An insulin pump is a small, battery-powered microcomputer. It looks like a pager and is usually worn in a pocket, or clipped to a belt or waistband. The pump holds a syringe filled with rapid-acting insulin (Humalog™ or NovaRapid™). The syringe is attached to an infusion set, which is a thin plastic tubing with a small needle at the end. The needle is inserted into the fatty tissue below the skin, and then removed. This leaves a tiny, flexible plastic tube in place. The pump is programmed to deliver insulin continuously through this tube. A small dressing holds the infusion set in place.
The insulin and infusion set must be changed every two to three days and moved to a new site. The abdomen is the most common place. Most infusion sets permit the pump and tubing to be disconnected from the insertion site for short periods to allow bathing, swimming, exercise and intimacy.
The insulin pump imitates a healthy pancreas. The pancreas releases small amounts of insulin continuously. The body uses this ‘background’ insulin to meet its energy needs between meals and during sleep. To maintain normal blood glucose levels when food is eaten, the pancreas releases a larger amount (a bolus) of insulin as needed.
When using a pump, the background insulin is called the basal. The basal rate is a very small amount of insulin that the pump releases around the clock. The pump can be programmed to deliver several different basal rates, depending on an individual’s special needs. Temporary increases or decreases to the basal rates can be set for activity, illness, menstrual cycle, or changes in routines.
A bolus of insulin is taken just before eating. The amount is based on the carbohydrate content of the food. An extra or corrective bolus of insulin can also be given if the blood glucose before meals is high. This individualized insulin delivery makes it possible to keep blood glucose in a close to normal range most of the time.
Although the pump tries to act like a pancreas, it cannot be considered an artificial pancreas. The pump is not automatic. You must tell it what to do. When using a pump, you need to learn to ‘think like a pancreas.’
Since the pump does not monitor blood glucose, it must be checked at least six times per day, including occasionally during the night.
Insulin pump therapy is especially appealing to those who want to improve control and increase flexibility, or lead active or unpredictable lifestyles. It can help those who have frequent problems with overnight lows, or can’t get their blood glucose under control despite their best efforts. Women considering pregnancy may also be interested. There is no age limit for using an insulin pump. Even toddlers and pre-schoolers can do well on an insulin pump — with their parents doing all of the programming, of course!
Insulin pump therapy is an option for anyone with Type 1 diabetes who has realistic expectations about what a pump can do, and is committed to checking blood glucose as required. For the safe use of a pump, you must be capable of learning how to use it properly, and be physically able to operate the pump.
Although insulin pumps have mainly been used for people with Type 1 diabetes, a pump can help those with Type 2 who are taking large doses of insulin. Type 2 diabetes is often a result of insulin resistance. Using a pump provides a more natural insulin delivery, which can lessen the body’s resistance to insulin. Weight loss can be easier when using an insulin pump. Since it is not necessary to eat to avoid blood glucose lows, you can safely cut down on food and skip snacks.
Insulin pump therapy has helped many people with diabetes improve their quality of life and blood glucose control. If you think an insulin pump may be an option for you, talk to your diabetes team about how it will fit with your treatment plan.