Using a Pump

By Gary Scheiner, MS CDE

How does a pump mimic a pancreas?

The human body stores sugar in the liver. Throughout the day and night, the liver releases small amounts of sugar into the bloodstream so that we always have fuel available to burn for energy. To help shuttle the sugar into the body's cells (and maintain the blood sugar at a steady level), the pancreas releases insulin into the bloodstream every few minutes. When we eat food that contains carbohydrates (sugar or starch), the blood sugar level rises quickly and the pancreas releases a large amount of insulin to prevent the blood sugar level from rising too high. The insulin pump is like the human pancreas by automatically releasing small amounts of fast-acting insulin (in tenths or hundreths of a unit) every few minutes. This is the basal rate of insulin, but the amount must be determined by the individual or else a consultation with the health care team may be in order. The basal rate keeps the blood sugar level steady between meals and during sleep. When food is eaten, the pump is programmed (at the touch of a button) to deliver a larger quantity of insulin very quickly. This is the bolus of insulin. The bolus is designed to match the amount of carbohydrate in the food. Boluses can also be used to lower high blood sugar levels. With a pump, you get large amounts of insulin when you need it, and small amounts when you don't need as much. With a pump, the basal rate of insulin holds your blood sugar steady between meals, so you can keep whatever schedule you like in terms of meals, activities and sleep. In other words, a near normal life.

How does a pump work?

Insulin pumps are beeper-sized devices that contain a cartridge filled with fast-acting insulin. They have a screen and buttons for programming the pump's internal computer, and a sensitive motor that turns very gradually to push insulin from the cartridge through a tube and into your body. The tubing that connects the pump to your body comes in various lengths and is very strong.

To get the insulin under your skin, an infusion set is worn. Most infusion sets use a needle (about the size of an insulin syringe needle) to insert a small, flexible plastic tube just under the skin, usually on the abdomen, buttocks, or hip. The needle is then removed and the infusion set is taped securely in place. A new infusion set is inserted every 2 to 4 days, depending on individual usage. Many infusion sets feature a "quick disconnect" mechanism that allows the user to temporarily unhook the pump and tubing for situations like bathing, contact sports, and intimacy.

The pump itself is usually worn on a belt/waistband or in a pocket. A variety of clips, cases, and fashion accessories make the pump easy to wear in just about any situation. Today's pumps also have multiple safety features that ensure against accidental insulin delivery – even under the most severe or unusual conditions.

All insulin pumps run multiple safety checks every second and have sensitive alarm systems. Insulin delivery is not affected by electro-magnetic fields, pressure changes, temperature extremes or physical impact. Because the pumps "lock up" and alarm in the event of any internal problem, there is no chance of accidental insulin delivery.

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