Patient Guide to Insulin

Insulin Pump Overview

How Insulin Pumps Work, Who Benefits From Them, and Different Types of Pumps

As people with diabetes know, keeping blood sugar levels in a safe range is extremely important. Good blood sugar control not only makes you feel well, but also helps prevent long-term diabetes complications, such as blindness, kidney failure and heart disease.

People with type 1 diabetes don’t produce insulin, a hormone that helps the body use sugar (glucose), a key source of energy that comes from carbohydrates. If you have type 1 diabetes you must make up for the lack of insulin with insulin therapy.

insulin pumps for diabetesMeanwhile, people with type 2 diabetes produce insulin, but their bodies don’t use insulin properly, or they don’t produce enough insulin. Diet, exercise and medication can often work to control glucose levels. However, in certain cases, these measures aren’t enough, and insulin therapy is needed to better control blood sugar levels.

While insulin can be given by self-injection, people who take multiple daily injections of insulin may also consider using an insulin pump.

An insulin pump provides continuous delivery of short acting insulin all day long. The insulin pump substitutes the need for long acting insulin. A pump also replaces the need for multiple daily injections with a continuous insulin infusion, and also helps to improve your blood sugar levels.

How Do Insulin Pumps Work?

Insulin pumps are small, computerized devices that mimic the way the human pancreas works by delivering small doses of short acting insulin continuously (basal rate). The device also is used to deliver variable amounts of insulin when a meal is eaten (bolus). The basal insulin rates are usually set up in your pump with your doctor, and you can have one or multiple basal settings programmed in your pump, based on your needs. You program the amount of insulin for your mealtime bolus directly on the pump. Most pumps come with built-in bolus calculators to help you figure out how much insulin you need at mealtime based on your glucose levels and the amount of carbohydrates you are eating.

The pump, which is about the size of a smart phone or deck of cards, is worn on the outside of your body and delivers insulin through a tube (catheter), connected to a thin cannula, placed into the layer of fat under your skin, typically around your stomach area. The pump can be worn around your waist in a pump case or attached to a belt or bra, in a pocket, or on an armband. There are a variety of custom-made accessories available so you can carry your insulin pump with style.

To use an insulin pump, you will need hands-on training from your diabetes care team. They will teach you how to fill a pump reservoir, prime tubing, select an infusion site, change an infusion set, disconnect the device, calculate and program basal and bolus doses, troubleshoot potential problems, create backup plans in case of pump failure, and prevent diabetic ketoacidosis.

Types of Pumps

A variety of insulin pumps are available, and your diabetes care team can help you choose the best pump for you. In general, there are two types of pump devices:

  1. Traditional Insulin pumps have an insulin reservoir (or container) and pumping mechanism, and attach to the body with tubing and an infusion set. The pump body contains buttons that allow you to program insulin delivery for meals, specific types of basal rates, or suspend the insulin infusion, if necessary.
  2. Insulin patch pumps are worn directly on the body and have a reservoir, pumping mechanism, and infusion set inside a small case. Patch pumps are controlled wirelessly by a separate device that allows programming of insulin delivery for meals from the patch.

Many pumps connect wirelessly with blood glucose meters, which measure blood sugar levels using a drop of blood from your fingertip. Some pumps connect wirelessly with continuous glucose monitoring devices, which are inserted under the skin and monitor blood sugar levels all day long. Talk to your health care provider about which pump is right for you. Most insurance companies cover insulin pump therapy with variable out-of-pocket expenses.

Pumps vary in how much insulin they hold, whether or not the pump has a touch screen or is waterproof, and have a variety of advanced features as well as safety features. Safety and user features may include programmable bolus, customizable reminders, alerts for missed bolus dose or missed glucose measurement, and alarms in the event of a blockage that prevents the continuous infusion of the insulin through the pump. One of the integrated systems that combines insulin pump and continuous glucose monitoring sensor can also be programmed to suspend insulin delivery if the glucose levels reaches a preset low threshold level.  

Nearly all pump manufacturers have a return policy—typically within 30 days of the ship date. So if the pump is not a good match for you after you have been properly trained to use it, you may be able to return it. Before purchasing, verify your insurance company's return policy on devices and reimbursement of any deductible or copayments.

What Are the Parts of an Insulin Pump?

Traditional insulin pumps contain three main parts:

- pump. Traditional insulin pumps are battery powered and contain an insulin reservoir (or container), pumping mechanism, and buttons or touch screen to program insulin delivery. Pumps send insulin through tubing into an infusion set that delivers the insulin to your body.

- tubing.  A thin plastic tube (catheter) is connected to the insulin reservoir and insulin flows into the subcutaneous tissue through the infusion set. There are several length sizes of tubing length. They are chosen based on how you wear the insulin pump. For example, longer tubing may be good for people who wear their pump far from the infusion set.

- infusion set.  Infusions sets are made of Teflon or steel and attach to your skin with an adhesive patch. On the underside of the infusion set is a short thin tube (cannula) that is inserted in your skin with a small needle that is housed within the cannula to deliver insulin into a layer of fatty tissue. The needle is necessary to puncture the skin and insert the set. After insertion, the needle is removed and the thin cannula stays under the skin. The set is usually implanted around your stomach area, but can be placed on the thigh, hips, upper arms, or buttocks

There are a variety of infusion sets to choose from, and your diabetes care team can help you choose what is best for you based on your body type, lifestyle, and a variety of other factors. Infusion sets fall into two categories:

- angled sets. These are inserted at a 30- to 45-degree angle to the surface of the skin; in general, these have longer cannulas. Athletes, thin or muscular people, pregnant women and active children may prefer these types of angled sets.

Angled sets also allow for view of the cannula at the insertion site, monitor for signs of redness  and  for potential infections at the insertion site.

- straight sets. These are inserted at a 90-degree angle to the surface of the skin. They have shorter needles, and may be preferred by people when they insert the set on the arms, or in hard to reach areas, such as the buttocks. Also, people who are afraid of needles can use this type of set with an insertion device that hides the needle.

People who are active or sweat a lot may need to use tape (such as Hy-Tape, IV3000, Micropore, Polyskin, Tegaderm, and Transpore) or stronger adhesive products (such as Mastisol) to keep the infusion set in place. Your diabetes care team can provide sources for where to order different types of tape.

Patch pumps contain three main parts:

The three main parts of a patch pump include an insulin reservoir, pumping
mechanism and cannula. But unlike traditional pumps, the parts are contained in one
case without tubing, and the device is worn directly on the body, attaching with a self-adhesive. The cannula is inserted automatically after attaching the patch on the skin  by programming the activation of the patch from a remote device. The patch pumps are usually replaced every three days.

Continue Reading
What Is Insulin?