump during the admission as long as they are able to self-manage. This means that the patient cannot be altered by medications (anesthesia) or illness (stroke, head injury, etc).

Some hospitals also allow family members to be responsible for dose adjustments and tubing/reservoir changes. But the family would need to be present at all times. 

Many policies include a patient ‘contract’ that lists the criteria for safe use while in the hospital. The contracts usually state that the patient has to provide all supplies for the pump. Remind patients about bringing at least 3 extra sets of pump supplies with them for planned hospital admissions if they plan to continue using the insulin pump. This includes bringing tubing, reservoirs, insertion devices, insulin, batteries, charging cord, etc. Hospitals do NOT stock these supplies. 

Also of note, hospitals cannot allow patients to use their own BG meter to determine insulin doses during an admission. Regulatory agencies  dictate specific quality control processes for lab equipment. Since the patient’s own meter does not follow these quality control processes, the data is not supported for care decisions. So the patient’s glucose is checked using the hospital meter.

Then the patient manually enters the glucose value into their home pump to determine the bolus dose. Manually entering the glucose does not change how the pump calculates a bolus dose.  It’s just an extra step for the patient.

Given the complexity and requirements for use, the medical team may opt to have the pump temporarily removed and the patient transitioned to MDI or an IV insulin infusion during the hospital stay. It’s not always ideal for glucose control, but it may be the safest option depending on the status of the patient. 

Myth or Truth #10: Insulin pumps are easy to use and require little training.

TRUTH…and MYTH?

 The car you’ll get after graduation. That is, if you win the lottery.  And  if you learn to drive stick.  (Image)

The car you’ll get after graduation. That is, if you win the lottery. And if you learn to drive stick. (Image)

Just like learning to drive a high end car without burning out the clutch, it takes preparation and training to use this insulin delivery device safely and effectively.  The training is different depending on the patient’s experience. 

Some folks get their pump, read the books, watch the videos, practice button pushing, and are ready to meet with the trainer to get connected with insulin. 

Others do not even open the box until they meet with a trainer, and then they start the process of understanding the theory, calculations, and button pushing. 

Some people choose to have a practice period during which they wear the pump filled with saline instead of insulin. This can build confidence with button pushing and infusion set insertion. 

Medtronic has a great online ‘pump school’ that patients can work through at their own pace. It explains basics about pump therapy and also allows for practice pushing buttons before insulin is ever put into the pump. 

From experience, the people who don’t open the box until they come to the office usually take longer to get connected and pumping. On the other hand, the person who is saavy with devices and has a solid understanding of insulin can be trained in a few hours and be considered safe. Both types of learners can be successful with insulin pump therapy as long as they understand the advantages and disadvantages of insulin pump therapy before embarking on the adventure.

Advantages of an insulin pump:

  1. No more syringes! (except a back-up supply)

  2. Fewer BG swings

  3. Less hypoglycemia

  4. More accurate doses (especially with smaller doses and basal customization)

  5. Often improved A1c (A1c = a blood test that reports the previous 2-3 month average BG)

  6. Easier boluses

  7. More flexibility, especially with eating and exercise

  8. Easier exercise without having to eat large amount of carbs

 Disadvantages of an insulin pump:

  1. Checking BG more frequently (unless using continuous glucose monitoring)

  2. Always connected to a device

  3. Infection risk at the infusion site

  4. Higher risk of high BG and DKA

  5. Weight gain

  6. Cost

  7. Intense initial training

 Myth or Truth #11: You can reduce the number of finger stick glucose tests once you are on a pump.    

  MAYBE…

Some of the coolest diabetes technology on the market now is the continuous glucose monitor (CGM).  These devices use a subcutaneous sensor that measures interstitial BG in real-time. A small electrode called a sensor is placed under the skin and measures interstitial BG every 1-5 minutes. It then transmits the result back to a receiver. The receiver can be a stand-alone receiver, an insulin pump, or an Iphone, Ipad, or Ipod Touch.  

Not all patients on an insulin pump use CGM.  There are 3 stand-alone CGM systems on the market. 

This means that a patient would have 2 insertion sites (one for the pump and one for the CGM sensor) and 2 receivers (the pump and the CGM receiver). That’s a lot of gadgets on the body, but some people prefer this option so they can take a break from CGM when needed (or maybe separate devices are what insurance will cover). When using 2 stand-alone products, patients have 2 sets of data for providers to review because the devices don’t talk to each other.

On the other hand, there are currently 5 combo products on the market. A combo product is an insulin pump and CGM in one unit. The user still needs to have a pump infusion set attached and also a sensor attached at a different site, so there are still 2 insertion sites. But patients only have 1 device instead of 2, and all the data is available in that device and can be downloaded.

One big caveat of CGM is that there is a difference between reading capillary BG (aka finger sticks) and interstitial BG (from a sensor). Because of this difference, the CGM must be calibrated. Calibration of the sensor means doing a finger stick BG and uploading it to the sensor transmitter. 

It’s recommended to calibrate 3-4 times per day initially to improve accuracy of the CGM. So for most people, using a CGM sensor eventually means not checking finger stick BG as much as they were prior to CGM.

Also because of this difference in site readings, patients need to know not to use the sensor glucose result if BG changes rapidly. Some examples of when patients should rely on a finger stick BG instead of a sensor BG are…

  • Suspected hypoglycemia or hyperglycemia

  • When calibrating the sensor

  • After eating

Despite this caveat, CGM has several major benefits, including the following:

  • Fewer finger stick BG checks once calibrated

  • Alerts for lows and highs (particularly helpful when sleeping)

  • Shows the direction that the BG is moving (allowing for earlier notification of lows and highs)

  • Gives info on how food, exercise, stress, meds, etc impact BG

  • Plethora of data to show trends and patterns over time to allow for pump “calculator” customizations

 Your face when you think about how close we are to an artificial pancreas!  (Image)

Your face when you think about how close we are to an artificial pancreas! (Image)

On that note, detail-oriented patients just LOVE all the BG data that is gathered from a CGM because it provides the ability to fine tune insulin management and stay healthy and safe. Providers love it too for the same reason!

So you must be asking yourself…can we not just combine the CGM data with the insulin pump and have them work independently?! Like an artificial pancreas???

Medtronic is the first company to develop a hybrid closed loop system. This is exciting for the diabetes community and especially for those people who struggle with frequent hypoglycemia. It’s not quite an artificial pancreas because it still requires some button pushing, but it’s pretty darn close. What it can do includes…

  • Automatically adjusting the basal insulin delivery every 5 minutes based on CGM results

  • Suspending insulin for up to 2 hours if BG reaches a preset target and patients don’t respond to the preset alarms

  • Automatically restarting insulin when BG levels recover

Too cool, right!?

Even more cool is the progress the University of Virginia has made towards an artificial pancreas system. Check out the research here.

Myth or Truth #12: There is an insulin delivery device alternative to an insulin pump if you don’t want a pump but do want to avoid MDI.

TRUTH!

 Smaller, thinner, and sticky: the V-Go pump patch.  (Image)

Smaller, thinner, and sticky: the V-Go pump patch. (Image)

The V-Go is considered a ‘patch pump’ and is designed for people with type 2 diabetes. It’s a disposable device that sticks to the body with an adhesive backing and delivers a standard preset basal rate for 24 hours. The V-Go comes empty, and it’s filled with insulin using a syringe/vial.

It’s attached to the same locations that patients can place an insulin pump infusion set. After 24 hours, patients remove the V-Go and replace it with another filled V-Go. Patients can also take a bolus dose of insulin with the V-Go, if needed, by pressing 2 buttons. 

There are several benefits to this type of insulin delivery system.

  • There’s no tubing, battery, or mechanical source.

  • It is water proof at a depth of 3’3” for 24 hours. 

  • It has a built-in 4.6mm stainless-steel needle with a 90-degree insertion angle for insulin delivery. (This is a very small, thin needle and is not visible to others.) 

  • The needle even retracts into the V-Go after use to prevent needle sticks.

The disadvantage of the V-Go is that it is pre-programmed to deliver specific doses. For example:

  • V-Go 20: delivers 20 units of basal insulin over 24 hours + has an extra 36 units available to bolus in 2 unit increments over the 24 hours

  • V-Go 30: delivers 30 units of basal insulin over 24 hours + has an extra 36 units available to bolus in 2 unit increments over the 24 hours

  • V-Go 40: delivers 40 units of basal insulin over 24 hours + has an extra 36 units available to bolus in 2 unit increments over the 24 hours

If these basal rates don’t work for a patient, they can’t be adjusted. Major sad face. 

As for the bolus doses, they are delivered in 2 unit increments each time patients push the 2 buttons. That is, if a patient needed a 10 unit bolus, he would have to push the 2 buttons 5 separate times to get the full 10 unit bolus. And if patients use more than 36 units/day for bolus doses, then they have to take the remainder by separate injections.

The V-Go only uses rapid-acting insulins (Novolog, Humalog, and Apidra). Also unfortunately, the V-Go does not download to a device and does not connect with any meters or CGMs.

Additional Resources

So there you have it, folks… the insulin pump primer.  For further information, pay a visit to the below resources:

  • The American Diabetes Association (ADA)

    • Diabetes Forecast is the ADA’s monthly magazine, full of good info!

    • The annual diabetes Consumer Guide is the ADA’s comparison document for diabetes products, including CGM, infusion sets, injection aids, insulin pens, medications, meters, pumps, and trends. It’s published each year in March and is usually available online.

    • www.diabetes.org is the ADA’s website where you can find accurate information for both your own learning and for patient resources.

  • Insulin pump companies

  • www.diabeteseducator.org (American Association of Diabetes Educators) sells insulin pump books and has free patient information on a wide variety of diabetes self-care topics.

  • And of course, the tl;dr pharmacy diabetes cheat sheet (perfect for all of your practice or NAPELX studying needs) :)

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